Calvin's Restrictions on Interest : Guidelines for the Credit Crisis

NARCIS (Netherlands)

Graafland, J.J.

2009-01-01

Calvin’s view on the legitimacy of interest has had a great impact on the economic development of Western society. Although Calvin took a fundamentally positive attitude to interest, he also proposed several restrictions on the charging of interest. In this article, we investigate the relevance of

Calvin dan Spiritualitas Kerahiman

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Stella Yessy Exlentya Pattipeilohy

2017-10-01

Full Text Available The keyword commonly used in mysticism and spirituality is "experience". The instilling of God's mercy, in fact, is a spiritual experience accosted by God's love. Such experience is shared in a transformative praxis. The mercy of God is a faith experience that could be made a meeting point in fostering a love-based religious life. In the Protestant tradition, we can find a foothold for the development of spiritual theology on John Calvin's work, i.e. the so-called merciful spirituality. Today's experience of God's mercy is influenced by the contextual concern abaout the image of the Homeless Jesus. The refugees not only "challenge" Christian communities to recognise the Christ within the needy strangers, but also welcome them in love and peace despite religious faith differences.

ON THE TRAIL OF JOHN CALVIN'S PHILOSO- PHY OF LANGUAGE ...

African Journals Online (AJOL)

how is it possible, Calvin contends, that human beings — sharing the same reason and ..... machine' and the boundaries of artificial intelligence. Speech .... And quite a few are of exceptional quality!36 It must be noted, however, that a great ...

Exercitium pietatis — Calvin's interpretation of the Lord's Prayer ...

African Journals Online (AJOL)

These sources reveal that, in the texts prior to 1555, Calvin placed a dogmatic emphasis on the six petitions. Later he shifted his attention to the actual practice of prayer. Initially he tried to understand the correct theological meaning of the Lord's Prayer; later he urged the person who prays to use it correctly. At the outset the ...

Calvin, Van Lodenstein and Barth: Three perspectives on the ...

African Journals Online (AJOL)

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How to cite: Dreyer, W.A., 2017, 'Calvin, Van Lodenstein and Barth: Three .... it is openly advertised what the price of Mass would be, as in an open market.99 ..... The Reformation during the 16th century was the start of a new and better ... to be church in the world as ecclesia semper reformanda. ...... Wagnalls, New York.

Calvin, Augustine of Hippo and South Africa: in discussion with Johannes van Oort

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J.W. Hofmeyr

2010-07-01

Full Text Available In this article the curtain is raised on the interesting and fascinating relation between Augustine of Hippo and John Cal- vin from Geneva, as seen through the eyes of the Dutch scholar Johannes van Oort. The influences of and links between Augustine and Calvin are immense. This has been the focus of various studies in the past. The purpose of this article is, however, not to re-invent the wheel about these relations, but rather to reflect on one of the most eminent scholars on Augustine, i.e. Van Oort’s vision on these links and to enter into a dialogue with him so as to shed some new light on this topic and on some aspects related to ecclesiology. After attention to the use of Augustine by Calvin, the focus is on the discussion with Van Oort and eventually on the relevance of this for us in South(ern Africa. It is concluded that in this era of post- modernism and relativism as well much can be learnt from both Augustine and Calvin, and especially with regard to the well- being of the church.

The significance of Calvin' s anthropology for preaching on ethical themes

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L. O.K. Lategan

1998-12-01

Full Text Available In this article the author highlights Calvin's anthropology. A main feature of this anthropology is his dualistic view on man. Calvin was very much influenced by the ancient Greek philosophy, which argued that man had two parts: a superior soul and an inferior body. The author argues that this perception is at odds with a Biblical image of man. According to the Bible no part of man is inferior or superior to any other part of his personhood. The article indicates that a Biblical perspective on anthropology will draw different conclusions in ethics compared to a dualistic perception of the nature of man. A correct appreciation of the anthropology of man is therefore needed to guide decisions in ethics, where the focus is constantly anthropological.

76 FR 20034 - Calvin Ramsey, M.D.; Revocation of Registration

Science.gov (United States)

2011-04-11

... DEPARTMENT OF JUSTICE Drug Enforcement Administration [Docket No. 10-25] Calvin Ramsey, M.D.; Revocation of Registration On December 18, 2009, the Deputy Assistant Administrator, Office of Diversion... constitutional right to appointed counsel in a proceeding under 21 U.S.C. 824(a). See Goldberg v. Kelly, 397 U.S...

Water-splitting-based, sustainable and efficient H2 production in green algae as achieved by substrate limitation of the Calvin-Benson-Bassham cycle.

Science.gov (United States)

Nagy, Valéria; Podmaniczki, Anna; Vidal-Meireles, André; Tengölics, Roland; Kovács, László; Rákhely, Gábor; Scoma, Alberto; Tóth, Szilvia Z

2018-01-01

Photobiological H 2 production has the potential of becoming a carbon-free renewable energy source, because upon the combustion of H 2 , only water is produced. The [Fe-Fe]-type hydrogenases of green algae are highly active, although extremely O 2 -sensitive. Sulphur deprivation is a common way to induce H 2 production, which, however, relies substantially on organic substrates and imposes a severe stress effect resulting in the degradation of the photosynthetic apparatus. We report on the establishment of an alternative H 2 production method by green algae that is based on a short anaerobic induction, keeping the Calvin-Benson-Bassham cycle inactive by substrate limitation and preserving hydrogenase activity by applying a simple catalyst to remove the evolved O 2 . Cultures remain photosynthetically active for several days, with the electrons feeding the hydrogenases mostly derived from water. The amount of H 2 produced is higher as compared to the sulphur-deprivation procedure and the process is photoautotrophic. Our protocol demonstrates that it is possible to sustainably use algal cells as whole-cell catalysts for H 2 production, which enables industrial application of algal biohydrogen production.

‘”Wipe out lines of Division (Not Distinctions)’ : Bennie Keet, Neo-Calvinism and the Struggle against Apartheid’

NARCIS (Netherlands)

Harinck, George

2017-01-01

Race was not a dominant factor in neo-Calvinism. Rather, stress was laid on the universal character of Christianity, especially in the case of Herman Bavinck. While some of the South African PhD students at the Vrije Universiteit's defended apartheid with reference to neo-Calvinism, it was B.B. Keet

Inhibition of photosynthetic CO₂ fixation in the coral Pocillopora damicornis and its relationship to thermal bleaching.

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Hill, Ross; Szabó, Milán; ur Rehman, Ateeq; Vass, Imre; Ralph, Peter J; Larkum, Anthony W D

2014-06-15

Two inhibitors of the Calvin-Benson cycle [glycolaldehyde (GA) and potassium cyanide (KCN)] were used in cultured Symbiodinium cells and in nubbins of the coral Pocillopora damicornis to test the hypothesis that inhibition of the Calvin-Benson cycle triggers coral bleaching. Inhibitor concentration range-finding trials aimed to determine the appropriate concentration to generate inhibition of the Calvin-Benson cycle, but avoid other metabolic impacts to the symbiont and the animal host. Both 3 mmol l(-1) GA and 20 μmol l(-1) KCN caused minimal inhibition of host respiration, but did induce photosynthetic impairment, measured by a loss of photosystem II function and oxygen production. GA did not affect the severity of bleaching, nor induce bleaching in the absence of thermal stress, suggesting inhibition of the Calvin-Benson cycle by GA does not initiate bleaching in P. damicornis. In contrast, KCN did activate a bleaching response through symbiont expulsion, which occurred in the presence and absence of thermal stress. While KCN is an inhibitor of the Calvin-Benson cycle, it also promotes reactive oxygen species formation, and it is likely that this was the principal agent in the coral bleaching process. These findings do not support the hypothesis that temperature-induced inhibition of the Calvin-Benson cycle alone induces coral bleaching. © 2014. Published by The Company of Biologists Ltd.

The independent prokaryotic origins of eukaryotic fructose-1, 6-bisphosphatase and sedoheptulose-1, 7-bisphosphatase and the implications of their origins for the evolution of eukaryotic Calvin cycle

Directory of Open Access Journals (Sweden)

Jiang Yong-Hai

2012-10-01

Full Text Available Abstract Background In the Calvin cycle of eubacteria, the dephosphorylations of both fructose-1, 6-bisphosphate (FBP and sedoheptulose-1, 7-bisphosphate (SBP are catalyzed by the same bifunctional enzyme: fructose-1, 6-bisphosphatase/sedoheptulose-1, 7-bisphosphatase (F/SBPase, while in that of eukaryotic chloroplasts by two distinct enzymes: chloroplastic fructose-1, 6-bisphosphatase (FBPase and sedoheptulose-1, 7-bisphosphatase (SBPase, respectively. It was proposed that these two eukaryotic enzymes arose from the divergence of a common ancestral eubacterial bifunctional F/SBPase of mitochondrial origin. However, no specific affinity between SBPase and eubacterial FBPase or F/SBPase can be observed in the previous phylogenetic analyses, and it is hard to explain why SBPase and/or F/SBPase are/is absent from most extant nonphotosynthetic eukaryotes according to this scenario. Results Domain analysis indicated that eubacterial F/SBPase of two different resources contain distinct domains: proteobacterial F/SBPases contain typical FBPase domain, while cyanobacterial F/SBPases possess FBPase_glpX domain. Therefore, like prokaryotic FBPase, eubacterial F/SBPase can also be divided into two evolutionarily distant classes (Class I and II. Phylogenetic analysis based on a much larger taxonomic sampling than previous work revealed that all eukaryotic SBPase cluster together and form a close sister group to the clade of epsilon-proteobacterial Class I FBPase which are gluconeogenesis-specific enzymes, while all eukaryotic chloroplast FBPase group together with eukaryotic cytosolic FBPase and form another distinct clade which then groups with the Class I FBPase of diverse eubacteria. Motif analysis of these enzymes also supports these phylogenetic correlations. Conclusions There are two evolutionarily distant classes of eubacterial bifunctional F/SBPase. Eukaryotic FBPase and SBPase do not diverge from either of them but have two independent origins

Calvin on Human Reason

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Nicolaas Vorster

2014-10-01

Full Text Available In his recent book The Unintended Reformation, Brad Gregory makes the statement that the Reformation replaced the teleological social ethics of Roman Catholicism based on virtue with formal social ethics based on rules and enforced by magistrates, because they regarded human reason as too depraved to acquire virtue. The result, according to Gregory, is that the relation between internalised values and rules were undermined. This article asks whether this accusation is true with regard to Calvin. The first section discusses the intellectual environment of Calvin’s day – something that inevitably influenced his theory on reason, whilst the second part analyses Calvin’s view on the created nature of reason. The third section investigates Calvin’s view on the effects of sin on reason; and the fourth section discusses Calvin’s perspective on the relation between grace and reason. The article concludes that Gregory’s accusation against the Reformation is not applicable to Calvin. Gregory fails to take into account Calvin’s modified position that the imago Dei was not totally destroyed by sin as well as his teaching on common grace that maintains that even non-believers are able to acquire virtue through the common grace of God. Calvyn oor Menslike Rede. In sy onlangse boek, The Unintended Reformation, maak Brad Gregory die stelling dat die Reformasie die substantiewe teleologiese deugde-etiek van die Rooms-Katolisisme vervang het met ‘n formele etiek gebaseer op reëls wat deur magistrate afgedwing moet word. Die Reformasie was, volgens Gregory, van mening dat die menslike rede sodanig deur sonde geskend is dat die mens nie langer deugde kan beoefen nie. Dit het tot ‘n skadelike skeiding tussen waardes en reëls gelei. Hierdie artikel ondersoek die vraag of Gregory se stelling op Calvyn van toepassing is. Die eerste afdeling bespreek die intellektuele omgewing waarin Calvyn gewerk het. Tweedens word Gregory se siening van die geskape

Voices in International School Psychology: Interviews in Honor of Calvin D. Catterall.

Science.gov (United States)

Culbertson, Frances M.

Following a brief memorial message and a dedicatory tribute to Calvin D. Catterall, a leader in the field of school psychology, this volume provides a description of the origins of the International School Psychology Association and interviews with five school psychologists: Bram Norwich, University of London, England; Tony Cline, London, England;…

The Arnon-Buchanan cycle: a retrospective, 1966-2016.

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Buchanan, Bob B; Sirevåg, Reidun; Fuchs, Georg; Ivanovsky, Ruslan N; Igarashi, Yasuo; Ishii, Masaharu; Tabita, F Robert; Berg, Ivan A

2017-11-01

For the first decade following its description in 1954, the Calvin-Benson cycle was considered the sole pathway of autotrophic CO 2 assimilation. In the early 1960s, experiments with fermentative bacteria uncovered reactions that challenged this concept. Ferredoxin was found to donate electrons directly for the reductive fixation of CO 2 into alpha-keto acids via reactions considered irreversible. Thus, pyruvate and alpha-ketoglutarate could be synthesized from CO 2 , reduced ferredoxin and acetyl-CoA or succinyl-CoA, respectively. This work opened the door to the discovery that reduced ferredoxin could drive the Krebs citric acid cycle in reverse, converting the pathway from its historical role in carbohydrate breakdown to one fixing CO 2 . Originally uncovered in photosynthetic green sulfur bacteria, the Arnon-Buchanan cycle has since been divorced from light and shown to function in a variety of anaerobic chemoautotrophs. In this retrospective, colleagues who worked on the cycle at its inception in 1966 and those presently working in the field trace its development from a controversial reception to its present-day inclusion in textbooks. This pathway is now well established in major groups of chemoautotrophic bacteria, instead of the Calvin-Benson cycle, and is increasingly referred to as the Arnon-Buchanan cycle. In this retrospective, separate sections have been written by the authors indicated. Bob Buchanan wrote the abstract and the concluding comments.

Ecology and Life Cycle Patterns of Echinococcus Species.

Science.gov (United States)

Romig, T; Deplazes, P; Jenkins, D; Giraudoux, P; Massolo, A; Craig, P S; Wassermann, M; Takahashi, K; de la Rue, M

2017-01-01

The genus Echinococcus is composed of eight generally recognized species and one genotypic cluster (Echinococcus canadensis cluster) that may in future be resolved into one to three species. For each species, we review existing information on transmission routes and life cycles in different geographical contexts and - where available - include basic biological information of parasites and hosts (e.g., susceptibility of host species). While some Echinococcus spp. are transmitted in life cycles that involve predominantly domestic animals (e.g., dog - livestock cycles), others are wildlife parasites that do or do not interact with domestic transmission. In many cases, life cycle patterns of the same parasite species differ according to geography. Simple life cycles contrast with transmission patterns that are highly complex, involving multihost systems that may include both domestic and wild mammals. Wildlife transmission may be primary or secondary, i.e., resulting from spillovers from domestic animals. For most of the species and regions, existing information does not yet permit a conclusive description of transmission systems. Such data, however, would be highly relevant, e.g., for anticipation of geographical changes of the presence and frequency of these parasites in a warming world, or for initiating evidence-based control strategies. Copyright © 2017 Elsevier Ltd. All rights reserved.

Prompt and easy activation by specific thioredoxins of calvin cycle enzymes of Arabidopsis thaliana associated in the GAPDH/CP12/PRK supramolecular complex.

Science.gov (United States)

Marri, Lucia; Zaffagnini, Mirko; Collin, Valérie; Issakidis-Bourguet, Emmanuelle; Lemaire, Stéphane D; Pupillo, Paolo; Sparla, Francesca; Miginiac-Maslow, Myroslawa; Trost, Paolo

2009-03-01

The Calvin cycle enzymes glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and phosphoribulokinase (PRK) can form under oxidizing conditions a supramolecular complex with the regulatory protein CP12. Both GAPDH and PRK activities are inhibited within the complex, but they can be fully restored by reduced thioredoxins (TRXs). We have investigated the interactions of eight different chloroplast thioredoxin isoforms (TRX f1, m1, m2, m3, m4, y1, y2, x) with GAPDH (A(4), B(4), and B(8) isoforms), PRK and CP12 (isoform 2), all from Arabidopsis thaliana. In the complex, both A(4)-GAPDH and PRK were promptly activated by TRX f1, or more slowly by TRXs m1 and m2, but all other TRXs were ineffective. Free PRK was regulated by TRX f1, m1, or m2, while B(4)- and B(8)-GAPDH were absolutely specific for TRX f1. Interestingly, reductive activation of PRK caged in the complex was much faster than reductive activation of free oxidized PRK, and activation of A(4)-GAPDH in the complex was much faster (and less demanding in terms of reducing potential) than activation of free oxidized B(4)- or B(8)-GAPDH. It is proposed that CP12-assembled supramolecular complex may represent a reservoir of inhibited enzymes ready to be released in fully active conformation following reduction and dissociation of the complex by TRXs upon the shift from dark to low light. On the contrary, autonomous redox-modulation of GAPDH (B-containing isoforms) would be more suited to conditions of very active photosynthesis.

Occurrence of neoxanthin and lutein epoxide cycle in parasitic Cuscuta species.

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Kruk, Jerzy; Szymańska, Renata

2008-01-01

In the present study, xanthophyll composition of eight parasitic Cuscuta species under different light conditions was investigated. Neoxanthin was not detected in four of the eight species examined, while in others it occurred at the level of several percent of total xanthophylls. In C. gronovii and C. lupuliformis it was additionally found that the neoxanthin content was considerably stimulated by strong light. In dark-adapted plants, lutein epoxide level amounted to 10-22% of total xanthophylls in only three species, the highest being for C. lupuliformis, while in others it was below 3%, indicating that the lutein epoxide cycle is limited to only certain Cuscuta species. The obtained data also indicate that the presence of the lutein epoxide cycle and of neoxanthin is independent and variable among the Cuscuta species. The xanthophyll cycle carotenoids violaxanthin, antheraxanthin and zeaxanthin were identified in all the examined species and occurred at the level found in other higher plants. The xanthophyll and lutein epoxide cycle pigments showed typical response to high light stress. The obtained results also suggest that the ability of higher plants to synthesize lutein epoxide probably does not depend on the substrate specificity of zeaxanthin epoxidase but on the availability of lutein for the enzyme.

Geochemical Cycling of Iodine Species in Soils

International Nuclear Information System (INIS)

Hu, Q.; Moran, J.E.; Blackwood, V.

2007-01-01

Iodine is an important element in studies of environmental protection and human health, global-scale hydrologic processes and nuclear nonproliferation. Biogeochemical cycling of iodine in soils is complex, because iodine occurs in multiple oxidation states and as inorganic and organic species that may be hydrophilic, atmophilic, and biophilic. In this study, we applied new analytical techniques to study the content and speciation of stable iodine in representative surface soils, and sorption and transport behavior of iodine species (iodide, iodate, and 4-iodoaniline) in sediments collected at numerous nuclear facilities in the United States, where anthropogenic 129 I from prior nuclear fuel processing activities poses an environmental risk. The surface soil samples were chosen for their geographic locations (e.g., near the ocean or nuclear facilities) and for their differing physico-chemical characteristics (organic matter, texture, etc). Extracted solutions were analyzed by IC and ICP-MS methods to determine iodine concentrations and to examine iodine speciation (iodide, iodate, and organic iodine). In natural soils, iodine is mostly (nearly 90% of total iodine) present as organic species, while inorganic iodine becomes important (up to 50%) only in sediments with low organic matter. Results from laboratory column studies, aimed at examining transport of different iodine species, showed much greater retardation of 4-iodoaniline than iodide or iodate. Careful attention must be given to potential interconversion among species when interpreting the biogeochemical behavior of iodine in the environment. In addition to speciation, input concentration and residence time effects will influence the biogeochemical cycling of anthropogenic 129I deposited on surface soils

Optimizing conservation of migratory species over their full annual cycle in the Western Hemisphere

OpenAIRE

Bennett, Joseph; Auer, Tom; Fink, Daniel; Arcese, Peter; Rodewald, Amanda; Wilson, Scott; Schuster, Richard

2018-01-01

Strategic plans to conserve migratory species require detailed knowledge on species distribution, abundance, and habitat use over the annual cycle, but such data are lacking for most species. We developed a hemispheric approach to planning using spatiotemporally explicit species abundance models to prioritize land needed to conserve ≥17% of the global populations of 109 species of Neotropical migratory birds. The efficiency of annual cycle plans was evaluated in comparisons to single-season p...

The LysR-type transcriptional regulator CbbR controlling autotrophic CO2 fixation by Xanthobacter flavus is an NADPH sensor

NARCIS (Netherlands)

van Keulen, G; Girbal, L; van den Bergh, E.R E; Dijkhuizen, L.; Meijer, W.G

Autotrophic growth of Xanthobacter flavus is dependent on the fixation of carbon dioxide via the Calvin cycle and on the oxidation of simple organic and inorganic compounds to provide the cell with energy. Maximal induction of the cbb and gap-pgk operons encoding enzymes of the Calvin cycle occurs

Cell Cycle Control in the Early Embryonic Development of Aquatic Animal Species

Science.gov (United States)

Siefert, Joseph C.; Clowdus, Emily A.; Sansam, Christopher L.

2016-01-01

The cell cycle is integrated with many aspects of embryonic development. Not only is proper control over the pace of cell proliferation important, but also the timing of cell cycle progression is coordinated with transcription, cell migration, and cell differentiation. Due to the ease with which the embryos of aquatic organisms can be observed and manipulated, they have been a popular choice for embryologists throughout history. In the cell cycle field, aquatic organisms have been extremely important because they have played a major role in the discovery and analysis of key regulators of the cell cycle. In particular, the frog Xenopus laevis has been instrumental for understanding how the basic embryonic cell cycle is regulated. More recently, the zebrafish has been used to understand how the cell cycle is remodeled during vertebrate development and how it is regulated during morphogenesis. This review describes how some of the unique strengths of aquatic species have been leveraged for cell cycle research and suggests how species such as Xenopus and zebrafish will continue to reveal the roles of the cell cycle in human biology and disease. PMID:26475527

John Calvin and John Locke on the Sensus Divinitatis and Innatism

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J. Caleb Clanton

2017-02-01

Full Text Available Inheritors of the Calvinist Reformed tradition have long disagreed about whether knowledge of God’s nature and existence can be or need be acquired inferentially by means of the standard arguments of natural theology. Nonetheless, they have traditionally coalesced around the thought that some sense or awareness of God is naturally implanted or innate in human beings. A root of this orientation can be found in John Calvin’s discussion of the sensus divinitatis in the first book of The Institutes of the Christian Religion. This paper outlines a pedagogical strategy for organizing and evaluating Calvin’s treatment of the sensus divinitatis, chiefly by putting it in tension with John Locke’s polemic against innatism in Book I of An Essay concerning Human Understanding. I begin by reconstructing Calvin’s depiction of the sensus divinitatis, as well as his case for thinking that it is innate. I then explain how Locke’s critique of innatism offers a fairly direct response to Calvin and, hence, a useful framework for exploring the limits of Calvin’s treatment of the sensus divinitatis.

New Sarcocystis species with a snake-gecko life cycle

Czech Academy of Sciences Publication Activity Database

Šlapeta, J.; Modrý, D.; Koudela, Břetislav

1998-01-01

Roč. 45, č. 1 (1998), s. 7 ISSN 1066-5234. [New Sarcocystis species with a snake -gecko life cycle. 01.01.1998-02.01.1998, Praha] R&D Projects: GA ČR GA508/95/0273 Subject RIV: fp - Other Medical Disciplines

DOE Research and Development Accomplishments Site Index (A-Z)

Science.gov (United States)

Fermi Wigner atomic hydrogen maser atomic nucleus ATP B Bardeen, John Batteries lithium-ion radioisotope - 1959) Calvin, Melvin carbon Calvin Dresselhaus carbon cycle carbon 14 carbon dating carbocation , John C. medicine metathesis method Methanococus jannaschii methanol economy Microwave Background

A tale of two mixotrophic chrysophytes: Insights into the metabolisms of two Ochromonas species (Chrysophyceae through a comparison of gene expression.

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Alle A Y Lie

Full Text Available Ochromonas spp. strains CCMP1393 and BG-1 are phagotrophic phytoflagellates with different nutritional strategies. Strain CCMP1393 is an obligate phototroph while strain BG-1 readily grows in continuous darkness in the presence of bacterial prey. Growth and gene expression of strain CCMP1393 were investigated under conditions allowing phagotrophic, mixotrophic, or phototrophic nutrition. The availability of light and bacterial prey led to the differential expression of 42% or 45-59% of all genes, respectively. Data from strain CCMP1393 were compared to those from a study conducted previously on strain BG-1, and revealed notable differences in carbon and nitrogen metabolism between the 2 congeners under similar environmental conditions. Strain BG-1 utilized bacterial carbon and amino acids through glycolysis and the tricarboxylic acid cycle, while downregulating light harvesting and carbon fixation in the Calvin cycle when both light and bacteria were available. In contrast, the upregulation of genes related to photosynthesis, light harvesting, chlorophyll synthesis, and carbon fixation in the presence of light and prey for strain CCMP1393 implied that this species is more phototrophic than strain BG-1, and that phagotrophy may have enhanced phototrophy. Cellular chlorophyll a content was also significantly higher in strain CCMP1393 supplied with bacteria compared to those without prey. Our results thus point to very different physiological strategies for mixotrophic nutrition in these closely related chrysophyte species.

THE WEBER THESIS OF CALVINISM AND CAPITALISM--ITS VARIOUS VERSIONS AND THEIR "FATE" IN SOCIAL SCIENCE.

Science.gov (United States)

Zafirovski, Milan

2016-01-01

The paper identifies and examines various multiple renditions of the so-called Weber Thesis of an historical association and convergence between ascetic Protestantism, above all Calvinism, and the emergence and development of modern capitalism as an economic spirit and system. Specifically, it detects at least four different versions and formulations or interpretations, thus casting doubt in the common view of the Weber Thesis as a single and monolithic theory or hypothesis. The paper also considers the status of the multiple versions of the Weber Thesis in post-Weberian and contemporary sociology and related disciplines like economics and history. It concludes that the weaker, relaxed renditions of the Weber Thesis have attained a greater success and more endured in contemporary social science than have its stronger, stricter versions. © 2015 Wiley Periodicals, Inc.

Le discours publicitaire – un discours non-constituant - investigation de l’iconotexte dans la publicité pour le parfum Beauty créé par Calvin Klein -

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GAFENCU I. Tiberiu

2012-12-01

Full Text Available The advertising discourse is a non-constituent discourse. In what follows we shall present an analysis of the advertisement for the Calvin Klein perfume called “Beauty”. Our investigation is focused on the way in which the iconical component and the textual one convey the message of the advertising process by engaging in a reciprocal movement of response, thus completing each other.

Invasive species' leaf traits and dissimilarity from natives shape their impact on nitrogen cycling: a meta-analysis.

Science.gov (United States)

Lee, Marissa R; Bernhardt, Emily S; van Bodegom, Peter M; Cornelissen, J Hans C; Kattge, Jens; Laughlin, Daniel C; Niinemets, Ülo; Peñuelas, Josep; Reich, Peter B; Yguel, Benjamin; Wright, Justin P

2017-01-01

Many exotic species have little apparent impact on ecosystem processes, whereas others have dramatic consequences for human and ecosystem health. There is growing evidence that invasions foster eutrophication. We need to identify species that are harmful and systems that are vulnerable to anticipate these consequences. Species' traits may provide the necessary insights. We conducted a global meta-analysis to determine whether plant leaf and litter functional traits, and particularly leaf and litter nitrogen (N) content and carbon: nitrogen (C : N) ratio, explain variation in invasive species' impacts on soil N cycling. Dissimilarity in leaf and litter traits among invaded and noninvaded plant communities control the magnitude and direction of invasion impacts on N cycling. Invasions that caused the greatest increases in soil inorganic N and mineralization rates had a much greater litter N content and lower litter C : N in the invaded than the reference community. Trait dissimilarities were better predictors than the trait values of invasive species alone. Quantifying baseline community tissue traits, in addition to those of the invasive species, is critical to understanding the impacts of invasion on soil N cycling. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

Contribution of arsenic species in unicellular algae to the cycling of arsenic in marine ecosystems.

Science.gov (United States)

Duncan, Elliott G; Maher, William A; Foster, Simon D

2015-01-06

This review investigates the arsenic species produced by and found in marine unicellular algae to determine if unicellular algae contribute to the formation of arsenobetaine (AB) in higher marine organisms. A wide variety of arsenic species have been found in marine unicellular algae including inorganic species (mainly arsenate--As(V)), methylated species (mainly dimethylarsenate (DMA)), arsenoribosides (glycerol, phosphate, and sulfate) and metabolites (dimethylarsenoethanol (DMAE)). Subtle differences in arsenic species distributions exist between chlorophyte and heterokontophyte species with As(V) commonly found in water-soluble cell fractions of chlorophyte species, while DMA is more common in heterokontophyte species. Additionally, different arsenoriboside species are found in each phyla with glycerol and phosphate arsenoribosides produced by chlorophytes, whereas glycerol, phosphate, and sulfate arsenoribosides are produced by heterokontophytes, which is similar to existing data for marine macro-algae. Although arsenoribosides are the major arsenic species in many marine unicellular algal species, AB has not been detected in unicellular algae which supports the hypothesis that AB is formed in marine animals via the ingestion and further metabolism of arsenoribosides. The observation of significant DMAE concentrations in some unicellular algal cultures suggests that unicellular algae-based detritus contains arsenic species that can be further metabolized to form AB in higher marine organisms. Future research establishing how environmental variability influences the production of arsenic species by marine unicellular algae and what effect this has on arsenic cycling within marine food webs is essential to clarify the role of these organisms in marine arsenic cycling.

The phylogeny and life cycle of two species of Profilicollis (Acanthocephala: Polymorphidae) in marine hosts off the Pacific coast of Chile.

Science.gov (United States)

Rodríguez, S M; D'Elía, G; Valdivia, N

2017-09-01

Resolving complex life cycles of parasites is a major goal of parasitological research. The aim of this study was to analyse the life cycle of two species of the genus Profilicollis, the taxonomy of which is still unstable and life cycles unclear. We extracted individuals of Profilicollis from two species of crustaceans (intermediate hosts) and four species of seagulls (definitive hosts) from sandy-shore and estuarine habitats along the south-east Pacific coast of Chile. Mitochondrial DNA analyses showed that two species of Profilicollis infected intermediate hosts from segregated habitats: while P. altmani larvae infected exclusively molecrabs of the genus Emerita from fully marine habitats, P. antarcticus larvae infected the crab Hemigrapsus crenulatus from estuarine habitats. Moreover, P. altmani completed its life cycle in four seagulls, Chroicocephalus maculipennis, Leucopheus pipixcan, Larus modestus and L. dominicanus, while P. antarcticus, on the other hand, completed its life cycle in the kelp gull L. dominicanus. Accordingly, our results show that two congeneric parasites use different and spatially segregated species as intermediate hosts, and both are capable of infecting one species of definitive hosts. As such, our analyses allow us to shed light on a complex interaction network.

What are the key characteristics of a Christian life? A comparison of the ethics of Calvin to that of Augustine and their relevance today

Directory of Open Access Journals (Sweden)

J.H. van Wyk

2010-07-01

Full Text Available Augustine and Calvin are two of the greatest (western theologians of all times and it is illuminating and inspiring to investigate what they have to teach as far as Christian life is concerned. Augustine never wrote a work on Christian ethics in the modern sense of the word but from his many writings we can easily deduce what the key characteristics are. He accepted the natural virtues of philosophers (prudence, for- titude, temperance and justice but subordinated them to the “infused virtues” of faith, hope and love. Special attention was also paid to inter alia happiness, humility and truth. Calvin, on the other hand, although following Augustine in many aspects of theology, rejected the virtue ethics of the Greek philosophers and developed a Christological ethics within the broader context of pneumatology. The key characteristics of a Christian life are self-denial, cross-bearing and meditation on the future life – and of course the correct enjoyment of the present life. Although we appreciate much of what the two church fathers have to say, we live in a totally different world context today, facing challenges of far greater proportions, like economical uncertainty, political instability and an immense ecological crisis. Morality is chal- lenged today as never before in world history. Today we have to rethink the relevance of Christian life not only from an individual personal perspective but also in terms of broader social Christian ethics.

HIV-1 Vif's Capacity To Manipulate the Cell Cycle Is Species Specific.

Science.gov (United States)

Evans, Edward L; Becker, Jordan T; Fricke, Stephanie L; Patel, Kishan; Sherer, Nathan M

2018-04-01

Cells derived from mice and other rodents exhibit profound blocks to HIV-1 virion production, reflecting species-specific incompatibilities between viral Tat and Rev proteins and essential host factors cyclin T1 (CCNT1) and exportin-1 (XPO1, also known as CRM1), respectively. To determine if mouse cell blocks other than CCNT1 and XPO1 affect HIV's postintegration stages, we studied HIV-1 NL4-3 gene expression in mouse NIH 3T3 cells modified to constitutively express HIV-1-compatible versions of CCNT1 and XPO1 (3T3.CX cells). 3T3.CX cells supported both Rev-independent and Rev-dependent viral gene expression and produced relatively robust levels of virus particles, confirming that CCNT1 and XPO1 represent the predominant blocks to these stages. Unexpectedly, however, 3T3.CX cells were remarkably resistant to virus-induced cytopathic effects observed in human cell lines, which we mapped to the viral protein Vif and its apparent species-specific capacity to induce G 2 /M cell cycle arrest. Vif was able to mediate rapid degradation of human APOBEC3G and the PPP2R5D regulatory B56 subunit of the PP2A phosphatase holoenzyme in mouse cells, thus demonstrating that Vif NL4-3 's modulation of the cell cycle can be functionally uncoupled from some of its other defined roles in CUL5-dependent protein degradation. Vif was also unable to induce G 2 /M cell cycle arrest in other nonhuman cell types, including cells derived from nonhuman primates, leading us to propose that one or more human-specific cofactors underpin Vif's ability to modulate the cell cycle. IMPORTANCE Cells derived from mice and other rodents exhibit profound blocks to HIV-1 replication, thus hindering the development of a low-cost small-animal model for studying HIV/AIDS. Here, we engineered otherwise-nonpermissive mouse cells to express HIV-1-compatible versions of two species-specific host dependency factors, cyclin T1 (CCNT1) and exportin-1 (XPO1) (3T3.CX cells). We show that 3T3.CX cells rescue HIV-1

Accumulation and biological cycling of heavy metal in four salt marsh species, from Tagus estuary (Portugal)

Energy Technology Data Exchange (ETDEWEB)

Duarte, B., E-mail: baduarte@fc.ul.p [Centro de Oceanografia, Instituto de Oceanografia, Campo Grande, 1749-1016 Lisboa (Portugal); Caetano, M. [INRB/IPIMAR - Instituto Nacional de Recursos Biologicos, Av. Brasilia, 1449-006 Lisboa (Portugal); Almeida, P.R. [Centro de Oceanografia, Instituto de Oceanografia, Campo Grande, 1749-1016 Lisboa (Portugal); Departamento de Biologia, Universidade de Evora, Largo dos Colegiais 2, 7004-516 Evora (Portugal); Vale, C. [INRB/IPIMAR - Instituto Nacional de Recursos Biologicos, Av. Brasilia, 1449-006 Lisboa (Portugal); Cacador, I. [Centro de Oceanografia, Instituto de Oceanografia, Campo Grande, 1749-1016 Lisboa (Portugal)

2010-05-15

Pools of Zn, Cu, Cd and Co in leaf, stem and root tissues of Sarcocornia fruticosa, Sarcocornia perennis, Halimione portulacoides and Spartina maritima were analyzed on a bimonthly basis, in a Tagus estuary salt marsh. All the major concentrations were found in the root tissues, being the concentrations in the aboveground organs neglectable for sediment budget proposes, as seen by the low root-aboveground translocation. Metal annual accumulation, root turnovers and cycling coefficients were also assessed. S. maritima showed the higher root turnovers and cycling coefficients for most of the analyzed metals, making this a phytostabilizer specie. By contrast the low root turnover, cycling coefficient and low root necromass generation makes S. perennis the most suitable specie for phytoremediation processes. Although the high amounts of metal return to the sediments, due to root senescence, salt marshes can still be considered sinks of heavy metals, cycling heavy metals mostly between sediment and root. - The efficiency of the phytoremediative processes and metal budgets are greatly influenced by the turnover periods and necromass generation.

Mixed-reproductive strategies, competitive mating-type distribution and life cycle of fourteen black morel species.

Science.gov (United States)

Du, Xi-Hui; Zhao, Qi; Xia, En-Hua; Gao, Li-Zhi; Richard, Franck; Yang, Zhu L

2017-05-04

Morchella species are well known world-round as popular and prized edible fungi due to their unique culinary flavor. Recently, several species have been successfully cultivated in China. However, their reproductive modes are still unknown, and their basic biology needs to be elucidated. Here, we use the morel genome information to investigate mating systems and life cycles of fourteen black morel species. Mating type-specific primers were developed to screen and genotype ascospores, hymenia and stipes from 223 ascocarps of the 14 species from Asia and Europe. Our data indicated that they are all heterothallic and their life cycles are predominantly haploid, but sterile haploid fruiting also exists. Ascospores in all species are mostly haploid, homokaryotic, and multinuclear, whereas aborted ascospores without any nuclei were also detected. Interestingly, we monitored divergent spatial distribution of both mating types in natural morel populations and cultivated sites, where the fertile tissue of fruiting bodies usually harbored both mating types, whereas sterile tissue of wild morels constantly had one MAT allele, while the sterile tissue of cultivated strains always exhibited both MAT alleles. Furthermore, MAT1-1-1 was detected significantly more commonly than MAT1-2-1 in natural populations, which strongly suggested a competitive advantage for MAT1-1 strains.

Reproductive cycles in tropical intertidal gastropods are timed around tidal amplitude cycles.

Science.gov (United States)

Collin, Rachel; Kerr, Kecia; Contolini, Gina; Ochoa, Isis

2017-08-01

Reproduction in iteroparous marine organisms is often timed with abiotic cycles and may follow lunar, tidal amplitude, or daily cycles. Among intertidal marine invertebrates, decapods are well known to time larval release to coincide with large amplitude nighttime tides, which minimizes the risk of predation. Such bimonthly cycles have been reported for few other intertidal invertebrates. We documented the reproduction of 6 gastropod species from Panama to determine whether they demonstrate reproductive cycles, whether these cycles follow a 2-week cycle, and whether cycles are timed so that larval release occurs during large amplitude tides. Two of the species ( Crepidula cf. marginalis and Nerita scabricosta ) showed nonuniform reproduction, but without clear peaks in timing relative to tidal or lunar cycles. The other 4 species show clear peaks in reproduction occurring every 2 weeks. In 3 of these species ( Cerithideopsis carlifornica var. valida, Littoraria variegata , and Natica chemnitzi ), hatching occurred within 4 days of the maximum amplitude tides. Siphonaria palmata exhibit strong cycles, but reproduction occurred during the neap tides. Strong differences in the intensity of reproduction of Cerithideopsis carlifornica , and in particular, Littoraria variegata , between the larger and smaller spring tides of a lunar month indicate that these species time reproduction with the tidal amplitude cycle rather than the lunar cycle. For those species that reproduce during both the wet and dry seasons, we found that reproductive timing did not differ between seasons despite strong differences in temperature and precipitation. Overall, we found that most (4/6) species have strong reproductive cycles synchronized with the tidal amplitude cycle and that seasonal differences in abiotic factors do not alter these cycles.

Sing to the Lord a New Song: John Calvin and the Spiritual Discipline of Metrical Psalmody

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Brandon J. Bellanti

2014-11-01

Full Text Available The purpose of this essay is to evaluate the way that psalmody - specifically metrical psalmody - serves as a sort of spiritual discipline. In other words, this essay seeks to demonstrate how the singing of psalms can be a tool to aid in spiritual growth. Much of the research for this essay focuses on the theological writings of the Protestant reformer John Calvin, as well as the way in which he incorporated metrical psalmody into his liturgical framework. The research also comprises primary writings from Aristotle, Plato, Saint John Chrysostom, Saint Basil, and Saint Augustine - all of whom influenced Calvin’s own philosophy regarding the use of art, music, and psalmody in worship. Additional areas examined in this research include the historical musical development of psalmody and the collection and arrangement of metrical psalms into psalters. For reference, specific examples of metrical psalms and psalters have been added. These additional areas and examples help to give a more holistic understanding of the nature of metrical psalmody, and they help to show how it may accurately be considered a spiritual discipline.

Systems-Wide Analysis of Acclimation Responses to Long-Term Heat Stress and Recovery in the Photosynthetic Model Organism Chlamydomonas reinhardtii[W][OPEN

Science.gov (United States)

Hemme, Dorothea; Veyel, Daniel; Mühlhaus, Timo; Sommer, Frederik; Jüppner, Jessica; Unger, Ann-Katrin; Sandmann, Michael; Fehrle, Ines; Schönfelder, Stephanie; Steup, Martin; Geimer, Stefan; Kopka, Joachim; Giavalisco, Patrick; Schroda, Michael

2014-01-01

We applied a top-down systems biology approach to understand how Chlamydomonas reinhardtii acclimates to long-term heat stress (HS) and recovers from it. For this, we shifted cells from 25 to 42°C for 24 h and back to 25°C for ≥8 h and monitored abundances of 1856 proteins/protein groups, 99 polar and 185 lipophilic metabolites, and cytological and photosynthesis parameters. Our data indicate that acclimation of Chlamydomonas to long-term HS consists of a temporally ordered, orchestrated implementation of response elements at various system levels. These comprise (1) cell cycle arrest; (2) catabolism of larger molecules to generate compounds with roles in stress protection; (3) accumulation of molecular chaperones to restore protein homeostasis together with compatible solutes; (4) redirection of photosynthetic energy and reducing power from the Calvin cycle to the de novo synthesis of saturated fatty acids to replace polyunsaturated ones in membrane lipids, which are deposited in lipid bodies; and (5) when sinks for photosynthetic energy and reducing power are depleted, resumption of Calvin cycle activity associated with increased photorespiration, accumulation of reactive oxygen species scavengers, and throttling of linear electron flow by antenna uncoupling. During recovery from HS, cells appear to focus on processes allowing rapid resumption of growth rather than restoring pre-HS conditions. PMID:25415976

Thioredoxin-dependent Redox Regulation of Chloroplastic Phosphoglycerate Kinase from Chlamydomonas reinhardtii*

Science.gov (United States)

Morisse, Samuel; Michelet, Laure; Bedhomme, Mariette; Marchand, Christophe H.; Calvaresi, Matteo; Trost, Paolo; Fermani, Simona; Zaffagnini, Mirko; Lemaire, Stéphane D.

2014-01-01

In photosynthetic organisms, thioredoxin-dependent redox regulation is a well established mechanism involved in the control of a large number of cellular processes, including the Calvin-Benson cycle. Indeed, 4 of 11 enzymes of this cycle are activated in the light through dithiol/disulfide interchanges controlled by chloroplastic thioredoxin. Recently, several proteomics-based approaches suggested that not only four but all enzymes of the Calvin-Benson cycle may withstand redox regulation. Here, we characterized the redox features of the Calvin-Benson enzyme phosphoglycerate kinase (PGK1) from the eukaryotic green alga Chlamydomonas reinhardtii, and we show that C. reinhardtii PGK1 (CrPGK1) activity is inhibited by the formation of a single regulatory disulfide bond with a low midpoint redox potential (−335 mV at pH 7.9). CrPGK1 oxidation was found to affect the turnover number without altering the affinity for substrates, whereas the enzyme activation appeared to be specifically controlled by f-type thioredoxin. Using a combination of site-directed mutagenesis, thiol titration, mass spectrometry analyses, and three-dimensional modeling, the regulatory disulfide bond was shown to involve the not strictly conserved Cys227 and Cys361. Based on molecular mechanics calculation, the formation of the disulfide is proposed to impose structural constraints in the C-terminal domain of the enzyme that may lower its catalytic efficiency. It is therefore concluded that CrPGK1 might constitute an additional light-modulated Calvin-Benson cycle enzyme with a low activity in the dark and a TRX-dependent activation in the light. These results are also discussed from an evolutionary point of view. PMID:25202015

Species profiles: Life histories and environmental requirements of coastal fishes and invertebrates (Pacific Northwest)--ghost and blue mud shrimp

Science.gov (United States)

Hornig, S.; Sterling, A.; Smith, Styles

1989-01-01

Geographic range: The ghost shrimp is found in intertidal areas along the west coast of North America from Mutiny Bay, Alaska, to the mouth of the Tijuana River, San Diego County, California; MacGinitie (1934) and Ricketts and Calvin (1968) reported finding specimens as far south as El Estuario de Punto Banda, Baja California Norte, Mexico. The blue mud shrimp is found from southeastern Alaska to San Quentin Bay (Bahia de San Quentin) in Baja California Norte. The general distribution of the two species in the Pacific Northwest is identical (Figure 3).

Identification of Bottlenecks in the Plant Life Cycle for Sustainable Conservation of Rare and Endangered Species

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Giovanna Aronne

2017-07-01

Full Text Available Long term survival of a species relies on maintenance of genetic variability and natural selection by means of successful reproduction and generation turnover. Although, basic to monitor the conservation status of a plant species, life history data are rarely available even for threatened species due to the gap between the large amount of information required and the limits in terms of time and available economic resources to gather these data. Here, the focus on bottlenecks in life-cycle of rare endangered plant species is proposed as a resolving approach to address the challenges of feasible conservation actions. Basic considerations for this approach are: (a all biological and ecological studies on plant species can be scientifically important, but not all of them are equally relevant to conservation planning and management requirements; (b under a changing environment, long term survival of a species relies on generation turnover; (c for conservation purposes, priority should be given to studies aimed to focus on bottlenecks in the succession of generations because they prevent, or slow down natural selection processes. The proposed procedure, named Systematic Hazard Analysis of Rare-endangered Plants (SHARP, consists of a preliminary survey of the already available information on the species and two main components. The first component is the identification of the bottlenecks in the life cycle by means of field surveys. The second is the diagnosis of the causes of the bottleneck by appropriate experimental methods. The target is to provide researchers, managers and practitioners with substantiated indications for sustainable conservation measures.

Few vertebrate species dominate the Borrelia burgdorferi s.l. life cycle

Science.gov (United States)

Hofmeester, T. R.; Coipan, E. C.; van Wieren, S. E.; Prins, H. H. T.; Takken, W.; Sprong, H.

2016-04-01

Background. In the northern hemisphere, ticks of the Ixodidae family are vectors of diseases such as Lyme borreliosis, Rocky Mountain spotted fever and tick-borne encephalitis. Most of these ticks are generalists and have a three-host life cycle for which they are dependent on three different hosts for their blood meal. Finding out which host species contribute most in maintaining ticks and the pathogens they transmit, is imperative in understanding the drivers behind the dynamics of a disease. Methods. We performed a systematic review to identify the most important vertebrate host species for Ixodes ricinus and Borrelia burgdorferi s.l. as a well-studied model system for tick-borne diseases. We analyzed data from 66 publications and quantified the relative contribution for 15 host species. Review results. We found a positive correlation between host body mass and tick burdens for the different stages of I. ricinus. We show that nymphal burdens of host species are positively correlated with infection prevalence with B. burgdorferi s.l., which is again positively correlated with the realized reservoir competence of a host species for B. burgdorferi s.l. Our quantification method suggests that only a few host species, which are amongst the most widespread species in the environment (rodents, thrushes and deer), feed the majority of I. ricinus individuals and that rodents infect the majority of I. ricinus larvae with B. burgdorferi s.l. Discussion. We argue that small mammal-transmitted Borrelia spp. are maintained due to the high density of their reservoir hosts, while bird-transmitted Borrelia spp. are maintained due to the high infection prevalence of their reservoir hosts. Our findings suggest that Ixodes ricinus and Borrelia burgdorferi s.l. populations are maintained by a few widespread host species. The increase in distribution and abundance of these species, could be the cause for the increase in Lyme borreliosis incidence in Europe in recent decades.

The natural abundance of 15N in litter and soil profiles under six temperate tree species: N cycling depends on tree species traits and site fertility

DEFF Research Database (Denmark)

Callesen, Ingeborg; Nilsson, Lars Ola; Schmidt, Inger Kappel

2013-01-01

We investigated the influence of tree species on the natural 15N abundance in forest stands under elevated ambient N deposition.We analysed δ15N in litter, the forest floor and three mineral soil horizons along with ecosystem N status variables at six sites planted three decades ago with five Eur...... to nitrate leaching or other N transformation processes....... species leached more nitrate.The δ15N pattern reflected tree species related traits affecting the N cycling as well as site fertility and former land use, and possibly differences in N leaching. The tree species δ15N patterns reflected fractionation caused by uptake of N through mycorrhiza rather than due...

Life Cycle and Secondary Production of Four Species from Functional Feeding Groups in a Tropical Stream of South India

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Sankarappan Anbalagan

2014-01-01

Full Text Available This study focused on life strategies of species from functional feeding groups (FFGs found in a tropical stream of the Sirumalai hills, South India. We examined the life cycle and secondary production of species of shredders (Lepidostoma nuburagangai, scrapers (Baetis sp., collectors (Choroterpes alagarensis, and predators (Neoperla biseriata. In addition, we studied the assemblage structure of functional feeding groups. We found the collectors occupied the highest percentage, followed in turn by scrapers, predators, and shredders. The diversity of FFGs was higher at riffle areas and assemblage with stream substrates differing in each functional group. An asynchronous life cycle was observed for Baetis, C. alagarensis, and N. biseriata, while L. nuburagangai was found in four to five generations per year. We acquired data on secondary production of scraper species of Baetis, which reached the highest values among all investigated species. This observation stresses the importance of scrapers as playing a key role in converting coarse particulate organic matter to fine particulate organic matter with low or high abundances of shredder population and maintaining the food chain in tropical streams.

Diversification and reproductive isolation: cryptic species in the only New World high-duty cycle bat, Pteronotus parnellii

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Clare Elizabeth L

2013-01-01

Full Text Available Abstract Background Molecular techniques are increasingly employed to recognize the presence of cryptic species, even among commonly observed taxa. Previous studies have demonstrated that bats using high-duty cycle echolocation may be more likely to speciate quickly. Pteronotus parnellii is a widespread Neotropical bat and the only New World species to use high-duty cycle echolocation, a trait otherwise restricted to Old World taxa. Here we analyze morphological and acoustic variation and genetic divergence at the mitochondrial COI gene, the 7th intron region of the y-linked Dby gene and the nuclear recombination-activating gene 2, and provide extensive evidence that P. parnellii is actually a cryptic species complex. Results Central American populations form a single species while three additional species exist in northern South America: one in Venezuela, Trinidad and western Guyana and two occupying sympatric ranges in Guyana and Suriname. Reproductive isolation appears nearly complete (only one potential hybrid individual found. The complex likely arose within the last ~6 million years with all taxa diverging quickly within the last ~1-2 million years, following a pattern consistent with the geological history of Central and northern South America. Significant variation in cranial measures and forearm length exists between three of the four groups, although no individual morphological character can discriminate these in the field. Acoustic analysis reveals small differences (5–10 kHz in echolocation calls between allopatric cryptic taxa that are unlikely to provide access to different prey resources but are consistent with divergence by drift in allopatric species or through selection for social recognition. Conclusions This unique approach, considering morphological, acoustic and multi-locus genetic information inherited maternally, paternally and bi-parentally, provides strong support to conclusions about the cessation of gene flow and

Modes of carbon fixation in an arsenic and CO₂-rich shallow hydrothermal ecosystem

DEFF Research Database (Denmark)

Callac, Nolwenn; Posth, Nicole R.; Rattray, Jayne E.

2017-01-01

for autotrophic carbon fixation used in the Calvin-Benson-Bassham (CBB) and reverse tricaboxylic acid (rTCA) cycles. Both forms of RuBisCO, together with ATP citrate lyase genes in the rTCA cycle, increase with distance from the active hydrothermal centres and decrease with sediment depth. Clustering of Ru...

Population cycles and species diversity in dynamic Kill-the-Winner model of microbial ecosystems

Science.gov (United States)

Maslov, Sergei; Sneppen, Kim

2017-01-01

Determinants of species diversity in microbial ecosystems remain poorly understood. Bacteriophages are believed to increase the diversity by the virtue of Kill-the-Winner infection bias preventing the fastest growing organism from taking over the community. Phage-bacterial ecosystems are traditionally described in terms of the static equilibrium state of Lotka-Volterra equations in which bacterial growth is exactly balanced by losses due to phage predation. Here we consider a more dynamic scenario in which phage infections give rise to abrupt and severe collapses of bacterial populations whenever they become sufficiently large. As a consequence, each bacterial population in our model follows cyclic dynamics of exponential growth interrupted by sudden declines. The total population of all species fluctuates around the carrying capacity of the environment, making these cycles cryptic. While a subset of the slowest growing species in our model is always driven towards extinction, in general the overall ecosystem diversity remains high. The number of surviving species is inversely proportional to the variation in their growth rates but increases with the frequency and severity of phage-induced collapses. Thus counter-intuitively we predict that microbial communities exposed to more violent perturbations should have higher diversity. PMID:28051127

Use of phosphorus to alleviate stress induced by cadmium and zinc ...

African Journals Online (AJOL)

STORAGESEVER

2009-05-18

May 18, 2009 ... synthesis of photosynthetic pigments and enzymes of the. Calvin cycle, or reduction in the chloroplast density and size which led to the damage of the photosynthetic cycle;. Xun (2004) had reported that the Cd and Zn weakened the capacity of resisting ROS, resulting in lipid peroxidation or deesterification ...

Differences in ecosystem carbon distribution and nutrient cycling linked to forest tree species composition in a mid-successional boreal forest

Science.gov (United States)

Melvin, April M.; Mack, Michelle C.; Johnstone, Jill F.; McGuire, A. David; Genet, Helene; Schuur, Edward A.G.

2015-01-01

In the boreal forest of Alaska, increased fire severity associated with climate change is expanding deciduous forest cover in areas previously dominated by black spruce (Picea mariana). Needle-leaf conifer and broad-leaf deciduous species are commonly associated with differences in tree growth, carbon (C) and nutrient cycling, and C accumulation in soils. Although this suggests that changes in tree species composition in Alaska could impact C and nutrient pools and fluxes, few studies have measured these linkages. We quantified C, nitrogen, phosphorus, and base cation pools and fluxes in three stands of black spruce and Alaska paper birch (Betula neoalaskana) that established following a single fire event in 1958. Paper birch consistently displayed characteristics of more rapid C and nutrient cycling, including greater aboveground net primary productivity, higher live foliage and litter nutrient concentrations, and larger ammonium and nitrate pools in the soil organic layer (SOL). Ecosystem C stocks (aboveground + SOL + 0–10 cm mineral soil) were similar for the two species; however, in black spruce, 78% of measured C was found in soil pools, primarily in the SOL, whereas aboveground biomass dominated ecosystem C pools in birch forest. Radiocarbon analysis indicated that approximately one-quarter of the black spruce SOL C accumulated prior to the 1958 fire, whereas no pre-fire C was observed in birch soils. Our findings suggest that tree species exert a strong influence over C and nutrient cycling in boreal forest and forest compositional shifts may have long-term implications for ecosystem C and nutrient dynamics.

Carbon assimilation in Eucalyptus urophylla grown under high atmospheric CO2 concentrations: A proteomics perspective.

Science.gov (United States)

Santos, Bruna Marques Dos; Balbuena, Tiago Santana

2017-01-06

Photosynthetic organisms may be drastically affected by the future climate projections of a considerable increase in CO 2 concentrations. Growth under a high concentration of CO 2 could stimulate carbon assimilation-especially in C3-type plants. We used a proteomics approach to test the hypothesis of an increase in the abundance of the enzymes involved in carbon assimilation in Eucalyptus urophylla plants grown under conditions of high atmospheric CO 2 . Our strategy allowed the profiling of all Calvin-Benson cycle enzymes and associated protein species. Among the 816 isolated proteins, those involved in carbon fixation were found to be the most abundant ones. An increase in the abundance of six key enzymes out of the eleven core enzymes involved in carbon fixation was detected in plants grown at a high CO 2 concentration. Proteome changes were corroborated by the detection of a decrease in the stomatal aperture and in the vascular bundle area in Eucalyptus urophylla plantlets grown in an environment of high atmospheric CO 2 . Our proteomics approach indicates a positive metabolic response regarding carbon fixation in a CO 2 -enriched atmosphere. The slight but significant increase in the abundance of the Calvin enzymes suggests that stomatal closure did not prevent an increase in the carbon assimilation rates. The sample enrichment strategy and data analysis used here enabled the identification of all enzymes and most protein isoforms involved in the Calvin-Benson-Bessham cycle in Eucalyptus urophylla. Upon growth in CO 2 -enriched chambers, Eucalyptus urophylla plantlets responded by reducing the vascular bundle area and stomatal aperture size and by increasing the abundance of six of the eleven core enzymes involved in carbon fixation. Our proteome approach provides an estimate on how a commercially important C3-type plant would respond to an increase in CO 2 concentrations. Additionally, confirmation at the protein level of the predicted genes involved in

God's servant working for your own good: Notes from modern South Africa on Calvin's commentary on Romans 13: 1-7 and the state

Directory of Open Access Journals (Sweden)

P. J. Strauss

1998-12-01

Full Text Available This article aims at demonstrating that Calvin's grasp of the message of Romans 13 in its reference to the state is highly relevant for the present South Africa. This includes the belief that the authority of rulers is ordained by God, be it that of a just or an unjust government, and that their right to govern should therefore be respected; that government should maintain a public order of justice and peace within which people can serve God in all spheres of life; that state authorities should use the sword and even the death penalty when needed, and not shy away from this God-given responsibility; that a society in which crime threatens to create chaos needs stronger measures of punishment; and that rebellion against the government or disruption of public life should be resorted to only as an ultimate means and when carefully considered as in the general interest.

Drivers of Tree Species Effects on Phosphorus and Cation Cycling in Plantations at La Selva Biological Station, Costa Rica

Science.gov (United States)

Russell, A. E.

2014-12-01

Fast-growing trees in secondary forests and plantations in the humid tropics play an important role in the atmospheric CO2 balance owing to their high rates of carbon sequestration. Because plants require nutrients to sustain high CO2 uptake, differences among tree species in traits related to nutrient uptake, retention and recycling could influence ecosystem-scale carbon cycling. A better understanding of the relationships among plant traits, nutrient and carbon cycling will thus improve ecosystem- to global scale modeling of effects of vegetation change on carbon cycling. In an experimental setting in which state factors were similar among four species of tropical trees situated on an Oxisol in replicated, 25-yr-old, mono-dominant plantations, I evaluated various drivers of aboveground storage of phosphorus (P) and cations, measuring nutrient fluxes in litterfall and fine-root growth and storage in biomass and soil to 1-m depth. Because fine roots increase the capacity to scavenge nutrients already on exchange sites within the soil environment, I hypothesized that P and cation uptake would be correlated directly with fine-root growth. The four tree species in this experiment, Hieronyma alchorneoides, Pentaclethra macroloba, Virola koschnyi, and Vochysia guatemalensis differed significantly in net cation uptake over the first 25 years of growth (P = 0.013, Ca; P >0.0001, Mg, Mn, K, Al, Fe, and Sr). For all cations, aboveground tree biomass was highly correlated with fine-root ingrowth length, with P values >0.0001 for all cations except Ca (P = 0.013). In contrast for P, differences among species were only marginally significant (P = 0.062). Similarly, P in aboveground tree biomass was marginally correlated with fine-root ingrowth (P = 0.068). Neither cation nor P uptake was correlated with measures of available P and cations, organic or total P in surface soil. For P, the less significant correlation with fine-root growth suggests that some other mechanism, such

Regulation of Autotrophic and Heterotrophic Metabolism in Pseudomonas oxalaticus OX1. Growth on Fructose and on Mixtures of Fructose and Formate in Batch and Continuous Cultures

NARCIS (Netherlands)

Dijkhuizen, L.; Harder, W.

1984-01-01

In Pseudomonas oxalaticus the synthesis of enzymes involved in autotrophic CO2 fixation via the Calvin cycle is regulated by repression/derepression. During growth of the organism on fructose alone, the synthesis of ribulosebisphosphate carboxylase (RuBPCase) remained fully repressed, both in batch

Recovery of Physiological Traits in Saplings of Invasive Bischofia Tree Compared with Three Species Native to the Bonin Islands under Successive Drought and Irrigation Cycles.

Science.gov (United States)

Yazaki, Kenichi; Kuroda, Katsushi; Nakano, Takashi; Kitao, Mitsutoshi; Tobita, Hiroyuki; Ogasa, Mayumi Y; Ishida, Atsushi

2015-01-01

Partial leaf shedding induced by hydraulic failure under prolonged drought can prevent excess water consumption, resulting in delayed recovery of carbon productivity following rainfall. To understand the manner of water use of invasive species in oceanic island forests under a fluctuating water regime, leaf shedding, multiple physiological traits, and the progress of embolism in the stem xylem under repeated drought-irrigation cycles were examined in the potted saplings of an invasive species, Bischofia javanica Blume, and three endemic native species, Schima mertensiana (Sieb. Et Zucc,) Koitz., Hibiscus glaber Matsum, and Distylium lepidotum Nakai, from the Bonin Islands, Japan. The progress of xylem embolism was observed by cryo-scanning electron microscopy. The samples exhibited different processes of water saving and drought tolerance based on the different combinations of partial leaf shedding involved in embolized conduits following repeated de-rehydration. Predawn leaf water potential largely decreased with each successive drought-irrigation cycle for all tree species, except for B. javanica. B. javanica shed leaves conspicuously under drought and showed responsive stomatal conductance to VPD, which contributed to recover leaf gas exchange in the remaining leaves, following a restored water supply. In contrast, native tree species did not completely recover photosynthetic rates during the repeated drought-irrigation cycles. H. glaber and D. lepidotum preserved water in vessels and adjusted leaf osmotic rates but did not actively shed leaves. S. mertensiana exhibited partial leaf shedding during the first cycle with an osmotic adjustment, but they showed less responsive stomatal conductance to VPD. Our data indicate that invasive B. javanica saplings can effectively use water supplied suddenly under drought conditions. We predict that fluctuating precipitation in the future may change tree distributions even in mesic or moist sites in the Bonin Islands.

Recovery of Physiological Traits in Saplings of Invasive Bischofia Tree Compared with Three Species Native to the Bonin Islands under Successive Drought and Irrigation Cycles.

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Kenichi Yazaki

Full Text Available Partial leaf shedding induced by hydraulic failure under prolonged drought can prevent excess water consumption, resulting in delayed recovery of carbon productivity following rainfall. To understand the manner of water use of invasive species in oceanic island forests under a fluctuating water regime, leaf shedding, multiple physiological traits, and the progress of embolism in the stem xylem under repeated drought-irrigation cycles were examined in the potted saplings of an invasive species, Bischofia javanica Blume, and three endemic native species, Schima mertensiana (Sieb. Et Zucc, Koitz., Hibiscus glaber Matsum, and Distylium lepidotum Nakai, from the Bonin Islands, Japan. The progress of xylem embolism was observed by cryo-scanning electron microscopy. The samples exhibited different processes of water saving and drought tolerance based on the different combinations of partial leaf shedding involved in embolized conduits following repeated de-rehydration. Predawn leaf water potential largely decreased with each successive drought-irrigation cycle for all tree species, except for B. javanica. B. javanica shed leaves conspicuously under drought and showed responsive stomatal conductance to VPD, which contributed to recover leaf gas exchange in the remaining leaves, following a restored water supply. In contrast, native tree species did not completely recover photosynthetic rates during the repeated drought-irrigation cycles. H. glaber and D. lepidotum preserved water in vessels and adjusted leaf osmotic rates but did not actively shed leaves. S. mertensiana exhibited partial leaf shedding during the first cycle with an osmotic adjustment, but they showed less responsive stomatal conductance to VPD. Our data indicate that invasive B. javanica saplings can effectively use water supplied suddenly under drought conditions. We predict that fluctuating precipitation in the future may change tree distributions even in mesic or moist sites in the

Seed thioredoxin h

DEFF Research Database (Denmark)

Hägglund, Per; Finnie, Christine; Yano, Hiroyuki

2016-01-01

, for example chloroplastic f- and m-type thioredoxins involved in regulation of the Calvin-Benson cycle. The cytosolic h-type thioredoxins act as key regulators of seed germination and are recycled by NADPH-dependent thioredoxin reductase. The present review on thioredoxin h systems in plant seeds focuses...

Immunochemical localization of ribulose-1,5-bisphosphate carboxylase in the symbiont-containing gills of Solemya velum (Bivalvia : Mollusca)

NARCIS (Netherlands)

Cavanaugh, Colleen M.; Abbott, Marilyn S.; Veenhuis, Marten

1988-01-01

The distribution of the Calvin cycle enzyme ribulose-1,5-bisphosphate carboxylase (RbuP2Case; EC 4.1.1.39) was examined by using two immunological methods in tissues of Solemya velum, an Atlantic coast bivalve containing putative chemoautotrophic symbionts. Antibodies elicited by the purified large

Induction of the gap-pgk operon encoding glyceraldehyde-3-phosphate dehydrogenase and 3-phosphoglycerate kinase of Xanthobacter flavus requires the LysR-type transcriptional activator CbbR

NARCIS (Netherlands)

Meijer, W.G; van den Bergh, E.R E; Smith, L.M

In a previous study, a gene (pgk) encoding phosphoglycerate kinase was isolated from a genomic labrid of Xanthobacter flavus. Although this gene is essential for autotrophic growth, it is not located within the cbb operon encoding other Calvin cycle enzymes. An analysis of the nucleotide sequence

Regulation of carbon dioxide fixation in facultatively autotrophic bacteria. A phisiological and genetical study.

NARCIS (Netherlands)

Meijer, Wilhelmus Gerhardus

1990-01-01

Autotrophic bactcria are capable of CO2 fixation via the Calvin cycle, emplofng energy derived from the oxidation of anorganic substrates (e.g. Hz), simple organic substrates (one-carbon compounds, e.g. methanol, formate), or from light. Ribulose-1,5-bisphospbate carboxylase/oxygenase (RuBisC/O),

Short- and long-term modulation of the lutein epoxide and violaxanthin cycles in two species of the Lauraceae: sweet bay laurel (Laurus nobilis L.) and avocado (Persea americana Mill.).

Science.gov (United States)

Esteban, R; Jiménez, M S; Morales, D; Jiménez, E T; Hormaetxe, K; Becerril, J M; Osmond, B; García-Plazaola, J I

2008-05-01

Short- and long-term responses of the violaxanthin (V) and lutein epoxide (Lx) cycles were studied in two species of Lauraceae: sweet bay laurel (Laurus nobilis L.) and avocado (Persea americana L.). The Lx content exceeded the V content in shade leaves of both species. Both Lx and V were de-epoxidised on illumination, but only V was fully restored by epoxidation in low light. Violaxanthin was preferentially de-epoxidised in low light in L. nobilis. This suggests that Lx accumulates with leaf ageing, partly because its conversion to lutein is limited in shade. After exposure to strong light, shade leaves of avocado readjusted the total pools of alpha- and beta-xanthophyll cycles by de novo synthesis of antheraxanthin, zeaxanthin and lutein. This occurred in parallel with a sustained depression of F(v)/F(m). In Persea indica, a closely related but low Lx species, F(v)/F(m) recovered faster after a similar light treatment, suggesting the involvement of the Lx cycle in sustained energy dissipation. Furthermore, the seasonal correlation between non-reversible Lx and V photoconversions and pre-dawn F(v)/F(m) in sun leaves of sweet bay supported the conclusion that the Lx cycle is involved in a slowly reversible downregulation of photosynthesis analogous to the V cycle.

Ecological Impact on Nitrogen and Phosphorus Cycling of a Widespread Fast-growing Leguminous Tropical Forest Plantation Tree Species, Acacia mangium

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Shigehiro Ishizuka

2011-11-01

Full Text Available Symbiotic nitrogen fixation is one of the major pathways of N input to forest ecosystems, enriching N availability, particularly in lowland tropics. Recently there is growing concern regarding the wide areas of fast-growing leguminous plantations that could alter global N2O emissions. Here, we highlight substantially different N and phosphorus utilization and cycling at a plantation of Acacia mangium, which is N2-fixing and one of the major plantation species in tropical/subtropical Asia. The litterfall, fresh leaf quality and fine-root ingrowth of A. mangium were compared to those of non-N2-fixing Swietenia macrophylla and coniferous Araucaria cunninghamii in wet tropical climates in Borneo, Malaysia. The N and P concentrations of the A. mangium fresh leaves were higher than those of the other two species, whereas the P concentration in the leaf-litterfall of A. mangium was less than half that of the others; in contrast the N concentration was higher. The N:P ratio in the A. mangium leaf was markedly increased from fresh-leaf (29 to leaf-litterfall (81. Although the N flux in the total litterfall at the A. mangium plantation was large, the fine-root ingrowth of A. mangium significantly increased by applying both N and P. In conclusion, large quantities of N were accumulated and returned to the forest floor in A. mangium plantation, while its P resorption capacity was efficient. Such large N cycling and restricted P cycling in wide areas of monoculture A. mangium plantations may alter N and P cycling and their balance in the organic layer and soil on a stand level.

[Contribution to the study of Microphallidae Travassos 1920 (trematoda). XXXII. Microphallus breviatus n. sp., a species with an abbreviated evolutive cycle from a Mediterranean pond in the Languedoc].

Science.gov (United States)

Deblock, S; Maillard, C

1975-01-01

Contribution to the study of Microphallidae Travassos, 1920 (Trematoda). XXXII. - Microphallus breviatus n. sp., a short life-cycle species of a mediterranean pond of Languedoc. The whole larval life-cycle of M. breviatus takes place in one host, Hydrobia ventrosa (Montagu), Mollusc Hydrobiidae. Hepato-pancreatic sporocysts produce morphologically altered xiphidio-cercariae which become encysted metacercariae in the sporocyts themselves. This species is defined in the genus by the anatomic characteristics of its cercariae and metacercariae, allied with its uncommon biology including two hosts only.

Biological processing of carbon dioxide. ; Photosynthetic function of plants, and carbon dioxide fixing function of marine organisms. Nisanka tanso no seibutsuteki shori. ; Shokubutsu no kogosei kino to kaiyo seibutsu no nisanka tanso kotei kino

Energy Technology Data Exchange (ETDEWEB)

Hirai, M [National Research Inst. for Pollution and Resources, Tsukuba (Japan)

1991-02-15

This paper describes photosynthetic function of plants, and CO {sub 2} fixing function of marine organisms. Among the photosythetic reaction systems, the C {sub 3} type reaction carries out CO {sub 2} fixation using the Calvin cycle, and takes out the carbon dioxide out of the system through enzymatic reactions of 3-phosphoglycerate {yields} fructose-6-phosphate. The C {sub 4} type reaction has a special cycle to supply CO {sub 2} to the Calvin cycle, i. e. C {sub 4} dicarboxylic acid cycle. The CAM type reaction enables the photosynthetic type to be converted according to variations in the growing environment. The majority of the surace agricultural crops are from C {sub 3} plants, of which yield may be increased when grown in a high CO {sub 2} atmosphere. On the one hand, gene engineering may make possible breeding of plants having high CO {sub 2} fixing capability. In the area of marine organisms, lime algae growing in clusters around coral reefs form and deposit CaCO {sub 3}. Reef creating corals have symbiotically in their stomach layer brown algae having photosynthetic function to build CaCO {sub 3} skeleton. The corals calcify algae quickly and in a large quantity, hence play an important role in fixing underwater CO {sub 2}. 2 tabs.

Species diversity and chemical properties of litter influence non-additive effects of litter mixtures on soil carbon and nitrogen cycling.

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Bing Mao

Full Text Available Decomposition of litter mixtures generally cannot be predicted from the component species incubated in isolation. Therefore, such non-additive effects of litter mixing on soil C and N dynamics remain poorly understood in terrestrial ecosystems. In this study, litters of Mongolian pine and three dominant understory species and soil were collected from a Mongolian pine plantation in Northeast China. In order to examine the effects of mixed-species litter on soil microbial biomass N, soil net N mineralization and soil respiration, four single litter species and their mixtures consisting of all possible 2-, 3- and 4-species combinations were added to soils, respectively. In most instances, species mixing produced synergistic non-additive effects on soil microbial biomass N and soil respiration, but antagonistic non-additive effects on net N mineralization. Species composition rather than species richness explained the non-additive effects of species mixing on soil microbial biomass N and net N mineralization, due to the interspecific differences in litter chemical composition. Both litter species composition and richness explained non-additive soil respiration responses to mixed-species litter, while litter chemical diversity and chemical composition did not. Our study indicated that litter mixtures promoted soil microbial biomass N and soil respiration, and inhibited net N mineralization. Soil N related processes rather than soil respiration were partly explained by litter chemical composition and chemical diversity, highlighting the importance of functional diversity of litter on soil N cycling.

Species diversity and chemical properties of litter influence non-additive effects of litter mixtures on soil carbon and nitrogen cycling.

Science.gov (United States)

Mao, Bing; Mao, Rong; Zeng, De-Hui

2017-01-01

Decomposition of litter mixtures generally cannot be predicted from the component species incubated in isolation. Therefore, such non-additive effects of litter mixing on soil C and N dynamics remain poorly understood in terrestrial ecosystems. In this study, litters of Mongolian pine and three dominant understory species and soil were collected from a Mongolian pine plantation in Northeast China. In order to examine the effects of mixed-species litter on soil microbial biomass N, soil net N mineralization and soil respiration, four single litter species and their mixtures consisting of all possible 2-, 3- and 4-species combinations were added to soils, respectively. In most instances, species mixing produced synergistic non-additive effects on soil microbial biomass N and soil respiration, but antagonistic non-additive effects on net N mineralization. Species composition rather than species richness explained the non-additive effects of species mixing on soil microbial biomass N and net N mineralization, due to the interspecific differences in litter chemical composition. Both litter species composition and richness explained non-additive soil respiration responses to mixed-species litter, while litter chemical diversity and chemical composition did not. Our study indicated that litter mixtures promoted soil microbial biomass N and soil respiration, and inhibited net N mineralization. Soil N related processes rather than soil respiration were partly explained by litter chemical composition and chemical diversity, highlighting the importance of functional diversity of litter on soil N cycling.

Drought and ecosystem carbon cycling

NARCIS (Netherlands)

Molen, M.K. van der; Dolman, A.J.; Ciais, P.; Eglin, T.; Gobron, N.; Law, B.E.; Meir, P.; Peters, P.; Philips, O.L.; Reichstein, M.; Chen, T.; Dekker, S.C.; Doubkova, M.; Friedl, M.A.; Jung, M.; Hurk, B.J.J.M. van den; Jeu, R.A.M. de; Kruijt, B.; Ohta, T.; Rebel, K.T.; Plummer, S.; Seneviratne, S.I.; Sitch, S.; Teuling, A.J.; Werf, G.R. van der; Wang, G.

2011-01-01

Drought as an intermittent disturbance of the water cycle interacts with the carbon cycle differently than the ‘gradual’ climate change. During drought plants respond physiologically and structurally to prevent excessive water loss according to species-specific water use strategies. This has

The nitrogen cycle: Atmosphere interactions

Science.gov (United States)

Levine, J. S.

1984-01-01

Atmospheric interactions involving the nitrogen species are varied and complex. These interactions include photochemical reactions, initiated by the absorption of solar photons and chemical kinetic reactions, which involve both homogeneous (gas-to-gas reactions) and heterogeneous (gas-to-particle) reactions. Another important atmospheric interaction is the production of nitrogen oxides by atmospheric lightning. The nitrogen cycle strongly couples the biosphere and atmosphere. Many nitrogen species are produced by biogenic processes. Once in the atmosphere nitrogen oxides are photochemically and chemically transformed to nitrates, which are returned to the biosphere via precipitation, dry deposition and aerosols to close the biosphere-atmosphere nitrogen cycle. The sources, sinks and photochemistry/chemistry of the nitrogen species; atmospheric nitrogen species; souces and sinks of nitrous oxide; sources; sinks and photochemistry/chemistry of ammonia; seasonal variation of the vertical distribution of ammonia in the troposphere; surface and atmospheric sources of the nitrogen species, and seasonal variation of ground level ammonia are summarized.

High-resolution assessment of land use impacts on biodiversity in life cycle assessment using species habitat suitability models.

Science.gov (United States)

de Baan, Laura; Curran, Michael; Rondinini, Carlo; Visconti, Piero; Hellweg, Stefanie; Koellner, Thomas

2015-02-17

Agricultural land use is a main driver of global biodiversity loss. The assessment of land use impacts in decision-support tools such as life cycle assessment (LCA) requires spatially explicit models, but existing approaches are either not spatially differentiated or modeled at very coarse scales (e.g., biomes or ecoregions). In this paper, we develop a high-resolution (900 m) assessment method for land use impacts on biodiversity based on habitat suitability models (HSM) of mammal species. This method considers potential land use effects on individual species, and impacts are weighted by the species' conservation status and global rarity. We illustrate the method using a case study of crop production in East Africa, but the underlying HSMs developed by the Global Mammals Assessment are available globally. We calculate impacts of three major export crops and compare the results to two previously developed methods (focusing on local and regional impacts, respectively) to assess the relevance of the methodological innovations proposed in this paper. The results highlight hotspots of product-related biodiversity impacts that help characterize the links among agricultural production, consumption, and biodiversity loss.

Metagenomic profiling of a microbial assemblage associated with the California mussel: a node in networks of carbon and nitrogen cycling.

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Catherine A Pfister

2010-05-01

Full Text Available Mussels are conspicuous and often abundant members of rocky shores and may constitute an important site for the nitrogen cycle due to their feeding and excretion activities. We used shotgun metagenomics of the microbial community associated with the surface of mussels (Mytilus californianus on Tatoosh Island in Washington state to test whether there is a nitrogen-based microbial assemblage associated with mussels. Analyses of both tidepool mussels and those on emergent benches revealed a diverse community of Bacteria and Archaea with approximately 31 million bp from 6 mussels in each habitat. Using MG-RAST, between 22.5-25.6% were identifiable using the SEED non-redundant database for proteins. Of those fragments that were identifiable through MG-RAST, the composition was dominated by Cyanobacteria and Alpha- and Gamma-proteobacteria. Microbial composition was highly similar between the tidepool and emergent bench mussels, suggesting similar functions across these different microhabitats. One percent of the proteins identified in each sample were related to nitrogen cycling. When normalized to protein discovery rate, the high diversity and abundance of enzymes related to the nitrogen cycle in mussel-associated microbes is as great or greater than that described for other marine metagenomes. In some instances, the nitrogen-utilizing profile of this assemblage was more concordant with soil metagenomes in the Midwestern U.S. than for open ocean system. Carbon fixation and Calvin cycle enzymes further represented 0.65 and 1.26% of all proteins and their abundance was comparable to a number of open ocean marine metagenomes. In sum, the diversity and abundance of nitrogen and carbon cycle related enzymes in the microbes occupying the shells of Mytilus californianus suggest these mussels provide a node for microbial populations and thus biogeochemical processes.

Discovery of a modified tetrapolar sexual cycle in Cryptococcus amylolentus and the evolution of MAT in the Cryptococcus species complex.

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Keisha Findley

Full Text Available Sexual reproduction in fungi is governed by a specialized genomic region called the mating-type locus (MAT. The human fungal pathogenic and basidiomycetous yeast Cryptococcus neoformans has evolved a bipolar mating system (a, α in which the MAT locus is unusually large (>100 kb and encodes >20 genes including homeodomain (HD and pheromone/receptor (P/R genes. To understand how this unique bipolar mating system evolved, we investigated MAT in the closely related species Tsuchiyaea wingfieldii and Cryptococcus amylolentus and discovered two physically unlinked loci encoding the HD and P/R genes. Interestingly, the HD (B locus sex-specific region is restricted (∼2 kb and encodes two linked and divergently oriented homeodomain genes in contrast to the solo HD genes (SXI1α, SXI2a of C. neoformans and Cryptococcus gattii. The P/R (A locus contains the pheromone and pheromone receptor genes but has expanded considerably compared to other outgroup species (Cryptococcus heveanensis and is linked to many of the genes also found in the MAT locus of the pathogenic Cryptococcus species. Our discovery of a heterothallic sexual cycle for C. amylolentus allowed us to establish the biological roles of the sex-determining regions. Matings between two strains of opposite mating-types (A1B1×A2B2 produced dikaryotic hyphae with fused clamp connections, basidia, and basidiospores. Genotyping progeny using markers linked and unlinked to MAT revealed that meiosis and uniparental mitochondrial inheritance occur during the sexual cycle of C. amylolentus. The sexual cycle is tetrapolar and produces fertile progeny of four mating-types (A1B1, A1B2, A2B1, and A2B2, but a high proportion of progeny are infertile, and fertility is biased towards one parental mating-type (A1B1. Our studies reveal insights into the plasticity and transitions in both mechanisms of sex determination (bipolar versus tetrapolar and sexual reproduction (outcrossing versus inbreeding with

Nucleosome-coupled expression differences in closely-related species

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Gebbia Marinella

2011-09-01

Full Text Available Abstract Background Genome-wide nucleosome occupancy is negatively related to the average level of transcription factor motif binding based on studies in yeast and several other model organisms. The degree to which nucleosome-motif interactions relate to phenotypic changes across species is, however, unknown. Results We address this challenge by generating nucleosome positioning and cell cycle expression data for Saccharomyces bayanus and show that differences in nucleosome occupancy reflect cell cycle expression divergence between two yeast species, S. bayanus and S. cerevisiae. Specifically, genes with nucleosome-depleted MBP1 motifs upstream of their coding sequence show periodic expression during the cell cycle, whereas genes with nucleosome-shielded motifs do not. In addition, conserved cell cycle regulatory motifs across these two species are more nucleosome-depleted compared to those that are not conserved, suggesting that the degree of conservation of regulatory sites varies, and is reflected by nucleosome occupancy patterns. Finally, many changes in cell cycle gene expression patterns across species can be correlated to changes in nucleosome occupancy on motifs (rather than to the presence or absence of motifs. Conclusions Our observations suggest that alteration of nucleosome occupancy is a previously uncharacterized feature related to the divergence of cell cycle expression between species.

Journal of Chemical Sciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

We particularly show that the steps involving the formation of G3P from 3-PG and the regeneration of RuBP from Ru5P are thermodynamically strongly favored, and therefore, they take part in driving the metabolic process. We have illustrated Calvin cycle by vividly distinguishing the controlling steps from the potentially ...

Carbon dioxide fixation by Calvin-Cycle enzymes improves ethanol yield in yeast

NARCIS (Netherlands)

Guadalupe-Medina, V.; Wisselink, H.W.; Luttik, M.A.H.; De Hulster, E.; Daran, J.M.; Pronk, J.T.; Van Maris, A.J.A.

2013-01-01

Background Redox-cofactor balancing constrains product yields in anaerobic fermentation processes. This challenge is exemplified by the formation of glycerol as major by-product in yeast-based bioethanol production, which is a direct consequence of the need to reoxidize excess NADH and causes a loss

PRM1 and KAR5 function in cell-cell fusion and karyogamy to drive distinct bisexual and unisexual cycles in the Cryptococcus pathogenic species complex.

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Ci Fu

2017-11-01

Full Text Available Sexual reproduction is critical for successful evolution of eukaryotic organisms in adaptation to changing environments. In the opportunistic human fungal pathogens, the Cryptococcus pathogenic species complex, C. neoformans primarily undergoes bisexual reproduction, while C. deneoformans undergoes both unisexual and bisexual reproduction. During both unisexual and bisexual cycles, a common set of genetic circuits regulates a yeast-to-hyphal morphological transition, that produces either monokaryotic or dikaryotic hyphae. As such, both the unisexual and bisexual cycles can generate genotypic and phenotypic diversity de novo. Despite the similarities between these two cycles, genetic and morphological differences exist, such as the absence of an opposite mating-type partner and monokaryotic instead of dikaryotic hyphae during C. deneoformans unisexual cycle. To better understand the similarities and differences between these modes of sexual reproduction, we focused on two cellular processes involved in sexual reproduction: cell-cell fusion and karyogamy. We identified orthologs of the plasma membrane fusion protein Prm1 and the nuclear membrane fusion protein Kar5 in both Cryptococcus species, and demonstrated their conserved roles in cell fusion and karyogamy during C. deneoformans α-α unisexual reproduction and C. deneoformans and C. neoformans a-α bisexual reproduction. Notably, karyogamy occurs inside the basidum during bisexual reproduction in C. neoformans, but often occurs earlier following cell fusion during bisexual reproduction in C. deneoformans. Characterization of these two genes also showed that cell fusion is dispensable for solo unisexual reproduction in C. deneoformans. The blastospores produced along hyphae during C. deneoformans unisexual reproduction are diploid, suggesting that diploidization occurs early during hyphal development, possibly through either an endoreplication pathway or cell fusion-independent karyogamy

Hunting billbug (Coleoptera: Curculionidae) life cycle and damaging life stage in North Carolina, with notes on other billbug species abundance.

Science.gov (United States)

Doskocil, J P; Brandenburg, R L

2012-12-01

In the southeastern United States, hunting billbug, Sphenophorus venatus vestitus Chittenden, adults are often observed in turfgrass, but our knowledge of their biology and ecology is limited. Field surveys and experiments were conducted to determine the species composition, life cycle, damaging life stage, and distribution of billbugs within the soil profile in turfgrass in North Carolina. Linear pitfall trapping revealed six species of billbug, with the hunting billbug making up 99.7% of all beetles collected. Data collected from turf plus soil sampling suggest that hunting billbugs have two overlapping generations per year in North Carolina and that they overwinter as both adults and larvae. Field experiments provided evidence that adult hunting billbugs are capable of damaging warm season turfgrasses.

Mosquito Life Cycle

Science.gov (United States)

Knowing the stages of the mosquito's life will help you prevent mosquitoes around your home and help you choose the right pesticides for your needs, if you decide to use them. All mosquito species go through four distinct stages during their live cycle.

A Short-Term Advantage for Syngamy in the Origin of Eukaryotic Sex: Effects of Cell Fusion on Cell Cycle Duration and Other Effects Related to the Duration of the Cell Cycle-Relationship between Cell Growth Curve and the Optimal Size of the Species, and Circadian Cell Cycle in Photosynthetic Unicellular Organisms.

Science.gov (United States)

Mancebo Quintana, J M; Mancebo Quintana, S

2012-01-01

The origin of sex is becoming a vexatious issue for Evolutionary Biology. Numerous hypotheses have been proposed, based on the genetic effects of sex, on trophic effects or on the formation of cysts and syncytia. Our approach addresses the change in cell cycle duration which would cause cell fusion. Several results are obtained through graphical and mathematical analysis and computer simulations. (1) In poor environments, cell fusion would be an advantageous strategy, as fusion between cells of different size shortens the cycle of the smaller cell (relative to the asexual cycle), and the majority of mergers would occur between cells of different sizes. (2) The easiest-to-evolve regulation of cell proliferation (sexual/asexual) would be by modifying the checkpoints of the cell cycle. (3) A regulation of this kind would have required the existence of the G2 phase, and sex could thus be the cause of the appearance of this phase. Regarding cell cycle, (4) the exponential curve is the only cell growth curve that has no effect on the optimal cell size in unicellular species; (5) the existence of a plateau with no growth at the end of the cell cycle explains the circadian cell cycle observed in unicellular algae.

Life cycle replacement by gene introduction under an allee effect in periodical cicadas.

Science.gov (United States)

Nariai, Yukiko; Hayashi, Saki; Morita, Satoru; Umemura, Yoshitaka; Tainaka, Kei-ichi; Sota, Teiji; Cooley, John R; Yoshimura, Jin

2011-04-06

Periodical cicadas (Magicicada spp.) in the USA are divided into three species groups (-decim, -cassini, -decula) of similar but distinct morphology and behavior. Each group contains at least one species with a 17-year life cycle and one with a 13-year cycle; each species is most closely related to one with the other cycle. One explanation for the apparent polyphyly of 13- and 17-year life cycles is that populations switch between the two cycles. Using a numerical model, we test the general feasibility of life cycle switching by the introduction of alleles for one cycle into populations of the other cycle. Our results suggest that fitness reductions at low population densities of mating individuals (the Allee effect) could play a role in life cycle switching. In our model, if the 13-year cycle is genetically dominant, a 17-year cycle population will switch to a 13-year cycle given the introduction of a few 13-year cycle alleles under a moderate Allee effect. We also show that under a weak Allee effect, different year-classes ("broods") with 17-year life cycles can be generated. Remarkably, the outcomes of our models depend only on the dominance relationships of the cycle alleles, irrespective of any fitness advantages.

Life cycle replacement by gene introduction under an allee effect in periodical cicadas.

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Yukiko Nariai

2011-04-01

Full Text Available Periodical cicadas (Magicicada spp. in the USA are divided into three species groups (-decim, -cassini, -decula of similar but distinct morphology and behavior. Each group contains at least one species with a 17-year life cycle and one with a 13-year cycle; each species is most closely related to one with the other cycle. One explanation for the apparent polyphyly of 13- and 17-year life cycles is that populations switch between the two cycles. Using a numerical model, we test the general feasibility of life cycle switching by the introduction of alleles for one cycle into populations of the other cycle. Our results suggest that fitness reductions at low population densities of mating individuals (the Allee effect could play a role in life cycle switching. In our model, if the 13-year cycle is genetically dominant, a 17-year cycle population will switch to a 13-year cycle given the introduction of a few 13-year cycle alleles under a moderate Allee effect. We also show that under a weak Allee effect, different year-classes ("broods" with 17-year life cycles can be generated. Remarkably, the outcomes of our models depend only on the dominance relationships of the cycle alleles, irrespective of any fitness advantages.

Lactobacillus Decelerates Cervical Epithelial Cell Cycle Progression

Science.gov (United States)

Vielfort, Katarina; Weyler, Linda; Söderholm, Niklas; Engelbrecht, Mattias; Löfmark, Sonja; Aro, Helena

2013-01-01

We investigated cell cycle progression in epithelial cervical ME-180 cells during colonization of three different Lactobacillus species utilizing live cell microscopy, bromodeoxyuridine incorporation assays, and flow cytometry. The colonization of these ME-180 cells by L. rhamnosus and L. reuteri, originating from human gastric epithelia and saliva, respectively, was shown to reduce cell cycle progression and to cause host cells to accumulate in the G1 phase of the cell cycle. The G1 phase accumulation in L. rhamnosus-colonized cells was accompanied by the up-regulation and nuclear accumulation of p21. By contrast, the vaginal isolate L. crispatus did not affect cell cycle progression. Furthermore, both the supernatants from the lactic acid-producing L. rhamnosus colonies and lactic acid added to cell culture media were able to reduce the proliferation of ME-180 cells. In this study, we reveal the diversity of the Lactobacillus species to affect host cell cycle progression and demonstrate that L. rhamnosus and L. reuteri exert anti-proliferative effects on human cervical carcinoma cells. PMID:23675492

Lactobacillus decelerates cervical epithelial cell cycle progression.

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Katarina Vielfort

Full Text Available We investigated cell cycle progression in epithelial cervical ME-180 cells during colonization of three different Lactobacillus species utilizing live cell microscopy, bromodeoxyuridine incorporation assays, and flow cytometry. The colonization of these ME-180 cells by L. rhamnosus and L. reuteri, originating from human gastric epithelia and saliva, respectively, was shown to reduce cell cycle progression and to cause host cells to accumulate in the G1 phase of the cell cycle. The G1 phase accumulation in L. rhamnosus-colonized cells was accompanied by the up-regulation and nuclear accumulation of p21. By contrast, the vaginal isolate L. crispatus did not affect cell cycle progression. Furthermore, both the supernatants from the lactic acid-producing L. rhamnosus colonies and lactic acid added to cell culture media were able to reduce the proliferation of ME-180 cells. In this study, we reveal the diversity of the Lactobacillus species to affect host cell cycle progression and demonstrate that L. rhamnosus and L. reuteri exert anti-proliferative effects on human cervical carcinoma cells.

A "footprint" of plant carbon fixation cycle functions during the development of a heterotrophic fungus.

Science.gov (United States)

Lyu, Xueliang; Shen, Cuicui; Xie, Jiatao; Fu, Yanping; Jiang, Daohong; Hu, Zijin; Tang, Lihua; Tang, Liguang; Ding, Feng; Li, Kunfei; Wu, Song; Hu, Yanping; Luo, Lilian; Li, Yuanhao; Wang, Qihua; Li, Guoqing; Cheng, Jiasen

2015-08-11

Carbon fixation pathway of plants (CFPP) in photosynthesis converts solar energy to biomass, bio-products and biofuel. Intriguingly, a large number of heterotrophic fungi also possess enzymes functionally associated with CFPP, raising the questions about their roles in fungal development and in evolution. Here, we report on the presence of 17 CFPP associated enzymes (ten in Calvin-Benson-Basham reductive pentose phosphate pathway and seven in C4-dicarboxylic acid cycle) in the genome of Sclerotinia sclerotiorum, a heterotrophic phytopathogenic fungus, and only two unique enzymes: ribulose-1, 5-bisphosphate carboxylase-oxygenase (Rubisco) and phosphoribulokinase (PRK) were absent. This data suggested an incomplete CFPP-like pathway (CLP) in fungi. Functional profile analysis demonstrated that the activity of the incomplete CLP was dramatically regulated during different developmental stages of S. sclerotiorum. Subsequent experiments confirmed that many of them were essential to the virulence and/or sclerotial formation. Most of the CLP associated genes are conserved in fungi. Phylogenetic analysis showed that many of them have undergone gene duplication, gene acquisition or loss and functional diversification in evolutionary history. These findings showed an evolutionary links in the carbon fixation processes of autotrophs and heterotrophs and implicated the functions of related genes were in course of continuous change in different organisms in evolution.

Photosynthetic carbon fixation characteristics of fruiting structures of Brassica campestris L

International Nuclear Information System (INIS)

Singal, H.R.; Sheoran, I.S.; Singh, R.

1987-01-01

Activities of key enzymes of the Calvin cycle and C 4 metabolism, rates of CO 2 fixation, and the initial products of photosynthetic 14 CO 2 fixation were determined in the podwall, seed coat (fruiting structures), and the subtending leaf (leaf below a receme) of Brassica campestris L. cv Toria. Compared to activities of ribulose-1,5-bisphosphate carboxylase and other Calvin cycle enzymes, e.g. NADP-glyceraldehyde-3-phosphate-dehydrogenase and ribulose-5-phosphate kinase, the activities of phosphoenol pyruvate carboxylase and other enzymes of C 4 metabolism, viz. NADP-malate dehydrogenase, NADP-malic enzyme, glutamate pyruvate transaminase, and glutamate oxaloacetate transaminase, were generally much higher in seed than in podwall and leaf. Podwall and leaf were comparable to each other. Pulse-chase experiments showed that in seed the major product of 14 CO 2 assimilation was malate (in short time), whereas in podwall and leaf, the label initially appeared in 3-PGA. With time, the label moved to sucrose. In contrast to legumes, Brassica pods were able to fix net CO 2 during light. However, respiratory losses were very high during the dark period

Decreased TK activity alters growth, yield and tolerance to low temperature and low light intensity in transgenic cucumber plants.

Science.gov (United States)

Bi, Huangai; Dong, Xubing; Wu, Guoxiu; Wang, Meiling; Ai, Xizhen

2015-02-01

Four CsTK antisense transgenic cucumber plants were obtained. Decreased TK activity decreased the photosynthetic rate, seed germination rate, growth yield, and the tolerance to low temperature and weak light stress. Transketolase (TK, EC 2.2.1.1) is a key enzyme in the photosynthetic carbon reduction cycle (Calvin cycle). A cDNA fragment (526 bp) encoding transketolase was cloned from cucumber plants (Cucumis sativa L. cv 'Jinyou 3') by RT-PCR. The antisense expression [(PBI-CsTK(-)] vector containing the CsTK gene fragment was constructed. The resulting plasmid was introduced into the cucumber inbred lines '08-1' using the agrobacterium-mediated method, and four antisense transgenic cucumber plants were obtained. Decreased CsTK expression either unaltered or slightly increased the mRNA abundance and activities of the other main enzymes in the Calvin cycle, however, it decreased the TK activity and net photosynthetic rate (Pn) in antisense transgenic cucumber leaves. Antisense plants showed decreases in the growth, ratio of female flowers and yield compared with the wild-type (WT) plants. The decrease in Pn, stomatal conductance (Gs), transpiration rate (Tr), photochemical efficiency (Fv/Fm) and actual photochemical efficiency of PSII (ΦPSII) and the increase in electrolyte leakage (EL) were greater in antisense transgenic plants than in WT plants under low temperature (5 °C) and low light intensity (100 μmol m(-2) s(-1)).

Single generation cycles and delayed feedback cycles are not separate phenomena.

Science.gov (United States)

Pfaff, T; Brechtel, A; Drossel, B; Guill, C

2014-12-01

We study a simple model for generation cycles, which are oscillations with a period of one or a few generation times of the species. The model is formulated in terms of a single delay-differential equation for the population density of an adult stage, with recruitment to the adult stage depending on the intensity of competition during the juvenile phase. This model is a simplified version of a group of models proposed by Gurney and Nisbet, who were the first to distinguish between single-generation cycles and delayed-feedback cycles. According to these authors, the two oscillation types are caused by different mechanisms and have periods in different intervals, which are one to two generation times for single-generation cycles and two to four generation times for delayed-feedback cycles. By abolishing the strict coupling between the maturation time and the time delay between competition and its effect on the population dynamics, we find that single-generation cycles and delayed-feedback cycles occur in the same model version, with a gradual transition between the two as the model parameters are varied over a sufficiently large range. Furthermore, cycle periods are not bounded to lie within single octaves. This implies that a clear distinction between different types of generation cycles is not possible. Cycles of all periods and even chaos can be generated by varying the parameters that determine the time during which individuals from different cohorts compete with each other. This suggests that life-cycle features in the juvenile stage and during the transition to the adult stage are important determinants of the dynamics of density limited populations. Copyright © 2014 Elsevier Inc. All rights reserved.

Dormancy cycling in seeds: mechanisms and regulation

NARCIS (Netherlands)

Claessens, S.M.C.

2012-01-01

The life cycle of most plants starts, and ends, at the seed stage. In most species mature seeds are shed and dispersed on the ground. At this stage of its life cycle the seed may be dormant and will, by definition, not germinate under favourable conditions (Bewley, 1997).

Seasonal

Microbial nitrogen cycling in Arctic snowpacks

International Nuclear Information System (INIS)

Larose, Catherine; Vogel, Timothy M; Dommergue, Aurélien

2013-01-01

Arctic snowpacks are often considered as chemical reactors for a variety of chemicals deposited through wet and dry events, but are overlooked as potential sites for microbial metabolism of reactive nitrogen species. The fate of deposited species is critical since warming leads to the transfer of contaminants to snowmelt-fed ecosystems. Here, we examined the role of microorganisms and the potential pathways involved in nitrogen cycling in the snow. Next generation sequencing data were used to follow functional gene abundances and a 16S rRNA (ribosomal ribonucleic acid) gene microarray was used to follow shifts in microbial community structure during a two-month spring-time field study at a high Arctic site, Svalbard, Norway (79° N). We showed that despite the low temperatures and limited water supply, microbial communities inhabiting the snow cover demonstrated dynamic shifts in their functional potential to follow several different pathways of the nitrogen cycle. In addition, microbial specific phylogenetic probes tracked different nitrogen species over time. For example, probes for Roseomonas tracked nitrate concentrations closely and probes for Caulobacter tracked ammonium concentrations after a delay of one week. Nitrogen cycling was also shown to be a dominant process at the base of the snowpack. (letter)

The Annual Reproductive Cycle of Silurus microdorsalis, a Korean Endemic Species

Science.gov (United States)

Ki, Se-Un; Lee, Won-Kyo

2018-01-01

ABSTRACT The annual reproductive cycle of the Korean endemic slender catfish, Silurus microdorsalis, was examined histologically regarding water temperature and day length of habitat, gonadosomatic index (GSI), and development characteristics of female and male gonads. The maximum GSI value was found in May, 1.23±0.33 and 11.77±3.23 for male and female respectively (habitat water temperature 21.5°C/13.59hr day length). On the other hand, the minimal level was 0.63±0.10 in July (26.5°C/14.17) for male and 1.36±0.08 in October (20°C/11.2hr) for female. We compared and calculated the stages of testis and ovary development process in order to determine the germ cell development characteristics and the reproductive cycle. According to results, we classified the annual reproductive cycle of the slender catfish into five stages: Growing phase (December-February), Mature phase (March-April), Ripe and spawning phase / Releasing phase in male (May-June), Degenerative phase (July-August), and Resting phase (September-November).

Circadian cycles in growth and feeding rates of heterotrophic protist plankton

DEFF Research Database (Denmark)

Jakobsen, Hans Henrik; Strom, S.L.

2004-01-01

Growth and feeding rates of four species of planktonic marine heterotrophic protists showed pronounced diel cycles. In most cases, rates were higher during the day and lower at night. However, for the ciliate Strobilidium sp., growth was highest at night. In another ciliate species, Balanion...... comatum, no day-night difference in growth and feeding rates was found. Maintenance of day-night rate differences during 24-h exposures to continuous darkness demonstrated that most of these protists had circadian cycles. The heterotrophic dinoflagellate Oxyrrhis marina exhibited a clear irradiance...... to culturing in a day: night light cycle in O. marina and found that resetting the circadian cycle in this dinoflagellate temporarily arrested growth and feeding. We suggest that protists use a time-integrated light threshold rather than an instantaneous irradiance to maintain the circadian cell cycle...

Absorption of some mineral salts by root system of different woody species and accumulation over a whole vegetative cycle (1963)

International Nuclear Information System (INIS)

Gagnaire, J.; Gerard, J.M.

1963-01-01

The concentration power of plant tissues and the translocation speed of mineral salts are considerably varying with the absorbed salt, the botanical species, the considered tissue and the part of the vegetative cycle. In Grenoble, with Picea excelsa, the 'true dormancy' is short (half-november, end of december). It is accompanied by a pre-dormancy period (October, half-november) and a post dormancy period (January, february, march). In vegetative period, Picea excelsa leaves are less concentrating mineral salt than Acer campestris leaves (coefficient 2 for calcium - 3 for phosphates) and Populus nigra leaves (coefficient 3 for calcium, coefficient 5 for phosphates). (author) [fr

Dynamics of ovarian maturation during the reproductive cycle of Metynnis maculatus, a reservoir invasive fish species (Teleostei: Characiformes

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Thiago Scremin Boscolo Pereira

Full Text Available In this study, we evaluated the dynamics of ovarian maturation and the spawning processes during the reproductive cycle of Metynnis maculatus. Adult females (n = 36 were collected bimonthly between April 2010 and March 2011. The mean gonadosomatic index (GSI was determined, ovarian and blood samples were submitted for morphometric evaluation and the steroid plasma concentration was determined by ELISA. This species demonstrated asynchronous ovarian development with multiple spawns. This study revealed that, although defined as a multiple spawning species, the ovaries of M. maculatus have a pattern of development with a predominance of vitellogenesis between April and August and have an intensification in spawning in September; in October, a drop in the mean GSI values occurred, and the highest frequencies of post-ovulatory follicles (POFs were observed. We observed a positive correlation between the POF and the levels of 17α-hydroxyprogesterone. Metynnis maculatus has the potential to be used as a source of pituitary tissue for the preparation of crude extracts for hormonal induction; the theoretical period for use is from September to December, but specific studies to determine the feasibility of this approach must be conducted.

Investigations regarding the anthropic impact on the Krebs cycle dehydrogenases system on certain wood-species in mining areas, Suceava county

Directory of Open Access Journals (Sweden)

Marius Viorel Oniciuc

2013-03-01

Full Text Available The Krebs cycle, a second stage of cellular respiration that occurs in the mitochondrion of the leafcell and consist in a multistep processes plays a central role in catabolism of organic fuel molecules. The miningextraction technologies for both underground and surface, the preparation of copper ore and barite applied in Tarnia,respectively to the sulphur in Calimani Mountain and the excess of these elements in natural environment may causemalfunction of ecosystem. The dehydrogenases of Krebs cycle can give information on the type and the duration of theeffects of pollutants on the metabolic activity in leaves, to subsequent area pollution, therefore, the aim of the presentstudy has been to determine these effects on this enzymatic system activity. For this reason, the isocitrate dehydrogenase,the -ketoglutate dehydrogenase, the succinate ehydrogenase and the malate dehydrogenase activity was determined using the spectrophotometric method with triphenyl-tetrazolium and the analysis of experimental results shows the differences from one sample to another sample of closely related species specificity, but also the effect of environmentalfactors.

Interactive effects of herbicide and enhanced UV-B on growth, oxidative damage and the ascorbate-glutathione cycle in two Azolla species.

Science.gov (United States)

Prasad, Sheo Mohan; Kumar, Sushil; Parihar, Parul; Singh, Rachana

2016-11-01

A field experiment was conducted to investigate the impact of alone and combined exposures of herbicide pretilachlor (5, 10 and 20μgml(-1)) and enhanced UV-B radiation (UV-B1; ambient +2.2kJm(-2) day(-1) and UV-B2; ambient +4.4kJm(-2) day(-1)) on growth, oxidative stress and the ascorbate-glutathione (AsA-GSH) cycle in two agronomically important Azolla spp. viz., Azolla microphylla and Azolla pinnata. Decreased relative growth rate (RGR) in both the species under tested stress could be linked to enhanced oxidative stress, thus higher H2O2 accumulation was observed, that in turn might have caused severe damage to lipids and proteins, thereby decreasing membrane stability. The effects were exacerbated when spp. were exposed to combined treatments of enhanced UV-B and pretilachlor. Detoxification of H2O2 is regulated by enzymes/metabolites of AsA-GSH cycle such as ascorbate peroxidase (APX) and glutathione reductase (GR) activity that were found to be stimulated. While, dehydroascorabte reductase (DHAR) activity, and the amount of metabolites: ascorbate (AsA), glutathione (GSH) and ratios of reduced/oxidized AsA (AsA/DHA) and GSH (GSH/GSSG), showed significant reduction with increasing doses of both the stressors, either applied alone or in combination. Glutathione-S-transferase (GST), an enzyme involved in scavenging of xenobiotics, was found to be stimulated under the tested stress. This study suggests that decline in DHAR activity and in AsA/DHA ratio might have led to enhanced H2O2 accumulation, thus decreased RGR was noticed under tested stress in both the species and the effect was more pronounced in A. pinnata. Owing to better performance of AsA-GSH cycle in A. microphylla, this study substantiates the view that A. microphylla is more tolerant than A. pinnata. Copyright © 2016 Elsevier Inc. All rights reserved.

The role of reactive oxygen species (ROS) production on diallyl disulfide (DADS) induced apoptosis and cell cycle arrest in human A549 lung carcinoma cells

International Nuclear Information System (INIS)

Wu Xinjiang; Kassie, Fekadu; Mersch-Sundermann, Volker

2005-01-01

Diallyl disulfide (DADS), an oil soluble constituent of garlic (Allium sativum), has been reported to cause antimutagentic and anticarcinogenic effects in vitro and in vivo by modulating phases I and II enzyme activities. In recent years, several studies suggested that the chemopreventive effects of DADS can also be attributed to induction of cell cycle arrest and apoptosis in cancer cells. In the present study, we reported that DADS-induced cell cycle arrest at G2/M and apoptosis in human A549 lung cancer cells in a time- and dose-dependent manner. Additionally, a significant increase of intracellular reactive oxygen species (ROS) was induced in A549 cells less than 0.5 h after DADS treatment, indicating that ROS may be an early event in DADS-modulated apoptosis. Treatment of A549 cells with N-acetyl cysteine (NAC) completely abrogated DADS-induced cell cycle arrest and apoptosis. The result indicated that oxidative stress modulates cell proliferation and cell death induced by DADS

The role of reactive oxygen species (ROS) production on diallyl disulfide (DADS) induced apoptosis and cell cycle arrest in human A549 lung carcinoma cells

Energy Technology Data Exchange (ETDEWEB)

Wu Xinjiang [Institute of Indoor and Environmental Toxicology, Faculty of Medicine, Justus-Liebig-University of Giessen, Aulweg 123, D-35385 Giessen (Germany); Kassie, Fekadu [Institute of Indoor and Environmental Toxicology, Faculty of Medicine, Justus-Liebig-University of Giessen, Aulweg 123, D-35385 Giessen (Germany); Mersch-Sundermann, Volker [Institute of Indoor and Environmental Toxicology, Faculty of Medicine, Justus-Liebig-University of Giessen, Aulweg 123, D-35385 Giessen (Germany)]. E-mail: Volker.mersch-sundermann@uniklinikum-giessen.de

2005-11-11

Diallyl disulfide (DADS), an oil soluble constituent of garlic (Allium sativum), has been reported to cause antimutagentic and anticarcinogenic effects in vitro and in vivo by modulating phases I and II enzyme activities. In recent years, several studies suggested that the chemopreventive effects of DADS can also be attributed to induction of cell cycle arrest and apoptosis in cancer cells. In the present study, we reported that DADS-induced cell cycle arrest at G2/M and apoptosis in human A549 lung cancer cells in a time- and dose-dependent manner. Additionally, a significant increase of intracellular reactive oxygen species (ROS) was induced in A549 cells less than 0.5 h after DADS treatment, indicating that ROS may be an early event in DADS-modulated apoptosis. Treatment of A549 cells with N-acetyl cysteine (NAC) completely abrogated DADS-induced cell cycle arrest and apoptosis. The result indicated that oxidative stress modulates cell proliferation and cell death induced by DADS.

A life cycle database for parasitic acanthocephalans, cestodes, and nematodes

Science.gov (United States)

Benesh, Daniel P.; Lafferty, Kevin D.; Kuris, Armand

2017-01-01

Parasitologists have worked out many complex life cycles over the last ~150 years, yet there have been few efforts to synthesize this information to facilitate comparisons among taxa. Most existing host-parasite databases focus on particular host taxa, do not distinguish final from intermediate hosts, and lack parasite life-history information. We summarized the known life cycles of trophically transmitted parasitic acanthocephalans, cestodes, and nematodes. For 973 parasite species, we gathered information from the literature on the hosts infected at each stage of the parasite life cycle (8510 host-parasite species associations), what parasite stage is in each host, and whether parasites need to infect certain hosts to complete the life cycle. We also collected life-history data for these parasites at each life cycle stage, including 2313 development time measurements and 7660 body size measurements. The result is the most comprehensive data summary available for these parasite taxa. In addition to identifying gaps in our knowledge of parasite life cycles, these data can be used to test hypotheses about life cycle evolution, host specificity, parasite life-history strategies, and the roles of parasites in food webs.

Proteome dynamics and physiological responses to short-term salt stress in Leymus chinensis leaves.

Directory of Open Access Journals (Sweden)

Jikai Li

Full Text Available Salt stress is becoming an increasing threat to global agriculture. In this study, physiological and proteomics analysis were performed using a salt-tolerant grass species, Leymus chinensis (L. chinensis. The aim of this study is to understand the potential mechanism of salt tolerance in L. chinensis that used for crop molecular breeding. A series of short-term (<48 h NaCl treatments (0 ~ 700 mM were conducted. Physiological data indicated that the root and leaves growth were inhibited, chlorophyll contents decreased, while hydraulic conductivity, proline, sugar and sucrose were accumulated under salt stress. For proteomic analysis, we obtained 274 differentially expressed proteins in response to NaCl treatments. GO analysis revealed that 44 out of 274 proteins are involved in the biosynthesis of amino acids and carbon metabolism. Our findings suggested that L. chinensis copes with salt stress by stimulating the activities of POD, SOD and CAT enzymes, speeding up the reactions of later steps of citrate cycle, and synthesis of proline and sugar. In agreement with our physiological data, proteomic analysis also showed that salt stress depress the expression of photosystem relevant proteins, Calvin cycle, and chloroplast biosynthesis.

Biomass cycles, accumulation rates and nutritional characteristics of ...

African Journals Online (AJOL)

Annual biomass cycles, accumulation rates and nutritional characteristics of forage and non-forage species groups were determined in the canopied and open, uncanopied subhabitats of the herbaceous layer in Burkea africana savanna. The total amount of biomass of all species over the season was significantly greater in ...

Impact of herbivores on nitrogen cycling : contrasting effects of small and large species

NARCIS (Netherlands)

Bakker, ES; Olff, H; Boekhoff, M; Gleichman, JM; Berendse, F

Herbivores are reported to slow down as well as enhance nutrient cycling in grasslands. These conflicting results may be explained by differences in herbivore type. In this study we focus on herbivore body size as a factor that causes differences in herbivore effects on N cycling. We used an

Impact of herbivores on nitrogen cycling: contrasting effects of small and large species

NARCIS (Netherlands)

Bakker, E.S.; Olff, H.; Boekhoff, M.; Gleichman, J.M.; Berendse, F.

2004-01-01

Herbivores are reported to slow down as well as enhance nutrient cycling in grasslands. These conflicting results may be explained by differences in herbivore type. In this study we focus on herbivore body size as a factor that causes differences in herbivore effects on N cycling. We used an

Life cycle strategies of copepods in coastal upwelling zones

Science.gov (United States)

Peterson, W.

1998-06-01

Life cycles of copepods of coastal upwelling zones are of the multigenerational type—as many as 10 or more generations may be produced each year, depending upon water temperature, food concentration and length of the upwelling season. Abundant food resources and moderate temperature convey advantages to those copepods living in coastal upwelling zones, however, there is a clear disadvantage in that coastal upwelling zones are highly advective environments. Typically, water circulation patterns are such that surface waters are carried offshore, deeper waters carried onshore and most of the water column over the continental shelf is moving equatorward. The challenge to copepod species that inhabit upwelling systems is life cycle closure—how do eggs, nauplii, juveniles and adults avoid being swept out of these ecosystems in the face of persistent transport out of the system? In this review, I first list the species which dominate coastal upwelling ecosystems then discuss three variations on the multigenerational life cycle scheme that are observed in upwelling systems. The latter part of the review is devoted to discussion of how individuals are retained in the productive continental shelf waters within coastal upwelling ecosystems. The suggestion is made that the only copepod species that successfully achieve life cycle closure in such systems are those that are preadapted to upwelling circulation patterns. Our quantitative understanding of the relative importance of physical factors (such as advection) and biological factors (birth, growth, and mortality) on life cycle strategies and population dynamics is quite rudimentary. It would help our understanding if there were more field studies and more computer modeling studies that focused on seasonal cycles of abundance, development times and vertical distribution of life cycle stages, and measurements of water circulation patterns.

Increased SBPase activity improves photosynthesis and grain yield in wheat grown in greenhouse conditions.

Science.gov (United States)

Driever, Steven M; Simkin, Andrew J; Alotaibi, Saqer; Fisk, Stuart J; Madgwick, Pippa J; Sparks, Caroline A; Jones, Huw D; Lawson, Tracy; Parry, Martin A J; Raines, Christine A

2017-09-26

To meet the growing demand for food, substantial improvements in yields are needed. This is particularly the case for wheat, where global yield has stagnated in recent years. Increasing photosynthesis has been identified as a primary target to achieve yield improvements. To increase leaf photosynthesis in wheat, the level of the Calvin-Benson cycle enzyme sedoheptulose-1,7-biphosphatase (SBPase) has been increased through transformation and expression of a Brachypodium distachyon SBPase gene construct. Transgenic lines with increased SBPase protein levels and activity were grown under greenhouse conditions and showed enhanced leaf photosynthesis and increased total biomass and dry seed yield. This showed the potential of improving yield potential by increasing leaf photosynthesis in a crop species such as wheat. The results are discussed with regard to future strategies for further improvement of photosynthesis in wheat.This article is part of the themed issue 'Enhancing photosynthesis in crop plants: targets for improvement'. © 2017 The Authors.

Carbon isotope fractionation by thermophilic phototrophic sulfur bacteria: evidence for autotrophic growth in natural populations

Science.gov (United States)

Madigan, M. T.; Takigiku, R.; Lee, R. G.; Gest, H.; Hayes, J. M.

1989-01-01

Purple phototrophic bacteria of the genus Chromatium can grow as either photoautotrophs or photoheterotrophs. To determine the growth mode of the thermophilic Chromatium species, Chromatium tepidum, under in situ conditions, we have examined the carbon isotope fractionation patterns in laboratory cultures of this organism and in mats of C. tepidum which develop in sulfide thermal springs in Yellowstone National Park. Isotopic analysis (13C/12C) of total carbon, carotenoid pigments, and bacteriochlorophyll from photoautotrophically grown cultures of C. tepidum yielded 13C fractionation factors near -20%. Cells of C. tepidum grown on excess acetate, wherein synthesis of the Calvin cycle enzyme ribulose-1,5-bisphosphate carboxylase/oxygenase ribulose bisphosphate carboxylase) was greatly repressed, were isotopically heavier, fractionation factors of ca. -7% being observed. Fractionation factors determined by isotopic analyses of cells and pigment fractions of natural populations of C. tepidum growing in three different sulfide thermal springs in Yellowstone National Park were approximately -20%, indicating that this purple sulfur bacterium grows as a photoautotroph in nature.

Construction of analytically solvable models for interacting species. [biological species competition

Science.gov (United States)

Rosen, G.

1976-01-01

The basic form of a model representation for systems of n interacting biological species is a set of essentially nonlinear autonomous ordinary differential equations. A generic canonical expression for the rate functions in the equations is reported which permits the analytical general solution to be obtained by elementary computation. It is shown that a general analytical solution is directly obtainable for models where the rate functions are prescribed by the generic canonical expression from the outset. Some illustrative examples are given which demonstrate that the generic canonical expression can be used to construct analytically solvable models for two interacting species with limit-cycle dynamics as well as for a three-species interdependence.

Handbook of plant cell culture. Volume 2. Crop species

Energy Technology Data Exchange (ETDEWEB)

Sharp, W.R.; Evans, D.A.; Ammirato, P.V.; Yamada, Y. (eds.)

1984-01-01

In this volume the state-of-the-art plant cell culture techniques described in the first volume are applied to several agricultural and horticultural crops. In 21 chapters, they include maize, oats, wheat, beans, red clover and other forage legumes, asparagus, celery, cassava, sweet potato, banana, pawpaw, apple, grapes, conifers, date palm, rubber, sugarcane and tobacco. Each chapter contains (1) detailed protocols to serve as the foundation for current research, (2) a critical review of the literature, and (3) in-depth evaluations of the potential shown by plant cell culture for crop improvement. The history and economic importance of each crop are discussed. This volume also includes an essay, ''Oil from plants'', by M. Calvin.

Pleistocene glacial cycle effects on the phylogeography of the Chinese endemic bat species, Myotis davidii

Directory of Open Access Journals (Sweden)

Jiang Tinglei

2010-07-01

Full Text Available Abstract Background Global climatic oscillations, glaciation cycles and the unique geographic topology of China have profoundly influenced species population distributions. In most species, contemporary distributions of populations cannot be fully understood, except in a historical context. Complex patterns of Pleistocene glaciations, as well as other physiographic changes have influenced the distribution of bat species in China. Until this study, there had been no phylogeographical research on Myotis davidii, an endemic Chinese bat. We used a combination of nuclear and mitochondrial DNA markers to investigate genetic diversity, population structure, and the demographic history of M. davidii. In particular, we compared patterns of genetic variation to glacial oscillations, topography, and environmental variation during the Pleistocene in an effort to explain current distributions in light of these historical processes. Results M. davidii comprises three lineages (MEP, SWP and SH based on the results of molecular variance analysis (AMOVA and phylogenetic analyses. The results of a STRUCTURE analysis reveal multi-hierarchical population structure in M. davidii. Nuclear and mitochondrial genetic markers reveal different levels of gene flow among populations. In the case of mtDNA, populations adhere to an isolation-by-distance model, whereas the individual assignment test reveals considerable gene flow between populations. MDIV analysis indicate that the split of the MEP and SWP/SH lineages, and from the SWP and SH lineages were at 201 ka BP and 158 ka BP, respectively. The results of a mismatch distribution analysis and neutrality tests indicate a population expansion event at 79.17 ka BP and 69.12 ka BP in MEP and SWP, respectively. Conclusions The complex demographic history, discontinuous extant distribution of haplotypes, and multiple-hierarchy population structure of M. davidii appear associated with climatic oscillations, topography and eco

Reproductive cycles of deer.

Science.gov (United States)

Asher, G W

2011-04-01

The cervids are a complex assemblage of taxa showing extreme diversity in morphology, physiology, ecology and geographical distribution. Reproductive strategies adopted by various species are also diverse, and include a range from highly seasonal to completely aseasonal birth patterns. The recent growth in knowledge on cervid reproduction is strongly biased towards the larger-bodied, gregarious mixed grazer-browser species that have adapted well to human management and commercialisation. These species tend to represent 'K-selected' climax species characterised by very productive annual breeding success, singleton births and long breeding life (10+ years). Conversely, we know relatively little about the reproductive patterns of the 'r-selected' smaller-bodied, solitary (and often highly territorial), forest-dwelling browser species, often characterised by great fecundity (twinning) and shorter breeding life (<10 years). This group includes many of the endangered cervid taxa. This review extends earlier reviews to include more recent work on cervid reproductive cycles, particularly in relation to environmental factors influencing gestation length. Copyright © 2010 Elsevier B.V. All rights reserved.

Activity cycle of the pollen wasp, Trimeria howardi (Hymenoptera: Vespidae in Southeastern Brasil

Directory of Open Access Journals (Sweden)

Maria Rita Mech

1999-12-01

Full Text Available Among the wasps, the Masarinae are a peculiar subfamily. It is the only group of wasps that provisions brood cells with pollen and nectar. The studied species Trimeria howardi Bertoni, 1911, was until recently abundant in Ribeirão Preto, São Paulo, southeastern Brazil. This paper deals with plant species visited by T. howardi, in relation to the species’ annual cycle of activity, based on periods of nest foundation, flight activity, and development stages of immatures present in the cells. During the study period (five years T. howardi visited four species of plants in two botanical families: Bidens pilosa L.(Asteraceae; Xanthium spinosum L. (Asteraceae; Stylosanthes guianensis (Aulb. Sw. (Leguminosae, and Zornia diphylla (L. Pers. (Leguminosae. Based on the number of visited families, T. howardi can be considered a narrow polylectic species. In general, the species annual activity cycle consists of three phases: Active phase: January to July; Inactive phase: August - September; Active phase: October to December. The annual cycle is bivoltine or multivoltine and the diapause is facultative, because it occurs in a single generation during the year.

The functional biogeography of species

DEFF Research Database (Denmark)

Carstensen, Daniel W.; Dalsgaard, Bo; Svenning, Jens-Christian

2013-01-01

Biogeographical systems can be analyzed as networks of species and geographical units. Within such a biogeographical network, individual species may differ fundamentally in their linkage pattern, and therefore hold different topological roles. To advance our understanding of the relationship betw...... to distributions at the local community level. We finally discuss how our biogeographical species roles may correspond to the stages of the taxon cycle and other prominent theories of species assembly.......Biogeographical systems can be analyzed as networks of species and geographical units. Within such a biogeographical network, individual species may differ fundamentally in their linkage pattern, and therefore hold different topological roles. To advance our understanding of the relationship...... between species traits and large-scale species distribution patterns in archipelagos, we use a network approach to classify birds as one of four biogeographical species roles: peripherals, connectors, module hubs, and network hubs. These roles are based upon the position of species within the modular...

Levels of Arabidopsis thaliana leaf phosphatidic acids, phosphatidylserines, and most trienoate-containing polar lipid molecular species increase during the dark period of the diurnal cycle

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Sara eMaatta

2012-03-01

Full Text Available Previous work has demonstrated that plant leaf polar lipid fatty acid composition varies during the diurnal (dark-light cycle. Fatty acid synthesis occurs primarily during the light, but fatty acid desaturation continues in the absence of light, resulting in polyunsaturated fatty acids reaching their highest levels toward the end of the dark period. In this work, Arabidopsis thaliana were grown at constant (21°C temperature with 12-h light and 12-h dark periods. Collision induced dissociation time-of-flight mass spectrometry demonstrated that 16:3 and 18:3 fatty acid content in membrane lipids of leaves are higher at the end of the dark than at the end of the light period, while 16:1, 16:2, 18:0, and 18:1 content are higher at the end of the light period. Lipid profiling of membrane galactolipids, phospholipids, and lysophospholipids by electrospray ionization triple quadrupole mass spectrometry indicated that the monogalactosyldiacylglycerol, phosphatidylglycerol, and phosphatidylcholine classes include molecular species whose levels are highest at end of the light period and others that are highest at the end of the dark period. The levels of phosphatidic acid and phosphatidylserine classes were higher at the end of the dark period, and molecular species within these classes either followed the class pattern or were not significantly changed in the diurnal cycle. Phospholipase D (PLD is a family of enzymes that hydrolyzes phospholipids to produce phosphatidic acid. Analysis of several PLD mutant lines suggests that PLDζ2 and possibly PLDα1 may contribute to diurnal cycling of phosphatidic acid. The polar lipid compositional changes are considered in relation to recent data that demonstrate phosphatidylcholine acyl editing.

As above, so below? How the interplay between overstory species and edaphic factors influences the magnitude and mechanisms of belowground carbon cycles.

Science.gov (United States)

Desie, Ellen; Vancampenhout, Karen; Buelens, Jeroen; Verstraeten, Gorik; Verheyen, Kris; Heyens, Kathleen; Muys, Bart

2017-04-01

The choice of overstory species in relation to soil properties is one of the most important management decisions in forestry, especially when deciduous or mixed stands are replaced by coniferous monocultures. When assessed in relation to climate change, conversion effects are mainly studied in terms of total carbon stocks. These are generally considered to evolve linearly, according to similar stabilization processes across ecosystems. Here we show that the belowground carbon cycle is subject to ecosystem-specific stable process domains. The process domains are separated by steep thresholds, or even tipping points, where a small increase in environmental forcing can cause a drastic change in the way the ecosystem processes carbon. These effects are demonstrated in detail for the old-growth forest complex of the Gaume in Belgium. This forest spans a lithological gradient and mixed-species stands occur next to stands recently converted to Norway spruce (Picea abies) monocultures, creating a setting of paired plots that allow to address the magnitude of management choices relative to intrinsic natural potential. Vegetation descriptions, litter samples and soil samples at different depths were compared for above- and belowground functional biodiversity, litter layer characteristics, soil properties, nutrient status, bioturbation, soil carbon stocks and soil carbon functional pools. Results show that in soils with limited remaining buffer capacity, overstory-induced acidification under spruce causes a shift to an acid aluminum buffered environment, with a collapse in variability of abiotic and biotic soil properties. This entails a shift in soil fauna and depth relations, with a clear decoupling of the litter layer from the topsoil and the subsoil in terms of biological communities, carbon input and stochastic constraints. Finally, this study indicates that although spruce conversion increases the total soil carbon stocks, this extra carbon is stored in more labile

Biodegradation of endosulfan by mixed bacteria culture strains of ...

African Journals Online (AJOL)

Biodegradation of endosulfan by mixed bacteria culture strains of Pseudomonas aeruginosa and Staphylococcus aureus. Nsidibeabasi Calvin Nwokem, Calvin Onyedika Nwokem, Casmir Emmanuel Gimba, Beatrice Nkiruka Iwuala ...

Transpiration efficiency over an annual cycle, leaf gas exchange and wood carbon isotope ratio of three tropical tree species.

Science.gov (United States)

Cernusak, Lucas A; Winter, Klaus; Aranda, Jorge; Virgo, Aurelio; Garcia, Milton

2009-09-01

Variation in transpiration efficiency (TE) and its relationship with the stable carbon isotope ratio of wood was investigated in the saplings of three tropical tree species. Five individuals each of Platymiscium pinnatum (Jacq.) Dugand, Swietenia macrophylla King and Tectona grandis Linn. f. were grown individually in large (760 l) pots over 16 months in the Republic of Panama. Cumulative transpiration was determined by repeatedly weighing the pots with a pallet truck scale. Dry matter production was determined by destructive harvest. The TE, expressed as experiment-long dry matter production divided by cumulative water use, averaged 4.1, 4.3 and 2.9 g dry matter kg(-1) water for P. pinnatum, S. macrophylla and T. grandis, respectively. The TE of T. grandis was significantly lower than that of the other two species. Instantaneous measurements of the ratio of intercellular to ambient CO(2) partial pressures (c(i)/c(a)), taken near the end of the experiment, explained 66% of variation in TE. Stomatal conductance was lower in S. macrophylla than in T. grandis, whereas P. pinnatum had similar stomatal conductance to T. grandis, but with a higher photosynthetic rate. Thus, c(i)/c(a) and TE appeared to vary in response to both stomatal conductance and photosynthetic capacity. Stem-wood delta(13)C varied over a relatively narrow range of just 2.2 per thousand, but still explained 28% of variation in TE. The results suggest that leaf-level processes largely determined variation among the three tropical tree species in whole-plant water-use efficiency integrated over a full annual cycle.

Circadian rhythms differ between sexes and closely related species of Nasonia wasps.

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Rinaldo C Bertossa

Full Text Available Activity rhythms in 24 h light-dark cycles, constant darkness, and constant light conditions were analyzed in four different Nasonia species for each sex separately. Besides similarities, clear differences are evident among and within Nasonia species as well as between sexes. In all species, activity in a light-dark cycle is concentrated in the photophase, typical for diurnal organisms. Contrary to most diurnal insect species so far studied, Nasonia follows Aschoff's rule by displaying long (>24 h internal rhythms in constant darkness but short (<24 h in constant light. In constant light, N. vitripennis males display robust circadian activity rhythms, whereas females are usually arrhythmic. In contrast to other Nasonia species, N. longicornis males display anticipatory activity, i.e. activity shortly before light-on in a light-dark cycle. As expected, N. oneida shows activity patterns similar to those of N. giraulti but with important differences in key circadian parameters. Differences in circadian activity patterns and parameters between species may reflect synchronization of specific life-history traits to environmental conditions. Scheduling mating or dispersion to a specific time of the day could be a strategy to avoid interspecific hybridization in Nasonia species that live in sympatry.

Analysing how plants in coastal wetlands respond to varying tidal regimes throughout their life cycles.

Science.gov (United States)

Xie, Tian; Cui, Baoshan; Li, Shanze

2017-10-15

Important to conserve plant species in coastal wetlands throughout their life cycle. All life stages in these habitats are exposed to varying tidal cycles. It is necessary to investigate all life stages as to how they respond to varying tidal regimes. We examine three wetlands containing populations of an endangered halophyte species, each subjected to different tidal regimes: (1). wetlands completely closed to tidal cycles; (2). wetlands directly exposed to tidal cycles (3). wetlands exposed to a partially closed tidal regime. Our results showed that the most threatened stage varied between wetlands subjected to these varying tidal regimes. We hypothesis that populations of this species have adapted to these different tidal regimes. Such information is useful in developing management options for coastal wetlands and modifying future barriers restricting tidal flushing. Copyright © 2017 Elsevier Ltd. All rights reserved.

Life-cycle stages of Dinophysis acuminata (Dinophyceae) in the ...

African Journals Online (AJOL)

Despite many observations of different life-cycle stages of Dinophysis species, the complete life history of the genus is still unknown owing to the difficulties encountered in culturing these species. The seasonal distribution of D. acuminata was followed at two offshore stations in the brackish Baltic Sea by means of in situ ...

Combined Inoculation with Multiple Arbuscular Mycorrhizal Fungi Improves Growth, Nutrient Uptake and Photosynthesis in Cucumber Seedlings

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Shuangchen Chen

2017-12-01

Full Text Available Mycorrhizal inoculation stimulates growth, photosynthesis and nutrient uptake in a wide range of host plants. However, the ultimate effects of arbuscular mycorrhyzal (AM symbiosis vary with the plants and fungal species involved in the association. Therefore, identification of the appropriate combinations of AM fungi (AMF that interact synergistically to improve their benefits is of high significance. Here, three AM fungal compositions namely VT (Claroideoglomus sp., Funneliformis sp., Diversispora sp., Glomus sp., and Rhizophagus sp. and BF (Glomus intraradices, G. microageregatum BEG and G. Claroideum BEG 210, and Funneliformis mosseae (Fm were investigated with respect to the growth, gas exchange parameters, enzymes activities in Calvin cycles and related gene expression in cucumber seedlings. The results showed that VT, BF and Fm could successfully colonize cucumber root to a different degree with the colonization rates 82.38, 74.65, and 70.32% at 46 days post inoculation, respectively. The plant height, stem diameter, dry weight, root to shoot ratio of cucumber seedlings inoculated with AMF increased significantly compared with the non-inoculated control. Moreover, AMF colonization greatly increased the root activity, chlorophyll content, net photosynthetic rate, light saturated rate of the CO2 assimilation (Asat, maximum carboxylation rate (Vcmax and maximum ribulose-1,5-bis-phosphate (RuBP regeneration rate (Jmax, which were increased by 52.81, 30.75, 58.76, 47.00, 69.15, and 65.53% when inoculated with VT, respectively. The activities of some key enzymes such RuBP carboxylase/oxygenase (RuBisCO, D-fructose-1,6-bisphosphatase (FBPase, D-fructose-6-phosphatase (F6P and ribulose-5-phosphate kinase (Ru5PK, and related gene expression involved in the Calvin cycle including RCA, FBPase, FBPA, SBPase, rbcS and rbcL were upregulated by AMF colonization. AMF inoculation also improved macro- and micro nutrient contents such as N, P, K, S, Ca, Cu

Complementary models of tree species-soil relationships in old-growth temperate forests

Science.gov (United States)

Cross, Alison; Perakis, Steven S.

2011-01-01

Ecosystem level studies identify plant soil feed backs as important controls on soil nutrient availability,particularly for nitrogen and phosphorus. Although site and species specific studies of tree species soil relationships are relatively common,comparatively fewer studies consider multiple coexisting speciesin old-growth forests across a range of sites that vary underlying soil fertility. We characterized patterns in forest floor and mineral soil nutrients associated with four common tree species across eight undisturbed old-growth forests in Oregon, USA, and used two complementary conceptual models to assess tree species soil relationships. Plant soil feedbacks that could reinforce sitelevel differences in nutrient availability were assessed using the context dependent relationships model, where by relative species based differences in each soil nutrient divergedorconvergedas nutrient status changed across sites. Tree species soil relationships that did not reflect strong feedbacks were evaluated using a site independent relationships model, where by forest floor and surface mineral soil nutrient tools differed consistently by tree species across sites,without variation in deeper mineral soils. We found that theorganically cycled elements carbon, nitrogen, and phosphorus exhibited context-dependent differences among species in both forest floor and mineral soil, and most of ten followed adivergence model,where by species differences were greatest at high-nutrient sites. These patterns are consistent with the oryemphasizing biotic control of these elements through plant soil feedback mechanisms. Site independent species differences were strongest for pool so if the weather able cations calcium, magnesium, potassium,as well as phosphorus, in mineral soils. Site independent species differences in forest floor nutrients we reattributable too nespecies that displayed significant greater forest floor mass accumulation. Our finding confirmed that site-independent and

Tree species diversity mitigates disturbance impacts on the forest carbon cycle.

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Silva Pedro, Mariana; Rammer, Werner; Seidl, Rupert

2015-03-01

Biodiversity fosters the functioning and stability of forest ecosystems and, consequently, the provision of crucial ecosystem services that support human well-being and quality of life. In particular, it has been suggested that tree species diversity buffers ecosystems against the impacts of disturbances, a relationship known as the "insurance hypothesis". Natural disturbances have increased across Europe in recent decades and climate change is expected to amplify the frequency and severity of disturbance events. In this context, mitigating disturbance impacts and increasing the resilience of forest ecosystems is of growing importance. We have tested how tree species diversity modulates the impact of disturbance on net primary production and the total carbon stored in living biomass for a temperate forest landscape in Central Europe. Using the simulation model iLand to study the effect of different disturbance regimes on landscapes with varying levels of tree species richness, we found that increasing diversity generally reduces the disturbance impact on carbon storage and uptake, but that this effect weakens or even reverses with successional development. Our simulations indicate a clear positive relationship between diversity and resilience, with more diverse systems experiencing lower disturbance-induced variability in their trajectories of ecosystem functioning. We found that positive effects of tree species diversity are mainly driven by an increase in functional diversity and a modulation of traits related to recolonization and resource usage. The results of our study suggest that increasing tree species diversity could mitigate the effects of intensifying disturbance regimes on ecosystem functioning and improve the robustness of forest carbon storage and the role of forests in climate change mitigation.

High duty cycle to low duty cycle: echolocation behaviour of the hipposiderid bat Coelops frithii.

Science.gov (United States)

Ho, Ying-Yi; Fang, Yin-Ping; Chou, Cheng-Han; Cheng, Hsi-Chi; Chang, Hsueh-Wen

2013-01-01

Laryngeally echolocating bats avoid self-deafening (forward masking) by separating pulse and echo either in time using low duty cycle (LDC) echolocation, or in frequency using high duty cycle (HDC) echolocation. HDC echolocators are specialized to detect fluttering targets in cluttered environments. HDC echolocation is found only in the families Rhinolophidae and Hipposideridae in the Old World and in the New World mormoopid, Pteronotus parnellii. Here we report that the hipposiderid Coelops frithii, ostensibly an HDC bat, consistently uses an LDC echolocation strategy whether roosting, flying, or approaching a fluttering target rotating at 50 to 80 Hz. We recorded the echolocation calls of free-flying C. frithii in the field in various situations, including presenting bats with a mechanical fluttering target. The echolocation calls of C. frithii consisted of an initial narrowband component (0.5±0.3 ms, 90.6±2.0 kHz) followed immediately by a frequency modulated (FM) sweep (194 to 113 kHz). This species emitted echolocation calls at duty cycles averaging 7.7±2.8% (n = 87 sequences). Coelops frithii approached fluttering targets more frequently than did LDC bats (C.frithii, approach frequency  = 40.4%, n = 80; Myotis spp., approach frequency  = 0%, n = 13), and at the same frequency as sympatrically feeding HDC species (Hipposideros armiger, approach rate  = 53.3%, n = 15; Rhinolophus monoceros, approach rate  = 56.7%, n = 97). We propose that the LDC echolocation strategy used by C. frithii is derived from HDC ancestors, that this species adjusts the harmonic contents of its echolocation calls, and that it may use both the narrowband component and the FM sweep of echolocations calls to detect fluttering targets.

High duty cycle to low duty cycle: echolocation behaviour of the hipposiderid bat Coelops frithii.

Directory of Open Access Journals (Sweden)

Ying-Yi Ho

Full Text Available Laryngeally echolocating bats avoid self-deafening (forward masking by separating pulse and echo either in time using low duty cycle (LDC echolocation, or in frequency using high duty cycle (HDC echolocation. HDC echolocators are specialized to detect fluttering targets in cluttered environments. HDC echolocation is found only in the families Rhinolophidae and Hipposideridae in the Old World and in the New World mormoopid, Pteronotus parnellii. Here we report that the hipposiderid Coelops frithii, ostensibly an HDC bat, consistently uses an LDC echolocation strategy whether roosting, flying, or approaching a fluttering target rotating at 50 to 80 Hz. We recorded the echolocation calls of free-flying C. frithii in the field in various situations, including presenting bats with a mechanical fluttering target. The echolocation calls of C. frithii consisted of an initial narrowband component (0.5±0.3 ms, 90.6±2.0 kHz followed immediately by a frequency modulated (FM sweep (194 to 113 kHz. This species emitted echolocation calls at duty cycles averaging 7.7±2.8% (n = 87 sequences. Coelops frithii approached fluttering targets more frequently than did LDC bats (C.frithii, approach frequency  = 40.4%, n = 80; Myotis spp., approach frequency  = 0%, n = 13, and at the same frequency as sympatrically feeding HDC species (Hipposideros armiger, approach rate  = 53.3%, n = 15; Rhinolophus monoceros, approach rate  = 56.7%, n = 97. We propose that the LDC echolocation strategy used by C. frithii is derived from HDC ancestors, that this species adjusts the harmonic contents of its echolocation calls, and that it may use both the narrowband component and the FM sweep of echolocations calls to detect fluttering targets.

The drug ornidazole inhibits photosynthesis in a different mechanism described for protozoa and anaerobic bacteria.

Science.gov (United States)

Marcus, Yehouda; Tal, Noam; Ronen, Mordechai; Carmieli, Raanan; Gurevitz, Michael

2016-12-01

Ornidazole of the 5-nitroimidazole drug family is used to treat protozoan and anaerobic bacterial infections via a mechanism that involves preactivation by reduction of the nitro group, and production of toxic derivatives and radicals. Metronidazole, another drug family member, has been suggested to affect photosynthesis by draining electrons from the electron carrier ferredoxin, thus inhibiting NADP + reduction and stimulating radical and peroxide production. Here we show, however, that ornidazole inhibits photosynthesis via a different mechanism. While having a minute effect on the photosynthetic electron transport and oxygen photoreduction, ornidazole hinders the activity of two Calvin cycle enzymes, triose-phosphate isomerase (TPI) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Modeling of ornidazole's interaction with ferredoxin of the protozoan Trichomonas suggests efficient electron tunneling from the iron-sulfur cluster to the nitro group of the drug. A similar docking site of ornidazole at the plant-type ferredoxin does not exist, and the best simulated alternative does not support such efficient tunneling. Notably, TPI was inhibited by ornidazole in the dark or when electron transport was blocked by dichloromethyl diphenylurea, indicating that this inhibition was unrelated to the electron transport machinery. Although TPI and GAPDH isoenzymes are involved in glycolysis and gluconeogenesis, ornidazole's effect on respiration of photoautotrophs is moderate, thus raising its value as an efficient inhibitor of photosynthesis. The scarcity of Calvin cycle inhibitors capable of penetrating cell membranes emphasizes on the value of ornidazole for studying the regulation of this cycle. © 2016 The Author(s); published by Portland Press Limited on behalf of the Biochemical Society.

Few vertebrate species dominate the Borrelia burgdorferi s.l. Life cycle

NARCIS (Netherlands)

Hofmeester, T.R.; Coipan, E.C.; Wieren, van S.E.; Prins, H.H.T.; Takken, W.; Sprong, H.

2016-01-01

Background. In the northern hemisphere, ticks of the Ixodidae family are vectors of diseases such as Lyme borreliosis, Rocky Mountain spotted fever and tick-borne encephalitis. Most of these ticks are generalists and have a three-host life cycle for which they are dependent on three different

Features of the Phosphatidylinositol Cycle and its Role in Signal Transduction.

Science.gov (United States)

Epand, Richard M

2017-08-01

The phosphatidylinositol cycle (PI-cycle) has a central role in cell signaling. It is the major pathway for the synthesis of phosphatidylinositol and its phosphorylated forms. In addition, some lipid intermediates of the PI-cycle, including diacylglycerol and phosphatidic acid, are also important lipid signaling agents. The PI-cycle has some features that are important for the understanding of its role in the cell. As a cycle, the intermediates will be regenerated. The PI-cycle requires a large amount of metabolic energy. There are different steps of the cycle that occur in two different membranes, the plasma membrane and the endoplasmic reticulum. In order to complete the PI-cycle lipid must be transferred between the two membranes. The role of the Nir proteins in the process has recently been elucidated. The lipid intermediates of the PI-cycle are normally highly enriched with 1-stearoyl-2-arachidonoyl molecular species in mammals. This enrichment will be retained as long as the intermediates are segregated from other lipids of the cell. However, there is a significant fraction (>15 %) of lipids in the PI-cycle of normal cells that have other acyl chains. Phosphatidylinositol largely devoid of arachidonoyl chains are found in cancer cells. Phosphatidylinositol species with less unsaturation will not be as readily converted to phosphatidylinositol-3,4,5-trisphosphate, the lipid required for the activation of Akt with resulting effects on cell proliferation. Thus, the cyclical nature of the PI-cycle, its dependence on acyl chain composition and its requirement for lipid transfer between two membranes, explain many of the biological properties of this cycle.

12-Chloracetyl-PPD, a novel dammarane derivative, shows anti-cancer activity via delay the progression of cell cycle G2/M phase and reactive oxygen species-mediate cell apoptosis.

Science.gov (United States)

Wang, Xu De; Sun, Yuan Yuan; Zhao, Chen; Qu, Fan Zhi; Zhao, Yu Qing

2017-03-05

(20R)-Dammarane-3β, 12β, 20, 25-tetrol (25-OH-PPD) is a ginsenoside isolated from Panax ginseng (C. A. Meyer). This compound exhibits anti-cancer activities on many human cancer cell lines. In this study, we investigated anti-cancer mechanisms of 12β-O-( L -Chloracetyl)-dammar-20(22)-ene-3β,25-diol(12-Chloracetyl-PPD), a modified 25-OH-PPD. We found that compound 12-Chloracetyl-PPD resulted in a concentration-dependent inhibition of viability in prostate, breast, and gastric cancer cells, without affecting the viability of normal cell (human gastric epithelial cell line-GES-1, hair follicle dermal papilla cell line-HHDPC and rat myocardial cell line-H9C2). In MDA-MB-435 and C4-2B cancer cells, 12-Chloracetyl-PPD induced G2/M cell cycle arrest, down-regulated mouse double minute 2 (MDM2) expression, up-regulated p53 expression, triggered apoptosis, and stimulated reactive oxygen species production. Apoptosis can be attenuated by the reactive oxygen species scavenger N-acetylcysteine. Our results suggested that compound 12-Chloracetyl-PPD showed obvious anti-cancer activity based on delaying cell cycle arrest and inducing cell apoptosis by reactive oxygen species production, which supported development of 12-Chloracetyl-PPD as a potential agent for cancer chemotherapy. Copyright © 2017 Elsevier B.V. All rights reserved.

Limit cycles in quantum systems

Energy Technology Data Exchange (ETDEWEB)

Niemann, Patrick

2015-04-27

In this thesis we investigate Limit Cycles in Quantum Systems. Limit cycles are a renormalization group (RG) topology. When degrees of freedom are integrated out, the coupling constants flow periodically in a closed curve. The presence of limit cycles is restricted by the necessary condition of discrete scale invariance. A signature of discrete scale invariance and limit cycles is log-periodic behavior. The first part of this thesis is concerned with the study of limit cycles with the similarity renormalization group (SRG). Limit cycles are mainly investigated within conventional renormalization group frameworks, where degrees of freedom, which are larger than a given cutoff, are integrated out. In contrast, in the SRG potentials are unitarily transformed and thereby obtain a band-diagonal structure. The width of the band structure can be regarded as an effective cutoff. We investigate the appearance of limit cycles in the SRG evolution. Our aim is to extract signatures as well as the scaling factor of the limit cycle. We consider the 1/R{sup 2}-potential in a two-body system and a three-body system with large scattering lengths. Both systems display a limit cycle. Besides the frequently used kinetic energy generator we apply the exponential and the inverse generator. In the second part of this thesis, Limit Cycles at Finite Density, we examine the pole structure of the scattering amplitude for distinguishable fermions at zero temperature in the medium. Unequal masses and a filled Fermi sphere for each fermion species are considered. We focus on negative scattering lengths and the unitary limit. The properties of the three-body spectrum in the medium and implications for the phase structure of ultracold Fermi gases are discussed.

Ambient UV-B radiation reduces PSII performance and net photosynthesis in high Arctic Salix arctica

DEFF Research Database (Denmark)

Albert, Kristian Rost; Mikkelsen, Teis Nørgaard; Ro-Poulsen, H.

2011-01-01

, nitrogen and UV-B absorbing compounds. Compared to a 60% reduced UV-B irradiance, the ambient solar UV-B reduced net photosynthesis in Salix arctica leaves fixed in the 45° position which exposed leaves to maximum natural irradiance. Also a reduced Calvin Cycle capacity was found, i.e. the maximum rate...... across position in the vegetation. These findings add to the evidence that the ambient solar UV-B currently is a significant stress factor for plants in high Arctic Greenland....

Quantifying the Adaptive Cycle.

Directory of Open Access Journals (Sweden)

David G Angeler

Full Text Available The adaptive cycle was proposed as a conceptual model to portray patterns of change in complex systems. Despite the model having potential for elucidating change across systems, it has been used mainly as a metaphor, describing system dynamics qualitatively. We use a quantitative approach for testing premises (reorganisation, conservatism, adaptation in the adaptive cycle, using Baltic Sea phytoplankton communities as an example of such complex system dynamics. Phytoplankton organizes in recurring spring and summer blooms, a well-established paradigm in planktology and succession theory, with characteristic temporal trajectories during blooms that may be consistent with adaptive cycle phases. We used long-term (1994-2011 data and multivariate analysis of community structure to assess key components of the adaptive cycle. Specifically, we tested predictions about: reorganisation: spring and summer blooms comprise distinct community states; conservatism: community trajectories during individual adaptive cycles are conservative; and adaptation: phytoplankton species during blooms change in the long term. All predictions were supported by our analyses. Results suggest that traditional ecological paradigms such as phytoplankton successional models have potential for moving the adaptive cycle from a metaphor to a framework that can improve our understanding how complex systems organize and reorganize following collapse. Quantifying reorganization, conservatism and adaptation provides opportunities to cope with the intricacies and uncertainties associated with fast ecological change, driven by shifting system controls. Ultimately, combining traditional ecological paradigms with heuristics of complex system dynamics using quantitative approaches may help refine ecological theory and improve our understanding of the resilience of ecosystems.

[Specific manifestations of polyvariant life cycles in ground beetles (Coleoptera, Carabidae) along latitudinal gradient].

Science.gov (United States)

Matalin, A V

2014-01-01

The life cycles of Carabidae are highly diverse, and 25 variants of these cycles are realized In the European part of Russia, from semideserts to continental tundras. The diversity of the life cycle spectrum sharply decreases (by more than half) upon transition from nemoral to boreal forest communities, and its phenological unification takes place at high latitudes. The greatest proportion of species with polyvariant development (25%) is characteristic of temporal latitudes, which may be explained by relatively long growing season and considerable cenotic diversity. In both southern (semidesert and steppe) and northern regions (middle and northern boreal forests), this proportion does not exceed 5%. At low latitudes, the polyvariant pattern of development is often manifested in the form of facultative bivoltine life cycles or as facultative biennial life cycles in species with the initial "spring" breeding type.

Photochemical cycle of bacteriorhodopsin studied by resonance Raman spectroscopy.

Science.gov (United States)

Stockburger, M; Klusmann, W; Gattermann, H; Massig, G; Peters, R

1979-10-30

Individual species of the photochemical cycle of bacteriorhodopsin, a retinal-protein complex of Halobacteria, were studied in aqueous suspensions of the "purple membrane" at room temperature by resonance Raman (RR) spectroscopy with flow systems. Two pronounced deuterium shifts were found in the RR spectra of the all-trans complex BR-570 in H2O-D2O suspensions. The first is ascribed to C=NH+ (C=ND+) stretching vibrations of the protonated Schiff base which links retinal to opsin. The second is assigned tentatively to an "X-H" ("X-D") bending mode, where "X" is an atom which carries an exchangeable proton. A RR spectrum of the 13-cis-retinal complex "BR-548" could be deduced from spectra of the dark-adapted purple membrane. The RR spectrum of the M-412 intermediate was monitored in a double-beam pump-probe experiment. The main vibrational features of the intermediate M' in the reaction M-412 in equilibrium hv M' leads to delta BR-570 could be deduced from a photostationary mixture of M-412 and M'. Difference procedures were applied to obtain RR spectra of the L-550 intermediate and of two new long-lived species, R1'-590 and R2-550. From kinetic data it is suggested that T1'-590 links the proton-translocating cycle to the "13-cis" cycle of BR-548. The protonation and isomeric states of the different species are discussed in light of the new spectroscopic and kinetic data. It is found that conformational changes during the photochemical cycle play an important role.

Global Metabolic Regulation of the Snow Alga Chlamydomonas nivalis in Response to Nitrate or Phosphate Deprivation by a Metabolome Profile Analysis.

Science.gov (United States)

Lu, Na; Chen, Jun-Hui; Wei, Dong; Chen, Feng; Chen, Gu

2016-05-10

In the present work, Chlamydomonas nivalis, a model species of snow algae, was used to illustrate the metabolic regulation mechanism of microalgae under nutrient deprivation stress. The seed culture was inoculated into the medium without nitrate or phosphate to reveal the cell responses by a metabolome profile analysis using gas chromatography time-of-flight mass spectrometry (GC/TOF-MS). One hundred and seventy-one of the identified metabolites clustered into five groups by the orthogonal partial least squares discriminant analysis (OPLS-DA) model. Among them, thirty of the metabolites in the nitrate-deprived group and thirty-nine of the metabolites in the phosphate-deprived group were selected and identified as "responding biomarkers" by this metabolomic approach. A significant change in the abundance of biomarkers indicated that the enhanced biosynthesis of carbohydrates and fatty acids coupled with the decreased biosynthesis of amino acids, N-compounds and organic acids in all the stress groups. The up- or down-regulation of these biomarkers in the metabolic network provides new insights into the global metabolic regulation and internal relationships within amino acid and fatty acid synthesis, glycolysis, the tricarboxylic acid cycle (TCA) and the Calvin cycle in the snow alga under nitrate or phosphate deprivation stress.

Natriuretic peptide receptor A inhibition suppresses gastric cancer development through reactive oxygen species-mediated G2/M cell cycle arrest and cell death.

Science.gov (United States)

Li, Zheng; Wang, Ji-Wei; Wang, Wei-Zhi; Zhi, Xiao-Fei; Zhang, Qun; Li, Bo-Wen; Wang, Lin-Jun; Xie, Kun-Ling; Tao, Jin-Qiu; Tang, Jie; Wei, Song; Zhu, Yi; Xu, Hao; Zhang, Dian-Cai; Yang, Li; Xu, Ze-Kuan

2016-10-01

Natriuretic peptide receptor A (NPRA), the major receptor for atrial natriuretic peptide (ANP), has been implicated in tumorigenesis; however, the role of ANP-NPRA signaling in the development of gastric cancer remains unclear. Immunohistochemical analyses indicated that NPRA expression was positively associated with gastric tumor size and cancer stage. NPRA inhibition by shRNA induced G2/M cell cycle arrest, cell death, and autophagy in gastric cancer cells, due to accumulation of reactive oxygen species (ROS). Either genetic or pharmacologic inhibition of autophagy led to caspase-dependent cell death. Therefore, autophagy induced by NPRA silencing may represent a cytoprotective mechanism. ROS accumulation activated c-Jun N-terminal kinase (JNK) and AMP-activated protein kinase (AMPK). ROS-mediated activation of JNK inhibited cell proliferation by disturbing cell cycle and decreased cell viability. In addition, AMPK activation promoted autophagy in NPRA-downregulated cancer cells. Overall, our results indicate that the inhibition of NPRA suppresses gastric cancer development and targeting NPRA may represent a promising strategy for the treatment of gastric cancer. Copyright © 2016 Elsevier Inc. All rights reserved.

Molecular Epidemiology of Fonsecaea Species

NARCIS (Netherlands)

Najafzadeh, M.J.; Sun, J.; Vicente, V.A.; Klaassen, C.H.W.; Bonifaz, A.; Gerrits van den Ende, A.H.G.; Menken, S.B.J.; de Hoog, G.S.

2011-01-01

To assess population diversities among 81 strains of fungi in the genus Fonsecaea that had been identified down to species level, we applied amplified fragment-length polymorphism (AFLP) technology and sequenced the internal transcribed spacer regions and the partial cell division cycle, β-tubulin,

Concentration-dependent induction of reactive oxygen species, cell cycle arrest and apoptosis in human liver cells after nickel nanoparticles exposure.

Science.gov (United States)

Ahmad, Javed; Alhadlaq, Hisham A; Siddiqui, Maqsood A; Saquib, Quaiser; Al-Khedhairy, Abdulaziz A; Musarrat, Javed; Ahamed, Maqusood

2015-02-01

Due to advent of nanotechnology, nickel nanoparticles (Ni NPs) are increasingly recognized for their utility in various applications including catalysts, sensors and electronics. However, the environmental and human health effects of Ni NPs have not been fully investigated. In this study, we examined toxic effects of Ni NPs in human liver (HepG2) cells. Ni NPs were prepared and characterized by X-ray diffraction, transmission electron microscopy and dynamic light scattering. We observed that Ni NPs (size, ∼28 nm; concentration range, 25-100 μg/mL) induced cytotoxicity in HepG2 cells and degree of induction was concentration-dependent. Ni NPs were also found to induce oxidative stress in dose-dependent manner evident by induction of reactive oxygen species and depletion of glutathione. Cell cycle analysis of cells treated with Ni NPs exhibited significant increase of apoptotic cell population in subG1 phase. Ni NPs also induced caspase-3 enzyme activity and apoptotic DNA fragmentation. Upregulation of cell cycle checkpoint gene p53 and bax/bcl-2 ratio with a concomitant loss in mitochondrial membrane potential suggested that Ni NPs induced apoptosis in HepG2 cells was mediated through mitochondrial pathway. This study warrants that applications of Ni NPs should be carefully assessed as to their toxicity to human health. © 2013 Wiley Periodicals, Inc.

[Influence of PCR cycle number on microbial diversity analysis through next generation sequencing].

Science.gov (United States)

An, Yunhe; Gao, Lijuan; Li, Junbo; Tian, Yanjie; Wang, Jinlong; Zheng, Xuejuan; Wu, Huijuan

2016-08-25

Using of high throughput sequencing technology to study the microbial diversity in complex samples has become one of the hottest issues in the field of microbial diversity research. In this study, the soil and sheep rumen chyme samples were used to extract DNA, respectively. Then the 25 ng total DNA was used to amplify the 16S rRNA V3 region with 20, 25, 30 PCR cycles, and the final sequencing library was constructed by mixing equal amounts of purified PCR products. Finally, the operational taxonomic unit (OUT) amount, rarefaction curve, microbial number and species were compared through data analysis. It was found that at the same amount of DNA template, the proportion of the community composition was not the best with more numbers of PCR cycle, although the species number was much more. In all, when the PCR cycle number is 25, the number of species and proportion of the community composition were the most optimal both in soil or chyme samples.

A yeast pheromone-based inter-species communication system.

Science.gov (United States)

Hennig, Stefan; Clemens, André; Rödel, Gerhard; Ostermann, Kai

2015-02-01

We report on a pheromone-based inter-species communication system, allowing for a controlled cell-cell communication between the two species Saccharomyces cerevisiae and Schizosaccharomyces pombe as a proof of principle. It exploits the mating response pathways of the two yeast species employing the pheromones, α- or P-factor, as signaling molecules. The authentic and chimeric pheromone-encoding genes were engineered to code for the P-factor in S. cerevisiae and the α-factor in S. pombe. Upon transformation of the respective constructs, cells were enabled to express the mating pheromone of the opposite species. The supernatant of cultures of S. pombe cells expressing α-factor were able to induce a G1 arrest in the cell cycle, a change in morphology to the typical shmoo effect and expression driven by the pheromone-responsive FIG1 promoter in S. cerevisiae. The supernatant of cultures of S. cerevisiae cells expressing P-factor similarly induced cell cycle arrest in G1, an alteration in morphology typical for mating as well as the activation of the pheromone-responsive promoters of the rep1 and sxa2 genes in a pheromone-hypersensitive reporter strain of S. pombe. Apparently, both heterologous pheromones were correctly processed and secreted in an active form by the cells of the other species. Our data clearly show that the species-specific pheromone systems of yeast species can be exploited for a controlled inter-species communication.

Electrofishing power requirements in relation to duty cycle

Science.gov (United States)

Miranda, L.E.; Dolan, C.R.

2004-01-01

Under controlled laboratory conditions we measured the electrical peak power required to immobilize (i.e., narcotize or tetanize) fish of various species and sizes with duty cycles (i.e., percentage of time a field is energized) ranging from 1.5% to 100%. Electrofishing effectiveness was closely associated with duty cycle. Duty cycles of 10-50% required the least peak power to immobilize fish; peak power requirements increased gradually above 50% duty cycle and sharply below 10%. Small duty cycles can increase field strength by making possible higher instantaneous peak voltages that allow the threshold power needed to immobilize fish to radiate farther away from the electrodes. Therefore, operating within the 10-50% range of duty cycles would allow a larger radius of immobilization action than operating with higher duty cycles. This 10-50% range of duty cycles also coincided with some of the highest margins of difference between the electrical power required to narcotize and that required to tetanize fish. This observation is worthy of note because proper use of duty cycle could help reduce the mortality associated with tetany documented by some authors. Although electrofishing with intermediate duty cycles can potentially increase effectiveness of electrofishing, our results suggest that immobilization response is not fully accounted for by duty cycle because of a potential interaction between pulse frequency and duration that requires further investigation.

A Short-Term Advantage for Syngamy in the Origin of Eukaryotic Sex: Effects of Cell Fusion on Cell Cycle Duration and Other Effects Related to the Duration of the Cell Cycle—Relationship between Cell Growth Curve and the Optimal Size of the Species, and Circadian Cell Cycle in Photosynthetic Unicellular Organisms

Science.gov (United States)

Mancebo Quintana, J. M.; Mancebo Quintana, S.

2012-01-01

The origin of sex is becoming a vexatious issue for Evolutionary Biology. Numerous hypotheses have been proposed, based on the genetic effects of sex, on trophic effects or on the formation of cysts and syncytia. Our approach addresses the change in cell cycle duration which would cause cell fusion. Several results are obtained through graphical and mathematical analysis and computer simulations. (1) In poor environments, cell fusion would be an advantageous strategy, as fusion between cells of different size shortens the cycle of the smaller cell (relative to the asexual cycle), and the majority of mergers would occur between cells of different sizes. (2) The easiest-to-evolve regulation of cell proliferation (sexual/asexual) would be by modifying the checkpoints of the cell cycle. (3) A regulation of this kind would have required the existence of the G2 phase, and sex could thus be the cause of the appearance of this phase. Regarding cell cycle, (4) the exponential curve is the only cell growth curve that has no effect on the optimal cell size in unicellular species; (5) the existence of a plateau with no growth at the end of the cell cycle explains the circadian cell cycle observed in unicellular algae. PMID:22666626

Calvin’s modification of Augustine’s doctrine of original sin

Directory of Open Access Journals (Sweden)

N. Vorster

2010-07-01

Full Text Available Augustine was Calvin’s main source of reference in the “Insti- tutes”. However, his treatment of Augustine’s views was not uncritical. This article discusses the way in which Calvin modi- fied Augustine’s doctrine of original sin. The main differences can be attributed to different theological aims. Augustine deve- loped his doctrine of original sin against the teachings of the Manicheans and Pelagians, whereas Calvin shifted the focus to knowledge of God and the self. Calvin understood original sin noetically as religious and moral blindness – whereas Augus- tine viewed sexual concupiscence as the main principle of original sin. Augustine made a considerable effort to explain that sin does not find its origin in God. God foresaw the fall, but did not compel it. Calvin located sin in God’s eternal decree and permission. Augustine, furthermore, understood the transmis- sion of original sin biologically, whereas Calvin ascribed it to God’s eternal permissive will. These differences culminated in a different understanding of the meaning of Jesus’ virgin birth. The article concludes by discussing the relevance of Calvin’s noetic approach to original sin.

Julma USA sõdurit ootab elu vanglas / Evelyn Kaldoja

Index Scriptorium Estoniae

Kaldoja, Evelyn, 1980-

2011-01-01

USA sõjavägi hakkab mõistma kohut veebel Calvin Gibbsi üle, keda peetakse afgaani tsiviilisikuid tapnud ja ohvrite laipu rüvetanud jõugu eestvedajaks. Calvin Gibbs eitab kõiki talle esitatud süüdistusi

Cell cycle gene expression networks discovered using systems biology: Significance in carcinogenesis

Science.gov (United States)

Scott, RE; Ghule, PN; Stein, JL; Stein, GS

2015-01-01

The early stages of carcinogenesis are linked to defects in the cell cycle. A series of cell cycle checkpoints are involved in this process. The G1/S checkpoint that serves to integrate the control of cell proliferation and differentiation is linked to carcinogenesis and the mitotic spindle checkpoint with the development of chromosomal instability. This paper presents the outcome of systems biology studies designed to evaluate if networks of covariate cell cycle gene transcripts exist in proliferative mammalian tissues including mice, rats and humans. The GeneNetwork website that contains numerous gene expression datasets from different species, sexes and tissues represents the foundational resource for these studies (www.genenetwork.org). In addition, WebGestalt, a gene ontology tool, facilitated the identification of expression networks of genes that co-vary with key cell cycle targets, especially Cdc20 and Plk1 (www.bioinfo.vanderbilt.edu/webgestalt). Cell cycle expression networks of such covariate mRNAs exist in multiple proliferative tissues including liver, lung, pituitary, adipose and lymphoid tissues among others but not in brain or retina that have low proliferative potential. Sixty-three covariate cell cycle gene transcripts (mRNAs) compose the average cell cycle network with p = e−13 to e−36. Cell cycle expression networks show species, sex and tissue variability and they are enriched in mRNA transcripts associated with mitosis many of which are associated with chromosomal instability. PMID:25808367

77 FR 53248 - Culturally Significant Objects Imported for Exhibition Determinations: “Swiss Treasures: From...

Science.gov (United States)

2012-08-31

... DEPARTMENT OF STATE [Public Notice 8004] Culturally Significant Objects Imported for Exhibition Determinations: ``Swiss Treasures: From Biblical Papyrus and Parchment to Erasmus, Zwingli, Calvin, and Barth... Parchment to Erasmus, Zwingli, Calvin, and Barth,'' imported from abroad for temporary exhibition within the...

Materials to the Zygnemaceae of Poland. I. Development cycle and supplementation of diagnosis of Zygnema allorgei Gauthier-Lievre 1965, a species new for the European flora

Directory of Open Access Journals (Sweden)

Joanna Z. Kadłubowska

2014-01-01

Full Text Available In the water sample taken on September 7, 1976 from the pond in Głowno (Łódź District filaments of Zygnema were found in vegetative stage. In culture a full development cycle of this alga was observed: vegetative filaments, conjugation, zygotes and their germination. The taxon was identified as Zygnema allorgei Gauthier-Lievre. Its diagnosis was supplemented. It is the second site of occurance of the species in the world. Z. allorgei was described for the first time in 1965 in Algeria.

The Genome of Deep-Sea Vent Chemolithoautotroph Thiomicrospiracrunogena XCL-2

Energy Technology Data Exchange (ETDEWEB)

Scott, Kathleen M.; Sievert, Stefan M.; Abril, Fereniki N.; Ball,Lois A.; Barrett, Chantell J.; Blake, Rodrigo A.; Boller, Amanda J.; Chain, Patrick S.G.; Clark, Justine A.; Davis, Carisa R.; Detter, Chris; Do, Kimberly F.; Dobrinski, Kimberly P.; Faza, BrandonI.; Fitzpatrick,Kelly A.; Freyermuth, Sharyn K.; Harmer, Tara L.; Hauser, Loren J.; Hugler, Michael; Kerfeld, Cheryl A.; Klotz, Martin G.; Kong, William W.; Land, Miriam; Lapidus, Alla; Larimer, Frank W.; Longo, Dana L.; Lucas,Susan; Malfatti, Stephanie A.; Massey, Steven E.; Martin, Darlene D.; McCuddin, Zoe; Meyer, Folker; Moore, Jessica L.; Ocampo, Luis H.; Paul,John H.; Paulsen, Ian T.; Reep, Douglas K.; Ren, Qinghu; Ross, Rachel L.; Sato, Priscila Y.; Thomas, Phaedra; Tinkham, Lance E.; Zeruth, Gary T.

2006-08-23

Presented here is the complete genome sequence ofThiomicrospira crunogena XCL-2, representative of ubiquitouschemolithoautotrophic sulfur-oxidizing bacteria isolated from deep-seahydrothermal vents. This gammaproteobacterium has a single chromosome(2,427,734 bp), and its genome illustrates many of the adaptations thathave enabled it to thrive at vents globally. It has 14 methyl-acceptingchemotaxis protein genes, including four that may assist in positioningit in the redoxcline. A relative abundance of CDSs encoding regulatoryproteins likely control the expression of genes encoding carboxysomes,multiple dissolved inorganic nitrogen and phosphate transporters, as wellas a phosphonate operon, which provide this species with a variety ofoptions for acquiring these substrates from the environment. T. crunogenaXCL-2 is unusual among obligate sulfur oxidizing bacteria in relying onthe Sox system for the oxidation of reduced sulfur compounds. A 38 kbprophage is present, and a high level of prophage induction was observed,which may play a role in keeping competing populations of close relativesin check. The genome has characteristics consistent with an obligatelychemolithoautotrophic lifestyle, including few transporters predicted tohave organic allocrits, and Calvin-Benson-Bassham cycle CDSs scatteredthroughout the genome.

Female reproductive cycles of wild female felids.

Science.gov (United States)

Brown, Janine L

2011-04-01

Many felid species are endangered because of destructive human activities. As a result, zoos are being tasked with sustaining genetically healthy populations in case of catastrophic extinctions. Unfortunately, with the exception of a few species, most felids do not reproduce well in captivity. The ability to track reproductive activity via hormones is key to developing successful ex situ breeding programs. Through the development of noninvasive fecal hormone monitoring techniques, a high degree of variability in estrous cycle characteristics has been found to exist across the taxon, including the type of ovulation. For example, although all felids have induced ovulations, the occurrence of spontaneous ovulations varies across species, and even between individuals within a species. Clouded leopards, fishing cats and margays frequently have spontaneous ovulations, whereas these are rarely observed in the cheetah, tigrina and ocelot. There are marked species differences in the impact of season on reproductive function, with some being exquisitely sensitive to photoperiod (e.g., Pallas' cat), some moderately affected (tiger, clouded leopard, snow leopard), and others that are not influenced at all (e.g., ocelot, tigrina, margay, lion, leopard, fishing cat). One of the greatest challenges remaining is overcoming the problems associated with highly variable ovarian responses to ovulation induction therapies used with assisted reproductive procedures, like artificial insemination (AI). Success is relatively high in the cheetah and ocelot, but few pregnancies have resulted after AI in clouded leopard, fishing cat and tiger. Current knowledge of the reproductive physiology of nondomestic felids, including aspects of the anatomy, behavior and ovarian cycles will be presented, and how the rapidly growing endocrine database is aiding ex situ management efforts. Published by Elsevier B.V.

Validation Test Report For The CRWMS Analysis and Logistics Visually Interactive Model Version 3.0, 10074-Vtr-3.0-00

International Nuclear Information System (INIS)

Gillespie, S.

2000-01-01

This report describes the tests performed to validate the CRWMS ''Analysis and Logistics Visually Interactive'' Model (CALVIN) Version 3.0 (V3.0) computer code (STN: 10074-3.0-00). To validate the code, a series of test cases was developed in the CALVIN V3.0 Validation Test Plan (CRWMS M and O 1999a) that exercises the principal calculation models and options of CALVIN V3.0. Twenty-five test cases were developed: 18 logistics test cases and 7 cost test cases. These cases test the features of CALVIN in a sequential manner, so that the validation of each test case is used to demonstrate the accuracy of the input to subsequent calculations. Where necessary, the test cases utilize reduced-size data tables to make the hand calculations used to verify the results more tractable, while still adequately testing the code's capabilities. Acceptance criteria, were established for the logistics and cost test cases in the Validation Test Plan (CRWMS M and O 1999a). The Logistics test cases were developed to test the following CALVIN calculation models: Spent nuclear fuel (SNF) and reactivity calculations; Options for altering reactor life; Adjustment of commercial SNF (CSNF) acceptance rates for fiscal year calculations and mid-year acceptance start; Fuel selection, transportation cask loading, and shipping to the Monitored Geologic Repository (MGR); Transportation cask shipping to and storage at an Interim Storage Facility (ISF); Reactor pool allocation options; and Disposal options at the MGR. Two types of cost test cases were developed: cases to validate the detailed transportation costs, and cases to validate the costs associated with the Civilian Radioactive Waste Management System (CRWMS) Management and Operating Contractor (M and O) and Regional Servicing Contractors (RSCs). For each test case, values calculated using Microsoft Excel 97 worksheets were compared to CALVIN V3.0 scenarios with the same input data and assumptions. All of the test case results compare with

Heaoluühiskond kui luterluse tagajärg: Welfare Society as a Consequence of Lutheranism

DEFF Research Database (Denmark)

Põder, Johann-Christian

2018-01-01

Essay on Max Weber, Calvinism and Capitalism, Lutheranism and the modern Welfare State Opinion Section of the Estonian Public Broadcasting/TV......Essay on Max Weber, Calvinism and Capitalism, Lutheranism and the modern Welfare State Opinion Section of the Estonian Public Broadcasting/TV...

Novel forests maintain ecosystem processes after the decline of native tree species

Science.gov (United States)

Joseph Mascaro; Flint Hughes; Stefan A. Schnitzer

2012-01-01

The positive relationship between species diversity (richness and evenness) and critical ecosystem functions, such as productivity, carbon storage, and nutrient cycling, is often used to predict the consequences of extinction. At regional scales, however, plant species richness is mostly increasing rather than decreasing because successful plant species introductions...

Functional interrogation of Plasmodium genus metabolism identifies species- and stage-specific differences in nutrient essentiality and drug targeting.

Directory of Open Access Journals (Sweden)

Alyaa M Abdel-Haleem

2018-01-01

Full Text Available Several antimalarial drugs exist, but differences between life cycle stages among malaria species pose challenges for developing more effective therapies. To understand the diversity among stages and species, we reconstructed genome-scale metabolic models (GeMMs of metabolism for five life cycle stages and five species of Plasmodium spanning the blood, transmission, and mosquito stages. The stage-specific models of Plasmodium falciparum uncovered stage-dependent changes in central carbon metabolism and predicted potential targets that could affect several life cycle stages. The species-specific models further highlight differences between experimental animal models and the human-infecting species. Comparisons between human- and rodent-infecting species revealed differences in thiamine (vitamin B1, choline, and pantothenate (vitamin B5 metabolism. Thus, we show that genome-scale analysis of multiple stages and species of Plasmodium can prioritize potential drug targets that could be both anti-malarials and transmission blocking agents, in addition to guiding translation from non-human experimental disease models.

Functional interrogation of Plasmodium genus metabolism identifies species- and stage-specific differences in nutrient essentiality and drug targeting

KAUST Repository

Abdel-Haleem, Alyaa M.

2018-01-04

Several antimalarial drugs exist, but differences between life cycle stages among malaria species pose challenges for developing more effective therapies. To understand the diversity among stages and species, we reconstructed genome-scale models (GEMs) of metabolism for five life cycle stages and five species of Plasmodium spanning the blood, transmission, and mosquito stages. The stage-specific models of Plasmodium falciparum uncovered stage-dependent changes in central carbon metabolism and predicted potential targets that could affect several life cycle stages. The species-specific models further highlight differences between experimental animal models and the human-infecting species. Comparisons between human- and rodent-infecting species revealed differences in thiamine (vitamin B1), choline, and pantothenate (vitamin B5) metabolism. Thus, we show that genome-scale analysis of multiple stages and species of Plasmodium can prioritize potential drug targets that could be both anti-malarials and transmission blocking agents, in addition to guiding translation from non-human experimental disease models.

Super-performance in a palm species

NARCIS (Netherlands)

Jansen, Merel

2016-01-01

The world is changing rapidly due to anthropogenic disturbance. Effects include: global warming, massive pollution, a changed global nitrogen cycle, high rates of land-use change, and exotic species spread. This has a tremendous impact on both natural and agricultural systems. To understand these

Cyanobacterial carbon metabolism: Fluxome plasticity and oxygen dependence: Cyanobacterial Carbon Metabolism

Energy Technology Data Exchange (ETDEWEB)

Wan, Ni [Washington Univ., St. Louis, MO (United States); DeLorenzo, Drew M. [Washington Univ., St. Louis, MO (United States); He, Lian [Washington Univ., St. Louis, MO (United States); You, Le [Washington Univ., St. Louis, MO (United States); Immethun, Cheryl M. [Washington Univ., St. Louis, MO (United States); Wang, George [Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Baidoo, Edward E. K. [Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Hollinshead, Whitney [Washington Univ., St. Louis, MO (United States); Keasling, Jay D. [Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States); Technical Univ. of Denmark, Lyngby (Denmark); Moon, Tae Seok [Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis Missouri 63130; Tang, Yinjie J. [Washington Univ., St. Louis, MO (United States)

2017-03-30

Synechocystis sp. strain PCC 6803 has been widely used as a photo-biorefinery chassis. Based on its genome annotation, this species contains a complete TCA cycle, an Embden-Meyerhof-Parnas pathway (EMPP), an oxidative pentose phosphate pathway (OPPP), and an Entner–Doudoroff pathway (EDP). To evaluate how Synechocystis 6803 catabolizes glucose under heterotrophic conditions, we performed ¹³C metabolic flux analysis, metabolite pool size analysis, gene knockouts, and heterologous expressions. The results revealed a cyclic mode of flux through the OPPP. Small, but non-zero, fluxes were observed through the TCA cycle and the malic shunt. Independent knockouts of 6-phosphogluconate dehydrogenase (gnd) and malic enzyme (me) corroborated these results, as neither mutant could grow under dark heterotrophic conditions. Our data also indicate that Synechocystis 6803 metabolism relies upon oxidative phosphorylation to generate ATP from NADPH under dark or insufficient light conditions. The pool sizes of intermediates in the TCA cycle, particularly acetyl-CoA, were found to be several fold lower in Synechocystis 6803 (compared to E. coli metabolite pool sizes), while its sugar phosphate intermediates were several-fold higher. Moreover, negligible flux was detected through the native, or heterologous, EDP in the wild type or Δgnd strains under heterotrophic conditions. Comparing photoautotrophic, photomixotrophic, and heterotrophic conditions, the Calvin cycle, OPPP, and EMPP in Synechocystis 6803 possess the ability to regulate their fluxes under various growth conditions (plastic), whereas its TCA cycle always maintains at low levels (rigid). This work also demonstrates how genetic profiles do not always reflect actual metabolic flux through native or heterologous pathways. Biotechnol. Bioeng. 2017;114: 1593–1602. © 2017 Wiley Periodicals, Inc.

On the surprising lack of differences between two congeneric calanoid copepod species, Calanus finmarchicus and C. helgolandicus

Science.gov (United States)

Wilson, Robert J.; Speirs, Douglas C.; Heath, Michael R.

2015-05-01

The important calanoid copepod species Calanus finmarchicus and C. helgolandicus have distinct geographic ranges which are changing under the influence of climate change. Understanding the mechanisms underlying their distributions is becoming increasingly important as a result of the possible ecological impacts of these range shifts. Here we review inter-species differences in key life cycle traits that influence each species' geographic distribution, in particular development and growth, fecundity, feeding behaviour, vertical migration and overwintering behaviour. The distinct temperature niche of each species leads to an a priori assumption that the response of life cycle traits to temperature is a key determinant of their contrasting geographic distributions. A new development model was created to reconcile published experimental development times for each species. Model output indicates that at temperatures below approximately 12-13 °C, C. finmarchicus is the faster developing species, but above these temperatures C. helgolandicus develops more quickly. Conventionally Calanus development time is assumed to decrease monotonically with temperature; however our model indicates that the response of development time to temperature is instead U-shaped. Differences in life cycle aspects such as seasonality and vertical structuring are interpreted in light of this development model. Body size and lipid accumulation abilities could be significant influences on each species' geographic distribution; however evidence is consistent with inter-species differences not existing for these traits. Published evidence shows that inter-species differences in egg production may exist, but do not follow a clear pattern. Diapause is an important and well studied life cycle adaptation of C. finmarchicus, but has received little attention in C. helgolandicus. We reviewed knowledge of diapause and suggest the hypothesis that C. helgolandicus is restricted to continental shelf regions

Implementation An image processing technique for video motion analysis during the gait cycle canine

Science.gov (United States)

López, G.; Hernández, J. O.

2017-01-01

Nowadays the analyses of human movement, more specifically of the gait have ceased to be a priority for our species. Technological advances and implementations engineering have joined to obtain data and information regarding the gait cycle in another animal species. The aim of this paper is to analyze the canine gait in order to get results that describe the behavior of the limbs during the gait cycle. The research was performed by: 1. Dog training, where it is developed the step of adaptation and trust; 2. Filming gait cycle; 3. Data acquisition, in order to obtain values that describe the motion cycle canine and 4. Results, obtaining the kinematics variables involved in the march. Which are essential to determine the behavior of the limbs, as well as for the development of prosthetic or orthotic. This project was carried out with conventional equipment and using computational tools easily accessible.

UTILITY OF A FULL LIFE-CYCLE COPEPOD BIOASSAY APPROACH FOR ASSESSMENT OF SEDIMENT-ASSOCIATED CONTAMINANT MIXTURES. (R825279)

Science.gov (United States)

AbstractWe compared a 21 day full life-cycle bioassay with an existing 14 day partial life-cycle bioassay for two species of meiobenthic copepods, Microarthridion littorale and Amphiascus tenuiremis. We hypothesized that full life-cycle tests would bette...

Cell cycle arrest and cell survival induce reverse trends of cardiolipin remodeling.

Directory of Open Access Journals (Sweden)

Yu-Jen Chao

Full Text Available Cell survival from the arrested state can be a cause of the cancer recurrence. Transition from the arrest state to the growth state is highly regulated by mitochondrial activity, which is related to the lipid compositions of the mitochondrial membrane. Cardiolipin is a critical phospholipid for the mitochondrial integrity and functions. We examined the changes of cardiolipin species by LC-MS in the transition between cell cycle arrest and cell reviving in HT1080 fibrosarcoma cells. We have identified 41 cardiolipin species by MS/MS and semi-quantitated them to analyze the detailed changes of cardiolipin species. The mass spectra of cardiolipin with the same carbon number form an envelope, and the C64, C66, C68, C70 C72 and C74 envelopes in HT1080 cells show a normal distribution in the full scan mass spectrum. The cardiolipin quantity in a cell decreases while entering the cell cycle arrest, but maintains at a similar level through cell survival. While cells awakening from the arrested state and preparing itself for replication, the groups with short acyl chains, such as C64, C66 and C68 show a decrease of cardiolipin percentage, but the groups with long acyl chains, such as C70 and C72 display an increase of cardiolipin percentage. Interestingly, the trends of the cardiolipin species changes during the arresting state are completely opposite to cell growing state. Our results indicate that the cardiolipin species shift from the short chain to long chain cardiolipin during the transition from cell cycle arrest to cell progression.

The influence of day/night cycles on biomass yield and composition of Neochloris oleoabundans

NARCIS (Netherlands)

Winter, de Lenneke; Dominguez Teles, Iago; Martens, Dirk E.; Wijffels, René H.; Barbosa, Maria J.

2017-01-01

Background: Day/night cycles regulate the circadian clock of organisms to program daily activities. Many species of microalgae have a synchronized cell division when grown under a day/night cycle, and synchronization might influence biomass yield and composition. Therefore, the aim of this study

Mammalian cycles: internally defined periods and interaction-driven amplitudes

Directory of Open Access Journals (Sweden)

LR Ginzburg

2015-08-01

Full Text Available The cause of mammalian cycles—the rise and fall of populations over a predictable period of time—has remained controversial since these patterns were first observed over a century ago. In spite of extensive work on observable mammalian cycles, the field has remained divided upon what the true cause is, with a majority of opinions attributing it to either predation or to intra-species mechanisms. Here we unite the eigenperiod hypothesis, which describes an internal, maternal effect-based mechanism to explain the cycles’ periods with a recent generalization explaining the amplitude of snowshoe hare cycles in northwestern North America based on initial predator abundance. By explaining the period and the amplitude of the cycle with separate mechanisms, a unified and consistent view of the causation of cycles is reached. Based on our suggested theory, we forecast the next snowshoe hare cycle (predicted peak in 2016 to be of extraordinarily low amplitude.

Lipids as paleomarkers to constrain the marine nitrogen cycle.

Science.gov (United States)

Rush, Darci; Sinninghe Damsté, Jaap S

2017-06-01

Global climate is, in part, regulated by the effect of microbial processes on biogeochemical cycling. The nitrogen cycle, in particular, is driven by microorganisms responsible for the fixation and loss of nitrogen, and the reduction-oxidation transformations of bio-available nitrogen. Within marine systems, nitrogen availability is often the limiting factor in the growth of autotrophic organisms, intrinsically linking the nitrogen and carbon cycles. In order to elucidate the state of these cycles in the past, and help envisage present and future variability, it is essential to understand the specific microbial processes responsible for transforming bio-available nitrogen species. As most microorganisms are soft-bodied and seldom leave behind physical fossils in the sedimentary record, recalcitrant lipid biomarkers are used to unravel microbial processes in the geological past. This review emphasises the recent advances in marine nitrogen cycle lipid biomarkers, underlines the missing links still needed to fully elucidate past shifts in this biogeochemically-important cycle, and provides examples of biomarker applications in the geological past. © 2017 The Authors. Environmental Microbiology published by Society for Applied Microbiology and John Wiley & Sons Ltd.

From Calvin to Spinoza

DEFF Research Database (Denmark)

Albertsen, Niels

2005-01-01

Max Weber employed the concept of a spirit of capitalism only in the context of the historical emergence of modern capitalism. Following Luc Boltanski and Ève Chiapello this article presents a transformed concept that applies also to established capitalisms. The concept includes justificatory...... their argument, Spinoza is proposed as the grammarian. This implies the paradox that Spinoza, the philosopher of immanence, is turned into a grammarian of a transcendent order of worth. However, this paradox exactly preserves a central ingredient of Weber’s concept: transcendence....

Phase locking and multiple oscillating attractors for the coupled mammalian clock and cell cycle

NARCIS (Netherlands)

C. Feillet (Céline); C.A. Krusche; F. Tamanini (Filippo); R. Janssens (Roel); R.A. Downey (Roger); P. Martin (Patrick); J.L. Teboul (Jean Louis); S. Saito (Seiji); F.A. Lévi (Francis); T. Bretschneider (Till); G.T.J. van der Horst (Gijsbertus); F. Delaunay (Franck); D.A. Rand (David)

2014-01-01

textabstractDaily synchronous rhythms of cell division at the tissue or organism level are observed in many species and suggest that the circadian clock and cell cycle oscillators are coupled. For mammals, despite known mechanistic interactions, the effect of such coupling on clock and cell cycle

Molecular machinery of signal transduction and cell cycle regulation in Plasmodium.

Science.gov (United States)

Koyama, Fernanda C; Chakrabarti, Debopam; Garcia, Célia R S

2009-05-01

The regulation of the Plasmodium cell cycle is not understood. Although the Plasmodium falciparum genome is completely sequenced, about 60% of the predicted proteins share little or no sequence similarity with other eukaryotes. This feature impairs the identification of important proteins participating in the regulation of the cell cycle. There are several open questions that concern cell cycle progression in malaria parasites, including the mechanism by which multiple nuclear divisions is controlled and how the cell cycle is managed in all phases of their complex life cycle. Cell cycle synchrony of the parasite population within the host, as well as the circadian rhythm of proliferation, are striking features of some Plasmodium species, the molecular basis of which remains to be elucidated. In this review we discuss the role of indole-related molecules as signals that modulate the cell cycle in Plasmodium and other eukaryotes, and we also consider the possible role of kinases in the signal transduction and in the responses it triggers.

Revisiting the ants of Melanesia and the taxon cycle: historical and human-mediated invasions of a tropical archipelago.

Science.gov (United States)

Economo, Evan P; Sarnat, Eli M

2012-07-01

Understanding the historical evolution of biotas and the dynamics of contemporary human-mediated species introductions are two central tasks of biology. One hypothesis may address both-the taxon cycle. Taxon cycles are phases of range expansion and contraction coupled to ecological and evolutionary niche shifts. These historical invasion processes resemble human-mediated invasions in pattern and possibly mechanism, but both the existence of historical cycles and the roles of recent introductions are in question. We return to the system that originally inspired the taxon cycle-Melanesian ants-and perform novel tests of the hypothesis. We analyze (i) the habitat distributions of Fiji's entire ant fauna (183 species), (ii) ecological shifts associated with the in situ radiation of Fijian Pheidole in a phylogenetic context, and (iii) the ecological structure of a massive exotic ant invasion of the archipelago. Our analyses indicate lineages shift toward primary habitats, higher elevation, rarity, and ecological specialization with increasing level of endemism, consistent with taxon cycle predictions. The marginal habitats that historically formed a dispersal conduit in the Pacific are now mostly replaced by human-modified habitats dominated by a colonization pulse of exotic species. We propose this may represent the first phase of an incipient global cycle of human-mediated colonization, ecological shifts, and diversification.

Krebs Cycle Intermediates Protective against Oxidative Stress by Modulating the Level of Reactive Oxygen Species in Neuronal HT22 Cells

Directory of Open Access Journals (Sweden)

Kenta Sawa

2017-03-01

Full Text Available Krebs cycle intermediates (KCIs are reported to function as energy substrates in mitochondria and to exert antioxidants effects on the brain. The present study was designed to identify which KCIs are effective neuroprotective compounds against oxidative stress in neuronal cells. Here we found that pyruvate, oxaloacetate, and α-ketoglutarate, but not lactate, citrate, iso-citrate, succinate, fumarate, or malate, protected HT22 cells against hydrogen peroxide-mediated toxicity. These three intermediates reduced the production of hydrogen peroxide-activated reactive oxygen species, measured in terms of 2′,7′-dichlorofluorescein diacetate fluorescence. In contrast, none of the KCIs—used at 1 mM—protected against cell death induced by high concentrations of glutamate—another type of oxidative stress-induced neuronal cell death. Because these protective KCIs did not have any toxic effects (at least up to 10 mM, they have potential use for therapeutic intervention against chronic neurodegenerative diseases.

Electron sub-cycling in particle simulation of plasma

International Nuclear Information System (INIS)

Adam, J.C.; Serveniere, A.G.; Langdon, A.B.

1982-01-01

A straightforward modification which reduces by half the computational cost of standard particle-in-cell algorithms for simulation of plasmas is described. The saving is obtained by integrating only the electrons through a number of time steps (sub-cycle) in order to resolve their evolution, while integrating the much slower ions only once per cycle, i.e., to match the time step of each species to their characteristic frequencies. A dispersion relation is derived which describes the numerical instabilities expected by sampling frequency arguments. Simulations support the broad features of the analytical results, viz., the maximum growth rate and domain of the instability, and its stabilization by the addition of weak damping. An implicit sub-cycling algorithm is suggested which may provide further saving while avoiding a limitation of implicit algorithms described elsewhere

PO2 Cycling Reduces Diaphragm Fatigue by Attenuating ROS Formation

OpenAIRE

Zuo, Li; Diaz, Philip T.; Chien, Michael T.; Roberts, William J.; Kishek, Juliana; Best, Thomas M.; Wagner, Peter D.

2014-01-01

Prolonged muscle exposure to low PO2 conditions may cause oxidative stress resulting in severe muscular injuries. We hypothesize that PO2 cycling preconditioning, which involves brief cycles of diaphragmatic muscle exposure to a low oxygen level (40 Torr) followed by a high oxygen level (550 Torr), can reduce intracellular reactive oxygen species (ROS) as well as attenuate muscle fatigue in mouse diaphragm under low PO2. Accordingly, dihydrofluorescein (a fluorescent probe) was used to monito...

Effects of Land Use Change on C-N cycling: Microbes Matter.

Science.gov (United States)

Hofmockel, K.

2012-12-01

Large swaths of the terrestrial landscape have been altered by human actions on Earth's biophysical systems, resulting in the homogenization of Earth's biota, while simultaneously increasing greenhouse gases and reactive nitrogen (N). This is especially poignant in grasslands that have been largely replaced by managed agricultural systems with substantial N inputs, or by unmanaged grasslands that are dominated by exotic species. Impacted ecosystems may be important for global C models, because they comprise a major portion of the global land area, terrestrial NPP and the world's soil C stocks. This research investigates how anthropogenic changes in plant community composition and agricultural management systems influence the composition and function of microbial communities that mediate key aspects of belowground C and N cycling and storage. Data from agroecology and grassland climate change experiments are used to illustrate how microbial responses can have important implications for large scale coupling of C and N cycles. In this study exotic plant species significantly decreased root inputs, causing shifts in microbial community composition, including both specific taxa and functional guilds of bacteria. By contrast, climate change (precipitation manipulation) caused functional responses (increased carbon and phosphorus cycling) that were not detected in the microbial community composition. Mycorrhizal fungi in managed systems were responsive to both root biomass and nitrogen inputs, significantly altering hydrolytic enzyme activity and aggregate turnover. Collectively small-scale processes can alter the ecosystem biogeochemical cycles. Together theses results suggest that linking microbial communities to coupled C-N cycles may have important implications for terrestrial C cycling feedbacks that are an integral part of the anthropocene era.

The seminiferous epithelium cycle and daily spermatic production in the adult maned wolf (Chrysocyon brachyurus, Illiger, 1811).

Science.gov (United States)

Bitencourt, Viviane Lewicki; de Paula, Tarcízio Antônio Rego; da Matta, Sérgio Luis Pinto; Fonseca, Cláudio César; dos Anjos Benjamin, Laércio; Costa, Deiler Sampaio

2007-01-01

The duration of the seminiferous epithelium cycle was estimated in adult maned wolves (Chrysocyon brachyurus, Illiger, 1811), by applying intratesticular injections with tritiated thymidine. The total duration of the seminiferous epithelium cycle in this species was calculated in 8.99 days. So, taking into account that approximately 4.5 cycles of the seminiferous epithelium are necessary for the whole spermatogenesis process to complete, the production of spermatozoa from one spermatogonia will take about 40.45 days. The duration of the spermiogenesis was calculated to be 12.3 days. The eight stages of the seminiferous epithelium cycle were described by the tubular morphology method, which is based either on the form and position of the spermatid nuclei and the occurrence of meiotic divisions. The values of the relative frequency for the pre-meiotic, meiotic and post-meiotic phases in this species were 3.5, 0.78 and 4.8 days, respectively. The maned wolf produces about 29 million spermatozoa a day for each testis gram, therefore being classified among the species provided with a high spermatogenetic efficiency.

The production of reactive oxygen species and the mitochondrial membrane potential are modulated during onion oil-induced cell cycle arrest and apoptosis in A549 cells.

Science.gov (United States)

Wu, Xin-jiang; Stahl, Thorsten; Hu, Ying; Kassie, Fekadu; Mersch-Sundermann, Volker

2006-03-01

Protective effects of Allium vegetables against cancers have been shown extensively in experimental animals and epidemiologic studies. We investigated cell proliferation and the induction of apoptosis by onion oil extracted from Allium cepa, a widely consumed Allium vegetable, in human lung cancer A549 cells. GC/MS analysis suggested that propyl sulfides but not allyl sulfides are major sulfur-containing constituents of onion oil. Onion oil at 12.5 mg/L significantly induced apoptosis (13% increase of apoptotic cells) as indicated by sub-G1 DNA content. It also caused cell cycle arrest at the G2/M phase; 25 mg/L onion oil increased the percentage of G2/M cells almost 6-fold compared with the dimethyl sulfoxide control. The action of onion oil may occur via a reactive oxygen species-dependent pathway because cell cycle arrest and apoptosis were blocked by the antioxidants N-acetylcysteine and exogenous glutathione. Marked collapse of the mitochondrial membrane potential suggested that dysfunction of the mitochondria may be involved in the oxidative burst and apoptosis induced by onion oil. Expression of phospho-cdc2 and phospho-cyclin B1 were downregulated by onion oil, perhaps accounting for the G2/M arrest. Overall, these results suggest that onion oil may exert chemopreventive action by inducing cell cycle arrest and apoptosis in tumor cells.

Evidence of taxon cycles in an Indo-Pacific passerine bird radiation (Aves: Pachycephala)

Science.gov (United States)

Jønsson, Knud Andreas; Irestedt, Martin; Christidis, Les; Clegg, Sonya M.; Holt, Ben G.; Fjeldså, Jon

2014-01-01

Many insular taxa possess extraordinary abilities to disperse but may differ in their abilities to diversify and compete. While some taxa are widespread across archipelagos, others have disjunct (relictual) populations. These types of taxa, exemplified in the literature by selections of unrelated taxa, have been interpreted as representing a continuum of expansions and contractions (i.e. taxon cycles). Here, we use molecular data of 35 out of 40 species of the avian genus Pachycephala (including 54 out of 66 taxa in Pachycephala pectoralis (sensu lato), to assess the spatio-temporal evolution of the group. We also include data on species distributions, morphology, habitat and elevational ranges to test a number of predictions associated with the taxon-cycle hypothesis. We demonstrate that relictual species persist on the largest and highest islands across the Indo-Pacific, whereas recent archipelago expansions resulted in colonization of all islands in a region. For co-occurring island taxa, the earliest colonists generally inhabit the interior and highest parts of an island, with little spatial overlap with later colonists. Collectively, our data support the idea that taxa continuously pass through phases of expansions and contractions (i.e. taxon cycles). PMID:24403319

Earth Without Life: A Systems Model of a Global Abiotic Nitrogen Cycle.

Science.gov (United States)

Laneuville, Matthieu; Kameya, Masafumi; Cleaves, H James

2018-03-20

Nitrogen is the major component of Earth's atmosphere and plays important roles in biochemistry. Biological systems have evolved a variety of mechanisms for fixing and recycling environmental nitrogen sources, which links them tightly with terrestrial nitrogen reservoirs. However, prior to the emergence of biology, all nitrogen cycling was abiological, and this cycling may have set the stage for the origin of life. It is of interest to understand how nitrogen cycling would proceed on terrestrial planets with comparable geodynamic activity to Earth, but on which life does not arise. We constructed a kinetic mass-flux model of nitrogen cycling in its various major chemical forms (e.g., N 2 , reduced (NH x ) and oxidized (NO x ) species) between major planetary reservoirs (the atmosphere, oceans, crust, and mantle) and included inputs from space. The total amount of nitrogen species that can be accommodated in each reservoir, and the ways in which fluxes and reservoir sizes may have changed over time in the absence of biology, are explored. Given a partition of volcanism between arc and hotspot types similar to the modern ones, our global nitrogen cycling model predicts a significant increase in oceanic nitrogen content over time, mostly as NH x , while atmospheric N 2 content could be lower than today. The transport timescales between reservoirs are fast compared to the evolution of the environment; thus atmospheric composition is tightly linked to surface and interior processes. Key Words: Nitrogen cycle-Abiotic-Planetology-Astrobiology. Astrobiology 18, xxx-xxx.

Respek vir die liturgiese teks: J. Calvyn en J.S. Bach | Schulze | Acta ...

African Journals Online (AJOL)

Despite obvious differences in terms of historical and theological aspects between Calvin and Bach, both share a respect for the priority of the Biblical text in worship.The anomaly between Calvin's engagement in the versification of the Psalter and Bach's preference for the literal (rather than a versified) use of the Biblical ...

Empiriese perspektief op kerkwees

African Journals Online (AJOL)

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Backus, I. & Benedict, P., 2011, Calvin and his influence, 1509–2009, Oxford University ... Barth, K., 1995, The theology of John Calvin, transl. ... Brunner, E., 1960, Die christliche Lehre von der Kirche, vom Glauben und von der ..... the dominant religious force in the Western world in a few centuries, Harper Collins, San.

[Life cycles of ground beetles (Coleoptera, Carabidae) from the mountain taiga and mountain forest-steppe in the Eastern Sayan].

Science.gov (United States)

Khobrakova, L Ts; Sharova, I Kh

2005-01-01

Seasonal dynamics and demographic structure was studied in 15 dominant ground beetle species in the mountain taiga and mountain forest-steppe belts of the Eastern Sayan (Okinskoe Plateau). Life cycles of the dominant ground beetle species were classified by developmental time, seasonal dynamics, and intrapopulation groups with different reproduction timing. The strategies of carabid life cycles adapted to severe mountain conditions of the Eastern Sayan were revealed.

Cell cycle arrest in the jewel wasp Nasonia vitripennis in larval diapause.

Science.gov (United States)

Shimizu, Yuta; Mukai, Ayumu; Goto, Shin G

2018-04-01

Insects enter diapause to synchronise their life cycle with biotic and abiotic environmental conditions favourable for their development, reproduction, and survival. One of the most noticeable characteristics of diapause is the blockage of ontogeny. Although this blockage should occur with the cessation of cellular proliferation, i.e. cell cycle arrest, it was confirmed only in a few insect species and information on the molecular pathways involved in cell cycle arrest is limited. In the present study, we investigated developmental and cell cycle arrest in diapause larvae of the jewel wasp Nasonia vitripennis. Developmental and cell cycle arrest occur in the early fourth instar larval stage of N. vitripennis under short days. By entering diapause, the S fraction of the cell cycle disappears and approximately 80% and 20% of cells arrest their cell cycle in the G0/G1 and G2 phases, respectively. We further investigated expression of cell cycle regulatory genes and some housekeeping genes to dissect molecular mechanisms underlying the cell cycle arrest. Copyright © 2016 Elsevier Ltd. All rights reserved.

Foliar pH as a new plant trait: can it explain variation in foliar chemistry and carbon cycling processes among subarctic plant species and types?

Science.gov (United States)

Cornelissen, J H C; Quested, H M; van Logtestijn, R S P; Pérez-Harguindeguy, N; Gwynn-Jones, D; Díaz, S; Callaghan, T V; Press, M C; Aerts, R

2006-03-01

Plant traits have become popular as predictors of interspecific variation in important ecosystem properties and processes. Here we introduce foliar pH as a possible new plant trait, and tested whether (1) green leaf pH or leaf litter pH correlates with biochemical and structural foliar traits that are linked to biogeochemical cycling; (2) there is consistent variation in green leaf pH or leaf litter pH among plant types as defined by nutrient uptake mode and higher taxonomy; (3) green leaf pH can predict a significant proportion of variation in leaf digestibility among plant species and types; (4) leaf litter pH can predict a significant proportion of variation in leaf litter decomposability among plant species and types. We found some evidence in support of all four hypotheses for a wide range of species in a subarctic flora, although cryptogams (fern allies and a moss) tended to weaken the patterns by showing relatively poor leaf digestibility or litter decomposability at a given pH. Among seed plant species, green leaf pH itself explained only up to a third of the interspecific variation in leaf digestibility and leaf litter up to a quarter of the interspecific variation in leaf litter decomposability. However, foliar pH substantially improved the power of foliar lignin and/or cellulose concentrations as predictors of these processes when added to regression models as a second variable. When species were aggregated into plant types as defined by higher taxonomy and nutrient uptake mode, green-specific leaf area was a more powerful predictor of digestibility or decomposability than any of the biochemical traits including pH. The usefulness of foliar pH as a new predictive trait, whether or not in combination with other traits, remains to be tested across more plant species, types and biomes, and also in relation to other plant or ecosystem traits and processes.

In Vitro Characterization of Thermostable CAM Rubisco Activase Reveals a Rubisco Interacting Surface Loop1[OPEN

Science.gov (United States)

Shivhare, Devendra

2017-01-01

To maintain metabolic flux through the Calvin-Benson-Bassham cycle in higher plants, dead-end inhibited complexes of Rubisco must constantly be engaged and remodeled by the molecular chaperone Rubisco activase (Rca). In C3 plants, the thermolability of Rca is responsible for the deactivation of Rubisco and reduction of photosynthesis at moderately elevated temperatures. We reasoned that crassulacean acid metabolism (CAM) plants must possess thermostable Rca to support Calvin-Benson-Bassham cycle flux during the day when stomata are closed. A comparative biochemical characterization of rice (Oryza sativa) and Agave tequilana Rca isoforms demonstrated that the CAM Rca isoforms are approximately10°C more thermostable than the C3 isoforms. Agave Rca also possessed a much higher in vitro biochemical activity, even at low assay temperatures. Mixtures of rice and agave Rca form functional hetero-oligomers in vitro, but only the rice isoforms denature at nonpermissive temperatures. The high thermostability and activity of agave Rca mapped to the N-terminal 244 residues. A Glu-217-Gln amino acid substitution was found to confer high Rca activity to rice Rca. Further mutational analysis suggested that Glu-217 restricts the flexibility of the α4-β4 surface loop that interacts with Rubisco via Lys-216. CAM plants thus promise to be a source of highly functional, thermostable Rca candidates for thermal fortification of crop photosynthesis. Careful characterization of their properties will likely reveal further protein-protein interaction motifs to enrich our mechanistic model of Rca function. PMID:28546437

In Vitro Characterization of Thermostable CAM Rubisco Activase Reveals a Rubisco Interacting Surface Loop.

Science.gov (United States)

Shivhare, Devendra; Mueller-Cajar, Oliver

2017-07-01

To maintain metabolic flux through the Calvin-Benson-Bassham cycle in higher plants, dead-end inhibited complexes of Rubisco must constantly be engaged and remodeled by the molecular chaperone Rubisco activase (Rca). In C3 plants, the thermolability of Rca is responsible for the deactivation of Rubisco and reduction of photosynthesis at moderately elevated temperatures. We reasoned that crassulacean acid metabolism (CAM) plants must possess thermostable Rca to support Calvin-Benson-Bassham cycle flux during the day when stomata are closed. A comparative biochemical characterization of rice ( Oryza sativa ) and Agave tequilana Rca isoforms demonstrated that the CAM Rca isoforms are approximately10°C more thermostable than the C3 isoforms. Agave Rca also possessed a much higher in vitro biochemical activity, even at low assay temperatures. Mixtures of rice and agave Rca form functional hetero-oligomers in vitro, but only the rice isoforms denature at nonpermissive temperatures. The high thermostability and activity of agave Rca mapped to the N-terminal 244 residues. A Glu-217-Gln amino acid substitution was found to confer high Rca activity to rice Rca Further mutational analysis suggested that Glu-217 restricts the flexibility of the α4-β4 surface loop that interacts with Rubisco via Lys-216. CAM plants thus promise to be a source of highly functional, thermostable Rca candidates for thermal fortification of crop photosynthesis. Careful characterization of their properties will likely reveal further protein-protein interaction motifs to enrich our mechanistic model of Rca function. © 2017 American Society of Plant Biologists. All Rights Reserved.

Características fotosintéticas de la yuca Manihot esculenta Crantz., anatomía foliar, ultraestructura de cloroplastos, tasas fotosintéticas y productos iniciales de la fijación del CO2 con 14C

Directory of Open Access Journals (Sweden)

López F. Yamel

1987-09-01

Full Text Available Se alimentaron hojas de yuca, fríjol y maíz con 14 C02 en luz y los productos primarios de la fotosíntesis se identificaron 5 y 10 segundos después de la asimilación. En maíz, aproximadamente tres cuartas partes del carbón marcado se incorporó en los ácidos C4, en fríjol alrededor de las dos terceras partes en PGA, en yuca aproximadamente el 40-60 % en ácidos C3 con 30- 50 % en PGA. Estos datos indican que la yuca posee el ciclo fotosintético C4. La planta presenta una corona alrededor del haz vascular y diferenciación entre cloroplastos, pero la anatomía no es perfecta, por consiguiente una asimilación apreciable del carbono tiene lugar directamente a través de el ciclo de Calvin-Benson-Bassham.Cassava, bean and maize leaves were fed with 14C02 in light and the primary products of photosynthesis identified 5 and 10 seconds after assimilation. In maize, approximately three quarters of the labelled carbon was incorporated in C4 acids, in bean about two thirds in PGA, and in cassava approximately 40-60 % in C3 acids with 30 . 50 % in PGA. These data indicate that cassava possesses the C4 photosynthetic cycle. Plant present vascular bundle sheath and differentiation between chloroplast, but the anatomy is not perfect, consequently appreciable carbon assimilation takes place directly through the Calvin-Benson-Bassham cycle.

Transcription of ribosomal RNA genes is initiated in the third cell cycle of bovine embryos

DEFF Research Database (Denmark)

Jakobsen, Anne Sørig; Avery, Birthe; Dieleman, Steph J.

2006-01-01

Transcription from the embryos own ribosomal genes is initiated in most species at the same time as the maternal-embryonic transition. Recently data have indicated that a minor activation may take place during the third embryonic cell cycle in the bovine, one cell cycle before the major activation...

Comparison of algae cultivation methods for bioenergy production using a combined life cycle assessment and life cycle costing approach.

Science.gov (United States)

Resurreccion, Eleazer P; Colosi, Lisa M; White, Mark A; Clarens, Andres F

2012-12-01

Algae are an attractive energy source, but important questions still exist about the sustainability of this technology on a large scale. Two particularly important questions concern the method of cultivation and the type of algae to be used. This present study combines elements of life cycle analysis (LCA) and life cycle costing (LCC) to evaluate open pond (OP) systems and horizontal tubular photobioreactors (PBRs) for the cultivation of freshwater (FW) or brackish-to-saline water (BSW) algae. Based on the LCA, OPs have lower energy consumption and greenhouse gas emissions than PBRs; e.g., 32% less energy use for construction and operation. According to the LCC, all four systems are currently financially unattractive investments, though OPs are less so than PBRs. BSW species deliver better energy and GHG performance and higher profitability than FW species in both OPs and PBRs. Sensitivity analyses suggest that improvements in critical cultivation parameters (e.g., CO(2) utilization efficiency or algae lipid content), conversion parameters (e.g., anaerobic digestion efficiency), and market factors (e.g., costs of CO(2) and electricity, or sale prices for algae biodiesel) could alter these results. Copyright © 2012 Elsevier Ltd. All rights reserved.

Geographic body size variation in the periodical cicadas Magicicada: implications for life cycle divergence and local adaptation.

Science.gov (United States)

Koyama, T; Ito, H; Kakishima, S; Yoshimura, J; Cooley, J R; Simon, C; Sota, T

2015-06-01

Seven species in three species groups (Decim, Cassini and Decula) of periodical cicadas (Magicicada) occupy a wide latitudinal range in the eastern United States. To clarify how adult body size, a key trait affecting fitness, varies geographically with climate conditions and life cycle, we analysed the relationships of population mean head width to geographic variables (latitude, longitude, altitude), habitat annual mean temperature (AMT), life cycle and species differences. Within species, body size was larger in females than males and decreased with increasing latitude (and decreasing habitat AMT), following the converse Bergmann's rule. For the pair of recently diverged 13- and 17-year species in each group, 13-year cicadas were equal in size or slightly smaller on average than their 17-year counterparts despite their shorter developmental time. This fact suggests that, under the same climatic conditions, 17-year cicadas have lowered growth rates compared to their 13-years counterparts, allowing 13-year cicadas with faster growth rates to achieve body sizes equivalent to those of their 17-year counterparts at the same locations. However, in the Decim group, which includes two 13-year species, the more southerly, anciently diverged 13-year species (Magicicada tredecim) was characterized by a larger body size than the other, more northerly 13- and 17-year species, suggesting that local adaptation in warmer habitats may ultimately lead to evolution of larger body sizes. Our results demonstrate how geographic clines in body size may be maintained in sister species possessing different life cycles. © 2015 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2015 European Society For Evolutionary Biology.

[CHROMATIN ORGANIZATION IN CELL CYCLE OF AMOEBA PROTEUS ACCORDING TO OPTICAL TOMOGRAPHY DATA].

Science.gov (United States)

Demin, S Yu; Berdieva, M A; Podlipaeva, Yu I; Yudin, A L; Goodkov, A V

2015-01-01

For the first time the nuclear cycle of large freshwater amoeba Amoeba proteus was studied by the method of optical tomography. The nuclei were fixed in situ in the cells of synchronized culture, stained by DAPI and examined by confocal laser scanning microscope. 3D-images of intranuclear chromatin were studied in details at different stages of nuclear cycle. The obtained data, together with literary ones allow represent the dynamics of structural organization of the nucleus in Amoeba proteus cell cycle in a new fashion. It was concluded that in this species the two-stage interphase takes place, as well as mitosis of peculiar type which does not correspond to any known type of mitosis according to classification existing now. It is presumed that in the course of nuclear cycle the chromosomes and/or their fragments are amplified, this presumption being in a good correspondence with the data about nuclear DNA hyperreplication in the cell cycle of A. proteus. As a result of chromosomes amplification their number may vary at different stages of cell cycle, and it allows to explain the contradictory data concerning the exact number of chromosomes in this species. The elimination of extra-DNA occurs mainly at the stage between prophase and prometaphase. We presume the majority of chromosomes, or may be even all of them to be referred to cholocentric type according to their behaviour during the mitosis.

Voorwoord

African Journals Online (AJOL)

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Backus, I. & Benedict, P., 2011, Calvin and his influence, 1509–2009, Oxford ... Barth, K., 1995, The theology of John Calvin, transl. ... Brunner, E., 1960, Die christliche Lehre von der Kirche, vom Glauben und von der ..... Testament in the Olivétan Bible of 1535', Koers 66(1/2) 1–22. http://dx.doi. .... Harper Collins, New York.

Bipolar mood cycles and lunar tidal cycles.

Science.gov (United States)

Wehr, T A

2018-04-01

In 17 patients with rapid cycling bipolar disorder, time-series analyses detected synchronies between mood cycles and three lunar cycles that modulate the amplitude of the moon's semi-diurnal gravimetric tides: the 14.8-day spring-neap cycle, the 13.7-day declination cycle and the 206-day cycle of perigee-syzygies ('supermoons'). The analyses also revealed shifts among 1:2, 1:3, 2:3 and other modes of coupling of mood cycles to the two bi-weekly lunar cycles. These shifts appear to be responses to the conflicting demands of the mood cycles' being entrained simultaneously to two different bi-weekly lunar cycles with slightly different periods. Measurements of circadian rhythms in body temperature suggest a biological mechanism through which transits of one of the moon's semi-diurnal gravimetric tides might have driven the patients' bipolar cycles, by periodically entraining the circadian pacemaker to its 24.84-h rhythm and altering the pacemaker's phase-relationship to sleep in a manner that is known to cause switches from depression to mania.

Role of economics in endangered species act activities related to Snake River salmon

International Nuclear Information System (INIS)

Woodruff, E.J.; Huppert, D.D.

1993-01-01

The development of recovery actions for the species of Snake River Salmon listed under the Endangered Species Act (ESA) must consider a wide range of actions covering the different life-cycles of the species. This paper examines the possible role of economic analysis in assisting in selection of actions to undertake and draws heavily on similar opinions presented by others in the region

Species differences in the regulation of tyrosine hydroxylase in Cnemidophorus whiptail lizards.

Science.gov (United States)

Woolley, Sarah C; Crews, David

2004-09-05

Evolution of behavioral phenotype involves changes in the underlying neural substrates. Cnemidophorus whiptail lizards enable the study of behavioral and neural evolution because ancestral species involved in producing unisexual, hybrid species still exist. Catecholaminergic systems modulate the expression of social behaviors in a number of vertebrates, including whiptails, and therefore we investigated how changes in catecholamine production correlated with evolutionary changes in behavioral phenotype by measuring the size and number of catecholamine producing (tyrosine hydroxylase-immunoreactive, or TH-ir) cells across the reproductive cycle in females from two related whiptail species. Cnemidophorusuniparens is a triploid, parthenogenetic species that arose from hybridization events involving the diploid, sexual species C. inornatus. Prior to ovulation, females from both species display femalelike receptive behaviors. However, after ovulation, only parthenogenetic individuals display malelike mounting behavior. In all nuclei measured, we found larger TH-ir cells in the parthenogen, a difference consistent with species differences in ploidy. In contrast, species differences in the number of TH-ir cells were nucleus specific. In the preoptic area and anterior hypothalamus, parthenogens had fewer TH-ir cells than females of the sexual species. Reproductive state only affected TH-ir cell number in the substantia nigra pars compacta (SNpc), and C. uniparens individuals had more TH-ir cells after ovulation than when previtellogenic. Thus, species differences over the reproductive cycle in the SNpc are correlated with species differences in behavior, and it appears that the process of speciation may have produced a novel neural and behavioral phenotype in the parthenogen.

The Geologic Nitrogen Cycle

Science.gov (United States)

Johnson, B. W.; Goldblatt, C.

2013-12-01

N2 is the dominant gas in Earth's atmosphere, and has been so through the majority of the planet's history. Originally thought to only be cycled in significant amounts through the biosphere, it is becoming increasingly clear that a large degree of geologic cycling can occur as well. N is present in crustal rocks at 10s to 100s of ppm and in the mantle at 1s to perhaps 10s of ppm. In light of new data, we present an Earth-system perspective of the modern N cycle, an updated N budget for the silicate Earth, and venture to explain the evolution of the N cycle over time. In an fashion similar to C, N has a fast, biologically mediated cycle and a slower cycle driven by plate tectonics. Bacteria fix N2 from the atmosphere into bioavailable forms. N is then cycled through the food chain, either by direct consumption of N-fixing bacteria, as NH4+ (the primary waste form), or NO3- (the most common inorganic species in the modern ocean). Some organic material settles as sediment on the ocean floor. In anoxic sediments, NH4+ dominates; due to similar ionic radii, it can readily substitute for K+ in mineral lattices, both in sedimentary rocks and in oceanic lithosphere. Once it enters a subduction zone, N may either be volatilized and returned to the atmosphere at arc volcanoes as N2 or N2O, sequestered into intrusive igneous rocks (as NH4+?), or subducted deep into the mantle, likely as NH4+. Mounting evidence indicates that a significant amount of N may be sequestered into the solid Earth, where it may remain for long periods (100s m.y.) before being returned to the atmosphere/biosphere by volcanism or weathering. The magnitude fluxes into the solid Earth and size of geologic N reservoirs are poorly constrained. The size of the N reservoirs contained in the solid Earth directly affects the evolution of Earth's atmosphere. It is possible that N now sequestered in the solid Earth was once in the atmosphere, which would have resulted in a higher atmospheric pressure, and

Functional interrogation of Plasmodium genus metabolism identifies species- and stage-specific differences in nutrient essentiality and drug targeting

KAUST Repository

Abdel-Haleem, Alyaa M.; Hefzi, Hooman; Mineta, Katsuhiko; Gao, Xin; Gojobori, Takashi; Palsson, Bernhard O.; Lewis, Nathan E.; Jamshidi, Neema

2018-01-01

and predicted potential targets that could affect several life cycle stages. The species-specific models further highlight differences between experimental animal models and the human-infecting species. Comparisons between human- and rodent-infecting species

Life-cycle of the European compost worm Dendrobaena veneta ...

African Journals Online (AJOL)

1990-06-05

Jun 5, 1990 ... that this species does have potential to combat organic waste problems. The complete life-cycle of D. veneta has not been documented yeL We therefore included this ... in plastic containers with gauze lids. Fifty grams of the stabilized culture medium per wonn was added when the experiment was started.

[Effects of biochar on soil nitrogen cycle and related mechanisms: a review].

Science.gov (United States)

Pan, Yi-Fan; Yang, Min; Dong, Da; Wu, Wei-Xiang

2013-09-01

Biochar has its unique physical and chemical properties, playing a significant role in soil amelioration, nutrient retention, fertility improvement, and carbon storage, and being a hotspot in the research areas of soil ecosystem, biogeochemical cycling, and agricultural carbon sequestration. As a kind of anthropogenic materials, biochar has the potential in controlling soil nitrogen (N) cycle directly or indirectly, and thus, has profound effects on soil ecological functions. This paper reviewed the latest literatures regarding the effects of biochar applications on soil N cycle, with the focuses on the nitrogen species adsorption and the biochemical processes (nitrification, denitrification, and nitrogen fixation) , and analyzed the related action mechanisms of biochar. The future research areas for better understanding the interactions between biochar and soil N cycle were proposed.

Habitat-based constraints on food web structure and parasite life cycles.

Science.gov (United States)

Rossiter, Wayne; Sukhdeo, Michael V K

2014-04-01

Habitat is frequently implicated as a powerful determinant of community structure and species distributions, but few studies explicitly evaluate the relationship between habitat-based patterns of species' distributions and the presence or absence of trophic interactions. The complex (multi-host) life cycles of parasites are directly affected by these factors, but almost no data exist on the role of habitat in constraining parasite-host interactions at the community level. In this study the relationship(s) between species abundances, distributions and trophic interactions (including parasitism) were evaluated in the context of habitat structure (classic geomorphic designations of pools, riffles and runs) in a riverine community (Raritan River, Hunterdon County, NJ, USA). We report 121 taxa collected over a 2-year period, and compare the observed food web patterns to null model expectations. The results show that top predators are constrained to particular habitat types, and that species' distributions are biased towards pool habitats. However, our null model (which incorporates cascade model assumptions) accurately predicts the observed patterns of trophic interactions. Thus, habitat strongly dictates species distributions, and patterns of trophic interactions arise as a consequence of these distributions. Additionally, we find that hosts utilized in parasite life cycles are more overlapping in their distributions, and this pattern is more pronounced among those involved in trophic transmission. We conclude that habitat structure may be a strong predictor of parasite transmission routes, particularly within communities that occupy heterogeneous habitats.

The Genome of Deep-Sea Vent Chemolithoautotroph Thiomicrospira crunogena XCL-2

Energy Technology Data Exchange (ETDEWEB)

Scott, K M; Sievert, S M; Abril, F N; Ball, L A; Barrett, C J; Blake, R A; Boller, A J; Chain, P G; Clark, J A; Davis, C R; Detter, C; Do, K F; Dobrinski, K P; Faza, B I; Fitzpatrick, K A; Freyermuth, S K; Harmer, T L; Hauser, L J; Hugler, M; Kerfeld, C A; Klotz, M G; Kong, W W; Land, M; Lapidus, A; Larimer, F W; Longo, D L; Lucas, S; Malfatti, S A; Massey, S E; Martin, D D; McCuddin, Z; Meyer, F; Moore, J L; Ocampo Jr., L H; Paul, J H; Paulsen, I T; Reep, D K; Ren, Q; Ross, R L; Sato, P Y; Thomas, P; Tinkham, L E; Zerugh, G T

2007-01-10

Presented here is the complete genome sequence of Thiomicrospira crunogena XCL-2, representative of ubiquitous chemolithoautotrophic sulfur-oxidizing bacteria isolated from deep-sea hydrothermal vents. This gammaproteobacterium has a single chromosome (2,427,734 bp), and its genome illustrates many of the adaptations that have enabled it to thrive at vents globally. It has 14 methyl-accepting chemotaxis protein genes, including four that may assist in positioning it in the redoxcline. A relative abundance of CDSs encoding regulatory proteins likely control the expression of genes encoding carboxysomes, multiple dissolved inorganic nitrogen and phosphate transporters, as well as a phosphonate operon, which provide this species with a variety of options for acquiring these substrates from the environment. T. crunogena XCL-2 is unusual among obligate sulfur oxidizing bacteria in relying on the Sox system for the oxidation of reduced sulfur compounds. A 38 kb prophage is present, and a high level of prophage induction was observed, which may play a role in keeping competing populations of close relatives in check. The genome has characteristics consistent with an obligately chemolithoautotrophic lifestyle, including few transporters predicted to have organic allocrits, and Calvin-Benson-Bassham cycle CDSs scattered throughout the genome.

Faster recovery of a diatom from UV damage under ocean acidification.

Science.gov (United States)

Wu, Yaping; Campbell, Douglas A; Gao, Kunshan

2014-11-01

Diatoms are the most important group of primary producers in marine ecosystems. As oceanic pH declines and increased stratification leads to the upper mixing layer becoming shallower, diatoms are interactively affected by both lower pH and higher average exposures to solar ultraviolet radiation. The photochemical yields of a model diatom, Phaeodactylum tricornutum, were inhibited by ultraviolet radiation under both growth and excess light levels, while the functional absorbance cross sections of the remaining photosystem II increased. Cells grown under ocean acidification (OA) were less affected during UV exposure. The recovery of PSII under low photosynthetically active radiation was much faster than in the dark, indicating that photosynthetic processes were essential for the full recovery of photosystem II. This light dependent recovery required de novo synthesized protein. Cells grown under ocean acidification recovered faster, possibly attributable to higher CO₂ availability for the Calvin cycle producing more resources for repair. The lower UV inhibition combined with higher recovery rate under ocean acidification could benefit species such as P.tricornutum, and change their competitiveness in the future ocean. Copyright © 2014 Elsevier B.V. All rights reserved.

Pyruvate cycle increases aminoglycoside efficacy and provides respiratory energy in bacteria.

Science.gov (United States)

Su, Yu-Bin; Peng, Bo; Li, Hui; Cheng, Zhi-Xue; Zhang, Tian-Tuo; Zhu, Jia-Xin; Li, Dan; Li, Min-Yi; Ye, Jin-Zhou; Du, Chao-Chao; Zhang, Song; Zhao, Xian-Liang; Yang, Man-Jun; Peng, Xuan-Xian

2018-02-13

The emergence and ongoing spread of multidrug-resistant bacteria puts humans and other species at risk for potentially lethal infections. Thus, novel antibiotics or alternative approaches are needed to target drug-resistant bacteria, and metabolic modulation has been documented to improve antibiotic efficacy, but the relevant metabolic mechanisms require more studies. Here, we show that glutamate potentiates aminoglycoside antibiotics, resulting in improved elimination of antibiotic-resistant pathogens. When exploring the metabolic flux of glutamate, it was found that the enzymes that link the phosphoenolpyruvate (PEP)-pyruvate-AcCoA pathway to the TCA cycle were key players in this increased efficacy. Together, the PEP-pyruvate-AcCoA pathway and TCA cycle can be considered the pyruvate cycle (P cycle). Our results show that inhibition or gene depletion of the enzymes in the P cycle shut down the TCA cycle even in the presence of excess carbon sources, and that the P cycle operates routinely as a general mechanism for energy production and regulation in Escherichia coli and Edwardsiella tarda These findings address metabolic mechanisms of metabolite-induced potentiation and fundamental questions about bacterial biochemistry and energy metabolism.

Nature as creation from an eco-hermeneutical perspective: From a ‘natural theology’ to a ‘theology of nature’

Directory of Open Access Journals (Sweden)

Johan Buitendag

2009-11-01

Full Text Available For researchers who are interested in the relationship between theology and the natural sciences, 2009 is of special importance. It is now 500 years since Calvin was born and 450 years since his Institution of the Christian Religion was finally published. It is also 200 years since Darwin’s birth and 150 years since his On the Origin of Species appeared in print for the first time. Calvin and Darwin are representative of two separate lines which converge in a particular ‘transversal space’. Such insights are regenerating light on our search for scientific truth today. Neither the absolutisation of transcendent revelation, nor that of immanent knowledge of nature, provides an accountable understanding of reality. Against this background, the challenge for Systematic Theology today is to conceive of a ‘theology of nature’, which can be offered as a dialectical third option. An ‘ecohermeneutics’ offers a possibility of establishing such an option for theology. However, such an option will, on the one hand, have to deconstruct the reformed criticism of a natural theology and will, on the other hand, have to make serious work of an evolutionary epistemology.

Long-term competitive dynamics of two cryptic rotifer species: diapause and fluctuating conditions.

Directory of Open Access Journals (Sweden)

Carmen Gabaldón

Full Text Available Life-history traits may have an important role in promoting species coexistence. However, the complexity of certain life cycles makes it difficult to draw conclusions about the conditions for coexistence or exclusion based on the study of short-term competitive dynamics. Brachionus plicatilis and B. manjavacasare two cryptic rotifer species co-occurring in many lakes on the Iberian Peninsula. They have a complex life cycle in which cyclical parthenogenesis occurs with diapausing stages being the result of sexual reproduction. B. plicatilis and B. manjavacasare identical in morphology and size, their biotic niches are broadly overlapping, and they have similar competitive abilities. However, the species differ in life-history traits involving sexual reproduction and diapause, and respond differently to salinity and temperature. As in the case of certain other species that are extremely similar in morphology, a fluctuating environment are considered to be important for their coexistence. We studied the long-term competitive dynamics of B. plicatilis and B. manjavacas under different salinity regimes (constant and fluctuating. Moreover, we focused on the dynamics of the diapausing egg bank to explore how the outcome of the entire life cycle of these rotifers can work to mediate stable coexistence. We demonstrated that these species do not coexist under constant-salinity environment, as the outcome of competition is affected by the level of salinity-at low salinity, B. plicatilis excluded B. manjavacas, and the opposite outcome occurred at high salinity. Competitive dynamics under fluctuating salinity showed that the dominance of one species over the other also tended to fluctuate. The duration of co-occurrence of these species was favoured by salinity fluctuation and perhaps by the existence of a diapausing egg bank. Stable coexistence was not found in our system, which suggests that other factors or other salinity fluctuation patterns might act as

Long-term competitive dynamics of two cryptic rotifer species: diapause and fluctuating conditions.

Science.gov (United States)

Gabaldón, Carmen; Carmona, María José; Montero-Pau, Javier; Serra, Manuel

2015-01-01

Life-history traits may have an important role in promoting species coexistence. However, the complexity of certain life cycles makes it difficult to draw conclusions about the conditions for coexistence or exclusion based on the study of short-term competitive dynamics. Brachionus plicatilis and B. manjavacasare two cryptic rotifer species co-occurring in many lakes on the Iberian Peninsula. They have a complex life cycle in which cyclical parthenogenesis occurs with diapausing stages being the result of sexual reproduction. B. plicatilis and B. manjavacasare identical in morphology and size, their biotic niches are broadly overlapping, and they have similar competitive abilities. However, the species differ in life-history traits involving sexual reproduction and diapause, and respond differently to salinity and temperature. As in the case of certain other species that are extremely similar in morphology, a fluctuating environment are considered to be important for their coexistence. We studied the long-term competitive dynamics of B. plicatilis and B. manjavacas under different salinity regimes (constant and fluctuating). Moreover, we focused on the dynamics of the diapausing egg bank to explore how the outcome of the entire life cycle of these rotifers can work to mediate stable coexistence. We demonstrated that these species do not coexist under constant-salinity environment, as the outcome of competition is affected by the level of salinity-at low salinity, B. plicatilis excluded B. manjavacas, and the opposite outcome occurred at high salinity. Competitive dynamics under fluctuating salinity showed that the dominance of one species over the other also tended to fluctuate. The duration of co-occurrence of these species was favoured by salinity fluctuation and perhaps by the existence of a diapausing egg bank. Stable coexistence was not found in our system, which suggests that other factors or other salinity fluctuation patterns might act as stabilizing

DNA endoreplication level in endosperm during seed development in three monocotyledonous species

Directory of Open Access Journals (Sweden)

Kazimierz Marciniak

2014-01-01

Full Text Available The DNA content after the Feulgen reaction in the endosperm of three monocotyledonous plant species (Asparagus officinalis, Muscari comosom, Haemanthus kurharinae differing in their 2C DNA content, was cytophotometrically measured. During endosperm development 1-6 endoreplication cycles take place, depending on the species. Differences in nuclear DNA endoreplication dynamics in the tested species are similar to those occurring in root parenchyma, but the endoreplication level in the endosperm is higher.

The Krebs Uric Acid Cycle: A Forgotten Krebs Cycle.

Science.gov (United States)

Salway, Jack G

2018-05-25

Hans Kornberg wrote a paper entitled 'Krebs and his trinity of cycles' commenting that every school biology student knows of the Krebs cycle, but few know that Krebs discovered two other cycles. These are (i) the ornithine cycle (urea cycle), (ii) the citric acid cycle (tricarboxylic acid or TCA cycle), and (iii) the glyoxylate cycle that was described by Krebs and Kornberg. Ironically, Kornberg, codiscoverer of the 'glyoxylate cycle', overlooked a fourth Krebs cycle - (iv) the uric acid cycle. Copyright © 2018 Elsevier Ltd. All rights reserved.

Numerical investigation into the existence of limit cycles in two-dimensional predator�prey systems

Directory of Open Access Journals (Sweden)

Quay van der Hoff

2013-05-01

Full Text Available There has been a surge of interest in developing and analysing models of interacting species in ecosystems, with specific interest in investigating the existence of limit cycles in systems describing the dynamics of these species. The original Lotka–Volterra model does not possess any limit cycles. In recent years this model has been modified to take disturbances into consideration and allow populations to return to their original numbers. By introducing logistic growth and a Holling Type II functional response to the traditional Lotka–Volterra-type models, it has been proven analytically that a unique, stable limit cycle exists. These proofs make use of Dulac functions, Liénard equations and invariant regions, relying on theory developed by Poincaré, Poincaré-Bendixson, Dulac and Liénard, and are generally perceived as difficult. Computer algebra systems are ideally suited to apply numerical methods to confirm or refute the analytical findings with respect to the existence of limit cycles in non-linear systems. In this paper a class of predator–prey models of a Gause type is used as the vehicle to illustrate the use of a simple, yet novel numerical algorithm. This algorithm confirms graphically the existence of at least one limit cycle that has analytically been proven to exist. Furthermore, adapted versions of the proposed algorithm may be applied to dynamic systems where it is difficult, if not impossible, to prove analytically the existence of limit cycles.

From species sensitivity to hypoxia to effect factors modelling in life cycle impact assessment (LCIA)

DEFF Research Database (Denmark)

Cosme, Nuno Miguel Dias; Hauschild, Michael Zwicky

’s sensitivity in five climate zone (polar, subpolar, temperate, subtropical, tropical). Species Sensitivity Distribution (SSD) curves combining DO concentrations and Potentially Affected Fractions (PAF) of species were plotted to estimate hazard concentrations (HC50LOEL) per climate zone, and Effect Factors (EF...

Alteronol induces cell cycle arrest and apoptosis via increased reactive oxygen species production in human breast cancer T47D cells.

Science.gov (United States)

Ren, Boxue; Li, Defang; Si, Lingling; Ding, Yangfang; Han, Jichun; Chen, Xiaoyu; Zheng, Qiusheng

2018-04-01

Emerging evidence showed that alteronol has a potential antitumour effect in several tumour cells. However, the antitumour effect of alteronol on breast cancer has not been reported. This study investigated the mechanisms of alteronol-induced cell proliferation inhibition in human breast cancer T47D cells. After treatment with alteronol, T47D cell proliferation was examined by MTT assay. The cell cycle distribution, cell apoptosis, reactive oxygen species level and mitochondrial membrane potential were evaluated via flow cytometry. Next, the protein levels of cyclin B1, cdc2, p21, p-cyclin B1, p-cdc2, p53, Bax, Bcl-2 and cytochrome c were analysed using Western blot analysis. Meanwhile, the mRNA levels of cyclin B1, cdc2, p21 and p53 were examined by qRT-PCR. Our data showed that alteronol inhibited the proliferation of T47D cells via inducing G2-phase arrest and cell apoptosis. Compared with control group, alteronol significantly increased ROS level and triggered mitochondrial dysfunction in alteronol-treated T47D cells. Further studies showed that the mRNA and protein levels of cdc2 and cyclin B1 were downregulated, while the mRNA and protein levels of p21, p53, p-cyclin B1, p-cdc2 and cytochrome c were upregulated. In addition, the expression level of Bax was increased, and the expression level of Bcl-2 was decreased. Alteronol induced T47D cell cycle arrest and cell apoptosis through increasing ROS production and triggering mitochondrial dysfunction, and subsequently inhibiting T47D cell proliferation. © 2018 Royal Pharmaceutical Society.

Links between plant litter chemistry, species diversity, and below-ground ecosystem function.

Science.gov (United States)

Meier, Courtney L; Bowman, William D

2008-12-16

Decomposition is a critical source of plant nutrients, and drives the largest flux of terrestrial C to the atmosphere. Decomposing soil organic matter typically contains litter from multiple plant species, yet we lack a mechanistic understanding of how species diversity influences decomposition processes. Here, we show that soil C and N cycling during decomposition are controlled by the composition and diversity of chemical compounds within plant litter mixtures, rather than by simple metrics of plant species diversity. We amended native soils with litter mixtures containing up to 4 alpine plant species, and we used 9 litter chemical traits to evaluate the chemical composition (i.e., the identity and quantity of compounds) and chemical diversity of the litter mixtures. The chemical composition of the litter mixtures was the strongest predictor of soil respiration, net N mineralization, and microbial biomass N. Soil respiration and net N mineralization rates were also significantly correlated with the chemical diversity of the litter mixtures. In contrast, soil C and N cycling rates were poorly correlated with plant species richness, and there was no relationship between species richness and the chemical diversity of the litter mixtures. These results indicate that the composition and diversity of chemical compounds in litter are potentially important functional traits affecting decomposition, and simple metrics like plant species richness may fail to capture variation in these traits. Litter chemical traits therefore provide a mechanistic link between organisms, species diversity, and key components of below-ground ecosystem function.

Mediterranean species of Caulerpa are polyploid with smaller genomes in the invasive ones.

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Elena Varela-Álvarez

Full Text Available Caulerpa species are marine green algae, which often act as invasive species with rapid clonal proliferation when growing outside their native biogeographical borders. Despite many publications on the genetics and ecology of Caulerpa species, their life history and ploidy levels are still to be resolved and are the subject of large controversy. While some authors claimed that the thallus found in nature has a haplodiplobiontic life cycle with heteromorphic alternation of generations, other authors claimed a diploid or haploid life cycle with only one generation involved. DAPI-staining with image analysis and microspectrophotometry were used to estimate relative nuclear DNA contents in three species of Caulerpa from the Mediterranean, at individual, population and species levels. Results show that ploidy levels and genome size vary in these three Caulerpa species, with a reduction in genome size for the invasive ones. Caulerpa species in the Mediterranean are polyploids in different life history phases; all sampled C. taxifolia and C. racemosa var. cylindracea were in haplophasic phase, but in C. prolifera, the native species, individuals were found in both diplophasic and haplophasic phases. Different levels of endopolyploidy were found in both C. prolifera and C. racemosa var. cylindracea. Life history is elucidated for the Mediterranean C. prolifera and it is hypothesized that haplophasic dominance in C. racemosa var. cylindracea and C. taxifolia is a beneficial trait for their invasive strategies.

Mangrove habitat partitioning by Ucides cordatus (Ucididae): effects of the degree of tidal flooding and tree-species composition during its life cycle

Science.gov (United States)

Wunderlich, A. C.; Pinheiro, M. A. A.

2013-06-01

Environmental factors strongly affect mangrove crabs, and some factors modulate population structure and habitat partitioning during the crabs' life cycle. However, the effect of these environmental factors on habitat selection by mangrove crabs is still unknown. We evaluated habitat selection by the mangrove crab Ucides cordatus in mangrove forests with different degrees of predominance of Rhizophora mangle, Laguncularia racemosa or Avicennia schaueriana, two tidal flooding levels (less- and more-flooded), and two biological periods (breeding and non-breeding seasons). Sampling was conducted in four mangrove forests with different influences of these biotic and abiotic parameters. We used the data for sex ratio to explain environmental partitioning by this species. Females predominated in R. mangle mangroves, independently of the biological period (breeding or non-breeding seasons), and males predominated only in the less-flooded L. racemosa mangroves. The flooding level affected the sex ratio of U. cordatus, with a predominance of males in less-flooded mangroves, independently of the biological period; and a gender balance in the more-flooded mangroves only during the breeding season. Outside the breeding season, the largest specimens were recorded in the R. mangle mangroves, but in the breeding season, the largest crabs were recorded in the L. racemosa mangroves with a higher level of flooding. These results suggest that tree-species composition and tidal flooding level can have a significant effect on the habitat partitioning of sexes and sizes of the mangrove crab U. cordatus both during and outside the breeding season.

Life-cycle of the European compost worm Dendrobaena veneta ...

African Journals Online (AJOL)

The life-cycle of Dendrobaena veneta was studied to assess the potential of this species in vermiculture. The development, growth and reproduction were investigated by rearing worms at 25°C on urine-free cattle manure with a moisture content of 80% over a period of 200 days. It was found that cocoons are produced at a ...

Shorter Fallow Cycles Affect the Availability of Noncrop Plant Resources in a Shifting Cultivation System

Directory of Open Access Journals (Sweden)

Sarah Paule. Dalle

2006-12-01

Full Text Available Shifting cultivation systems, one of the most widely distributed forms of agriculture in the tropics, provide not only crops of cultural significance, but also medicinal, edible, ritual, fuel, and forage resources, which contribute to the livelihoods, health, and cultural identity of local people. In many regions across the globe, shifting cultivation systems are undergoing important changes, one of the most pervasive being a shortening of the fallow cycle. Although there has been much attention drawn to declines in crop yields in conjunction with reductions in fallow times, little if any research has focused on the dynamics of noncrop plant resources. In this paper, we use a data set of 26 fields of the same age, i.e., ~1.5 yr, but differing in the length and frequency of past fallow cycles, to examine the impact of shorter fallow periods on the availability of noncrop plant resources. The resources examined are collected in shifting cultivation fields by the Yucatec Maya in Quintana Roo, Mexico. These included firewood, which is cut from remnant trees and stumps spared at the time of felling, and 17 forage species that form part of the weed vegetation. Firewood showed an overall decrease in basal area with shorter fallow cycles, which was mostly related to the smaller diameter of the spared stumps and trees in short-fallow milpas. In contrast, forage species showed a mixed response. Species increasing in abundance in short-fallow milpas tended to be short-lived herbs and shrubs often with weedy habits, whereas those declining in abundance were predominantly pioneer trees and animal-dispersed species. Coppicing tree species showed a neutral response to fallow intensity. Within the cultural and ecological context of our study area, we expect that declines in firewood availability will be most significant for livelihoods because of the high reliance on firewood for local fuel needs and the fact that the main alternative source of firewood, forest

Rond de schuldbelijdenis in de liturgie

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K. Deddens

1995-06-01

Full Text Available This study deals with what happens in the first part of the reformed worship service on Sunday mornings. The article offers a historical review of confession practices in the liturgy, especially during the time of the Reformation, particularly concerning the ideas of John Calvin in liturgical respect. In this article it is argued that the first part of Calvin's order of liturgy (the part preceding the prayer serving to open God’s Word formed an organic whole according to the triad: misery, deliverance and thankfulness. Calvin rightly emphasized the element of humility at the very beginning of the worship service. This humility is expressed in the confession of sins, which is to be followed directly by a word of comfort from Scripture and the declaration of forgiveness of sins for believers. Calvin followed this order in Strassbourg from which he was banished from 1538-1541. He, however, was not able to practise this procedure in Genéve after his return, although he advised the churches to keep this order. This study advocates the maintenance, c.q. re-introduction of this apt beginning of Calvin’s liturgy at Strassbourg.

Latitudinal variation in the reproductive cycle of two bivalves with contrasting biogeographical origin along the Humboldt Current Upwelling Ecosystem

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Roberto A. Uribe

2012-10-01

Full Text Available Argopecten purpuratus (Lamarck, 1819 and Mesodesma donacium (Lamarck, 1818 are bivalves that inhabit the Humboldt Current Upwelling Ecosystem. They have contrasting biogeographical origins, suggesting that their responses to exogenous factors should differ. Using circular statistics, we examine synchrony/asynchrony in the reproductive cycle between populations of each species. The results indicate that there is reproductive asynchrony in both species along their distributional range. However, there was synchrony for A. purpuratus in several location-pairs, including Paita-Chimbote, Chimbote-Callao, Callao-Pisco and Pisco-Antofagasta. For M. donacium, there were only two synchronic groups: Camaná-Capellanía-Mehuín and Hornitos-Peñuelas-Longotoma-La Ligua-Cucao-Quilanlar. A. purpuratus showed gametogenenic activity throughout the year. In contrast, M. donacium showed strong seasonality, with gametogenesis in winter and spawning in spring/summer. In conclusion, the patterns observed for these sympatric species suggest that on a large scale the reproductive cycles follow the expected patterns for the contrasting biogeographic origin of each species, so it could be argued that they are modulated by endogenous factors. However, at a local scale, the reproductive cycles of these species show variation, likely determined by local oceanographic or hydrographic processes.

The life-cycle of the compost worm (Oligochaeta) | Venter | African ...

African Journals Online (AJOL)

To determine the full potential of the compost worm Eisenia fetida as waste processor and as source of protein, the life-cycle of this species had to be studied thoroughly. The development, growth and reproduction of Eisenia fetida were studied on cattle manure under favourable conditions of moisture, temperature and ...

Regulation of salt marsh mosquito populations by the 18.6-yr lunar-nodal cycle.

Science.gov (United States)

Rochlin, Ilia; Morris, James T

2017-08-01

The 18.6-yr lunar-nodal cycle drives changes in tidal amplitude globally, affecting coastal habitat formation, species and communities inhabiting rocky shores, and salt marsh vegetation. However, the cycle's influence on salt marsh fauna lacked sufficient long-term data for testing its effect. We circumvented this problem by using salt marsh mosquito records obtained over a period of over four decades in two estuaries in the northeastern USA. Salt marsh mosquito habitat is near the highest tide level where the impact of the nodal cycle on flood frequency is greatest. Wavelet spectral and cross-correlation analyses revealed periodicity in salt marsh mosquito abundance that was negatively correlated with tidal amplitude. Tidal amplitude was a significant predictor of salt marsh mosquito abundance with the cycle maxima coinciding with lower mosquito populations, possibly due to access by predatory fish. However, these effects were detected only at the location with extensive salt marsh habitat and astronomical tides and were weakened or lacked significance at the location with small microtidal salt marshes and wind-driven tides. Mosquitoes can serve as proxy indicators for numerous invertebrate species on the salt marsh. These predictable cycles and their effects need to be taken into consideration when investigating, restoring, or managing intertidal communities that are also facing sea-level rise. © 2017 by the Ecological Society of America.

Coral-Associated Bacterial Diversity is Conserved Across Two Deep-Sea Anthothela Species

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Stephanie Nichole Lawler

2016-04-01

Full Text Available Cold-water corals, similar to tropical corals, contain diverse and complex microbial assemblages. These bacteria provide essential biological functions within coral holobionts, facilitating increased nutrient utilization and production of antimicrobial compounds. To date, few cold-water octocoral species have been analyzed to explore the diversity and abundance of their microbial associates. For this study, 23 samples of the family Anthothelidae were collected from Norfolk (n = 12 and Baltimore Canyons (n = 11 from the western Atlantic in August 2012 and May 2013. Genetic testing found that these samples comprised two Anthothela species (Anthothela grandiflora and Anthothela sp. and Alcyonium grandiflorum. DNA was extracted and sequenced with primers targeting the V4-V5 variable region of the 16S rRNA gene using 454 pyrosequencing with GS FLX Titanium chemistry. Results demonstrated that the coral host was the primary driver of bacterial community composition. Al. grandiflorum, dominated by Alteromonadales and Pirellulales had much higher species richness, and a distinct bacterial community compared to Anthothela samples. Anthothela species (A. grandiflora and Anthothela sp. had very similar bacterial communities, dominated by Oceanospirillales and Spirochaetes. Additional analysis of core-conserved bacteria at 90% sample coverage revealed genus level conservation across Anthothela samples. This core included unclassified Oceanospirillales, Kiloniellales, Campylobacterales, and genus Spirochaeta. Members of this core were previously recognized for their functional capabilities in nitrogen cycling and suggest the possibility of a nearly complete nitrogen cycle within Anthothela species. Overall, many of the bacterial associates identified in this study have the potential to contribute to the acquisition and cycling of nutrients within the coral holobiont.

Recurrent sublethal warming reduces embryonic survival, inhibits juvenile growth, and alters species distribution projections under climate change.

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Carlo, Michael A; Riddell, Eric A; Levy, Ofir; Sears, Michael W

2018-01-01

The capacity to tolerate climate change often varies across ontogeny in organisms with complex life cycles. Recently developed species distribution models incorporate traits across life stages; however, these life-cycle models primarily evaluate effects of lethal change. Here, we examine impacts of recurrent sublethal warming on development and survival in ecological projections of climate change. We reared lizard embryos in the laboratory under temperature cycles that simulated contemporary conditions and warming scenarios. We also artificially warmed natural nests to mimic laboratory treatments. In both cases, recurrent sublethal warming decreased embryonic survival and hatchling sizes. Incorporating survivorship results into a mechanistic species distribution model reduced annual survival by up to 24% compared to models that did not incorporate sublethal warming. Contrary to models without sublethal effects, our model suggests that modest increases in developmental temperatures influence species ranges due to effects on survivorship. © 2017 John Wiley & Sons Ltd/CNRS.

Leaf litter traits of invasive species slow down decomposition compared to Spanish natives: a broad phylogenetic comparison.

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Godoy, Oscar; Castro-Díez, Pilar; Van Logtestijn, Richard S P; Cornelissen, Johannes H C; Valladares, Fernando

2010-03-01

Leaf traits related to the performance of invasive alien species can influence nutrient cycling through litter decomposition. However, there is no consensus yet about whether there are consistent differences in functional leaf traits between invasive and native species that also manifest themselves through their "after life" effects on litter decomposition. When addressing this question it is important to avoid confounding effects of other plant traits related to early phylogenetic divergences and to understand the mechanism underlying the observed results to predict which invasive species will exert larger effects on nutrient cycling. We compared initial leaf litter traits, and their effect on decomposability as tested in standardized incubations, in 19 invasive-native pairs of co-familial species from Spain. They included 12 woody and seven herbaceous alien species representative of the Spanish invasive flora. The predictive power of leaf litter decomposition rates followed the order: growth form > family > status (invasive vs. native) > leaf type. Within species pairs litter decomposition tended to be slower and more dependent on N and P in invaders than in natives. This difference was likely driven by the higher lignin content of invader leaves. Although our study has the limitation of not representing the natural conditions from each invaded community, it suggests a potential slowing down of the nutrient cycle at ecosystem scale upon invasion.

Vertical patterns of ichthyoplankton at the interface between a temperate estuary and adjacent coastal waters: Seasonal relation to diel and tidal cycles

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Primo, Ana Lígia; Azeiteiro, Ulisses M.; Marques, Sónia C.; Ré, Pedro; Pardal, Miguel A.

2012-07-01

Vertical distribution and migration pattern of ichthyoplankton assemblage in the Mondego estuary were investigated in relation to diel and tidal cycle. Summer and winter communities were sampled, at surface and bottom, over a diel cycle during spring and neap tides at a fixed station at the mouth of the estuary. Summer presented higher larvae density mainly of Pomatoschistus spp., Gobius niger and Parablennius pilicornis. Main species in winter assemblages were Pomatoschistus spp. and Sardina pilchardus. There were no differences between depth stratums across diel or tide cycle. Nevertheless, main species larval densities showed significant periodic variation associated with tide (M2) and diel (K1) cycles presenting generally, higher density at night and around low tide. Conversely, vertical patterns observed could not be related with diel or tidal cycle. Tough, main species presented some extent of vertical migration. Vertical patterns observed appear to be related to seasonal stratification and river flow, increasing amplitude during periods of less stratification and lower water currents. Present study provides a better understanding of ichthyoplankton vertical movement patterns and of small scale dynamics at the interface of two coastal European systems.

Molecular evidence for sequential colonization and taxon cycling in freshwater decapod shrimps on a Caribbean island

Science.gov (United States)

Benjamin D. Cook; Catherine M. Pringle; Jane M. Hughes

2008-01-01

Taxon cycling, i.e. sequential phases of expansions and contractions in species’ distributions associated with ecological or morphological shifts, are postulated to characterize dynamic biogeographic histories in various island faunas. The Caribbean freshwater shrimp assemblage is mostly widespread and sympatric throughout the region, although one species (Atyidae:...

Still acting green: continued expression of photosynthetic genes in the heterotrophic Dinoflagellate Pfiesteria piscicida (Peridiniales, Alveolata.

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Gwang Hoon Kim

Full Text Available The loss of photosynthetic function should lead to the cessation of expression and finally loss of photosynthetic genes in the new heterotroph. Dinoflagellates are known to have lost their photosynthetic ability several times. Dinoflagellates have also acquired photosynthesis from other organisms, either on a long-term basis or as "kleptoplastids" multiple times. The fate of photosynthetic gene expression in heterotrophs can be informative into evolution of gene expression patterns after functional loss, and the dinoflagellates ability to acquire new photosynthetic function through additional endosymbiosis. To explore this we analyzed a large-scale EST database consisting of 151,091 unique sequences (29,170 contigs, 120,921 singletons obtained from 454 pyrosequencing of the heterotrophic dinoflagellate Pfiesteria piscicida. About 597 contigs from P. piscicida showed significant homology (E-value Calvin-Benson cycle were found, genes of the light-dependent reaction were also identified. Also genes of associated pathways including the chorismate pathway and genes involved in starch metabolism were discovered. BLAST searches and phylogenetic analysis suggest that these plastid-associated genes originated from several different photosynthetic ancestors. The Calvin-Benson cycle genes are mostly associated with genes derived from the secondary plastids of peridinin-containing dinoflagellates, while the light-harvesting genes are derived from diatoms, or diatoms that are tertiary plastids in other dinoflagellates. The continued expression of many genes involved in photosynthetic pathways indicates that the loss of transcriptional regulation may occur well after plastid loss and could explain the organism's ability to "capture" new plastids (i.e. different secondary endosymbiosis or tertiary symbioses to renew photosynthetic function.

Still acting green: continued expression of photosynthetic genes in the heterotrophic Dinoflagellate Pfiesteria piscicida (Peridiniales, Alveolata).

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Kim, Gwang Hoon; Jeong, Hae Jin; Yoo, Yeong Du; Kim, Sunju; Han, Ji Hee; Han, Jong Won; Zuccarello, Giuseppe C

2013-01-01

The loss of photosynthetic function should lead to the cessation of expression and finally loss of photosynthetic genes in the new heterotroph. Dinoflagellates are known to have lost their photosynthetic ability several times. Dinoflagellates have also acquired photosynthesis from other organisms, either on a long-term basis or as "kleptoplastids" multiple times. The fate of photosynthetic gene expression in heterotrophs can be informative into evolution of gene expression patterns after functional loss, and the dinoflagellates ability to acquire new photosynthetic function through additional endosymbiosis. To explore this we analyzed a large-scale EST database consisting of 151,091 unique sequences (29,170 contigs, 120,921 singletons) obtained from 454 pyrosequencing of the heterotrophic dinoflagellate Pfiesteria piscicida. About 597 contigs from P. piscicida showed significant homology (E-value Calvin-Benson cycle were found, genes of the light-dependent reaction were also identified. Also genes of associated pathways including the chorismate pathway and genes involved in starch metabolism were discovered. BLAST searches and phylogenetic analysis suggest that these plastid-associated genes originated from several different photosynthetic ancestors. The Calvin-Benson cycle genes are mostly associated with genes derived from the secondary plastids of peridinin-containing dinoflagellates, while the light-harvesting genes are derived from diatoms, or diatoms that are tertiary plastids in other dinoflagellates. The continued expression of many genes involved in photosynthetic pathways indicates that the loss of transcriptional regulation may occur well after plastid loss and could explain the organism's ability to "capture" new plastids (i.e. different secondary endosymbiosis or tertiary symbioses) to renew photosynthetic function.

Horizontal transfer of a eukaryotic plastid-targeted protein gene to cyanobacteria

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Keeling Patrick J

2007-06-01

Full Text Available Abstract Background Horizontal or lateral transfer of genetic material between distantly related prokaryotes has been shown to play a major role in the evolution of bacterial and archaeal genomes, but exchange of genes between prokaryotes and eukaryotes is not as well understood. In particular, gene flow from eukaryotes to prokaryotes is rarely documented with strong support, which is unusual since prokaryotic genomes appear to readily accept foreign genes. Results Here, we show that abundant marine cyanobacteria in the related genera Synechococcus and Prochlorococcus acquired a key Calvin cycle/glycolytic enzyme from a eukaryote. Two non-homologous forms of fructose bisphosphate aldolase (FBA are characteristic of eukaryotes and prokaryotes respectively. However, a eukaryotic gene has been inserted immediately upstream of the ancestral prokaryotic gene in several strains (ecotypes of Synechococcus and Prochlorococcus. In one lineage this new gene has replaced the ancestral gene altogether. The eukaryotic gene is most closely related to the plastid-targeted FBA from red algae. This eukaryotic-type FBA once replaced the plastid/cyanobacterial type in photosynthetic eukaryotes, hinting at a possible functional advantage in Calvin cycle reactions. The strains that now possess this eukaryotic FBA are scattered across the tree of Synechococcus and Prochlorococcus, perhaps because the gene has been transferred multiple times among cyanobacteria, or more likely because it has been selectively retained only in certain lineages. Conclusion A gene for plastid-targeted FBA has been transferred from red algae to cyanobacteria, where it has inserted itself beside its non-homologous, functional analogue. Its current distribution in Prochlorococcus and Synechococcus is punctate, suggesting a complex history since its introduction to this group.

C1 metabolism plays an important role during formaldehyde metabolism and detoxification in petunia under liquid HCHO stress.

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Zhang, Wei; Tang, Lijuan; Sun, Huiqun; Han, Shuang; Wang, Xinjia; Zhou, Shengen; Li, Kunzhi; Chen, Limei

2014-10-01

Petunia hybrida is a model ornamental plant grown worldwide. To understand the HCHO-uptake efficiency and metabolic mechanism of petunia, the aseptic petunia plants were treated in HCHO solutions. An analysis of HCHO-uptake showed that petunia plants effectively removed HCHO from 2, 4 and 6 mM HCHO solutions. The (13)C NMR analyses indicated that H(13)CHO was primarily used to synthesize [5-(13)C]methionine (Met) via C1 metabolism in petunia plants treated with 2 mM H(13)CHO. Pretreatment with cyclosporin A (CSA) or l-carnitine (LC), the inhibitors of mitochondrial permeability transition pores, did not affect the synthesis of [5-(13)C]Met in petunia plants under 2 mM H(13)CHO stress, indicating that the Met-generated pathway may function in the cytoplasm. Under 4 or 6 mM liquid H(13)CHO stress, H(13)CHO metabolism in petunia plants produced considerable amount of H(13)COOH and [2-(13)C]glycine (Gly) through C1 metabolism and a small amount of [U-(13)C]Gluc via the Calvin Cycle. Pretreatment with CSA or LC significantly inhibited the production of [2-(13)C]Gly in 6 mM H(13)CHO-treated petunia plants, which suggests that chloroplasts and peroxisomes might be involved in the generation of [2-(13)C]Gly. These results revealed that the C1 metabolism played an important role, whereas the Calvin Cycle had only a small contribution during HCHO metabolism and detoxification in petunia under liquid HCHO stress. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Chilli anthracnose disease caused by Colletotrichum species.

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Than, Po Po; Prihastuti, Haryudian; Phoulivong, Sitthisack; Taylor, Paul W J; Hyde, Kevin D

2008-10-01

Anthracnose disease is one of the major economic constraints to chilli production worldwide, especially in tropical and subtropical regions. Accurate taxonomic information is necessary for effective disease control management. In the Colletotrichum patho-system, different Colletotrichum species can be associated with anthracnose of the same host. Little information is known concerning the interactions of the species associated with the chilli anthracnose although several Colletotrichum species have been reported as causal agents of chilli anthracnose disease worldwide. The ambiguous taxonomic status of Colletotrichum species has resulted in inaccurate identification which may cause practical problems in plant breeding and disease management. Although the management and control of anthracnose disease are still being extensively researched, commercial cultivars of Capsicum annuum that are resistant to the pathogens that cause chilli anthracnose have not yet been developed. This paper reviews the causal agents of chilli anthracnose, the disease cycle, conventional methods in identification of the pathogen and molecular approaches that have been used for the identification of Colletotrichum species. Pathogenetic variation and population structure of the causal agents of chilli anthracnose along with the current taxonomic status of Colletotrichum species are discussed. Future developments leading to the disease management strategies are suggested.

Biogeochemical Cycling and Environmental Stability of Pu Relevant to Long-Term Stewardship of DOE Sites

Energy Technology Data Exchange (ETDEWEB)

Francis, Arokiasamy J.; Santschi, Peter H.; Honeyman, Bruce D.

2005-06-01

The overall objective of this proposed research is to understand the biogeochemical cycling of Pu in environments of interest to long-term DOE stewardship issues. Central to Pu cycling (transport initiation to immobilization) is the role of microorganisms. The hypothesis underlying this proposal is that microbial activity is the causative agent in initiating the mobilization of Pu in near-surface environments: through the transformation of Pu associated with solid phases, production of extracellular polymeric substances (EPS) carrier phases, and the creation of microenvironments. Also, microbial processes are central to the immobilization of Pu species, through the metabolism of organically complexed Pu species and Pu associated with extracellular carrier phases and the creation of environments favorable for Pu transport retardation.

Biogeochemical Cycling and Environmental Stability of Pu Relevant to Long-Term Stewardship of DOE Sites

Energy Technology Data Exchange (ETDEWEB)

Honeyman, Bruce D.

2006-06-01

The overall objective of this proposed research is to understand the biogeochemical cycling of Pu in environments of interest to long-term DOE stewardship issues. Central to Pu cycling (transport initiation to immobilization) is the role of microorganisms. The hypothesis underlying this proposal is that microbial activity is the causative agent in initiating the mobilization of Pu in near-surface environments: through the transformation of Pu associated with solid phases, production of extracellular polymeric substances (EPS) carrier phases, and the creation of microenvironments. Also, microbial processes are central to the immobilization of Pu species, through the metabolism of organically complexed Pu species and Pu associated with extracellular carrier phases and the creation of environments favorable for Pu transport retardation.

Dynamical principles of cell-cycle arrest: Reversible, irreversible, and mixed strategies

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Pfeuty, Benjamin

2012-08-01

Living cells often alternate between proliferating and nonproliferating states as part of individual or collective strategies to adapt to complex and changing environments. To this aim, they have evolved a biochemical regulatory network enabling them to switch between cell-division cycles (i.e., oscillatory state) and cell-cycle arrests (i.e., steady state) in response to extracellular cues. This can be achieved by means of a variety of bifurcation mechanisms that potentially give rise to qualitatively distinct cell-cycle arrest properties. In this paper, we study the dynamics of a minimal biochemical network model in which a cell-division oscillator and a differentiation switch mutually antagonize. We identify the existence of three biologically plausible bifurcation scenarios organized around a codimension-four swallowtail-homoclinic singularity. As a result, the model exhibits a broad repertoire of cell-cycle arrest properties in terms of reversibility of these arrests, tunability of interdivision time, and ability to track time-varying signals. This dynamic versatility would explain the diversity of cell-cycle arrest strategies developed in different living species and functional contexts.

First Comparative Analysis of the Community Structures and Carbon Metabolic Pathways of the Bacteria Associated with Alvinocaris longirostris in a Hydrothermal Vent of Okinawa Trough.

Science.gov (United States)

Sun, Qing-Lei; Zeng, Zhi-Gang; Chen, Shuai; Sun, Li

2016-01-01

Alvinocaris longirostris is a species of shrimp existing in the hydrothermal fields of Okinawa Trough. To date the structure and function of the microbial community associated with A. longirostris are essentially unknown. In this study, by employment of the techniques of high through-put sequencing and clone library construction and analysis, we compared for the first time the community structures and metabolic profiles of microbes associated with the gill and gut of A. longirostris in a hydrothermal field of Okinawa Trough. Fourteen phyla were detected in the gill and gut communities, of which 11 phyla were shared by both tissues. Proteobacteria made up a substantial proportion in both tissues, while Firmicutes was abundant only in gut. Although gill and gut communities were similar in bacterial diversities, the bacterial community structures in these two tissues were significantly different. Further, we discovered for the first time the existence in the gill and gut communities of A. longirostris the genes (cbbM and aclB) encoding the key enzymes of Calvin-Benson-Bassham (CBB) cycle and the reductive tricarboxylic acid (rTCA) cycle, and that both cbbM and aclB were significantly more abundant in gill than in gut. Taken together, these results provide the first evidence that at least two carbon fixation pathways are present in both the gill and the gut communities of A. longirostris, and that the communities in different tissues likely differ in autotrophic productivity.

First Comparative Analysis of the Community Structures and Carbon Metabolic Pathways of the Bacteria Associated with Alvinocaris longirostris in a Hydrothermal Vent of Okinawa Trough.

Directory of Open Access Journals (Sweden)

Qing-Lei Sun

Full Text Available Alvinocaris longirostris is a species of shrimp existing in the hydrothermal fields of Okinawa Trough. To date the structure and function of the microbial community associated with A. longirostris are essentially unknown. In this study, by employment of the techniques of high through-put sequencing and clone library construction and analysis, we compared for the first time the community structures and metabolic profiles of microbes associated with the gill and gut of A. longirostris in a hydrothermal field of Okinawa Trough. Fourteen phyla were detected in the gill and gut communities, of which 11 phyla were shared by both tissues. Proteobacteria made up a substantial proportion in both tissues, while Firmicutes was abundant only in gut. Although gill and gut communities were similar in bacterial diversities, the bacterial community structures in these two tissues were significantly different. Further, we discovered for the first time the existence in the gill and gut communities of A. longirostris the genes (cbbM and aclB encoding the key enzymes of Calvin-Benson-Bassham (CBB cycle and the reductive tricarboxylic acid (rTCA cycle, and that both cbbM and aclB were significantly more abundant in gill than in gut. Taken together, these results provide the first evidence that at least two carbon fixation pathways are present in both the gill and the gut communities of A. longirostris, and that the communities in different tissues likely differ in autotrophic productivity.

Comparative genomic analysis of carbon and nitrogen assimilation mechanisms in three indigenous bioleaching bacteria: predictions and validations

Science.gov (United States)

Levicán, Gloria; Ugalde, Juan A; Ehrenfeld, Nicole; Maass, Alejandro; Parada, Pilar

2008-01-01

Background Carbon and nitrogen fixation are essential pathways for autotrophic bacteria living in extreme environments. These bacteria can use carbon dioxide directly from the air as their sole carbon source and can use different sources of nitrogen such as ammonia, nitrate, nitrite, or even nitrogen from the air. To have a better understanding of how these processes occur and to determine how we can make them more efficient, a comparative genomic analysis of three bioleaching bacteria isolated from mine sites in Chile was performed. This study demonstrated that there are important differences in the carbon dioxide and nitrogen fixation mechanisms among bioleaching bacteria that coexist in mining environments. Results In this study, we probed that both Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans incorporate CO2 via the Calvin-Benson-Bassham cycle; however, the former bacterium has two copies of the Rubisco type I gene whereas the latter has only one copy. In contrast, we demonstrated that Leptospirillum ferriphilum utilizes the reductive tricarboxylic acid cycle for carbon fixation. Although all the species analyzed in our study can incorporate ammonia by an ammonia transporter, we demonstrated that Acidithiobacillus thiooxidans could also assimilate nitrate and nitrite but only Acidithiobacillus ferrooxidans could fix nitrogen directly from the air. Conclusion The current study utilized genomic and molecular evidence to verify carbon and nitrogen fixation mechanisms for three bioleaching bacteria and provided an analysis of the potential regulatory pathways and functional networks that control carbon and nitrogen fixation in these microorganisms. PMID:19055775

Alternative ORC bottoming cycles FOR combined cycle power plants

International Nuclear Information System (INIS)

Chacartegui, R.; Sanchez, D.; Munoz, J.M.; Sanchez, T.

2009-01-01

In this work, low temperature Organic Rankine Cycles are studied as bottoming cycle in medium and large scale combined cycle power plants. The analysis aims to show the interest of using these alternative cycles with high efficiency heavy duty gas turbines, for example recuperative gas turbines with lower gas turbine exhaust temperatures than in conventional combined cycle gas turbines. The following organic fluids have been considered: R113, R245, isobutene, toluene, cyclohexane and isopentane. Competitive results have been obtained for toluene and cyclohexane ORC combined cycles, with reasonably high global efficiencies. The paper is structured in four main parts. A review of combined cycle and ORC cycle technologies is presented, followed by a thermodynamic analysis of combined cycles with commercial gas turbines and ORC low temperature bottoming cycles. Then, a parametric optimization of an ORC combined cycle plant is performed in order to achieve a better integration between these two technologies. Finally, some economic considerations related to the use of ORC in combined cycles are discussed.

Moonstruck how lunar cycles affect life

CERN Document Server

Naylor, Ernest

2015-01-01

Throughout history, the influence of the full Moon on humans and animals has featured in folklore and myths. Yet it has become increasingly apparent that many organisms really are influenced indirectly, and in some cases directly, by the lunar cycle. Breeding behaviour among some marine animals has been demonstrated to be controlled by internal circalunar biological clocks, to the point where lunar-daily and lunar-monthly patterns of Moon-generated tides are embedded in their genes. Yet, intriguingly, Moon-related behaviours are also found in dry land and fresh water species living far beyond the influence of any tides. In Moonstruck, Ernest Naylor dismisses the myths concerning the influence of the Moon, but shows through a range of fascinating examples the remarkable real effects that we are now finding through science. He suggests that since the advent of evolution on Earth, which occurred shortly after the formation of the Moon, animals evolved adaptations to the lunar cycle, and considers whether, if Moo...

Molecular analyses reveal high species diversity of trematodes in a sub-Arctic lake

Science.gov (United States)

Soldánová, Miroslava; Georgieva, Simona; Roháčováa, Jana; Knudsen, Rune; Kuhn, Jesper A.; Henriksen, Eirik H.; Siwertsson, Anna; Shaw, Jenny C.; Kuris, Armand M.; Amundsen, Per-Arne; Scholz, Tomáš; Lafferty, Kevin D.; Kostadinova, Aneta

2017-01-01

To identify trematode diversity and life-cycles in the sub-Arctic Lake Takvatn, Norway, we characterised 120 trematode isolates from mollusc first intermediate hosts, metacercariae from second intermediate host fishes and invertebrates, and adults from fish and invertebrate definitive hosts, using molecular techniques. Phylogenies based on nuclear and/or mtDNA revealed high species richness (24 species or species-level genetic lineages), and uncovered trematode diversity (16 putative new species) from five families typical in lake ecosystems (Allocreadiidae, Diplostomidae, Plagiorchiidae, Schistosomatidae and Strigeidae). Sampling potential invertebrate hosts allowed matching of sequence data for different stages, thus achieving molecular elucidation of trematode life-cycles and exploration of host-parasite interactions. Phylogenetic analyses also helped identify three major mollusc intermediate hosts (Radix balthica, Pisidium casertanum and Sphaerium sp.) in the lake. Our findings increase the known trematode diversity at the sub-Arctic Lake Takvatn, showing that digenean diversity is high in this otherwise depauperate sub-Arctic freshwater ecosystem, and indicating that sub-Arctic and Arctic ecosystems may be characterised by unique trematode assemblages.

Cycling infrastructure for reducing cycling injuries in cyclists.

Science.gov (United States)

Mulvaney, Caroline A; Smith, Sherie; Watson, Michael C; Parkin, John; Coupland, Carol; Miller, Philip; Kendrick, Denise; McClintock, Hugh

2015-12-10

Cycling is an attractive form of transport. It is beneficial to the individual as a form of physical activity that may fit more readily into an individual's daily routine, such as for cycling to work and to the shops, than other physical activities such as visiting a gym. Cycling is also beneficial to the wider community and the environment as a result of fewer motorised journeys. Cyclists are seen as vulnerable road users who are frequently in close proximity to larger and faster motorised vehicles. Cycling infrastructure aims to make cycling both more convenient and safer for cyclists. This review is needed to guide transport planning. To:1. evaluate the effects of different types of cycling infrastructure on reducing cycling injuries in cyclists, by type of infrastructure;2. evaluate the effects of cycling infrastructure on reducing the severity of cycling injuries in cyclists;3. evaluate the effects of cycling infrastructure on reducing cycling injuries in cyclists with respect to age, sex and social group. We ran the most recent search on 2nd March 2015. We searched the Cochrane Injuries Group Specialised Register, CENTRAL (The Cochrane Library), MEDLINE (OvidSP), Embase Classic + Embase(OvidSP), PubMed and 10 other databases. We searched websites, handsearched conference proceedings, screened reference lists of included studies and previously published reviews and contacted relevant organisations. We included randomised controlled trials, cluster randomised controlled trials, controlled before-after studies, and interrupted time series studies which evaluated the effect of cycling infrastructure (such as cycle lanes, tracks or paths, speed management, roundabout design) on cyclist injury or collision rates. Studies had to include a comparator, that is, either no infrastructure or a different type of infrastructure. We excluded studies that assessed collisions that occurred as a result of competitive cycling. Two review authors examined the titles and

Changes induced by the Pepper mild mottle tobamovirus on the chloroplast proteome of Nicotiana benthamiana.

Science.gov (United States)

Pineda, M; Sajnani, C; Barón, M

2010-01-01

We have analyzed the chloroplast proteome of Nicotiana benthamiana using two-dimensional gel electrophoresis and mass spectrometry followed by a database search. In order to improve the resolution of the two-dimensional electrophoresis gels, we have made separate maps for the low and the high pH range. At least 200 spots were detected. We identified 72 polypeptides, some being isoforms of different multiprotein families. In addition, changes in this chloroplast proteome induced by the infection with the Spanish strain of the Pepper mild mottle virus were investigated. Viral infection induced the down-regulation of several chloroplastidic proteins involved in both the photosynthetic electron-transport chain and the Benson-Calvin cycle.

Microbial diversity and carbon cycling in San Francisco Bay wetlands

Energy Technology Data Exchange (ETDEWEB)

Theroux, Susanna [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.; Hartman, Wyatt [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.; He, Shaomei [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.; Univ. of Wisconsin, Madison, WI (United States); Tringe, Susannah [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.

2014-03-21

Wetland restoration efforts in San Francisco Bay aim to rebuild habitat for endangered species and provide an effective carbon storage solution, reversing land subsidence caused by a century of industrial and agricultural development. However, the benefits of carbon sequestration may be negated by increased methane production in newly constructed wetlands, making these wetlands net greenhouse gas (GHG) sources to the atmosphere. We investigated the effects of wetland restoration on below-ground microbial communities responsible for GHG cycling in a suite of historic and restored wetlands in SF Bay. Using DNA and RNA sequencing, coupled with real-time GHG monitoring, we profiled the diversity and metabolic potential of wetland soil microbial communities. The wetland soils harbor diverse communities of bacteria and archaea whose membership varies with sampling location, proximity to plant roots and sampling depth. Our results also highlight the dramatic differences in GHG production between historic and restored wetlands and allow us to link microbial community composition and GHG cycling with key environmental variables including salinity, soil carbon and plant species.

Life cycle and spring phenology of Temora longicornis in the Baltic Sea

DEFF Research Database (Denmark)

Dutz, Jörg; Mohrholz, V.; van Beusekom, J. E. E.

2010-01-01

The seasonal variation in abundance, biomass and vertical distribution of nauplii and copepodites of Temora longicornis in the Bornholm Basin was studied from March 2002 to May 2003 to understand the overwintering, spring development and life cycle of this species in the Baltic Sea. The analysis...... of the life cycle by means of stage structure, copepodite length and stage duration revealed that T. longicornis produced 5 to 6 generations yr–1. The species overwintered in low abundance as an active, slowly developing generation with adults appearing from February/March onwards. The onset of the spring...... bloom in April triggered reproduction and initiated the first spring generation (G1) with a strong rise in nauplii abundance. The stock biomass increased in May with the occurrence of the copepodites of G1 and remained high during the succeeding generations G2 and G3 until August. The stock...

Global climate change and introduced species in United States forests

Energy Technology Data Exchange (ETDEWEB)

Simberloff, D. [Department of Ecology and Evolutionary Biology, University of Tennessee, 37996 Knoxville, TN (United States)

2000-11-15

Introduced species already cause billions of dollars of damage annually in United States forests, plus massive ecological damage whose economic value has often not been estimated. The variety of impacts is staggering and includes herbivory, predation, disease, parasitism, competition, habitat destruction, hybridization, and changed disturbance regimes and nutrient cycles. How global climate change will affect these impacts has scarcely been assessed. Range changes of existing introduced species will be prominent, as many species' biogeographic ranges are set primarily by climate. Similarly, some species that might otherwise not have survived will be able to establish populations in a changed climate. It is more difficult to predict what the impacts of the introduced species will be. What is most needed are studies of the combined impacts of changing climate, CO{sub 2}, and nutrients. Certain aspects of the biology of introduced species, such as evolution and autonomous dispersal, greatly complicate the prediction of spread and impact of introduced species.

An elaborated feeding cycle model for reductions in vectorial capacity of night-biting mosquitoes by insecticide-treated nets.

Science.gov (United States)

Le Menach, Arnaud; Takala, Shannon; McKenzie, F Ellis; Perisse, Andre; Harris, Anthony; Flahault, Antoine; Smith, David L

2007-01-25

Insecticide Treated Nets (ITNs) are an important tool for malaria control. ITNs are effective because they work on several parts of the mosquito feeding cycle, including both adult killing and repelling effects. Using an elaborated description of the classic feeding cycle model, simple formulas have been derived to describe how ITNs change mosquito behaviour and the intensity of malaria transmission, as summarized by vectorial capacity and EIR. The predicted changes are illustrated as a function of the frequency of ITN use for four different vector populations using parameter estimates from the literature. The model demonstrates that ITNs simultaneously reduce mosquitoes' lifespans, lengthen the feeding cycle, and by discouraging human biting divert more bites onto non-human hosts. ITNs can substantially reduce vectorial capacity through small changes to all of these quantities. The total reductions in vectorial capacity differ, moreover, depending on baseline behavior in the absence of ITNs. Reductions in lifespan and vectorial capacity are strongest for vector species with high baseline survival. Anthropophilic and zoophilic species are affected differently by ITNs; the feeding cycle is lengthened more for anthrophilic species, and the proportion of bites that are diverted onto non-human hosts is higher for zoophilic species. This model suggests that the efficacy of ITNs should be measured as a total reduction in transmission intensity, and that the quantitative effects will differ by species and by transmission intensity. At very high rates of ITN use, ITNs can generate large reductions in transmission intensity that could provide very large reductions in transmission intensity, and effective malaria control in some areas, especially when used in combination with other control measures. At high EIR, ITNs will probably not substantially reduce the parasite rate, but when transmission intensity is low, reductions in vectorial capacity combine with reductions in

Developing the User Experience for a Next Generation Nuclear Fuel Cycle Simulator (NGFCS)

International Nuclear Information System (INIS)

Wilson, Paul H.; Schneider, Erich; Pascucci, Valerio; Livnat, Yarden; Hiromoto, Robert; Scopatz, Anthony; Brossard, Dominique; Scheufele, Dietram

2017-01-01

This project made substantial progress on its original aim for providing a modern user experience for nuclear fuel cycle analysis while also creating a robust and functional next- generation fuel cycle simulator. The Cyclus kernel experienced a dramatic clari cation of its interfaces and data model, becoming a full- edged agent-based framework, with strong support for third party developers of novel archetypes. The most important contribution of this project to the the development of Cyclus was the introduction of tools to facilitate archetype development. These include automated code generation of routine archetype components, metadata annotations to provide re ection and rich description of each data member's purpose, and mechanisms for input validation and output of complex data. A comprehensive social science investigation of decision makers' interests in nuclear fuel cycles, and speci cally their interests in nuclear fuel cycle simulators (NFCSs) as tools for understanding nuclear fuel cycle options, was conducted. This included document review and analysis, stakeholder interviews, and a survey of decision makers. This information was used to study the role of visualization formats and features in communicating information about nuclear fuel cycles. A exible and user-friendly tool was developed for building Cyclus analysis models, featuring a drag-and-drop interface and automatic input form generation for novel archetypes. Cycic allows users to design fuel cycles from arbitrary collections of facilities for the first time, with mechanisms that contribute to consistency within that fuel cycle. Interacting with some of the metadata capabilities introduced in the above-mentioned tools to support archetype development, Cycic also automates the generation of user input forms for novel archetypes with little to no special knowledge required by the archetype developers. Translation of the fundamental metrics of Cyclus into more interesting quantities is

Developing the User Experience for a Next Generation Nuclear Fuel Cycle Simulator (NGFCS)

Energy Technology Data Exchange (ETDEWEB)

Wilson, Paul H. [Univ. of Wisconsin, Madison, WI (United States); Schneider, Erich [Univ. of Texas, Austin, TX (United States); Pascucci, Valerio [Univ. of Utah, Salt Lake City, UT (United States); Livnat, Yarden [Univ. of Utah, Salt Lake City, UT (United States); Hiromoto, Robert [Univ. of Idaho, Moscow, ID (United States); Scopatz, Anthony [Univ. of Wisconsin, Madison, WI (United States); Brossard, Dominique [Univ. of Wisconsin, Madison, WI (United States); Scheufele, Dietram [Univ. of Wisconsin, Madison, WI (United States)

2017-07-30

This project made substantial progress on its original aim for providing a modern user experience for nuclear fuel cycle analysis while also creating a robust and functional next- generation fuel cycle simulator. The Cyclus kernel experienced a dramatic clari cation of its interfaces and data model, becoming a full- edged agent-based framework, with strong support for third party developers of novel archetypes. The most important contribution of this project to the the development of Cyclus was the introduction of tools to facilitate archetype development. These include automated code generation of routine archetype components, metadata annotations to provide re ection and rich description of each data member's purpose, and mechanisms for input validation and output of complex data. A comprehensive social science investigation of decision makers' interests in nuclear fuel cycles, and speci cally their interests in nuclear fuel cycle simulators (NFCSs) as tools for understanding nuclear fuel cycle options, was conducted. This included document review and analysis, stakeholder interviews, and a survey of decision makers. This information was used to study the role of visualization formats and features in communicating information about nuclear fuel cycles. A exible and user-friendly tool was developed for building Cyclus analysis models, featuring a drag-and-drop interface and automatic input form generation for novel archetypes. Cycic allows users to design fuel cycles from arbitrary collections of facilities for the rst time, with mechanisms that contribute to consistency within that fuel cycle. Interacting with some of the metadata capabilities introduced in the above-mentioned tools to support archetype development, Cycic also automates the generation of user input forms for novel archetypes with little to no special knowledge required by the archetype developers. Translation of the fundamental metrics of Cyclus into more interesting quantities is

Eco-physiological Baltic picoplankton analysis and its implementation in Synechoccocus species life cycle numerical algorithm

Science.gov (United States)

Cieszyńska, Agata; Śliwińska-Wilczewska, Sylwia

2017-04-01

mixtures of conditions were applied in the laboratory experiments. Results from these experiments were the foundation to create picocyanobacteria life cycle algorithm - pico-bioalgorithm. The form of algorithm bases on the Ecological Regional Ocean Model formulas for functional phytoplankton groups. According to this, in pico-bioalgorithm the dependence on temperature and salinity of water body and the occurrence of nutrients are provided along with the coefficients determining mortality of picoplankton cells and coefficients of respiration and growth rates. In order to prescribe the limiting properties, modified Michaelis-Menten formula with squared arguments as a limiting function was used. Picoplanktonic organisms are very specific and can live in environments, which may be initially defined as impossible for such organisms to survive. The issue of picoplanktonic species inhabiting the Baltic Sea needs to be explored in details. Present study and proposed algorithm comprise an important step in this scientific exploration. This work has been funded by the National Centre of Science project (contract number: 2012/07/N/ST10/03485) entitled: "Improved understanding of phytoplankton blooms in the Baltic Sea based on numerical models and existing data sets". The Author (AC) received funding from National Centre of Sciences in doctoral scholarship program (contract number: 2016/20/T/ST10/00214);

LEAF RESIDUE DECOMPOSITION OF SELECTED ATLANTIC FOREST TREE SPECIES

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Helga Dias Arato

2018-02-01

Full Text Available ABSTRACT Biogeochemical cycling is essential to establish and maintain plant and animal communities. Litter is one of main compartments of this cycle, and the kinetics of leaf decomposition in forest litter depend on the chemical composition and environmental conditions. This study evaluated the effect of leaf composition and environmental conditions on leaf decomposition of native Atlantic Forest trees. The following species were analyzed: Mabea fistulifera Mart., Bauhinia forficata Link., Aegiphila sellowiana Cham., Zeyheria tuberculosa (Vell, Luehea grandiflora Mart. et. Zucc., Croton floribundus Spreng., Trema micrantha (L Blume, Cassia ferruginea (Schrad Schrad ex DC, Senna macranthera (DC ex Collad. H. S. Irwin and Barney and Schinus terebinthifolius Raddi (Anacardiaceae. For each species, litter bags were distributed on and fixed to the soil surface of soil-filled pots (in a greenhouse, or directly to the surface of the same soil type in a natural forest (field. Every 30 days, the dry weight and soil basal respiration in both environments were determined. The cumulative decomposition of leaves varied according to the species, leaf nutrient content and environment. In general, the decomposition rate was lowest for Aegiphila sellowiana and fastest for Bauhinia forficate and Schinus terebinthifolius. This trend was similar under the controlled conditions of a greenhouse and in the field. The selection of species with a differentiated decomposition pattern, suited for different stages of the recovery process, can help improve soil restoration.

Optimum gas turbine cycle for combined cycle power plant

International Nuclear Information System (INIS)

Polyzakis, A.L.; Koroneos, C.; Xydis, G.

2008-01-01

The gas turbine based power plant is characterized by its relatively low capital cost compared with the steam power plant. It has environmental advantages and short construction lead time. However, conventional industrial engines have lower efficiencies, especially at part load. One of the technologies adopted nowadays for efficiency improvement is the 'combined cycle'. The combined cycle technology is now well established and offers superior efficiency to any of the competing gas turbine based systems that are likely to be available in the medium term for large scale power generation applications. This paper has as objective the optimization of a combined cycle power plant describing and comparing four different gas turbine cycles: simple cycle, intercooled cycle, reheated cycle and intercooled and reheated cycle. The proposed combined cycle plant would produce 300 MW of power (200 MW from the gas turbine and 100 MW from the steam turbine). The results showed that the reheated gas turbine is the most desirable overall, mainly because of its high turbine exhaust gas temperature and resulting high thermal efficiency of the bottoming steam cycle. The optimal gas turbine (GT) cycle will lead to a more efficient combined cycle power plant (CCPP), and this will result in great savings. The initial approach adopted is to investigate independently the four theoretically possible configurations of the gas plant. On the basis of combining these with a single pressure Rankine cycle, the optimum gas scheme is found. Once the gas turbine is selected, the next step is to investigate the impact of the steam cycle design and parameters on the overall performance of the plant, in order to choose the combined cycle offering the best fit with the objectives of the work as depicted above. Each alterative cycle was studied, aiming to find the best option from the standpoint of overall efficiency, installation and operational costs, maintainability and reliability for a combined power

Photochemical Cycling of Reactive Oxygen Species in Hydrothermal Springs: Impacts on Biosignature Preservation

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Mave, M. A.; Hinman, N. W.; Stevens, L.

2017-12-01

Biosignatures can be preserved via rapid entombment by aqueous minerals in a system. Wilson et al. (2000) found that high UV flux leads to increased production of reactive oxygen species (ROS), which promote iron (Fe) oxidation, and possible accumulation on microbial surfaces, leading to detectable microfossils. Hydrogen peroxide (H2O2) is a measurable ROS that serves as proxy for less stable ROS. Overall diel cycling of H2O2 is likely controlled by changes in photoreactive speciation of Fe (McKnight et al., 1988) in Fe-rich systems. To test this hypothesis, we conducted a 48-hour photochemical field study of Elk Pool in the Norris Geyser Basin at Yellowstone National Park in July, 2017 in which we measured UVA and UVB, along with H2O2 via the scopoletin fluorescence quenching method (Holm et al., 1987). Measurements were taken every few hours, and we found that maximum ROS production occurred during maximum UV irradiation. We also ran several experiments on-site in which we collected and altered spring water to either inactivate or catalyze naturally occurring reactions as well as to isolate primary mechanisms responsible for production of H2O2. Experiments were run in UV permeable Whirlpak bags and Fisherbrand tubes. Elk Pool showed only trace Fe content (pH 4) at the time of our study, so Fe-silica coated petrographic slides were added to the tube experiments (Fe-added experiments). Both sets of experiments included filtered and unfiltered spring water to differentiate biotic from abiotic mechanisms, and both UV-exposed and dark controls to separate UV-induced mechanisms for ROS formation. UV-exposed water always had greater ROS than dark experiments. Filtered spring water had higher ROS concentrations than unfiltered water, except when Fe was added. In the Fe-added experiments, unfiltered spring water had slightly greater ROS production relative to filtered water and had the lowest pH and highest aqueous Fe content after 7 hours. All Fe-added experiments showed

Food-Web Complexity in Guaymas Basin Hydrothermal Vents and Cold Seeps.

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Marie Portail

Full Text Available In the Guaymas Basin, the presence of cold seeps and hydrothermal vents in close proximity, similar sedimentary settings and comparable depths offers a unique opportunity to assess and compare the functioning of these deep-sea chemosynthetic ecosystems. The food webs of five seep and four vent assemblages were studied using stable carbon and nitrogen isotope analyses. Although the two ecosystems shared similar potential basal sources, their food webs differed: seeps relied predominantly on methanotrophy and thiotrophy via the Calvin-Benson-Bassham (CBB cycle and vents on petroleum-derived organic matter and thiotrophy via the CBB and reductive tricarboxylic acid (rTCA cycles. In contrast to symbiotic species, the heterotrophic fauna exhibited high trophic flexibility among assemblages, suggesting weak trophic links to the metabolic diversity of chemosynthetic primary producers. At both ecosystems, food webs did not appear to be organised through predator-prey links but rather through weak trophic relationships among co-occurring species. Examples of trophic or spatial niche differentiation highlighted the importance of species-sorting processes within chemosynthetic ecosystems. Variability in food web structure, addressed through Bayesian metrics, revealed consistent trends across ecosystems. Food-web complexity significantly decreased with increasing methane concentrations, a common proxy for the intensity of seep and vent fluid fluxes. Although high fluid-fluxes have the potential to enhance primary productivity, they generate environmental constraints that may limit microbial diversity, colonisation of consumers and the structuring role of competitive interactions, leading to an overall reduction of food-web complexity and an increase in trophic redundancy. Heterogeneity provided by foundation species was identified as an additional structuring factor. According to their biological activities, foundation species may have the potential to

Sonoran Desert ecosystem transformation by a C4 grass without the grass/fire cycle

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Olsson, Aaryn D.; Betancourt, Julio; McClaran, Mitchel P.; Marsh, Stuart E.

2012-01-01

Aim Biological invasions facilitate ecosystem transformation by altering the structure and function, diversity, dominance and disturbance regimes. A classic case is the grass–fire cycle in which grass invasion increases the frequency, scale and/or intensity of wildfires and promotes the continued invasion of invasive grasses. Despite wide acceptance of the grass–fire cycle, questions linger about the relative roles that interspecific plant competition and fire play in ecosystem transformations. Location Sonoran Desert Arizona Upland of the Santa Catalina Mountains, Arizona, USA. Methods We measured species cover, density and saguaro (Carnegiea gigantea) size structure along gradients of Pennisetum ciliare invasion at 10 unburned/ungrazed P. ciliare patches. Regression models quantified differences in diversity, cover and density with respect to P. ciliare cover, and residence time and a Fisher's exact test detected demographic changes in saguaro populations. Because P. ciliare may have initially invaded locations that were both more invasible and less diverse, we ran analyses with and without the plots in which initial infestations were located. Results Richness and diversity decreased with P. ciliare cover as did cover and density of most dominant species. Richness and diversity declined with increasing time since invasion, suggesting an ongoing transformation. The proportion of old-to-young Carnegiea gigantea was significantly lower in plots with dominant P. ciliare cover. Main conclusions Rich desert scrub (15–25 species per plot) was transformed into depauperate grassland (2–5 species per plot) within 20 years following P. ciliare invasion without changes to the fire regime. While the onset of a grass–fire cycle may drive ecosystem change in the later stages and larger scales of grass invasions of arid lands, competition by P. ciliare can drive small-scale transformations earlier in the invasion. Linking competition-induced transformation rates with

PO2 cycling reduces diaphragm fatigue by attenuating ROS formation.

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Zuo, Li; Diaz, Philip T; Chien, Michael T; Roberts, William J; Kishek, Juliana; Best, Thomas M; Wagner, Peter D

2014-01-01

Prolonged muscle exposure to low PO2 conditions may cause oxidative stress resulting in severe muscular injuries. We hypothesize that PO2 cycling preconditioning, which involves brief cycles of diaphragmatic muscle exposure to a low oxygen level (40 Torr) followed by a high oxygen level (550 Torr), can reduce intracellular reactive oxygen species (ROS) as well as attenuate muscle fatigue in mouse diaphragm under low PO2. Accordingly, dihydrofluorescein (a fluorescent probe) was used to monitor muscular ROS production in real time with confocal microscopy during a lower PO2 condition. In the control group with no PO2 cycling, intracellular ROS formation did not appear during the first 15 min of the low PO2 period. However, after 20 min of low PO2, ROS levels increased significantly by ∼30% compared to baseline, and this increase continued until the end of the 30 min low PO2 condition. Conversely, muscles treated with PO2 cycling showed a complete absence of enhanced fluorescence emission throughout the entire low PO2 period. Furthermore, PO2 cycling-treated diaphragm exhibited increased fatigue resistance during prolonged low PO2 period compared to control. Thus, our data suggest that PO2 cycling mitigates diaphragm fatigue during prolonged low PO2. Although the exact mechanism for this protection remains to be elucidated, it is likely that through limiting excessive ROS levels, PO2 cycling initiates ROS-related antioxidant defenses.

PO2 cycling reduces diaphragm fatigue by attenuating ROS formation.

Directory of Open Access Journals (Sweden)

Li Zuo

Full Text Available Prolonged muscle exposure to low PO2 conditions may cause oxidative stress resulting in severe muscular injuries. We hypothesize that PO2 cycling preconditioning, which involves brief cycles of diaphragmatic muscle exposure to a low oxygen level (40 Torr followed by a high oxygen level (550 Torr, can reduce intracellular reactive oxygen species (ROS as well as attenuate muscle fatigue in mouse diaphragm under low PO2. Accordingly, dihydrofluorescein (a fluorescent probe was used to monitor muscular ROS production in real time with confocal microscopy during a lower PO2 condition. In the control group with no PO2 cycling, intracellular ROS formation did not appear during the first 15 min of the low PO2 period. However, after 20 min of low PO2, ROS levels increased significantly by ∼30% compared to baseline, and this increase continued until the end of the 30 min low PO2 condition. Conversely, muscles treated with PO2 cycling showed a complete absence of enhanced fluorescence emission throughout the entire low PO2 period. Furthermore, PO2 cycling-treated diaphragm exhibited increased fatigue resistance during prolonged low PO2 period compared to control. Thus, our data suggest that PO2 cycling mitigates diaphragm fatigue during prolonged low PO2. Although the exact mechanism for this protection remains to be elucidated, it is likely that through limiting excessive ROS levels, PO2 cycling initiates ROS-related antioxidant defenses.

Morphological and Phenological characterization of Mediterranean species in Northern Sardinia, Italy

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Piga, Alessandra; Duce, Pierpaolo; Cesaraccio, Carla

2016-04-01

Monitoring of vegetation, in particular methodologies for phenological and biometrical monitoring, are widely implied for climate change studies and their importance for understanding the consequences of global environmental change on vegetation is highlighted in the most recent IPCC reports. It is very likely that, during the next decades, the Mediterranean Regions will cope to the very negative effects of climatic changes. Consequently, due to the climate change impacts and the effects of anthropogenic pressures upon natural resources, these regions are among the most vulnerable ecosystems to the effects of climate change. Therefore, appears to be of crucial importance to better understand the physiological strategies for cope to climate change adaptation for the Mediterranean maquis shrub species which are key information for developing adaptation strategies guidelines. In this work, the biological and reproductive cycle of some Mediterranean species growing in an experimental area located within a nature reserve in the peninsula of Capo Caccia, north-west Sardinia, Italy, was investigated for a period of two years. In particular, the research was focused on: (1) the study of the development processes and the description of phenological phases, and (2) the analysis of the growth processes performed through biometric and floristic composition measurements. Specific BBCH scales for each species were developed. Shoot growth and floristic composition analysis did not show a clear trend in the response of the different species to climatic manipulations but a downward trend in the number of species. The results obtained in this study add useful information on the phenological cycle and growth of the Mediterranean species, improving the knowledge on the mechanisms of adaptation to adverse environmental conditions of these species

Phytoplankton IF-FISH: Species-specific labeling of cellular proteins by immunofluorescence (IF) with simultaneous species identification by fluorescence immunohybridization (FISH).

Science.gov (United States)

Meek, Megan E; Van Dolah, Frances M

2016-05-01

Phytoplankton rarely occur as unialgal populations. Therefore, to study species-specific protein expression, indicative of physiological status in natural populations, methods are needed that will both assay for a protein of interest and identify the species expressing it. Here we describe a protocol for IF-FISH, a dual labeling procedure using immunofluorescence (IF) labeling of a protein of interest followed by fluorescence in situ hybridization (FISH) to identify the species expressing that protein. The protocol was developed to monitor expression of the cell cycle marker proliferating cell nuclear antigen (PCNA) in the red tide dinoflagellate, Karenia brevis, using a large subunit (LSU) rRNA probe to identify K. brevis in a mixed population of morphologically similar Karenia species. We present this protocol as proof of concept that IF-FISH can be successfully applied to phytoplankton cells. This method is widely applicable for the analysis of single-cell protein expression of any protein of interest within phytoplankton communities. Copyright © 2016 Elsevier B.V. All rights reserved.

Determination of the species specificity of the primers for the detection of chicken and turkey meat by realtime PCR method

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Lenka Maršálková

2014-07-01

Full Text Available The aim of this work was to use TaqMan Real-Time PCR for quantitative authentication of chicken and turkey meat. To meet this purpose, a specific pair of primers and TaqMan probe was used. The test was aimed at identifying the reaction cycle of turkey and chicken meat using by two sets of primers. With first set of primer designed for chicken we obtained the following results: Cp = 16.18 for 100% chicken DNA Cp = 29, 18 100% turkey DNA It was also amplified DNA of pig that exceeded the detection threshold fluorescence intensities in the 31.07 cycle (Cp = 31.07. Using primers designed for turkey we obtained the following results Cp = 31.16 for 100% CHDNA, Cp =16.18 100% TDNA. It was also amplified the 100% DNA of rabbit in 31.63 cycle (Cp = 31.63 and deer in cycle 32 (Cp = 32. The DNA of all other animal species was amplificated after more than 35 cycles (Cp >35. It follows that the second detection primer pair is specific enough to unrelated species of animals by 30 cycles of the reaction. Species authentication based on DNA analysis from this perspective overcomes all the shortcomings of proteins. At present, DNA analysis use different types of PCR. Is the most progressive Real-time PCR, which is suitable for the specific use of detection (primers and TaqMan probe. The TaqMan Real-time PCR is within the sensitivity and specificity, clearly one of the best methods for identifying the species of chicken and turkey meat. The specificity of this method, however, depends primarily on the specificity of the primers and TaqMan probe. The 30 cycle reaction was chosen by us as the threshold for specificity using primers for authentication chicken and turkey meat.

Se um viajante numa noite de inverno: o leitor e a leitura a partir da interpretação e superinterpretação

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Wéllia Pimentel Santos

2013-12-01

Full Text Available This paper is a study of the novel Se um viajante numa noite de inverno (1979. This work was originally published in Italy in 1979 by Italo Calvino. Our study is based in the light of the theoretical framework proposed by the semiotician Umberto Eco, especially from his work Interpretation and Overinterpretation (2001. Assuming that the narrative construction of the reffered 'hyper-novel' of Calvin, we can be approximated to the theory advocated by Eco, the main point of contact between these seemingly distinct authors is in fact that both dedicated themselves to think, incisively the question of the interpretation of literary texts. Thus, the process of the making of the groundbreaking novel Calvin was attractive for further study of the work from a critical analysis and interpretation of the interpretation of the work of these prominent authors. Through the contrast of these books is noticed, especially in the work of Calvin that his main objective was to conduct a review of literature itself. Nevertheless, the comparative analysis of the works exemplified through their styles as different from one another , disruption suffered by calviniana scripture , so that Calvin himself breaks the paradigm of traditional perspective of reading as Eco suggests rethinking the understanding of literary texts going beyond appearance.

A strategy for selective detection based on interferent depleting and redox cycling using the plane-recessed microdisk array electrodes

International Nuclear Information System (INIS)

Zhu Feng; Yan Jiawei; Lu Miao; Zhou Yongliang; Yang Yang; Mao Bingwei

2011-01-01

Highlights: → A novel strategy based on a combination of interferent depleting and redox cycling is proposed for the plane-recessed microdisk array electrodes. → The strategy break up the restriction of selectively detecting a species that exhibits reversible reaction in a mixture with one that exhibits an irreversible reaction. → The electrodes enhance the current signal by redox cycling. → The electrodes can work regardless of the reversibility of interfering species. - Abstract: The fabrication, characterization and application of the plane-recessed microdisk array electrodes for selective detection are demonstrated. The electrodes, fabricated by lithographic microfabrication technology, are composed of a planar film electrode and a 32 x 32 recessed microdisk array electrode. Different from commonly used redox cycling operating mode for array configurations such as interdigitated array electrodes, a novel strategy based on a combination of interferent depleting and redox cycling is proposed for the electrodes with an appropriate configuration. The planar film electrode (the plane electrode) is used to deplete the interferent in the diffusion layer. The recessed microdisk array electrode (the microdisk array), locating within the diffusion layer of the plane electrode, works for detecting the target analyte in the interferent-depleted diffusion layer. In addition, the microdisk array overcomes the disadvantage of low current signal for a single microelectrode. Moreover, the current signal of the target analyte that undergoes reversible electron transfer can be enhanced due to the redox cycling between the plane electrode and the microdisk array. Based on the above working principle, the plane-recessed microdisk array electrodes break up the restriction of selectively detecting a species that exhibits reversible reaction in a mixture with one that exhibits an irreversible reaction, which is a limitation of single redox cycling operating mode. The

Genomic divergence and lack of introgressive hybridization between two 13-year periodical cicadas support life cycle switching in the face of climate change.

Science.gov (United States)

Koyama, Takuya; Ito, Hiromu; Fujisawa, Tomochika; Ikeda, Hiroshi; Kakishima, Satoshi; Cooley, John R; Simon, Chris; Yoshimura, Jin; Sota, Teiji

2016-11-01

Life history evolution spurred by post-Pleistocene climatic change is hypothesized to be responsible for the present diversity in periodical cicadas (Magicicada), but the mechanism of life cycle change has been controversial. To understand the divergence process of 13-year and 17-year cicada life cycles, we studied genetic relationships between two synchronously emerging, parapatric 13-year periodical cicada species in the Decim group, Magicicada tredecim and M. neotredecim. The latter was hypothesized to be of hybrid origin or to have switched from a 17-year cycle via developmental plasticity. Phylogenetic analysis using restriction-site-associated DNA sequences for all Decim species and broods revealed that the 13-year M. tredecim lineage is genomically distinct from 17-year Magicicada septendecim but that 13-year M. neotredecim is not. We detected no significant introgression between M. tredecim and M. neotredecim/M. septendecim thus refuting the hypothesis that M. neotredecim are products of hybridization between M. tredecim and M. septendecim. Further, we found that introgressive hybridization is very rare or absent in the contact zone between the two 13-year species evidenced by segregation patterns in single nucleotide polymorphisms, mitochondrial lineage identity and head width and abdominal sternite colour phenotypes. Our study demonstrates that the two 13-year Decim species are of independent origin and nearly completely reproductively isolated. Combining our data with increasing observations of occasional life cycle change in part of a cohort (e.g. 4-year acceleration of emergence in 17-year species), we suggest a pivotal role for developmental plasticity in Magicicada life cycle evolution. © 2016 John Wiley & Sons Ltd.

Curcumin induces apoptosis and cell cycle arrest via the activation of reactive oxygen species-independent mitochondrial apoptotic pathway in Smad4 and p53 mutated colon adenocarcinoma HT29 cells.

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Agarwal, Ayushi; Kasinathan, Akiladdevi; Ganesan, Ramamoorthi; Balasubramanian, Akhila; Bhaskaran, Jahnavi; Suresh, Samyuktha; Srinivasan, Revanth; Aravind, K B; Sivalingam, Nageswaran

2018-03-01

Curcumin is a natural dietary polyphenol compound that has various pharmacological activities such as antiproliferative and cancer-preventive activities on tumor cells. Indeed, the role reactive oxygen species (ROS) generated by curcumin on cell death and cell proliferation inhibition in colon cancer is poorly understood. In the present study, we hypothesized that curcumin-induced ROS may promote apoptosis and cell cycle arrest in colon cancer. To test this hypothesis, the apoptosis-inducing potential and cell cycle inhibition effect of ROS induced by curcumin was investigated in Smd4 and p53 mutated HT-29 colon adenocarcinoma cells. We found that curcumin treatment significantly increased the level of ROS in HT-29 cells in a dose- and time-dependent manner. Furthermore, curcumin treatment markedly decreased the cell viability and proliferation potential of HT-29 cells in a dose- and time-dependent manner. Conversely, generation of ROS and inhibitory effect of curcumin on HT-29 cells were abrogated by N-acetylcysteine treatment. In addition, curcumin treatment did not show any cytotoxic effects on HT-29 cells. Furthermore, curcumin-induced ROS generation caused the DNA fragmentation, chromatin condensation, and cell nuclear shrinkage and significantly increased apoptotic cells in a dose- and time-dependent manner in HT-29 cells. However, pretreatment of N-acetylcysteine inhibited the apoptosis-triggering effect of curcumin-induced ROS in HT-29 cells. In addition, curcumin-induced ROS effectively mediated cell cycle inhibition in HT-29 cells. In conclusion, our data provide the first evidence that curcumin induces ROS independent apoptosis and cell cycle arrest in colon cancer cells that carry mutation on Smad4 and p53. Copyright © 2018. Published by Elsevier Inc.

Warming delays autumn declines in photosynthetic capacity in a boreal conifer, Norway spruce (Picea abies).

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Stinziano, Joseph R; Hüner, Norman P A; Way, Danielle A

2015-12-01

Climate change, via warmer springs and autumns, may lengthen the carbon uptake period of boreal tree species, increasing the potential for carbon sequestration in boreal forests, which could help slow climate change. However, if other seasonal cues such as photoperiod dictate when photosynthetic capacity declines, warmer autumn temperatures may have little effect on when carbon uptake capacity decreases in these species. We investigated whether autumn warming would delay photosynthetic decline in Norway spruce (Picea abies (L.) H. Karst.) by growing seedlings under declining weekly photoperiods and weekly temperatures either at ambient temperature or a warming treatment 4 °C above ambient. Photosynthetic capacity was relatively constant in both treatments when weekly temperatures were >8 °C, but declined rapidly at lower temperatures, leading to a delay in the autumn decline in photosynthetic capacity in the warming treatment. The decline in photosynthetic capacity was not related to changes in leaf nitrogen or chlorophyll concentrations, but was correlated with a decrease in the apparent fraction of leaf nitrogen invested in Rubisco, implicating a shift in nitrogen allocation away from the Calvin cycle at low autumn growing temperatures. Our data suggest that as the climate warms, the period of net carbon uptake will be extended in the autumn for boreal forests dominated by Norway spruce, which could increase total carbon uptake in these forests. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Similar below-ground carbon cycling dynamics but contrasting modes of nitrogen cycling between arbuscular mycorrhizal and ectomycorrhizal forests.

Science.gov (United States)

Lin, Guigang; McCormack, M Luke; Ma, Chengen; Guo, Dali

2017-02-01

Compared with ectomycorrhizal (ECM) forests, arbuscular mycorrhizal (AM) forests are hypothesized to have higher carbon (C) cycling rates and a more open nitrogen (N) cycle. To test this hypothesis, we synthesized 645 observations, including 22 variables related to below-ground C and N dynamics from 100 sites, where AM and ECM forests co-occurred at the same site. Leaf litter quality was lower in ECM than in AM trees, leading to greater forest floor C stocks in ECM forests. By contrast, AM forests had significantly higher mineral soil C concentrations, and this result was strongly mediated by plant traits and climate. No significant differences were found between AM and ECM forests in C fluxes and labile C concentrations. Furthermore, inorganic N concentrations, net N mineralization and nitrification rates were all higher in AM than in ECM forests, indicating 'mineral' N economy in AM but 'organic' N economy in ECM trees. AM and ECM forests show systematic differences in mineral vs organic N cycling, and thus mycorrhizal type may be useful in predicting how different tree species respond to multiple environmental change factors. By contrast, mycorrhizal type alone cannot reliably predict below-ground C dynamics without considering plant traits and climate. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

Solar Spectral Irradiance Changes During Cycle 24

Science.gov (United States)

Marchenko, Sergey; Deland, Matthew

2014-01-01

We use solar spectra obtained by the Ozone Monitoring Instrument (OMI) on board the Aura satellite to detect and follow long-term (years) and short-term (weeks) changes in the solar spectral irradiance (SSI) in the 265-500 nm spectral range. During solar Cycle 24, in the relatively line-free regions the SSI changed by approximately 0.6% +/- 0.2% around 265 nm. These changes gradually diminish to 0.15% +/- 0.20% at 500 nm. All strong spectral lines and blends, with the notable exception of the upper Balmer lines, vary in unison with the solar "continuum." Besides the lines with strong chromospheric components, the most involved species include Fe I blends and all prominent CH, NH, and CN spectral bands. Following the general trend seen in the solar "continuum," the variability of spectral lines also decreases toward longer wavelengths. The long-term solar cycle SSI changes are closely, to within the quoted 0.1%-0.2% uncertainties, matched by the appropriately adjusted short-term SSI variations derived from the 27 day rotational modulation cycles. This further strengthens and broadens the prevailing notion about the general scalability of the UV SSI variability to the emissivity changes in the Mg II 280 nm doublet on timescales from weeks to years. We also detect subtle deviations from this general rule: the prominent spectral lines and blends at lambda approximately or greater than 350 nm show slightly more pronounced 27 day SSI changes when compared to the long-term (years) trends. We merge the solar data from Cycle 21 with the current Cycle 24 OMI and GOME-2 observations and provide normalized SSI variations for the 170-795 nm spectral region.

Cycles and Common Cycles in Property and Related Sectors

OpenAIRE

Peijie Wang

2003-01-01

This paper examines cycles and common cycles in the property market and the economy. While focusing on common cycles, the study also incorporates common trends in the meantime, so it covers the whole spectrum of dynamic analysis. It has been found that property shares common cycles, particularly with those sectors that are the user markets of property. The mechanisms of common cycles and the relative magnitudes of cycles of the sectors related to property are discussed to shed light on proper...

Chilli anthracnose disease caused by Colletotrichum species§

Science.gov (United States)

Than, Po Po; Prihastuti, Haryudian; Phoulivong, Sitthisack; Taylor, Paul W.J.; Hyde, Kevin D.

2008-01-01

Anthracnose disease is one of the major economic constraints to chilli production worldwide, especially in tropical and subtropical regions. Accurate taxonomic information is necessary for effective disease control management. In the Colletotrichum patho-system, different Colletotrichum species can be associated with anthracnose of the same host. Little information is known concerning the interactions of the species associated with the chilli anthracnose although several Colletotrichum species have been reported as causal agents of chilli anthracnose disease worldwide. The ambiguous taxonomic status of Colletotrichum species has resulted in inaccurate identification which may cause practical problems in plant breeding and disease management. Although the management and control of anthracnose disease are still being extensively researched, commercial cultivars of Capsicum annuum that are resistant to the pathogens that cause chilli anthracnose have not yet been developed. This paper reviews the causal agents of chilli anthracnose, the disease cycle, conventional methods in identification of the pathogen and molecular approaches that have been used for the identification of Colletotrichum species. Pathogenetic variation and population structure of the causal agents of chilli anthracnose along with the current taxonomic status of Colletotrichum species are discussed. Future developments leading to the disease management strategies are suggested. PMID:18837103

Cycling empirical antibiotic therapy in hospitals: meta-analysis and models.

Directory of Open Access Journals (Sweden)

Pia Abel zur Wiesch

2014-06-01

Full Text Available The rise of resistance together with the shortage of new broad-spectrum antibiotics underlines the urgency of optimizing the use of available drugs to minimize disease burden. Theoretical studies suggest that coordinating empirical usage of antibiotics in a hospital ward can contain the spread of resistance. However, theoretical and clinical studies came to different conclusions regarding the usefulness of rotating first-line therapy (cycling. Here, we performed a quantitative pathogen-specific meta-analysis of clinical studies comparing cycling to standard practice. We searched PubMed and Google Scholar and identified 46 clinical studies addressing the effect of cycling on nosocomial infections, of which 11 met our selection criteria. We employed a method for multivariate meta-analysis using incidence rates as endpoints and find that cycling reduced the incidence rate/1000 patient days of both total infections by 4.95 [9.43-0.48] and resistant infections by 7.2 [14.00-0.44]. This positive effect was observed in most pathogens despite a large variance between individual species. Our findings remain robust in uni- and multivariate metaregressions. We used theoretical models that reflect various infections and hospital settings to compare cycling to random assignment to different drugs (mixing. We make the realistic assumption that therapy is changed when first line treatment is ineffective, which we call "adjustable cycling/mixing". In concordance with earlier theoretical studies, we find that in strict regimens, cycling is detrimental. However, in adjustable regimens single resistance is suppressed and cycling is successful in most settings. Both a meta-regression and our theoretical model indicate that "adjustable cycling" is especially useful to suppress emergence of multiple resistance. While our model predicts that cycling periods of one month perform well, we expect that too long cycling periods are detrimental. Our results suggest that

Do traits of invasive species influence decomposition and soil respiration of disturbed ecosystems?

Science.gov (United States)

Wells, A. J.; Balster, N. J.

2009-12-01

Large-scale landscape disturbances typically alter the terrestrial carbon cycle leading to shifts in pools of soil carbon. Restoration of disturbed landscapes with prairie vegetation has thus been practiced with the intent of increasing carbon accrual in soils. However, since disturbed soils are prone to invasion by non-native invasive species, many ecological restorations have resulted in unexpected outcomes, which may be explained by differences in plant traits such as tissue quality and biomass allocation. Typically, the tissue of invasive species has lower C:N ratios relative to native species, and consequently, faster decomposition rates, which potentially can alter the balance in soil carbon. The primary objective of this research was to compare the effects of native prairie species versus non-native invasive species on the carbon cycling within a novel environment: a recently dewatered basin in southwestern Wisconsin following dam removal. We hypothesized that a higher invasive to native species ratio would result in faster litter decomposition and a higher rate of soil respiration. To test this hypothesis, we seeded newly exposed sediments with native prairie seeds in 2005, annually collected aboveground plant biomass (by species per plot), calculated decomposition rate of native and invasive litter (underneath both canopy types), and measured soil respiration during the growing season of 2009. After four years of seeding, the aboveground biomass of the native vegetation has increased significantly (p invasive species biomass has decreased from 459 to 296 g m-2. Senesced tissue from mixed native species had a higher C:N ratio, 27:1 (43% C: 1.6% N), than tissue from mixed invasive species, 24:1 (35% C: 1.5% N). However, after 7 months, we found that the rate of decomposition depended on both litter type and plant canopy type (p invasive plant tissue had a slightly faster decomposition rate than the native litter and this rate was elevated under invasive

HCl removal using cycled carbide slag from calcium looping cycles

International Nuclear Information System (INIS)

Xie, Xin; Li, Yingjie; Wang, Wenjing; Shi, Lei

2014-01-01

Highlights: • Cycled carbide slag from calcium looping cycles is used to remove HCl. • The optimum temperature for HCl removal of cycled carbide slag is 700 °C. • The presence of CO 2 restrains HCl removal of cycled carbide slag. • CO 2 capture conditions have important effects on HCl removal of cycled carbide slag. • HCl removal capacity of carbide slag drops with cycle number rising from 1 to 50. - Abstract: The carbide slag is an industrial waste from chlor-alkali plants, which can be used to capture CO 2 in the calcium looping cycles, i.e. carbonation/calcination cycles. In this work, the cycled carbide slag from the calcium looping cycles for CO 2 capture was proposed to remove HCl in the flue gas from the biomass-fired and RDFs-fired boilers. The effects of chlorination temperature, HCl concentration, particle size, presence of CO 2 , presence of O 2 , cycle number and CO 2 capture conditions in calcium looping cycles on the HCl removal behavior of the carbide slag experienced carbonation/calcination cycles were investigated in a triple fixed-bed reactor. The chlorination product of the cycled carbide slag from the calcium looping after absorbing HCl is not CaCl 2 but CaClOH. The optimum temperature for HCl removal of the cycled carbide slag from the carbonation/calcination cycles is 700 °C. The chlorination conversion of the cycled carbide slag increases with increasing the HCl concentration. The cycled carbide slag with larger particle size exhibits a lower chlorination conversion. The presence of CO 2 decreases the chlorination conversions of the cycled carbide slag and the presence of O 2 has a trifling impact. The chlorination conversion of the carbide slag experienced 1 carbonation/calcination cycle is higher than that of the uncycled calcined sorbent. As the number of carbonation/calcination cycles increases from 1 to 50, the chlorination conversion of carbide slag drops gradually. The high calcination temperature and high CO 2

Reproductive cycles of Mugil cephalus, Liza ramada and Liza aurata (Teleostei: Mugilidae).

Science.gov (United States)

Bartulović, V; Dulčić, J; Matić-Skoko, S; Glamuzina, B

2011-06-01

The reproductive cycles of three mullet species from the Eastern Adriatic coast were described using several biological parameters (gonado-somatic index, oocyte diameter and sex ratio) to improve knowledge about their reproduction. © 2011 The Authors. Journal of Fish Biology © 2011 The Fisheries Society of the British Isles.

Information processing through a bio-based redox capacitor: signatures for redox-cycling.

Science.gov (United States)

Liu, Yi; Kim, Eunkyoung; White, Ian M; Bentley, William E; Payne, Gregory F

2014-08-01

Redox-cycling compounds can significantly impact biological systems and can be responsible for activities that range from pathogen virulence and contaminant toxicities, to therapeutic drug mechanisms. Current methods to identify redox-cycling activities rely on the generation of reactive oxygen species (ROS), and employ enzymatic or chemical methods to detect ROS. Here, we couple the speed and sensitivity of electrochemistry with the molecular-electronic properties of a bio-based redox-capacitor to generate signatures of redox-cycling. The redox capacitor film is electrochemically-fabricated at the electrode surface and is composed of a polysaccharide hydrogel with grafted catechol moieties. This capacitor film is redox-active but non-conducting and can engage diffusible compounds in either oxidative or reductive redox-cycling. Using standard electrochemical mediators ferrocene dimethanol (Fc) and Ru(NH3)6Cl3 (Ru(3+)) as model redox-cyclers, we observed signal amplifications and rectifications that serve as signatures of redox-cycling. Three bio-relevant compounds were then probed for these signatures: (i) ascorbate, a redox-active compound that does not redox-cycle; (ii) pyocyanin, a virulence factor well-known for its reductive redox-cycling; and (iii) acetaminophen, an analgesic that oxidatively redox-cycles but also undergoes conjugation reactions. These studies demonstrate that the redox-capacitor can enlist the capabilities of electrochemistry to generate rapid and sensitive signatures of biologically-relevant chemical activities (i.e., redox-cycling). Published by Elsevier B.V.

Effects of menstrual cycle phase on cocaine self-administration in rhesus macaques.

Science.gov (United States)

Cooper, Ziva D; Foltin, Richard W; Evans, Suzette M

2013-01-01

Epidemiological findings suggest that men and women vary in their pattern of cocaine use resulting in differences in cocaine dependence and relapse rates. Preclinical laboratory studies have demonstrated that female rodents are indeed more sensitive to cocaine's reinforcing effects than males, with estrous cycle stage as a key determinant of this effect. The current study sought to extend these findings to normally cycling female rhesus macaques, a species that shares a nearly identical menstrual cycle to humans. Dose-dependent intravenous cocaine self-administration (0.0125, 0.0250, and 0.0500 mg/kg/infusion) using a progressive-ratio schedule of reinforcement was determined across the menstrual cycle. The menstrual cycle was divided into 5 discrete phases - menses, follicular, periovulatory, luteal, and late luteal phases - verified by the onset of menses and plasma levels of estradiol and progesterone. Dependent variables including number of infusions self-administered per session, progressive ratio breakpoint, and cocaine intake were analyzed according to cocaine dose and menstrual cycle phase. Analysis of plasma hormone levels verified phase-dependent fluctuations of estradiol and progesterone, with estrogen levels peaking during the periovulatory phase, and progesterone peaking during the luteal phase. Progressive ratio breakpoint, infusions self-administered, and cocaine intake did not consistently vary based on menstrual cycle phase. These findings demonstrate that under the current experimental parameters, the reinforcing effects of cocaine did not vary across the menstrual cycle in a systematic fashion in normally cycling rhesus macaques. Copyright © 2012 Elsevier Inc. All rights reserved.

Long-term litter decomposition controlled by manganese redox cycling.

Science.gov (United States)

Keiluweit, Marco; Nico, Peter; Harmon, Mark E; Mao, Jingdong; Pett-Ridge, Jennifer; Kleber, Markus

2015-09-22

Litter decomposition is a keystone ecosystem process impacting nutrient cycling and productivity, soil properties, and the terrestrial carbon (C) balance, but the factors regulating decomposition rate are still poorly understood. Traditional models assume that the rate is controlled by litter quality, relying on parameters such as lignin content as predictors. However, a strong correlation has been observed between the manganese (Mn) content of litter and decomposition rates across a variety of forest ecosystems. Here, we show that long-term litter decomposition in forest ecosystems is tightly coupled to Mn redox cycling. Over 7 years of litter decomposition, microbial transformation of litter was paralleled by variations in Mn oxidation state and concentration. A detailed chemical imaging analysis of the litter revealed that fungi recruit and redistribute unreactive Mn(2+) provided by fresh plant litter to produce oxidative Mn(3+) species at sites of active decay, with Mn eventually accumulating as insoluble Mn(3+/4+) oxides. Formation of reactive Mn(3+) species coincided with the generation of aromatic oxidation products, providing direct proof of the previously posited role of Mn(3+)-based oxidizers in the breakdown of litter. Our results suggest that the litter-decomposing machinery at our coniferous forest site depends on the ability of plants and microbes to supply, accumulate, and regenerate short-lived Mn(3+) species in the litter layer. This observation indicates that biogeochemical constraints on bioavailability, mobility, and reactivity of Mn in the plant-soil system may have a profound impact on litter decomposition rates.

Plant species richness regulates soil respiration through changes in productivity

NARCIS (Netherlands)

Dias, A.A.; Ruijven, van J.; Berendse, F.

2010-01-01

Soil respiration is an important pathway of the C cycle. However, it is still poorly understood how changes in plant community diversity can affect this ecosystem process. Here we used a long-term experiment consisting of a gradient of grassland plant species richness to test for effects of

Plant species richness regulates soil respiration through changes in productivity.

NARCIS (Netherlands)

Tavares Correa Dias, A.; van Ruijven, J.; Berendse, F.

2010-01-01

Soil respiration is an important pathway of the C cycle. However, it is still poorly understood how changes in plant community diversity can affect this ecosystem process. Here we used a long-term experiment consisting of a gradient of grassland plant species richness to test for effects of

A short history of RubisCO: the rise and fall (?) of Nature's predominant CO2 fixing enzyme.

Science.gov (United States)

Erb, Tobias J; Zarzycki, Jan

2018-02-01

Ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO) is arguably one of the most abundant proteins in the biosphere and a key enzyme in the global carbon cycle. Although RubisCO has been intensively studied, its evolutionary origins and rise as Nature's most dominant carbon dioxide (CO 2 )-fixing enzyme still remain in the dark. In this review we will bring together biochemical, structural, physiological, microbiological, as well as phylogenetic data to speculate on the evolutionary roots of the CO 2 -fixation reaction of RubisCO, the emergence of RubisCO-based autotrophic CO 2 -fixation in the context of the Calvin-Benson-Bassham cycle, and the further evolution of RubisCO into the 'RubisCOsome', a complex of various proteins assembling and interacting with the enzyme to improve its operational capacity (functionality) under different biological and environmental conditions. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Use of micro gas chromatography in the fuel cycle of fusion reactors

International Nuclear Information System (INIS)

Laesser, R.; Gruenhagen, S.; Kawamura, Y.

2003-01-01

Various analytical techniques exist to determine the compositions of gases handled in the fuel cycle of future fusion machines. Gas chromatography was found to be the most appropriate method. The main disadvantages of conventional gas chromatography were the long retention times for the heavy hydrogen species of >30 min. Recent progress in the development of micro-gas chromatography has reduced these retention times to ∼3 min. The usefulness of micro-gas chromatography for the analysis of hydrogen and impurity gas mixtures in the fuel cycle of future fusion machines is presented and the advantages and drawbacks are discussed

Life histories of microalgal species causing harmful blooms: Haploids, diploids and the relevance of benthic stages.

Science.gov (United States)

Figueroa, Rosa Isabel; Estrada, Marta; Garcés, Esther

2018-03-01

In coastal and offshore waters, Harmful Algal Blooms (HABs) currently threaten the well-being of coastal countries. These events, which can be localized or involve wide-ranging areas, pose risks to human health, marine ecosystems, and economic resources, such as tourism, fisheries, and aquaculture. Dynamics of HABs vary from one site to another, depending on the hydrographic and ecological conditions. The challenge in investigating HABs is that they are caused by organisms from multiple algal classes, each with its own unique features, including different life histories. The complete algal life cycle has been determined in life cycles of bloom-forming species is essential in developing preventative measures. The knowledge obtained thus far has confirmed the complexity of the algal life cycle, which is composed of discrete life stages whose morphology, ecological niche (plankton/benthos), function, and lifespan vary. The factors that trigger transitions between the different stages in nature are mostly unknown, but it is clear that an understanding of this process provides the key to effectively forecasting bloom recurrence, maintenance, and decline. Planktonic stages constitute an ephemeral phase of the life cycle of most species whereas resistant, benthic stages enable a species to withstand adverse conditions for prolonged periods, thus providing dormant reservoirs for eventual blooms and facilitating organismal dispersal. Here we review current knowledge of the life cycle strategies of major groups of HAB producers in marine and brackish waters. Rather than providing a comprehensive discussion, the objective was to highlight several of the research milestones that have changed our understanding of the plasticity and frequency of the different life cycle stages as well as the transitions between them. We also discuss the relevance of benthic and planktonic forms and their implications for HAB dynamics. Copyright © 2018. Published by Elsevier B.V.

Biological activities of undescribed North American lichen species.

Science.gov (United States)

Yeash, Erik A; Letwin, Lyndon; Malek, Lada; Suntres, Zacharias; Knudsen, Kerry; Christopher, Lew P

2017-11-01

Lichens provide a large array of compounds with the potential for pharmaceutical development. In the present study, extracts from three previously undescribed North American lichen species were examined for antioxidant, antibacterial and anticancer activities. The results from this study demonstrated the following: (i) Acarospora socialis ethanol extract exhibited significant DPPH antioxidant scavenging activities, which were concentration dependent; (ii) acetone and ethyl acetate extracts of Xanthoparmelia mexicana inhibited Gram-positive bacteria but had no effect on Gram-negative bacteria; X. mexicana acetone extract yielded a minimum inhibitory concentration (MIC) of 20.9 µg mL -1 against Staphylococcus aureus, and 41.9 µg mL -1 against Enterococcus faecalis; (iii) acetone extract of Lobothallia alphoplaca inhibited growth of cultured breast cancer MCF-7 cells with an effective concentration (EC 50 ) of 87 µg mL -1 ; the MCF-7 cell cycle appears arrested in the G2 phase, whereas the DNA synthesis cell cycle (S) may be inhibited. New lichen species that possess strong biological activities have been identified. These lichens comprise secondary metabolites that possess antioxidant, antibacterial and anticancer properties. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Links between plant litter chemistry, species diversity, and below-ground ecosystem function

OpenAIRE

Meier, Courtney L.; Bowman, William D.

2008-01-01

Decomposition is a critical source of plant nutrients, and drives the largest flux of terrestrial C to the atmosphere. Decomposing soil organic matter typically contains litter from multiple plant species, yet we lack a mechanistic understanding of how species diversity influences decomposition processes. Here, we show that soil C and N cycling during decomposition are controlled by the composition and diversity of chemical compounds within plant litter mixtures, rather than by simple metrics...

Metagenetic analysis of the bacterial communities of edible insects from diverse production cycles at industrial rearing companies.

Science.gov (United States)

Vandeweyer, D; Crauwels, S; Lievens, B; Van Campenhout, L

2017-11-16

Despite the continuing development of new insect-derived food products, microbial research on edible insects and insect-based foods is still very limited. The goal of this study was to increase the knowledge on the microbial quality of edible insects by comparing the bacterial community composition of mealworms (Tenebrio molitor) and crickets (Acheta domesticus and Gryllodes sigillatus) from several production cycles and rearing companies. Remarkable differences in the bacterial community composition were found between different mealworm rearing companies and mealworm production cycles from the same company. In comparison with mealworms, the bacterial community composition of the investigated crickets was more similar among different companies, and was highly similar between both cricket species investigated. Mealworm communities were dominated by Spiroplasma and Erwinia species, while crickets were abundantly colonised by (Para)bacteroides species. With respect to food safety, only a few operational taxonomic units could be associated with potential human pathogens such as Cronobacter or spoilage bacteria such as Pseudomonas. In summary, our results implicate that at least for cricket rearing, production cycles of constant and good quality in terms of bacterial composition can be obtained by different rearing companies. For mealworms however, more variation in terms of microbial quality occurs between companies. Copyright © 2017 Elsevier B.V. All rights reserved.

Analysis of temporal variation in human masticatory cycles during gum chewing.

Science.gov (United States)

Crane, Elizabeth A; Rothman, Edward D; Childers, David; Gerstner, Geoffrey E

2013-10-01

The study investigated modulation of fast and slow opening (FO, SO) and closing (FC, SC) chewing cycle phases using gum-chewing sequences in humans. Twenty-two healthy adult subjects participated by chewing gum for at least 20s on the right side and at least 20s on the left side while jaw movements were tracked with a 3D motion analysis system. Jaw movement data were digitized, and chewing cycle phases were identified and analysed for all chewing cycles in a complete sequence. All four chewing cycle phase durations were more variant than total cycle durations, a result found in other non-human primates. Significant negative correlations existed between the opening phases, SO and FO, and between the closing phases, SC and FC; however, there was less consistency in terms of which phases were negatively correlated both between subjects, and between chewing sides within subjects, compared with results reported in other species. The coordination of intra-cycle phases appears to be flexible and to follow complex rules during gum-chewing in humans. Alternatively, the observed intra-cycle phase relationships could simply reflect: (1) variation in jaw kinematics due to variation in how gum was handled by the tongue on a chew-by-chew basis in our experimental design or (2) by variation due to data sampling noise and/or how phases were defined and identified. Copyright © 2013 Elsevier Ltd. All rights reserved.

Exploring photosynthesis evolution by comparative analysis of metabolic networks between chloroplasts and photosynthetic bacteria

Directory of Open Access Journals (Sweden)

Hou Jing

2006-04-01

Full Text Available Abstract Background Chloroplasts descended from cyanobacteria and have a drastically reduced genome following an endosymbiotic event. Many genes of the ancestral cyanobacterial genome have been transferred to the plant nuclear genome by horizontal gene transfer. However, a selective set of metabolism pathways is maintained in chloroplasts using both chloroplast genome encoded and nuclear genome encoded enzymes. As an organelle specialized for carrying out photosynthesis, does the chloroplast metabolic network have properties adapted for higher efficiency of photosynthesis? We compared metabolic network properties of chloroplasts and prokaryotic photosynthetic organisms, mostly cyanobacteria, based on metabolic maps derived from genome data to identify features of chloroplast network properties that are different from cyanobacteria and to analyze possible functional significance of those features. Results The properties of the entire metabolic network and the sub-network that consists of reactions directly connected to the Calvin Cycle have been analyzed using hypergraph representation. Results showed that the whole metabolic networks in chloroplast and cyanobacteria both possess small-world network properties. Although the number of compounds and reactions in chloroplasts is less than that in cyanobacteria, the chloroplast's metabolic network has longer average path length, a larger diameter, and is Calvin Cycle -centered, indicating an overall less-dense network structure with specific and local high density areas in chloroplasts. Moreover, chloroplast metabolic network exhibits a better modular organization than cyanobacterial ones. Enzymes involved in the same metabolic processes tend to cluster into the same module in chloroplasts. Conclusion In summary, the differences in metabolic network properties may reflect the evolutionary changes during endosymbiosis that led to the improvement of the photosynthesis efficiency in higher plants. Our

Large fractions of CO2-fixing microorganisms in pristine limestone aquifers appear to be involved in the oxidation of reduced sulfur and nitrogen compounds

Science.gov (United States)

Herrmann, Martina; Rusznyák, Anna; Akob, Denise M.; Schulze, Isabel; Opitz, Sebastian; Totsche, Kai Uwe; Küsel, Kirsten

2015-01-01

The traditional view of the dependency of subsurface environments on surface-derived allochthonous carbon inputs is challenged by increasing evidence for the role of lithoautotrophy in aquifer carbon flow. We linked information on autotrophy (Calvin-Benson-Bassham cycle) with that from total microbial community analysis in groundwater at two superimposed—upper and lower—limestone groundwater reservoirs (aquifers). Quantitative PCR revealed that up to 17% of the microbial population had the genetic potential to fix CO2 via the Calvin cycle, with abundances of cbbM and cbbL genes, encoding RubisCO (ribulose-1,5-bisphosphate carboxylase/oxygenase) forms I and II, ranging from 1.14 × 103 to 6 × 106 genes liter−1 over a 2-year period. The structure of the active microbial communities based on 16S rRNA transcripts differed between the two aquifers, with a larger fraction of heterotrophic, facultative anaerobic, soil-related groups in the oxygen-deficient upper aquifer. Most identified CO2-assimilating phylogenetic groups appeared to be involved in the oxidation of sulfur or nitrogen compounds and harbored both RubisCO forms I and II, allowing efficient CO2 fixation in environments with strong oxygen and CO2 fluctuations. The genera Sulfuricellaand Nitrosomonas were represented by read fractions of up to 78 and 33%, respectively, within the cbbM and cbbL transcript pool and accounted for 5.6 and 3.8% of 16S rRNA sequence reads, respectively, in the lower aquifer. Our results indicate that a large fraction of bacteria in pristine limestone aquifers has the genetic potential for autotrophic CO2 fixation, with energy most likely provided by the oxidation of reduced sulfur and nitrogen compounds.

Bottle gourd rootstock-grafting promotes photosynthesis by regulating the stomata and non-stomata performances in leaves of watermelon seedlings under NaCl stress.

Science.gov (United States)

Yang, Yanjuan; Yu, Li; Wang, Liping; Guo, Shirong

2015-08-15

Previously, we found that the amelioration of photosynthetic capacity by bottle gourd (Lagenaria siceraria Standl.) rootstock in watermelon seedlings (Citrullus lanatus [Thunb.] Mansf.) with salt treatment might be closely related to the enzymes in Calvin cycle such as ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) (Yang et al., 2012). We confirmed this and showed more details in this study that improved photosynthesis of watermelon plants by bottle gourd rootstock was associated with the decreased stomata resistance and the increased photochemical activity and photosynthetic metabolism with or without 100mM NaCl stress for 3 days. The analysis of gas exchange parameters showed that self-grafted plants suffered serious non-stomatal limitation to photosynthesis under salt stress while rootstock-grafted plants were mainly affected by stomata limitation in stress conditions. Further, results showed that NaCl stress markedly reduced the chlorophyll content, damaged the structure of photosynthetic apparatus, and inhibited photochemical activity and CO2 assimilation in self-grafted plants. In contrast, rootstock-grafting increased the chlorophyll content, especially chlorophyll b, and minimized the harmful effects on photosystem II (PSII) reaction center and the thylakoids structure induced by NaCl stress. Furthermore, rootstock-grafting enhanced the content and activity of Rubisco and thus elevated carbon fixation in the leaves of watermelon scions under salt stress. The gene expressions of enzymes related to ribulose-1,5-bisphosphate (RuBP) regeneration were also up-regulated by rootstock and this probably guaranteed the sufficient supply of RuBP for the operation of Calvin cycle in watermelon scions under salt stress. Thus, bottle gourd rootstock promoted photosynthesis by the activation of stomatal and non-stomatal abilities, especially the regulation of a variety of photosynthetic enzymes, including Rubisco in grafted watermelon plants under NaCl stress

Malaria vector species in Colombia: a review

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James Montoya-Lerma

2011-08-01

Full Text Available Here we present a comprehensive review of the literature on the vectorial importance of the major Anopheles malaria vectors in Colombia. We provide basic information on the geographical distribution, altitudinal range, immature habitats, adult behaviour, feeding preferences and anthropophily, endophily and infectivity rates. We additionally review information on the life cycle, longevity and population fluctuation of Colombian Anopheles species. Emphasis was placed on the primary vectors that have been epidemiologically incriminated in malaria transmission: Anopheles darlingi, Anopheles albimanus and Anopheles nuneztovari. The role of a selection of local, regional or secondary vectors (e.g., Anopheles pseudopunctipennis and Anopheles neivai is also discussed. We highlight the importance of combining biological, morphological and molecular data for the correct taxonomical determination of a given species, particularly for members of the species complexes. We likewise emphasise the importance of studying the bionomics of primary and secondary vectors along with an examination of the local conditions affecting the transmission of malaria. The presence and spread of the major vectors and the emergence of secondary species capable of transmitting human Plasmodia are of great interest. When selecting control measures, the anopheline diversity in the region must be considered. Variation in macroclimate conditions over a species' geographical range must be well understood and targeted to plan effective control measures based on the population dynamics of the local Anopheles species.

Criteria to be considered to achieve a sustainable second cycle in Amazon Forest

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Evaldo Muñoz Braz

2015-09-01

Full Text Available Remnant forest structure and increment by diameter class play a decisive role in the recovery volume for the next cutting cycle. Tree species in the Amazon Forest do not present a defined pattern of diameter structure, which is discussed here using Cedrela odorata L. as a case study The aim of this study was to identify, by simulation, recovery from logging in a real situation at three timber production sites, and the alternatives that are available to ensure commercial timber volume to a second cut cycle in the Brazilian Amazon. The study is concerned regarding the diametric classes of productive trees to the next cycle, the comparison demonstrates that one of the strategies recovers stock volume more quickly than expected in the cut cycle defined by Brazilian law. The number of trees remaining at the sites does not corroborate the common assumption that forest management depletes large diameter trees. This paper presents assessment strategies to evaluate and establish the diametric structure that would enable the possible recovery in the second cut cycle, depending on the volume logged during the first cut cycle.

Temperature effects on gametophyte life-history traits and geographic distribution of two cryptic kelp species.

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L Valeria Oppliger

Full Text Available A major determinant of the geographic distribution of a species is expected to be its physiological response to changing abiotic variables over its range. The range of a species often corresponds to the geographic extent of temperature regimes the organism can physiologically tolerate. Many species have very distinct life history stages that may exhibit different responses to environmental factors. In this study we emphasized the critical role of the haploid microscopic stage (gametophyte of the life cycle to explain the difference of edge distribution of two related kelp species. Lessonia nigrescens was recently identified as two cryptic species occurring in parapatry along the Chilean coast: one located north and the other south of a biogeographic boundary at latitude 29-30°S. Six life history traits from microscopic stages were identified and estimated under five treatments of temperature in eight locations distributed along the Chilean coast in order to (1 estimate the role of temperature in the present distribution of the two cryptic L. nigrescens species, (2 compare marginal populations to central populations of the two cryptic species. In addition, we created a periodic matrix model to estimate the population growth rate (λ at the five temperature treatments. Differential tolerance to temperature was demonstrated between the two species, with the gametophytes of the Northern species being more tolerant to higher temperatures than gametophytes from the south. Second, the two species exhibited different life history strategies with a shorter haploid phase in the Northern species contrasted with considerable vegetative growth in the Southern species haploid stage. These results provide strong ecological evidence for the differentiation process of the two cryptic species and show local adaptation of the life cycle at the range limits of the distribution. Ecological and evolutionary implications of these findings are discussed.

Temporal controls of the asymmetric cell division cycle in Caulobacter crescentus.

Directory of Open Access Journals (Sweden)

Shenghua Li

2009-08-01

Full Text Available The asymmetric cell division cycle of Caulobacter crescentus is orchestrated by an elaborate gene-protein regulatory network, centered on three major control proteins, DnaA, GcrA and CtrA. The regulatory network is cast into a quantitative computational model to investigate in a systematic fashion how these three proteins control the relevant genetic, biochemical and physiological properties of proliferating bacteria. Different controls for both swarmer and stalked cell cycles are represented in the mathematical scheme. The model is validated against observed phenotypes of wild-type cells and relevant mutants, and it predicts the phenotypes of novel mutants and of known mutants under novel experimental conditions. Because the cell cycle control proteins of Caulobacter are conserved across many species of alpha-proteobacteria, the model we are proposing here may be applicable to other genera of importance to agriculture and medicine (e.g., Rhizobium, Brucella.

Temporal controls of the asymmetric cell division cycle in Caulobacter crescentus.

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Li, Shenghua; Brazhnik, Paul; Sobral, Bruno; Tyson, John J

2009-08-01

The asymmetric cell division cycle of Caulobacter crescentus is orchestrated by an elaborate gene-protein regulatory network, centered on three major control proteins, DnaA, GcrA and CtrA. The regulatory network is cast into a quantitative computational model to investigate in a systematic fashion how these three proteins control the relevant genetic, biochemical and physiological properties of proliferating bacteria. Different controls for both swarmer and stalked cell cycles are represented in the mathematical scheme. The model is validated against observed phenotypes of wild-type cells and relevant mutants, and it predicts the phenotypes of novel mutants and of known mutants under novel experimental conditions. Because the cell cycle control proteins of Caulobacter are conserved across many species of alpha-proteobacteria, the model we are proposing here may be applicable to other genera of importance to agriculture and medicine (e.g., Rhizobium, Brucella).

PCR cycles above routine numbers do not compromise high-throughput DNA barcoding results.

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Vierna, J; Doña, J; Vizcaíno, A; Serrano, D; Jovani, R

2017-10-01

High-throughput DNA barcoding has become essential in ecology and evolution, but some technical questions still remain. Increasing the number of PCR cycles above the routine 20-30 cycles is a common practice when working with old-type specimens, which provide little amounts of DNA, or when facing annealing issues with the primers. However, increasing the number of cycles can raise the number of artificial mutations due to polymerase errors. In this work, we sequenced 20 COI libraries in the Illumina MiSeq platform. Libraries were prepared with 40, 45, 50, 55, and 60 PCR cycles from four individuals belonging to four species of four genera of cephalopods. We found no relationship between the number of PCR cycles and the number of mutations despite using a nonproofreading polymerase. Moreover, even when using a high number of PCR cycles, the resulting number of mutations was low enough not to be an issue in the context of high-throughput DNA barcoding (but may still remain an issue in DNA metabarcoding due to chimera formation). We conclude that the common practice of increasing the number of PCR cycles should not negatively impact the outcome of a high-throughput DNA barcoding study in terms of the occurrence of point mutations.

Effects of complex life cycles on genetic diversity: cyclical parthenogenesis.

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Rouger, R; Reichel, K; Malrieu, F; Masson, J P; Stoeckel, S

2016-11-01

Neutral patterns of population genetic diversity in species with complex life cycles are difficult to anticipate. Cyclical parthenogenesis (CP), in which organisms undergo several rounds of clonal reproduction followed by a sexual event, is one such life cycle. Many species, including crop pests (aphids), human parasites (trematodes) or models used in evolutionary science (Daphnia), are cyclical parthenogens. It is therefore crucial to understand the impact of such a life cycle on neutral genetic diversity. In this paper, we describe distributions of genetic diversity under conditions of CP with various clonal phase lengths. Using a Markov chain model of CP for a single locus and individual-based simulations for two loci, our analysis first demonstrates that strong departures from full sexuality are observed after only a few generations of clonality. The convergence towards predictions made under conditions of full clonality during the clonal phase depends on the balance between mutations and genetic drift. Second, the sexual event of CP usually resets the genetic diversity at a single locus towards predictions made under full sexuality. However, this single recombination event is insufficient to reshuffle gametic phases towards full-sexuality predictions. Finally, for similar levels of clonality, CP and acyclic partial clonality (wherein a fixed proportion of individuals are clonally produced within each generation) differentially affect the distribution of genetic diversity. Overall, this work provides solid predictions of neutral genetic diversity that may serve as a null model in detecting the action of common evolutionary or demographic processes in cyclical parthenogens (for example, selection or bottlenecks).

Enhanced lipid accumulation and biodiesel production by oleaginous Chlorella protothecoides under a structured heterotrophic-iron (II) induction strategy.

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Li, Yuqin; Mu, Jinxiu; Chen, Di; Xu, Hua; Han, Fangxin

2015-05-01

A structured heterotrophic-iron (II) induction (HII) strategy was proposed to enhance lipid accumulation in oleaginous Chlorella protothecoides. C. protothecoides subjected to heterotrophic-iron (II) induction achieved a favorable lipid accumulation up to 62 % and a maximum lipid productivity of 820.17 mg/day, representing 2.78-fold and 3.64-fold increase respectively over heterotrophic cultivation alone. HII-induced cells produced significantly elevated levels of 16:0, 18:1(Δ9), and 18:2(Δ9,12) fatty acids (over 90 %). The lipid contents and plant lipid-like fatty acid compositions exhibit the potential of HII-induced C. protothecoides as biodiesel feedstock. Furthermore, 31 altered proteins in HII-induced algal cells were successfully identified. These differentially expressed proteins were assigned into nine molecular function categories, including carbohydrate metabolism, lipid biosynthesis, Calvin cycle, cellular respiration, photosynthesis, energy and transport, protein biosynthesis, regulate and defense, and unclassified. Analysis using the Kyoto encyclopedia of genes and genomes and gene ontology annotation showed that malic enzyme, acyltransferase, and ACP were key metabolic checkpoints found to modulate lipid accumulation in C. protothecoides. The results provided possible applications of HII cultivation strategy in other microalgal species and new possibilities in developing genetic and metabolic engineering microalgae for desirable lipid productivity.

Former land-use and tree species affect nitrogen oxide emissions from a tropical dry forest.

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Heather Erickson; Eric A. Davidson; Michael Keller

2002-01-01

Species composition in successional dry forests in the tropics varies widely, but the effect of this variation on biogeochemical processes is not well known. We examined fluxes of N oxides (nitrous and nitric oxide), soil N cycling, and litter chemistry (C/N ratio) in four successional dry forests on similar soils in western Puerto Rico with differing species...

Microbial Nitrogen-Cycle Gene Abundance in Soil of Cropland Abandoned for Different Periods.

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Huhe; Borjigin, Shinchilelt; Buhebaoyin; Wu, Yanpei; Li, Minquan; Cheng, Yunxiang

2016-01-01

In Inner Mongolia, steppe grasslands face desertification or degradation because of human overuse and abandonment after inappropriate agricultural management. The soils in these abandoned croplands exist in heterogeneous environments characterized by widely fluctuating microbial growth. Quantitative polymerase chain reaction analysis of microbial genes encoding proteins involved in the nitrogen cycle was used to study Azotobacter species, nitrifiers, and denitrifiers in the soils from steppe grasslands and croplands abandoned for 2, 6, and 26 years. Except for nitrifying archaea and nitrous oxide-reducing bacteria, the relative genotypic abundance of microbial communities involved in nitrogen metabolism differed by approximately 2- to 10-fold between abandoned cropland and steppe grassland soils. Although nitrogen-cycle gene abundances varied with abandonment time, the abundance patterns of nitrogen-cycle genes separated distinctly into abandoned cropland versus light-grazing steppe grassland, despite the lack of any cultivation for over a quarter-century. Plant biomass and plant diversity exerted a significant effect on the abundance of microbial communities that mediate the nitrogen cycle (P nitrogen cycle in recently abandoned croplands.

Leaf litter traits of invasive alien species slow down decomposition compared to Spanish natives: a broad phylogenetic comparison.

NARCIS (Netherlands)

Godoy, O.; Castro Diez, P.; van Logtestijn, R.S.P; Cornelissen, J.H.C.; Valladares, F.

2010-01-01

Leaf traits related to the performance of invasive alien species can influence nutrient cycling through litter decomposition. However, there is no consensus yet about whether there are consistent differences in functional leaf traits between invasive and native species that also manifest themselves

The Effect of Water Deficit Different Levels on Antioxidant System and Lipid Peroxidation in two Species Tagetes erecta and Tagetes patula of Marigold

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seyyed mousa mousavi

2018-02-01

Full Text Available Introduction: With regard to decrease of precipitation and poor distribution of rainfall during the dry phenomenon of urban, green spaces face problems. In fact, one of the most important environmental stress is drought stress at different stages of plant growth such as seed germination, seedling establishment and crop production. The effect of drought stress, plants photochemical activity ceased Calvin cycle enzymes and chlorophyll content also varies in the process of photosynthesis under drought stress. Under drought stress, reactive oxygen species (ROS such as hydrogen peroxide (H2O2, superoxide radicals (O2 • - and hydroxide (OH • increase their accumulation in cells that can lead to oxidative stress. To neutralize ROS, antioxidant enzymes systems in plant such as superoxide dismutase (SOD, peroxidase (POD, catalase (CAT and ascorbate peroxidase (APX are active. The response of antioxidants depends on the lack of water, the intensity of the stress and the type of plant species. Also, it is well known that photosynthetic systems in higher plants are most sensitive to drought stress. Indeed, drought is one of the factors affecting photosynthesis and chlorophyll content. Some of researchers reported that chlorophyll might estimate influence of environmental stress on growth because these parameters were closely correlated with the rate of carbon exchange. The aim of this study was an investigation of effect of water deficit different levels on antioxidant system and lipid peroxidation in two species of marigold. Therefore, an experiment was carried out as factorial in a randomized complete block design with three replication at Shahid Chamran University of Ahvaz in 2014 year. Materials and methods: Experimental treatments were irrigation with three levels: 100% ETcrop (no stress, 75% ETcrop (moderate stress and 50% ETcrop (severe stress and two species of marigold (African and French. Catalase activity decreased absorption at a wavelength

Variations upon a theme: Australian lizards provide insights into the endocrine control of vertebrate reproductive cycles.

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Jones, Susan M

2017-04-01

Australian lizards exhibit a broad array of different reproductive strategies and provide an extraordinary diversity and range of models with which to address fundamental problems in reproductive biology. Studies on lizards have frequently led to new insights into hormonal regulatory pathways or mechanisms of control, but we have detailed knowledge of the reproductive cycle in only a small percentage of known species. This review provides an overview and synthesis of current knowledge of the hormonal control of reproductive cycles in Australian lizards. Agamid lizards have provided useful models with which to test hypotheses about the hormonal regulation of the expression of reproductive behaviors, while research on viviparous skinks is providing insights into the evolution of the endocrine control of gestation. However, in order to better understand the potential risks that environmental factors such as climate change and endocrine disrupting chemicals pose to our fauna, better knowledge is required of the fundamental characteristics of the reproductive cycle in a broader range of lizard species. Copyright © 2015 Elsevier Inc. All rights reserved.

[Molecular techniques applied in species identification of Toxocara].

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Fogt, Renata

2006-01-01

Toxocarosis is still an important and actual problem in human medicine. It can manifest as visceral (VLM), ocular (OLM) or covert (CT) larva migrans syndroms. Complicated life cycle of Toxocara, lack of easy and practical methods of species differentiation of the adult nematode and embarrassing in recognition of the infection in definitive hosts create difficulties in fighting with the infection. Although studies on human toxocarosis have been continued for over 50 years there is no conclusive answer, which of species--T. canis or T. cati constitutes a greater risk of transmission of the nematode to man. Neither blood serological examinations nor microscopic observations of the morphological features of the nematode give the satisfied answer on the question. Since the 90-ths molecular methods were developed for species identification and became useful tools being widely applied in parasitological diagnosis. This paper cover the survey of methods of DNA analyses used for identification of Toxocara species. The review may be helpful for researchers focused on Toxocara and toxocarosis as well as on detection of new species. The following techniques are described: PCR (Polymerase Chain Reaction), RFLP (Restriction Fragment Length Polymorphism), RAPD (Random Amplified Polymorphic DNA) and SSCP (Single Strand Conformation Polymorphism).

Species Diversity and Botanical Composition of Permanent Grassland as a Response to Different Grazing Management Practices

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Marie Štýbnarová

2015-01-01

Full Text Available The effects of different levels of grazing utilization (two, three and four grazing cycles per year and mineral fertilization (nil-fertilization; N100P30K60 on the botanical composition of permanent grasslands were studied in the locality of Rapotín (Czech Republic, 332 m a.s.l. from 2003–2010. The vegetation of the experimental pasture was classified as Cynosurion. It was found that moderate treatment (three grazing cycles per year without mineral fertilization showed the highest value of diversity index (DI = 6.08, and maximum dominance of legumes (Dmax = 9.1%, particularly Trifolium repens. The highest dominance of grasses (Dmax = 77.7%, mainly Dactylis glomerata and Elytrigia repens, was achieved with the fertilized treatment utilized in two grazing cycles per year. Based on RDA results, tested management treatments explained 26% of species composition variability, where effect of number of grazing cycles per year was five-times higher than effect of fertilization. We recommend grassland utilization in three grazing cycles per year as the most suitable way from the objective of both species diversity and botanical composition of pastures in similar site conditions. Pasture fertilization should be more controlled by careful consideration of individual pasture goals, actual nutrient status of the soil and possible environmental risks.

Will Solar Cycles 25 and 26 Be Weaker than Cycle 24?

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Javaraiah, J.

2017-11-01

The study of variations in solar activity is important for understanding the underlying mechanism of solar activity and for predicting the level of activity in view of the activity impact on space weather and global climate. Here we have used the amplitudes (the peak values of the 13-month smoothed international sunspot number) of Solar Cycles 1 - 24 to predict the relative amplitudes of the solar cycles during the rising phase of the upcoming Gleissberg cycle. We fitted a cosine function to the amplitudes and times of the solar cycles after subtracting a linear fit of the amplitudes. The best cosine fit shows overall properties (periods, maxima, minima, etc.) of Gleissberg cycles, but with large uncertainties. We obtain a pattern of the rising phase of the upcoming Gleissberg cycle, but there is considerable ambiguity. Using the epochs of violations of the Gnevyshev-Ohl rule (G-O rule) and the `tentative inverse G-O rule' of solar cycles during the period 1610 - 2015, and also using the epochs where the orbital angular momentum of the Sun is steeply decreased during the period 1600 - 2099, we infer that Solar Cycle 25 will be weaker than Cycle 24. Cycles 25 and 26 will have almost same strength, and their epochs are at the minimum between the current and upcoming Gleissberg cycles. In addition, Cycle 27 is expected to be stronger than Cycle 26 and weaker than Cycle 28, and Cycle 29 is expected to be stronger than both Cycles 28 and 30. The maximum of Cycle 29 is expected to represent the next Gleissberg maximum. Our analysis also suggests a much lower value (30 - 40) for the maximum amplitude of the upcoming Cycle 25.

Culture in cycles: considering H.T. Odum's 'information cycle'

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Abel, Thomas

2014-01-01

'Culture' remains a conundrum in anthropology. When recast in the mold of 'information cycles,' culture is transformed. New fault lines appear. Information is splintered into parallel or nested forms. Dynamics becomes cycling. Energy is essential. And culture has function in a directional universe. The 'information cycle' is the crowning component of H.T. Odum's theory of general systems. What follows is an application of the information cycle to the cultural domains of discourse, social media, ritual, education, journalism, technology, academia, and law, which were never attempted by Odum. In information cycles, cultural information is perpetuated - maintained against Second Law depreciation. Conclusions are that culture is in fact a nested hierarchy of cultural forms. Each scale of information production is semi-autonomous, with its own evolutionary dynamics of production and selection in an information cycle. Simultaneously, each information cycle is channeled or entrained by its larger scale of information and ultimately human-ecosystem structuring.

Use of fish parasite species richness indices in analyzing anthropogenically impacted coastal marine ecosystems

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Dzikowski, R.; Paperna, I.; Diamant, A.

2003-10-01

The diversity of fish parasite life history strategies makes these species sensitive bioindicators of aquatic ecosystem health. While monoxenous (single-host) species may persist in highly perturbed, extreme environments, this is not necessarily true for heteroxenous (multiple-host) species. As many parasites possess complex life cycles and are transmitted through a chain of host species, their dependency on the latter to complete their life cycles renders them sensitive to perturbed environments. In the present study, parasite communities of grey mullet Liza aurata and Liza ramada (Mugilidae) were investigated at two Mediterranean coastal sites in northern Israel: the highly polluted Kishon Harbor (KH) and the relatively unspoiled reference site, Ma'agan Michael (MM). Both are estuarine sites in which grey mullet are one of the most common fish species. The results indicate that fish at the polluted site had significantly less trematode metacercariae than fish at the reference site. Heteroxenous gut helminths were completely absent at the polluted sampling site. Consequently, KH fish displayed lower mean parasite species richness. At the same time, KH fish mean monoxenous parasite richness was higher, although the prevalence of different monoxenous taxa was variable. Copepods had an increased prevalence while monogenean prevalence was significantly reduced at the polluted site. This variability may be attributed to the differential susceptibility of the parasites to the toxicity of different pollutants, their concentration, the exposure time and possible synergistic effects. In this study, we used the cumulative species curve model that extrapolates "true" species richness of a given habitat as a function of increasing sample size. We considered the heteroxenous and monoxenous species separately for each site, and comparison of curves yielded significant results. It is proposed to employ this approach, originally developed for estimating the "true" parasite

Changes in Nitrogen Cycling during Tropical Forest Secondary Succession on Abandoned Pastures

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Mirza, S.; Rivera, R. J.; Marin-Spiotta, E.

2017-12-01

Nitrogen (N) plays two important roles in Earth's climate. As a plant nutrient, the availability of N affects plant growth and the uptake of carbon (C) from the atmosphere into plant biomass. The accumulation of C in long-lived biomass and in soils contributes to reducing the amount of CO2 in the atmosphere. Secondly, excess N can lead to the production of N2O, which is a more potent greenhouse than CO2. Humans have altered the cycling of N in terrestrial ecosystems, affecting their potential to sequester C and help mitigate climate change. Land-use change, specifically deforestation and reforestation, can affect N availability for plant growth and N2O production. Long-term agricultural use can deplete nitrogen sources, even in tropical soils where N is not expected to limit productivity. Secondary succession and reforestation can allow for the recovery of N stocks and fluxes, with implications for C cycling and N2O emissions. N limitation in pastures and early successional forests increases the demand for N-fixing tree species, but previous research has shown that there is a greater abundance of N-fixing species in older forests (Batterman et. al 2013). Successional trends in N mineralization and denitrification vary across studies, with some showing greater rates in agricultural soils or in mature forest soils, compared to early successional sites. Here we examine changes in N-fixing species, above and belowground N pools, and N cycling rates in secondary forests on former pastures on Oxisols in the wet tropical forest life zone of Puerto Rico. The availability of a long-term well-replicated chronosequence provides us with the opportunity to study decadal trends in N processes during forest recovery after agricultural abandonment.

Plant selenium hyperaccumulation- Ecological effects and potential implications for selenium cycling and community structure.

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Reynolds, R Jason B; Pilon-Smits, Elizabeth A H

2018-04-25

Selenium (Se) hyperaccumulation occurs in ~50 plant taxa native to seleniferous soils in Western USA. Hyperaccumulator tissue Se levels, 1000-15,000 mg/kg dry weight, are typically 100 times higher than surrounding vegetation. Relative to other species, hyperaccumulators also transform Se more into organic forms. We review abiotic and biotic factors influencing soil Se distribution and bioavailability, soil being the source of the Se in hyperaccumulators. Next, we summarize the fate of Se in plants, particularly hyperaccumulators. We then extensively review the impact of plant Se accumulation on ecological interactions. Finally, we discuss the potential impact of Se hyperaccumulators on local community composition and Se cycling. Selenium (hyper)accumulation offers ecological advantages: protection from herbivores and pathogens and competitive advantage over other plants. The extreme Se levels in and around hyperaccumulators create a toxic environment for Se-sensitive ecological partners, while offering a niche for Se-resistant partners. Through these dual effects, hyperaccumulators may influence species composition in their local environment, as well as Se cycling. The implied effects of Se hyperaccumulation on community assembly and local Se cycling warrant further investigations into the contribution of hyperaccumulators and general terrestrial vegetation to global Se cycling and may serve as a case study for how trace elements influence ecological processes. Furthermore, understanding ecological implications of plant Se accumulation are vital for safe implementation of biofortification and phytoremediation, technologies increasingly implemented to battle Se deficiency and toxicity. Copyright © 2018. Published by Elsevier B.V.

Proliferation in cycle

Energy Technology Data Exchange (ETDEWEB)

Piao Yunsong [College of Physical Sciences, Graduate School of Chinese Academy of Sciences, Beijing 100049 (China)], E-mail: yspiao@gucas.ac.cn

2009-06-15

In the contracting phase with w{approx_equal}0, the scale invariant spectrum of curvature perturbation is given by the increasing mode of metric perturbation. In this Letter, it is found that if the contracting phase with w{approx_equal}0 is included in each cycle of a cycle universe, since the metric perturbation is amplified on super horizon scale cycle by cycle, after each cycle the universe will be inevitably separated into many parts independent of one another, each of which corresponds to a new universe and evolves up to next cycle, and then is separated again. In this sense, a cyclic multiverse scenario is actually presented, in which the universe proliferates cycle by cycle. We estimate the number of new universes proliferated in each cycle, and discuss the implications of this result.

Proliferation in cycle

International Nuclear Information System (INIS)

Piao Yunsong

2009-01-01

In the contracting phase with w≅0, the scale invariant spectrum of curvature perturbation is given by the increasing mode of metric perturbation. In this Letter, it is found that if the contracting phase with w≅0 is included in each cycle of a cycle universe, since the metric perturbation is amplified on super horizon scale cycle by cycle, after each cycle the universe will be inevitably separated into many parts independent of one another, each of which corresponds to a new universe and evolves up to next cycle, and then is separated again. In this sense, a cyclic multiverse scenario is actually presented, in which the universe proliferates cycle by cycle. We estimate the number of new universes proliferated in each cycle, and discuss the implications of this result.

Absorption of some mineral salts by root system of different woody species and accumulation over a whole vegetative cycle (1963); Absorption de quelques sels par l'appareil radiculaire de differentes especes ligneuses et accumulation au cours d'un cycle vegetatif complet (1963)

Energy Technology Data Exchange (ETDEWEB)

Gagnaire, J; Gerard, J M [Commisariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

1963-07-01

The concentration power of plant tissues and the translocation speed of mineral salts are considerably varying with the absorbed salt, the botanical species, the considered tissue and the part of the vegetative cycle. In Grenoble, with Picea excelsa, the 'true dormancy' is short (half-november, end of december). It is accompanied by a pre-dormancy period (October, half-november) and a post dormancy period (January, february, march). In vegetative period, Picea excelsa leaves are less concentrating mineral salt than Acer campestris leaves (coefficient 2 for calcium - 3 for phosphates) and Populus nigra leaves (coefficient 3 for calcium, coefficient 5 for phosphates). (author) [French] Le pouvoir de concentration de tissus vegetaux, et particulierement la vitesse de transport des sels mineraux varient beaucoup selon le sel mineral absorbe, l'espece vegetale, le tissu considere ainsi que la periode du cycle vegetatif. A Grenoble, pour les epiceas 'la dormance veritable' est courte (mi-novembre, fin decembre). Elle est encadree par des periodes de pre-dormance (octobre, mi-novembre) et de post-dormance (janvier, fevrier, mars). Pendant la periode vegetative, le pouvoir de concentration de sels mineraux des aiguilles d'epiceas est plus faible que celui des feuilles d'erables (coefficient 2 pour le calcium - coefficient 3 pour les phosphates) ou que celui des feuilles de peupliers (coefficient 3 pour le calcium - coefficient 5 pour les phosphates). (auteur)

Rapid ammonia gas transport accounts for futile transmembrane cycling under NH3/NH4+ toxicity in plant roots.

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Coskun, Devrim; Britto, Dev T; Li, Mingyuan; Becker, Alexander; Kronzucker, Herbert J

2013-12-01

Futile transmembrane NH3/NH4(+) cycling in plant root cells, characterized by extremely rapid fluxes and high efflux to influx ratios, has been successfully linked to NH3/NH4(+) toxicity. Surprisingly, the fundamental question of which species of the conjugate pair (NH3 or NH4(+)) participates in such fluxes is unresolved. Using flux analyses with the short-lived radioisotope (13)N and electrophysiological, respiratory, and histochemical measurements, we show that futile cycling in roots of barley (Hordeum vulgare) seedlings is predominately of the gaseous NH3 species, rather than the NH4(+) ion. Influx of (13)NH3/(13)NH4(+), which exceeded 200 µmol g(-1) h(-1), was not commensurate with membrane depolarization or increases in root respiration, suggesting electroneutral NH3 transport. Influx followed Michaelis-Menten kinetics for NH3 (but not NH4(+)), as a function of external concentration (Km = 152 µm, Vmax = 205 µmol g(-1) h(-1)). Efflux of (13)NH3/(13)NH4(+) responded with a nearly identical Km. Pharmacological characterization of influx and efflux suggests mediation by aquaporins. Our study fundamentally revises the futile-cycling model by demonstrating that NH3 is the major permeating species across both plasmalemma and tonoplast of root cells under toxicity conditions.

Population crises and population cycles.

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Russell, C; Russell, W M

2000-01-01

To prevent a population irretrievably depleting its resources, mammals have evolved a behavioural and physiological response to population crisis. When a mammalian population becomes dangerously dense, there is a reversal of behaviour. Co-operation and parental behaviour are replaced by competition, dominance and aggressive violence, leading to high mortality, especially of females and young, and a reduced population. The stress of overpopulation and the resulting violence impairs both the immune and the reproductive systems. Hence epidemics complete the crash of the population, and reproduction is slowed for three or four generations, giving the resources ample time to recover. In some mammal species, crisis and crisis response recur regularly, leading to cycles of population growth and relapse, oscillating about a fixed mean. Population crisis response and population cycles have been equally prominent in the history of human societies. But in man successive advances in food production have made possible growing populations, though with every such advance population soon outgrew resources again. Hence human cycles have been superimposed on a rising curve, producing a saw-tooth graph. Because advances in food production amounted to sudden disturbances in the relations between human populations and their environments, the crisis response in man has failed to avert famine and resource damage. In the large human societies evolved since the coming of settled agriculture and cities, the basic effects of violence, epidemics, famine and resource damage have been mediated by such specifically human disasters as inflation, unemployment, and political tyranny. An account of past crises, periods of relative relief from population pressure, and resulting cycles, is given for a number of regions: China, North Africa and Western Asia, the northern Mediterranean, and north-western Europe. The paper ends with an account of the present world-wide population crisis, and the solution

Comparative genomic analysis of carbon and nitrogen assimilation mechanisms in three indigenous bioleaching bacteria: predictions and validations

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Ehrenfeld Nicole

2008-12-01

Full Text Available Abstract Background Carbon and nitrogen fixation are essential pathways for autotrophic bacteria living in extreme environments. These bacteria can use carbon dioxide directly from the air as their sole carbon source and can use different sources of nitrogen such as ammonia, nitrate, nitrite, or even nitrogen from the air. To have a better understanding of how these processes occur and to determine how we can make them more efficient, a comparative genomic analysis of three bioleaching bacteria isolated from mine sites in Chile was performed. This study demonstrated that there are important differences in the carbon dioxide and nitrogen fixation mechanisms among bioleaching bacteria that coexist in mining environments. Results In this study, we probed that both Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans incorporate CO2 via the Calvin-Benson-Bassham cycle; however, the former bacterium has two copies of the Rubisco type I gene whereas the latter has only one copy. In contrast, we demonstrated that Leptospirillum ferriphilum utilizes the reductive tricarboxylic acid cycle for carbon fixation. Although all the species analyzed in our study can incorporate ammonia by an ammonia transporter, we demonstrated that Acidithiobacillus thiooxidans could also assimilate nitrate and nitrite but only Acidithiobacillus ferrooxidans could fix nitrogen directly from the air. Conclusion The current study utilized genomic and molecular evidence to verify carbon and nitrogen fixation mechanisms for three bioleaching bacteria and provided an analysis of the potential regulatory pathways and functional networks that control carbon and nitrogen fixation in these microorganisms.

Metabolome Analysis Reveals Betaine Lipids as Major Source for Triglyceride Formation, and the Accumulation of Sedoheptulose during Nitrogen-Starvation of Phaeodactylum tricornutum.

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Jennifer Popko

Full Text Available Oleaginous microalgae are considered as a promising resource for the production of biofuels. Especially diatoms arouse interest as biofuel producers since they are most productive in carbon fixation and very flexible to environmental changes in the nature. Naturally, triacylglycerol (TAG accumulation in algae only occurs under stress conditions like nitrogen-limitation. We focused on Phaeodactylum strain Pt4 (UTEX 646, because of its ability to grow in medium with low salinity and therefore being suited when saline water is less available or for wastewater cultivation strategies. Our data show an increase in neutral lipids during nitrogen-depletion and predominantly 16:0 and 16:1(n-7 accumulated in the TAG fraction. The molecular species composition of TAG suggests a remodeling primarily from the betaine lipid diacylglyceroltrimethylhomoserine (DGTS, but a contribution of the chloroplast galactolipid monogalactosyldiacylglycerol (MGDG cannot be excluded. Interestingly, the acyl-CoA pool is rich in 20:5(n-3 and 22:6(n-3 in all analyzed conditions, but these fatty acids are almost excluded from TAG. Other metabolites most obviously depleted under nitrogen-starvation were amino acids, lyso-phospholipids and tricarboxylic acid (TCA cycle intermediates, whereas sulfur-containing metabolites as dimethylsulfoniopropionate, dimethylsulfoniobutyrate and methylsulfate as well as short acyl chain carnitines, propanoyl-carnitine and butanoyl-carnitine increased upon nitrogen-starvation. Moreover, the Calvin cycle may be de-regulated since sedoheptulose accumulated after nitrogen-depletion. Together the data provide now the basis for new strategies to improve lipid production and storage in Phaeodactylum strain Pt4.

Surfing among species, populations and morphotypes: Inferring boundaries between two species of new world silversides (Atherinopsidae).

Science.gov (United States)

González-Castro, Mariano; Rosso, Juan José; Mabragaña, Ezequiel; Díaz de Astarloa, Juan Martín

2016-01-01

Atherinopsidae are widespread freshwater and shallow marine fish with singular economic importance. Morphological, genetical and life cycles differences between marine and estuarine populations were already reported in this family, suggesting ongoing speciation. Also, coexistence and interbreeding between closely related species were documented. The aim of this study was to infer boundaries among: (A) Odontesthes bonariensis and O. argentinensis at species level, and intermediate morphs; (B) the population of O. argentinensis of Mar Chiquita Lagoon and its marine conspecifics. To achieve this, we integrated, meristic, Geometrics Morphometrics and DNA Barcode approaches. Four groups were discriminated and subsequently characterized according to their morphological traits, shape and meristic characters. No shared haplotypes between O. bonariensis and O. argentinensis were found. Significative-meristic and body shape differences between the Mar Chiquita and marine individuals of O. argentinensis were found, suggesting they behave as well differentiated populations, or even incipient ecological species. The fact that the Odontesthes morphotypes shared haplotypes with both, O. argentinensis and O. bonariensis, but also possess meristic and morphometric distinctive traits open new questions related to the origin of this morphogroup. Copyright © 2015 Académie des sciences. Published by Elsevier SAS. All rights reserved.

Biogeochemical cycle of mercury species in the marine environment

International Nuclear Information System (INIS)

Branica, M.

1987-10-01

Mercury contamination of the coastal marine environment is an important concern as highly toxic methyl-mercury may be formed biogenically in sediments rich in organic matter. The present study was conducted using a highly sensitive adaptation of Cold Vapour Atomic Absorption Spectrophotometry (CVAAS) in which mercury was re-mineralised from a variety of marine matrices (water, sediments and organisms), separated and concentrated by ion-exchange chromatography, trapped as an amalgam in gold wool and subsequently re-released by heating to 900 deg. C. Total and organomercury forms were detected respectively by measuring, in the case of seawater, sample extracts treated and untreated with uv light and, in the case of solid matrices, by ''total digestion'' and 6M HCl extractions. Detection limits were 0.1 ng/1 from a 200 ml water sample and 0.2 μg/kg for a lg solid sample. Water, sediments and organisms were collected by scuba diving from the unpolluted Sibenik aquatorium (including the Krka river estuary), Yugoslavia, and the polluted Kastela Bay, which receives discharge from a chlor-alkali plant. Mercury levels were low in the Sibenik aquatorium (0.34-2.4 ng/dm 3 water, 78-1522 μg/kg sediments and 24-39 μg/kg w.w. in mussels). Organo-mercury was generally below detection limits in water and represented below 0.5% of the total Hg in sediments but 13-88% of the mercury in mussels and fish. In the Kastela Bay, up to 90 ng/dm 3 (water), 11870 μg/kg w.w. (mussels) and 48600 μg kg w.w. (oysters) of Hg was detected. Fortunately methyl-mercury was below 0.5% of this total in all matrices. Hg levels in mussels decreased to 41.3 μg/kg w.w. at 600 m from the source. Further research will now be conducted on the biogeochemical cycle of Hg in estuarine and marine environments, with special attention being paid to the fresh/saline water interface. 9 refs, 2 figs, 5 tabs

Seed and Germination Characteristics of 20 Amazonian Liana Species

Directory of Open Access Journals (Sweden)

Mareike Roeder

2013-01-01

Full Text Available Lianas are an important component of tropical forests, and may reach their highest densities in disturbed areas. However, information on seed and germination characteristics is scarce. Twenty Amazon liana species were screened for their germination characteristics, including light dependence, tolerance of desiccation and of alternating temperatures; these characteristics are considered important for the germination success in areas with relatively open canopies. Between 31–1,420 seeds per species were available, as 15 species seeds came from one mother plant. We studied seed biometry and conducted germination trials with fresh seeds (12 h light daily, or dark and desiccated seeds at 25 °C. Germination at alternating temperatures (20/30 °C, 15/35 °C was analyzed for nine species. Of the 20 species, eight species with the largest seeds had desiccation sensitive seeds; this is the first record for species of four genera and one family, where only desiccation tolerant seeds are otherwise recorded. Light-dependent germination was found in three species (0.01–0.015 g and is the first record for two; however, results were based on seeds from one plant per species. Alternating temperatures of 15/35 °C decreased final germination of four out of nine species, and response to 20/30 °C cycles varied compared to constant 25 °C. Seed and germination characteristics of the species ranged from pioneer to climax traits indicating that establishment of lianas from seeds may be confined to species specific niches.

Effect of tidal cycle and food intake on the baseline plasma corticosterone rhythm in intertidally foraging marine iguanas.

Science.gov (United States)

Woodley, Sarah K; Painter, Danika L; Moore, Michael C; Wikelski, Martin; Romero, L Michael

2003-06-15

In most species, plasma levels of baseline glucocorticoids such as corticosterone (B) have a circadian rhythm. This rhythm can be entrained by both photoperiod and food intake and is related to aspects of energy intake and metabolism. Marine iguanas (Amblyrhynchus cristatus) offer a unique opportunity to better understand the relative importance of the light:dark cycle versus food intake in influencing the rhythm in baseline B in a natural system. Compared to other species, food intake is not as strictly determined by the phase of the light:dark cycle. Animals feed in the intertidal zone so feeding activity is heavily influenced by the tidal cycle. We measured baseline plasma B levels in free-living iguanas over several 24-h periods that varied in the timing of low tide/foraging activity. We found that baseline B levels were higher during the day relative to night. However, when low tide occurred during the day, baseline B levels dropped coincident with the timing of low tide. Whether the baseline B rhythm (including the drop during foraging) is an endogenous rhythm with a circatidal component, or is simply a result of feeding and associated physiological changes needs to be tested. Together, these data suggest that the baseline B rhythm in marine iguanas is influenced by the tidal cycle/food intake as well as the light:dark cycle.

Modelling planktic foraminifer growth and distribution using an ecophysiological multi-species approach

DEFF Research Database (Denmark)

Lombard, Fabien; Labeyrie, L.; Michel, E.

2011-01-01

We present an eco-physiological model reproducing the growth of eight foraminifer species (Neogloboquadrina pachyderma, Neogloboquadrina incompta, Neogloboquadrina dutertrei, Globigerina bulloides, Globigerinoides ruber, Globigerinoides sacculifer, Globigerinella siphonifera and Orbulina universa...... in the marine carbon cycle....... ocean (PISCES) instead of satellite images as forcing variables gives also good results, but with lower efficiency (58.9%). Compared to core tops observations, the model also correctly reproduces the relative worldwide abundance and the diversity of the eight species when using either satellite data...

A new species of Stenomicra Coquillett (Diptera: Periscelididae) from the Brazilian Amazon and its life history.

Science.gov (United States)

Gomes, Eliane Solar; Ale-Rocha, Rosaly; Keppler, Ruth Leila Ferreira

2018-04-12

A new species of Stenomicra is described for the Neotropical Region, from phytotelmata of Araceae at an urban forest fragment in the city of Manaus, state of Amazonas, Brazil. Morphological descriptions of the immatures and the adults (male and female) are provided, together with biological information on the life cycle of the species and its "host" plant.

Pacing of Paleozoic macroevolutionary rates by Milankovitch grand cycles.

Science.gov (United States)

Crampton, James S; Meyers, Stephen R; Cooper, Roger A; Sadler, Peter M; Foote, Michael; Harte, David

2018-05-29

Periodic fluctuations in past biodiversity, speciation, and extinction have been proposed, with extremely long periods ranging from 26 to 62 million years, although forcing mechanisms remain speculative. In contrast, well-understood periodic Milankovitch climate forcing represents a viable driver for macroevolutionary fluctuations, although little evidence for such fluctuation exists except during the Late Cenozoic. The reality, magnitude, and drivers of periodic fluctuations in macroevolutionary rates are of interest given long-standing debate surrounding the relative roles of intrinsic biotic interactions vs. extrinsic environmental factors as drivers of biodiversity change. Here, we show that, over a time span of 60 million years, between 9 and 16% of the variance in biological turnover (i.e., speciation probability plus species extinction probability) in a major Early Paleozoic zooplankton group, the graptoloids, can be explained by long-period astronomical cycles (Milankovitch "grand cycles") associated with Earth's orbital eccentricity (2.6 million years) and obliquity (1.3 million years). These grand cycles modulate climate variability, alternating times of relative stability in the environment with times of maximum volatility. We infer that these cycles influenced graptolite speciation and extinction through climate-driven changes to oceanic circulation and structure. Our results confirm the existence of Milankovitch grand cycles in the Early Paleozoic Era and show that known processes related to the mechanics of the Solar System were shaping marine macroevolutionary rates comparatively early in the history of complex life. We present an application of hidden Markov models to macroevolutionary time series and protocols for the evaluation of statistical significance in spectral analysis.

Developmental Cycle and Genome Analysis of Protochlamydia massiliensis sp. nov. a New Species in the Parachlamydiacae Family

Directory of Open Access Journals (Sweden)

Samia Benamar

2017-08-01

Full Text Available Amoeba-associated microorganisms (AAMs are frequently isolated from water networks. In this paper, we report the isolation and characterization of Protochlamydia massiliensis, an obligate intracellular Gram-negative bacterium belonging to the Parachlamydiaceae family in the Chlamydiales order, from a cooling water tower. This bacterium was isolated on Vermamoeba vermiformis. It has a multiple range of hosts among amoeba and is characterized by a typical replication cycle of Chlamydiae with a particularity, recently shown in some chlamydia, which is the absence of inclusion vacuoles in the V. vermiformis host, adding by this a new member of Chlamydiae undergoing developmental cycle changes in the newly adapted host V. vermiformis. Draft genome sequencing revealed a chromosome of 2.86 Mb consisting of four contigs and a plasmid of 92 Kb.

Species-rich grassland can persist under nitrogen-rich but phosphorus-limited conditions

NARCIS (Netherlands)

Dobben, van Han F.; Wamelink, Wieger; Slim, Pieter A.; Kamiński, Jan; Piórkowski, Hubert

2017-01-01

Aim: Deposition of nitrogen is assumed to cause loss of botanical diversity, probably through increased production and exclusion of less competitive species. However, if production is (co-)limited by phosphorus, acceleration of the phosphorus cycle may be responsible for the diversity loss and,

Three cycles of water deficit from seed to young plants of Moringa oleifera woody species improves stress tolerance.

Science.gov (United States)

Rivas, Rebeca; Oliveira, Marciel T; Santos, Mauro G

2013-02-01

The main objective of this study was to assess whether recurring water stress occurring from seed germination to young plants of Moringa oleifera Lam. are able to mitigate the drought stress effects. Germination, gas exchange and biochemical parameters were analysed after three cycles of water deficit. Young plants were used 50 days after germination under three osmotic potentials (0.0, -0.3 and -0.4 MPa). For each germination treatment, control (irrigated) and stressed (10% of water control) plants were compared for a total of six treatments. There were two cycles of drought interspersed with 10 days of rehydration. The young plants of M. oleifera showed increased tolerance to repeated cycles of drought, maintaining high relative water content (RWC), high water use efficiency (WUE), increased photosynthetic pigments and increased activity of antioxidant enzymes. There was rapid recovery of the photosynthetic rate during the rehydration period. The stressed plants from the -0.3 and -0.4 MPa treatments showed higher tolerance compared to the control plants. The results suggest that seeds of M. oleifera subjected to mild water deficit have had increased the ability for drought tolerance when young plant. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

Bundle-sheath leakiness in C4 photosynthesis: a careful balancing act between CO2 concentration and assimilation.

Science.gov (United States)

Kromdijk, Johannes; Ubierna, Nerea; Cousins, Asaph B; Griffiths, Howard

2014-07-01

Crop species with the C4 photosynthetic pathway are generally characterized by high productivity, especially in environmental conditions favouring photorespiration. In comparison with the ancestral C3 pathway, the biochemical and anatomical modifications of the C4 pathway allow spatial separation of primary carbon acquisition in mesophyll cells and subsequent assimilation in bundle-sheath cells. The CO2-concentrating C4 cycle has to operate in close coordination with CO2 reduction via the Calvin-Benson-Bassham (CBB) cycle in order to keep the C4 pathway energetically efficient. The gradient in CO2 concentration between bundle-sheath and mesophyll cells facilitates diffusive leakage of CO2. This rate of bundle-sheath CO2 leakage relative to the rate of phosphoenolpyruvate carboxylation (termed leakiness) has been used to probe the balance between C4 carbon acquisition and subsequent reduction as a result of environmental perturbations. When doing so, the correct choice of equations to derive leakiness from stable carbon isotope discrimination (Δ(13)C) during gas exchange is critical to avoid biased results. Leakiness responses to photon flux density, either short-term (during measurements) or long-term (during growth and development), can have important implications for C4 performance in understorey light conditions. However, recent reports show leakiness to be subject to considerable acclimation. Additionally, the recent discovery of two decarboxylating C4 cycles operating in parallel in Zea mays suggests that flexibility in the transported C4 acid and associated decarboxylase could also aid in maintaining C4/CBB balance in a changing environment. In this paper, we review improvements in methodology to estimate leakiness, synthesize reports on bundle-sheath leakiness, discuss different interpretations, and highlight areas where future research is necessary. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology

Long-term fluctuations in intertidal communities in an Irish sea-lough: Limpet-fucoid cycles

Science.gov (United States)

Little, Colin; Trowbridge, Cynthia D.; Pilling, Graham M.; Stirling, Penny; Morritt, David; Williams, Gray A.

2017-09-01

Long-term cyclical changes in rocky shore community structure were documented over two decades at sheltered shores in Lough Hyne Marine Reserve, County Cork, Ireland. Three peaks of abundance were recorded for the limpet, Patella vulgata (1990-5, 2002-6 and 2010-14) with oscillations that varied in amplitude and frequency among sites. The cover of the fucoid Fucus vesiculosus varied inversely with limpet abundance and showed the strongest negative correlation with a lag time of 0-2 years. The species complex Fucus spiralis/guiryi showed a weaker correlation with a lag time of 1-2 years. Two other fucoid species showed no such negative correlations despite their close proximity to limpets within the lough's compressed tidal range. There was no relationship between overall barnacle cover (dominated by Austrominius modestus) and the limpet-fucoid cycles, suggesting that the shelter provided by A. modestus for algae to escape from limpet grazing pressure may not be necessary for these cycles to occur on wave-sheltered shores.

Your Menstrual Cycle

Science.gov (United States)

... your menstrual cycle What happens during your menstrual cycle The menstrual cycle includes not just your period, but the rise ... that take place over the weeks in your cycle. Want to know what happens on each day ...

NSA2, a novel nucleolus protein regulates cell proliferation and cell cycle

International Nuclear Information System (INIS)

Zhang, Heyu; Ma, Xi; Shi, Taiping; Song, Quansheng; Zhao, Hongshan; Ma, Dalong

2010-01-01

NSA2 (Nop seven-associated 2) was previously identified in a high throughput screen of novel human genes associated with cell proliferation, and the NSA2 protein is evolutionarily conserved across different species. In this study, we revealed that NSA2 is broadly expressed in human tissues and cultured cell lines, and located in the nucleolus of the cell. Both of the putative nuclear localization signals (NLSs) of NSA2, also overlapped with nucleolar localization signals (NoLSs), are capable of directing nucleolar accumulation. Moreover, over-expression of the NSA2 protein promoted cell growth in different cell lines and regulated the G1/S transition in the cell cycle. SiRNA silencing of the NSA2 transcript attenuated the cell growth and dramatically blocked the cell cycle in G1/S transition. Our results demonstrated that NSA2 is a nucleolar protein involved in cell proliferation and cell cycle regulation.

Fuel cycle cost uncertainty from nuclear fuel cycle comparison

International Nuclear Information System (INIS)

Li, J.; McNelis, D.; Yim, M.S.

2013-01-01

This paper examined the uncertainty in fuel cycle cost (FCC) calculation by considering both model and parameter uncertainty. Four different fuel cycle options were compared in the analysis including the once-through cycle (OT), the DUPIC cycle, the MOX cycle and a closed fuel cycle with fast reactors (FR). The model uncertainty was addressed by using three different FCC modeling approaches with and without the time value of money consideration. The relative ratios of FCC in comparison to OT did not change much by using different modeling approaches. This observation was consistent with the results of the sensitivity study for the discount rate. Two different sets of data with uncertainty range of unit costs were used to address the parameter uncertainty of the FCC calculation. The sensitivity study showed that the dominating contributor to the total variance of FCC is the uranium price. In general, the FCC of OT was found to be the lowest followed by FR, MOX, and DUPIC. But depending on the uranium price, the FR cycle was found to have lower FCC over OT. The reprocessing cost was also found to have a major impact on FCC

Towards 100,000 CPU Cycle-Scavenging by Genetic Algorithms

Science.gov (United States)

Globus, Al; Biegel, Bryan A. (Technical Monitor)

2001-01-01

We examine a web-centric design using standard tools such as web servers, web browsers, PHP, and mySQL. We also consider the applicability of Information Power Grid tools such as the Globus (no relation to the author) Toolkit. We intend to implement this architecture with JavaGenes running on at least two cycle-scavengers: Condor and United Devices. JavaGenes, a genetic algorithm code written in Java, will be used to evolve multi-species reactive molecular force field parameters.

Maintaining animal assemblages through single-species management: the case of threatened caribou in boreal forest.

Science.gov (United States)

Bichet, Orphé; Dupuch, Angélique; Hébert, Christian; Le Borgne, Hélène Le; Fortin, Daniel

2016-03-01

With the intensification of human activities, preserving animal populations is a contemporary challenge of critical importance. In this context, the umbrella species concept is appealing because preserving a single species should result in the protection of multiple co-occurring species. Practitioners, though, face the task of having to find suitable umbrellas to develop single-species management guidelines. In North America, boreal forests must be managed to facilitate the recovery of the threatened boreal caribou (Rangifer tarandus). Yet, the effect of caribou conservation on co-occurring animal species remains poorly documented. We tested if boreal caribou can constitute an effective umbrella for boreal fauna. Birds, small mammals, and insects were sampled along gradients of post-harvest and post-fire forest succession. Predictive models of occupancy were developed from the responses of 95 species to characteristics of forest stands and their surroundings. We then assessed the similarity of species occupancy expected between simulated harvested landscapes and a 90 000-km2 uncut landscape. Managed landscapes were simulated based on three levels of disturbance, two timber-harvest rotation cycles, and dispersed or aggregated cut-blocks. We found that management guidelines that were more likely to maintain caribou populations should also better preserve animal assemblages. Relative to fragmentation or harvest cycle, we detected a stronger effect of habitat loss on species assemblages. Disturbing 22%, 35%, and 45% of the landscape should result, respectively, in 80%, 60%, and 40% probability for caribou populations to be sustainable; in turn, this should result in regional species assemblages with Jaccard similarity indices of 0.86, 0.79, and 0.74, respectively, relative to the uncut landscape. Our study thus demonstrates the value of single-species management for animal conservation. Our quantitative approach allows for the evaluation of management guidelines prior

Fuelwood quality of promising tree species for alkaline soil sites in relation to tree age

Energy Technology Data Exchange (ETDEWEB)

Goel, V.L.; Behl, H.M. [National Botanical Research Inst., Lucknow (India). Biomass Research Center

1996-06-01

The fuelwood quality of five tree species suitable for afforestation of alkaline soil sites was investigated in relation to tree age for establishing harvest rotation cycles. Prosopis juliflora and Acacia nilotica were found to be the most suitable species for short rotation fuel wood forestry programmes because of their high wood density, biomass yield, low ash and moisture content, and good heat of combustion at the juvenile stage. The performance of other species like Acacia auriculiformis, Terminalia arjuna and Sesbania formosa is discussed. (author)

Microbial Nitrogen-Cycle Gene Abundance in Soil of Cropland Abandoned for Different Periods.

Directory of Open Access Journals (Sweden)

Huhe

Full Text Available In Inner Mongolia, steppe grasslands face desertification or degradation because of human overuse and abandonment after inappropriate agricultural management. The soils in these abandoned croplands exist in heterogeneous environments characterized by widely fluctuating microbial growth. Quantitative polymerase chain reaction analysis of microbial genes encoding proteins involved in the nitrogen cycle was used to study Azotobacter species, nitrifiers, and denitrifiers in the soils from steppe grasslands and croplands abandoned for 2, 6, and 26 years. Except for nitrifying archaea and nitrous oxide-reducing bacteria, the relative genotypic abundance of microbial communities involved in nitrogen metabolism differed by approximately 2- to 10-fold between abandoned cropland and steppe grassland soils. Although nitrogen-cycle gene abundances varied with abandonment time, the abundance patterns of nitrogen-cycle genes separated distinctly into abandoned cropland versus light-grazing steppe grassland, despite the lack of any cultivation for over a quarter-century. Plant biomass and plant diversity exerted a significant effect on the abundance of microbial communities that mediate the nitrogen cycle (P < 0.002 and P < 0.03, respectively. The present study elucidates the ecology of bacteria that mediate the nitrogen cycle in recently abandoned croplands.

Algorithm for the generation of nuclear spin species and nuclear spin statistical weights

International Nuclear Information System (INIS)

Balasubramanian, K.

1982-01-01

A set of algorithms for the computer generation of nuclear spin species and nuclear spin statistical weights potentially useful in molecular spectroscopy is developed. These algorithms generate the nuclear spin species from group structures known as generalized character cycle indices (GCCIs). Thus the required input for these algorithms is just the set of all GCCIs for the symmetry group of the molecule which can be computed easily from the character table. The algorithms are executed and illustrated with examples

DETECTING ALIEN LIMIT CYCLES NEAR A HAMILTONIAN 2-SADDLE CYCLE

OpenAIRE

LUCA, Stijn; DUMORTIER, Freddy; Caubergh, M.; Roussarie, R.

2009-01-01

This paper aims at providing and example of a cubic Hamiltonian 2-saddle cycle that after bifurcation can give rise to an alien limit cycle; this is a limit cycle that is not controlled by a zero of the related Abelian integral. To guarantee the existence of an alien limit cycle one can verify generic conditions on the Abelian integral and on the transition map associated to the connections of the 2-saddle cycle. In this paper, a general method is developed to compute the first and second der...

The trait contribution to wood decomposition rates of 15 neotropical tree species

NARCIS (Netherlands)

Geffen, van K.G.; Poorter, L.; Sass-Klaassen, U.; Logtestijn, R.S.P.; Cornelissen, J.H.C.

2010-01-01

The decomposition of dead wood is a critical uncertainty in models of the global carbon cycle. Despite this, relatively few studies have focused on dead wood decomposition, with a strong bias to higher latitudes. Especially the effect of inter-specific variation in species traits on differences wood

The trait contribution to wood decomposition rates of 15 Neotropical tree species.

NARCIS (Netherlands)

van Geffen, K.G.; Poorter, L.; Sass-Klaassen, U.; van Logtestijn, R.S.P; Cornelissen, J.H.C.

2010-01-01

The decomposition of dead wood is a critical uncertainty in models of the global carbon cycle. Despite this, relatively few studies have focused on dead wood decomposition, with a strong bias to higher latitudes. Especially the effect of interspecific variation in species traits on differences in

Hydraulic architecture of two species differing in wood density: opposing strategies in co-occurring tropical pioneer trees

Science.gov (United States)

Katherine A. McCulloh; Daniel M. Johnson; Frederick C. Meinzer; Steven L. Voelker; Barbara Lachenbruch; Jean-Christophe. Domec

2012-01-01

Co-occurring species often have different strategies for tolerating daily cycles of water stress. One underlying parameter that can link together the suite of traits that enables a given strategy is wood density. Here we compare hydraulic traits of two pioneer species from a tropical forest in Panama that differ in wood density: Miconia argentea...

Early Evolution of Earth's Geochemical Cycle and Biosphere: Implications for Mars Exobiology

Science.gov (United States)

DesMarais, David J.; Chang, Sherwood (Technical Monitor)

1997-01-01

Carbon (C) has played multiple key roles for life and its environment. C has formed organics, greenhouse gases, aquatic pH buffers, redox buffers, and magmatic constituents affecting plutonism and volcanism. These roles interacted across a network of reservoirs and processes known as the biogeochemical C cycle. Changes in the cycle over geologic time were driven by increasing solar luminosity, declining planetary heat flow, and continental and biological evolution. The early Archean C cycle was dominated by hydrothermal alteration of crustal rocks and by thermal emanations of CO2 and reduced species (eg., H2, Fe(2+) and sulfides). Bioorganic synthesis was achieved by nonphotosynthetic CO2-fixing bacteria (chemoautotrophs) and, possibly, bacteria (organotrophs) utilizing any available nonbiological organic C. Responding both to abundant solar energy and to a longterm decline in thermal sources of chemical energy and reducing power, the blaspheme first developed anoxygenic photosynthesis, then, ultimately, oxygenic photosynthesis. O2-photosynthesis played a central role in transforming the ancient environment and blaspheme to the modem world. The geochemical C cycles of early Earth and Mars were quite similar. The principal differences between the modem C cycles of these planets arose during the later evolution of their heat flows, crusts, atmospheres and, perhaps, their blasphemes.

Fideizm Jana Kalwina w doktrynie podwójnej predestynacji

Directory of Open Access Journals (Sweden)

Antoni SZWED

2015-12-01

Full Text Available Fideism, as a philosophical and theological view, is defined in various manners. Sometimes it is defined as the priority of faith over accounts of all kinds of cognition based on human reason. The Geneva reformer John Calvin (1509–1564 was a fideist, and he simultaneously admired Saint Augustine — traces of that admiration can be found very easy in the chief Calvin’s work Institutio christianae religionis. However, this does not mean that he shared Augustinian views on faith‑reason relations. John Calvin adopted late‑Augustinian interests, and was especially concerned with the issue of predestination. The Geneva reformer was the author of the double predestination doctrine. The chief claim of this doctrine is that: God intended one part of humanity for salvation; and the other one for damnation. This conclusion was supported with numerous quotations from the Old and the New Testament, and followed from the accepted exegetic principle that all words of the Holy Scripture are to be understood literally. Calvin also acted selectively and did not take into account other passages of the Bible contrary to them in sense. These different, even contradictory words and quotations create an incoherent image of God, which Calvin left unexplained as one of God’s mysteries. According to this image, God is a petulant despot, who by his irrational will treats people with unequal measure. God has settled a priori who would be saved and who would be damned, so the will of concrete man to act well or badly is without importance. In consequence, God is responsible for the evil and sins committed by people. Calvin’s God is unfair because he is merciful for one man, but not for other one. In approving a voluntaristic image of God, Calvin started becoming, particularly in the doctrine of double predestination, an extreme fideist, much more than his master Augustine. However, in later decades (especially in the seventeenth century, Calvin’s version of

Proposal of a nuclear cycle research and development plan in Tokai works. The roadmap from LWR cycle to FBR cycle

International Nuclear Information System (INIS)

Nakamura, Hirofumi; Abe, Tomoyuki; Kashimura, Takuo; Nagai, Toshihisa; Maeda, Seichiro; Yamaguchi, Toshiya; Kuroki, Ryoichiro

2003-07-01

The Generation-II Project Task Force Team has investigated a research and development plan of a future nuclear fuel cycle in Tokai works for about three months from December 19, 2002. First we have discussed about the present condition of Japanese nuclear fuel cycle and have recognized it as the following. The relation of the technology between the LWR-cycle and the FBR-cycle is not clear. MOX Fuel Use in Light Water Reactors is important to establish technology of the FBR fuel cycle. Radioactive waste disposal issue is urgent. Next we have proposed the three basic policies on R and D plan of nuclear fuel cycle in consideration of the F.S. on FBR-cycle. Establishment and advancement of 'the tough nuclear fuel cycle'. Early establishment of the FBR cycle technology to be able to supply energy stably for long-term. Establishment of the radioactive waste treatment and disposal technology, and optimization of nuclear fuel cycle technology from the viewpoint of radioactive waste. And we have proposed the Japanese technical holder system to integrate all LWR and FBR cycle technology. (author)

Simulation of Cycle-to-Cycle Variation in Dual-Fuel Engines

KAUST Repository

Jaasim, Mohammed

2017-03-13

Standard practices of internal combustion (IC) engine experiments are to conduct the measurements of quantities averaged over a large number of cycles. Depending on the operating conditions, the cycle-to-cycle variation (CCV) of quantities, such as the indicated mean effective pressure (IMEP) are observed at different levels. Accurate prediction of CCV in IC engines is an important but challenging task. Computational fluid dynamics (CFD) simulations using high performance computing (HPC) can be used effectively to visualize such 3D spatial distributions. In the present study, a dual fuel large engine is considered, with natural gas injected into the manifold accompanied with direct injection of diesel pilot fuel to trigger ignition. Multiple engine cycles in 3D are simulated in series as in the experiments to investigate the potential of HPC based high fidelity simulations to accurately capture the cycle to cycle variation in dual fuel engines. Open cycle simulations are conducted to predict the combined effect of the stratification of fuel-air mixture, temperature and turbulence on the CCV of pressure. The predicted coefficient of variation (COV) of pressure compared to the results from closed cycle simulations and the experiments.

Effects of plant diversity, N fertilization, and elevated carbon dioxide on grassland soil N cycling in a long-term experiment.

Science.gov (United States)

Mueller, Kevin E; Hobbie, Sarah E; Tilman, David; Reich, Peter B

2013-04-01

The effects of global environmental changes on soil nitrogen (N) pools and fluxes have consequences for ecosystem functions such as plant productivity and N retention. In a 13-year grassland experiment, we evaluated how elevated atmospheric carbon dioxide (CO2 ), N fertilization, and plant species richness alter soil N cycling. We focused on soil inorganic N pools, including ammonium and nitrate, and two N fluxes, net N mineralization and net nitrification. In contrast with existing hypotheses, such as progressive N limitation, and with observations from other, often shorter, studies, elevated CO2 had relatively static and small, or insignificant, effects on soil inorganic N pools and fluxes. Nitrogen fertilization had inconsistent effects on soil N transformations, but increased soil nitrate and ammonium concentrations. Plant species richness had increasingly positive effects on soil N transformations over time, likely because in diverse subplots the concentrations of N in roots increased over time. Species richness also had increasingly positive effects on concentrations of ammonium in soil, perhaps because more carbon accumulated in soils of diverse subplots, providing exchange sites for ammonium. By contrast, subplots planted with 16 species had lower soil nitrate concentrations than less diverse subplots, especially when fertilized, probably due to greater N uptake capacity of subplots with 16 species. Monocultures of different plant functional types had distinct effects on N transformations and nitrate concentrations, such that not all monocultures differed from diverse subplots in the same manner. The first few years of data would not have adequately forecast the effects of N fertilization and diversity on soil N cycling in later years; therefore, the dearth of long-term manipulations of plant species richness and N inputs is a hindrance to forecasting the state of the soil N cycle and ecosystem functions in extant plant communities. © 2012 Blackwell

Ontogeny reversal and phylogenetic analysis of Turritopsis sp.5 (Cnidaria, Hydrozoa, Oceaniidae, a possible new species endemic to Xiamen, China

Directory of Open Access Journals (Sweden)

Jun-yuan Li

2018-01-01

Full Text Available Ontogeny reversal, as seen in some cnidarians, is an unprecedented phenomenon in the animal kingdom involving reversal of the ordinary life cycle. Three species of Turritopsis have been shown to be capable of inverted metamorphosis, a process in which the pelagic medusa transforms back into a juvenile benthic polyp stage when faced with adverse conditions. Turritopsis sp.5 is a species of Turritopsis collected from Xiamen, China which presents a similar ability, being able to reverse its life cycle if injured by mechanical stress. Phylogenetic analysis based on both 16S rDNA and cytochrome c oxidase subunit I (COI genetic barcodes shows that Turritopsis sp.5 is phylogenetically clustered in a clade separate from other species of Turritopsis. The genetic distance between T. sp.5 and the Japanese species T. sp.2 is the shortest, when measured by the Kimura 2-Parameter metric, and the distance to the New Zealand species T. rubra is the largest. An experimental assay on the induction of reverse development in this species was initiated by cutting medusae into upper and lower parts. We show, for the first time, that the two dissected parts have significantly different potentials to transform into polyps. Also, a series of morphological changes of the reversed life cycle can be recognised, including medusa stage, contraction stage I, contraction stage II, cyst, cyst with stolons, and polyp. The discovery of species capable of reverse ontogeny caused by unfavorable conditions adds to the available systems with which to study the cell types that contribute to the developmental reversal and the molecular mechanisms of the directional determination of ontogeny.

CALVIN'S SUDDEN CONVERSION (SUBITA CONVERSIO) AND ...

African Journals Online (AJOL)

his conversion, it could be fruitful to consider it from both historical and theological perspectives. ... logical positions of the interpreters. For example, a ..... God, but as the true method of worshipping was altogether unknown to me, I stumbled at ...

Institute for the advancement of Calvinism

Directory of Open Access Journals (Sweden)

J. J. Snyman

1977-03-01

Full Text Available This publication presents all the papers read at a conference held at the Potchefstroom University for Christian Higher Education during September 1975. The theme of the conference (initiated by Prof. HJJ . Bingle, at the time rector of the PU for CHE was formulated as “ Reformed Institutions for Higher Education as a Bulwark for the Kingdom of God — present and future”. The idea of such institutions as a “bulwark for the Kingdom of God" is toned down in the title of this book. The difference in tone may be explained as the result of the difference between a stage of planning and a stage of looking back on what was carried out of that planning. Such a re­ view of this enterprise cannot be unaccompanied by the feelings of being “sadder but wiser” . Something of this is reflected in the prefatory notes of Prof. Bingle to this book. Experiences of the conference came to be com­ mitted to paper in this publication and Prof. Bingle remarks very aptly amongst other things that this collection of conference papers reveals a probable “identification of important differences of opinion on Christian Higher Education.” But if this insight meant a revision of the idea of in­ stitutions for Christian higher education as “bulwarks for the Kingdom of God”, this publication also serves to put on record another experience of the conference: “that there are encouraging signs -of a will to find one another in our common pursuit of an honest appraisal of the Christian principle in higher education”. These proceedings may be viewed (in the words of Prof. Bingle as a valuable expression and documentation of an “attem pt at ecumenicity within the context of Christian Higher Educa tion” .

Simulation of Cycle-to-Cycle Variation in Dual-Fuel Engines

KAUST Repository

Jaasim, Mohammed; Pasunurthi, Shyamsundar; Jupudi, Ravichandra S.; Gubba, Sreenivasa Rao; Primus, Roy; Klingbeil, Adam; Wijeyakulasuriya, Sameera; Im, Hong G.

2017-01-01

Standard practices of internal combustion (IC) engine experiments are to conduct the measurements of quantities averaged over a large number of cycles. Depending on the operating conditions, the cycle-to-cycle variation (CCV) of quantities

Temperature- and body mass-related variation in cyclic gas exchange characteristics and metabolic rate of seven weevil species: Broader implications.

Science.gov (United States)

Klok, C J; Chown, S L

2005-07-01

The influence of temperature on metabolic rate and characteristics of the gas exchange patterns of flightless, sub-Antarctic Ectemnorhinus-group species from Heard and Marion islands was investigated. All of the species showed cyclic gas exchange with no Flutter period, indicating that these species are not characterized by discontinuous gas exchange cycles. Metabolic rate estimates were substantially lower in this study than in a previous one of a subset of the species, demonstrating that open-system respirometry methods provide more representative estimates of standard metabolic rate than do many closed-system methods. We recommend that the latter, and especially constant-pressure methods, either be abandoned for estimates of standard metabolic rate in insects, or have their outputs subject to careful scrutiny, given the wide availability of the former. V(.)CO(2) increase with an increase in temperature (range: 0-15 degrees C) was modulated by an increase in cycle frequency, but typically not by an increase in burst volume. Previous investigations of temperature-related changes in cyclic gas exchange (both cyclic and discontinuous) in several other insect species were therefore substantiated. Interspecific mass-scaling of metabolic rate (ca. 0.466-0.573, excluding and including phylogenetic non-independence, respectively) produced an exponent lower than 0.75 (but not distinguishable from it or from 0.67). The increase of metabolic rate with mass was modulated by an increase in burst volume and not by a change in cycle frequency, in keeping with investigations of species showing discontinuous gas exchange. These findings are discussed in the context of the emerging macrophysiological metabolic theory of ecology.

The role of demographic compensation theory in incidental take assessments for endangered species

Science.gov (United States)

McGowan, Conor P.; Ryan, Mark R.; Runge, Michael C.; Millspaugh, Joshua J.; Cochrane, Jean Fitts

2011-01-01

Many endangered species laws provide exceptions to legislated prohibitions through incidental take provisions as long as take is the result of unintended consequences of an otherwise legal activity. These allowances presumably invoke the theory of demographic compensation, commonly applied to harvested species, by allowing limited harm as long as the probability of the species' survival or recovery is not reduced appreciably. Demographic compensation requires some density-dependent limits on survival or reproduction in a species' annual cycle that can be alleviated through incidental take. Using a population model for piping plovers in the Great Plains, we found that when the population is in rapid decline or when there is no density dependence, the probability of quasi-extinction increased linearly with increasing take. However, when the population is near stability and subject to density-dependent survival, there was no relationship between quasi-extinction probability and take rates. We note however, that a brief examination of piping plover demography and annual cycles suggests little room for compensatory capacity. We argue that a population's capacity for demographic compensation of incidental take should be evaluated when considering incidental allowances because compensation is the only mechanism whereby a population can absorb the negative effects of take without incurring a reduction in the probability of survival in the wild. With many endangered species there is probably little known about density dependence and compensatory capacity. Under these circumstances, using multiple system models (with and without compensation) to predict the population's response to incidental take and implementing follow-up monitoring to assess species response may be valuable in increasing knowledge and improving future decision making.

Life-cycle cost analysis of adsorption cycles for desalination

KAUST Repository

Thu, Kyaw

2010-08-01

This paper presents the thermo-economic analysis of the adsorption desalination (AD) cycle that is driven by low-temperature waste heat from exhaust of industrial processes or renewable sources. The AD cycle uses an adsorbent such as the silica gel to desalt the sea or brackish water. Based on an experimental prototype AD plant, the life-cycle cost analysis of AD plants of assorted water production capacities has been simulated and these predictions are translated into unit cost of water production. Our results show that the specific energy consumption of the AD cycle is 1.38 kWh/m3 which is the lowest ever reported. For a plant capacity of 1000 m3/d, the AD cycle offers a unit cost of $0.457/m3 as compared to more than $0.9 for the average RO plants. Besides being cost-effective, the AD cycle is also environment-friendly as it emits less CO2 emission per m3 generated, typically 85% less, by comparison to an RO process. © 2010 Desalination Publications.

Characterization of Chloroplastic Fructose 1,6-Bisphosphate Aldolases as Lysine-methylated Proteins in Plants*

Science.gov (United States)

Mininno, Morgane; Brugière, Sabine; Pautre, Virginie; Gilgen, Annabelle; Ma, Sheng; Ferro, Myriam; Tardif, Marianne; Alban, Claude; Ravanel, Stéphane

2012-01-01

In pea (Pisum sativum), the protein-lysine methyltransferase (PsLSMT) catalyzes the trimethylation of Lys-14 in the large subunit (LS) of ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco), the enzyme catalyzing the CO2 fixation step during photosynthesis. Homologs of PsLSMT, herein referred to as LSMT-like enzymes, are found in all plant genomes, but methylation of LS Rubisco is not universal in the plant kingdom, suggesting a species-specific protein substrate specificity of the methyltransferase. In this study, we report the biochemical characterization of the LSMT-like enzyme from Arabidopsis thaliana (AtLSMT-L), with a focus on its substrate specificity. We show that, in Arabidopsis, LS Rubisco is not naturally methylated and that the physiological substrates of AtLSMT-L are chloroplastic fructose 1,6-bisphosphate aldolase isoforms. These enzymes, which are involved in the assimilation of CO2 through the Calvin cycle and in chloroplastic glycolysis, are trimethylated at a conserved lysyl residue located close to the C terminus. Both AtLSMT-L and PsLSMT are able to methylate aldolases with similar kinetic parameters and product specificity. Thus, the divergent substrate specificity of LSMT-like enzymes from pea and Arabidopsis concerns only Rubisco. AtLSMT-L is able to interact with unmethylated Rubisco, but the complex is catalytically unproductive. Trimethylation does not modify the kinetic properties and tetrameric organization of aldolases in vitro. The identification of aldolases as methyl proteins in Arabidopsis and other species like pea suggests a role of protein lysine methylation in carbon metabolism in chloroplasts. PMID:22547063

Richness, biomass, and nutrient content of a wetland macrophyte community affect soil nitrogen cycling in a diversity-ecosystem functioning experiment

Science.gov (United States)

Korol, Alicia R.; Ahn, Changwoo; Noe, Gregory

2016-01-01

The development of soil nitrogen (N) cycling in created wetlands promotes the maturation of multiple biogeochemical cycles necessary for ecosystem functioning. This development proceeds from gradual changes in soil physicochemical properties and influential characteristics of the plant community, such as competitive behavior, phenology, productivity, and nutrient composition. In the context of a 2-year diversity experiment in freshwater mesocosms (0, 1, 2, 3, or 4 richness levels), we assessed the direct and indirect impacts of three plant community characteristics – species richness, total biomass, and tissue N concentration – on three processes in the soil N cycle – soil net ammonification, net nitrification, and denitrification potentials. Species richness had a positive effect on net ammonification potential (NAP) through higher redox potentials and likely faster microbial respiration. All NAP rates were negative, however, due to immobilization and high rates of ammonium removal. Net nitrification was inhibited at higher species richness without mediation from the measured soil properties. Higher species richness also inhibited denitrification potential through increased redox potential and decreased nitrification. Both lower biomass and/or higher tissue ratios of carbon to nitrogen, characteristics indicative of the two annual plants, were shown to have stimulatory effects on all three soil N processes. The two mediating physicochemical links between the young macrophyte community and microbial N processes were soil redox potential and temperature. Our results suggest that early-successional annual plant communities play an important role in the development of ecosystem N multifunctionality in newly created wetland soils.

Statistical approaches to use a model organism for regulatory sequences annotation of newly sequenced species.

Directory of Open Access Journals (Sweden)

Pietro Liò

Full Text Available A major goal of bioinformatics is the characterization of transcription factors and the transcriptional programs they regulate. Given the speed of genome sequencing, we would like to quickly annotate regulatory sequences in newly-sequenced genomes. In such cases, it would be helpful to predict sequence motifs by using experimental data from closely related model organism. Here we present a general algorithm that allow to identify transcription factor binding sites in one newly sequenced species by performing Bayesian regression on the annotated species. First we set the rationale of our method by applying it within the same species, then we extend it to use data available in closely related species. Finally, we generalise the method to handle the case when a certain number of experiments, from several species close to the species on which to make inference, are available. In order to show the performance of the method, we analyse three functionally related networks in the Ascomycota. Two gene network case studies are related to the G2/M phase of the Ascomycota cell cycle; the third is related to morphogenesis. We also compared the method with MatrixReduce and discuss other types of validation and tests. The first network is well known and provides a biological validation test of the method. The two cell cycle case studies, where the gene network size is conserved, demonstrate an effective utility in annotating new species sequences using all the available replicas from model species. The third case, where the gene network size varies among species, shows that the combination of information is less powerful but is still informative. Our methodology is quite general and could be extended to integrate other high-throughput data from model organisms.

Comparative gene expression analysis throughout the life cycle of Leishmania braziliensis: diversity of expression profiles among clinical isolates.

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Vanessa Adaui

Full Text Available BACKGROUND: Most of the Leishmania genome is reported to be constitutively expressed during the life cycle of the parasite, with a few regulated genes. Inter-species comparative transcriptomics evidenced a low number of species-specific differences related to differentially distributed genes or the differential regulation of conserved genes. It is of uppermost importance to ensure that the observed differences are indeed species-specific and not simply specific of the strains selected for representing the species. The relevance of this concern is illustrated by current study. METHODOLOGY/PRINCIPAL FINDINGS: We selected 5 clinical isolates of L. braziliensis characterized by their diversity of clinical and in vitro phenotypes. Real-time quantitative PCR was performed on promastigote and amastigote life stages to assess gene expression profiles at seven time points covering the whole life cycle. We tested 12 genes encoding proteins with roles in transport, thiol-based redox metabolism, cellular reduction, RNA poly(A-tail metabolism, cytoskeleton function and ribosomal function. The general trend of expression profiles showed that regulation of gene expression essentially occurs around the stationary phase of promastigotes. However, the genes involved in this phenomenon appeared to vary significantly among the isolates considered. CONCLUSION/SIGNIFICANCE: Our results clearly illustrate the unique character of each isolate in terms of gene expression dynamics. Results obtained on an individual strain are not necessarily representative of a given species. Therefore, extreme care should be taken when comparing the profiles of different species and extrapolating functional differences between them.

Biofouling on Coated Carbon Steel in Cooling Water Cycles Using Brackish Seawater

Directory of Open Access Journals (Sweden)

Pauliina Rajala

2016-11-01

Full Text Available Water cooling utilizing natural waters is typically used for cooling large industrial facilities such as power plants. The cooling water cycles are susceptible to biofouling and scaling, which may reduce heat transfer capacity and enhance corrosion. The performance of two fouling-release coatings combined with hypochlorite treatment were studied in a power plant utilizing brackish sea water from the Baltic Sea for cooling. The effect of hypochlorite as an antifouling biocide on material performance and species composition of microfouling formed on coated surfaces was studied during the summer and autumn. Microfouling on surfaces of the studied fouling-release coatings was intensive in the cooling water cycle during the warm summer months. As in most cases in a natural water environment the fouling consisted of both inorganic fouling and biofouling. Chlorination decreased the bacterial number on the surfaces by 10–1000 fold, but the efficacy depended on the coating. In addition to decreasing the bacterial number, the chlorination also changed the microbial species composition, forming the biofilm on the surfaces of two fouling-release coatings. TeknoTar coating was proven to be more efficient in combination with the hypochlorite treatment against microfouling under these experimental conditions.

How well can business cycle accounting account for business cycles?

OpenAIRE

Keisuke Otsu

2012-01-01

The business cycle accounting method introduced by Chari, Kehoe and McGrattan (2007) is a useful tool to decompose business cycle fluctuations into their contributing factors. However, the model estimated by the maximum likelihood method cannot replicate business cycle moments computed from data. Moment-based estimation might be an attractive alternative if the purpose of the research is to study business cycle properties such as volatility, persistence and cross-correlation of variables inst...

Equilibrium mercury isotope fractionation between dissolved Hg(II) species and thiol-bound Hg

NARCIS (Netherlands)

Wiederhold, Jan G.; Cramer, Christopher J.; Daniel, Kelly; Infante, Ivan; Bourdon, Bernard; Kretzschmar, Ruben

2010-01-01

Stable Hg isotope ratios provide a new tool to trace environmental Hg cycling. Thiols (-SH) are the dominant Hg-binding groups in natural organic matter. Here, we report experimental and computational results on equilibrium Hg isotope fractionation between dissolved Hg(II) species and thiol-bound

Soil warming opens the nitrogen cycle at the alpine treeline.

Science.gov (United States)

Dawes, Melissa A; Schleppi, Patrick; Hättenschwiler, Stephan; Rixen, Christian; Hagedorn, Frank

2017-01-01

Climate warming may alter ecosystem nitrogen (N) cycling by accelerating N transformations in the soil, and changes may be especially pronounced in cold regions characterized by N-poor ecosystems. We investigated N dynamics across the plant-soil continuum during 6 years of experimental soil warming (2007-2012; +4 °C) at a Swiss high-elevation treeline site (Stillberg, Davos; 2180 m a.s.l.) featuring Larix decidua and Pinus uncinata. In the soil, we observed considerable increases in the NH4+ pool size in the first years of warming (by >50%), but this effect declined over time. In contrast, dissolved organic nitrogen (DON) concentrations in soil solutions from the organic layer increased under warming, especially in later years (maximum of +45% in 2012), suggesting enhanced DON leaching from the main rooting zone. Throughout the experimental period, foliar N concentrations showed species-specific but small warming effects, whereas δ 15 N values showed a sustained increase in warmed plots that was consistent for all species analysed. The estimated total plant N pool size at the end of the study was greater (+17%) in warmed plots with Pinus but not in those containing Larix, with responses driven by trees. Irrespective of plot tree species identity, warming led to an enhanced N pool size of Vaccinium dwarf shrubs, no change in that of Empetrum hermaphroditum (dwarf shrub) and forbs, and a reduction in that of grasses, nonvascular plants, and fine roots. In combination, higher foliar δ 15 N values and the transient response in soil inorganic N indicate a persistent increase in plant-available N and greater cumulative plant N uptake in warmer soils. Overall, greater N availability and increased DON concentrations suggest an opening of the N cycle with global warming, which might contribute to growth stimulation of some plant species while simultaneously leading to greater N losses from treeline ecosystems and possibly other cold biomes. © 2016 John Wiley & Sons

Cycling in Sydney, Australia

Directory of Open Access Journals (Sweden)

Alexis Zander

2013-01-01

Full Text Available Introduction. Cycling can be an enjoyable way to meet physical activity recommendations and is suitable for older people; however cycling participation by older Australians is low. This qualitative study explored motivators, enablers, and barriers to cycling among older people through an age-targeted cycling promotion program. Methods. Seventeen adults who aged 50–75 years participated in a 12-week cycling promotion program which included a cycling skills course, mentor, and resource pack. Semistructured interviews at the beginning and end of the program explored motivators, enablers, and barriers to cycling. Results. Fitness and recreation were the primary motivators for cycling. The biggest barrier was fear of cars and traffic, and the cycling skills course was the most important enabler for improving participants’ confidence. Reported outcomes from cycling included improved quality of life (better mental health, social benefit, and empowerment and improved physical health. Conclusions. A simple cycling program increased cycling participation among older people. This work confirms the importance of improving confidence in this age group through a skills course, mentors, and maps and highlights additional strategies for promoting cycling, such as ongoing improvement to infrastructure and advertising.

pCO2 effects on species composition and growth of an estuarine phytoplankton community.

Science.gov (United States)

The effects of ongoing changes in ocean carbonate chemistry on plankton ecology have important implications for food webs and biogeochemical cycling. However, conflicting results have emerged regarding species-specific responses to pCO2 enrichment and thus community responses hav...

Marine nitrogen cycle

Digital Repository Service at National Institute of Oceanography (India)

Naqvi, S.W.A.

) such as the Marine nitrogen cycle The marine nitrogen cycle. ‘X’ and ‘Y’ are intra-cellular intermediates that do not accumulate in water column. (Source: Codispoti et al., 2001) Page 1 of 3Marine nitrogen cycle - Encyclopedia of Earth 11/20/2006http://www... and nitrous oxide budgets: Moving targets as we enter the anthropocene?, Sci. Mar., 65, 85-105, 2001. Page 2 of 3Marine nitrogen cycle - Encyclopedia of Earth 11/20/2006http://www.eoearth.org/article/Marine_nitrogen_cycle square6 Gruber, N.: The dynamics...

Optimal conservation of migratory species.

Directory of Open Access Journals (Sweden)

Tara G Martin

Full Text Available BACKGROUND: Migratory animals comprise a significant portion of biodiversity worldwide with annual investment for their conservation exceeding several billion dollars. Designing effective conservation plans presents enormous challenges. Migratory species are influenced by multiple events across land and sea-regions that are often separated by thousands of kilometres and span international borders. To date, conservation strategies for migratory species fail to take into account how migratory animals are spatially connected between different periods of the annual cycle (i.e. migratory connectivity bringing into question the utility and efficiency of current conservation efforts. METHODOLOGY/PRINCIPAL FINDINGS: Here, we report the first framework for determining an optimal conservation strategy for a migratory species. Employing a decision theoretic approach using dynamic optimization, we address the problem of how to allocate resources for habitat conservation for a Neotropical-Nearctic migratory bird, the American redstart Setophaga ruticilla, whose winter habitat is under threat. Our first conservation strategy used the acquisition of winter habitat based on land cost, relative bird density, and the rate of habitat loss to maximize the abundance of birds on the wintering grounds. Our second strategy maximized bird abundance across the entire range of the species by adding the constraint of maintaining a minimum percentage of birds within each breeding region in North America using information on migratory connectivity as estimated from stable-hydrogen isotopes in feathers. We show that failure to take into account migratory connectivity may doom some regional populations to extinction, whereas including information on migratory connectivity results in the protection of the species across its entire range. CONCLUSIONS/SIGNIFICANCE: We demonstrate that conservation strategies for migratory animals depend critically upon two factors: knowledge of

Hormone-dependent bacterial growth, persistence and biofilm formation--a pilot study investigating human follicular fluid collected during IVF cycles.

Directory of Open Access Journals (Sweden)

Elise S Pelzer

Full Text Available Human follicular fluid, considered sterile, is aspirated as part of an in vitro fertilization (IVF cycle. However, it is easily contaminated by the trans-vaginal collection route and little information exists in its potential to support the growth of microorganisms. The objectives of this study were to determine whether human follicular fluid can support bacterial growth over time, whether the steroid hormones estradiol and progesterone (present at high levels within follicular fluid contribute to the in vitro growth of bacterial species, and whether species isolated from follicular fluid form biofilms. We found that bacteria in follicular fluid could persist for at least 28 weeks in vitro and that the steroid hormones stimulated the growth of some bacterial species, specifically Lactobacillus spp., Bifidobacterium spp. Streptococcus spp. and E. coli. Several species, Lactobacillus spp., Propionibacterium spp., and Streptococcus spp., formed biofilms when incubated in native follicular fluids in vitro (18/24, 75%. We conclude that bacteria aspirated along with follicular fluid during IVF cycles demonstrate a persistent pattern of growth. This discovery is important since it can offer a new avenue for investigation in infertile couples.

Kinetic-quantum chemical model for catalytic cycles: the Haber-Bosch process and the effect of reagent concentration.

Science.gov (United States)

Kozuch, Sebastian; Shaik, Sason

2008-07-03

A combined kinetic-quantum chemical model is developed with the goal of estimating in a straightforward way the turnover frequency (TOF) of catalytic cycles, based on the state energies obtained by quantum chemical calculations. We describe how the apparent activation energy of the whole cycle, so-called energetic span (delta E), is influenced by the energy levels of two species: the TOF determining transition state (TDTS) and the TOF determining intermediate (TDI). Because these key species need not be adjoining states, we conclude that for catalysis there are no rate-determining steps, only rate determining states. In addition, we add here the influence of reactants concentrations. And, finally, the model is applied to the Haber-Bosch process of ammonia synthesis, for which we show how to calculate which catalyst will be the most effective under specific reagents conditions.

Po2 cycling protects diaphragm function during reoxygenation via ROS, Akt, ERK, and mitochondrial channels.

Science.gov (United States)

Zuo, Li; Pannell, Benjamin K; Re, Anthony T; Best, Thomas M; Wagner, Peter D

2015-12-01

Po2 cycling, often referred to as intermittent hypoxia, involves exposing tissues to brief cycles of low oxygen environments immediately followed by hyperoxic conditions. After experiencing long-term hypoxia, muscle can be damaged during the subsequent reintroduction of oxygen, which leads to muscle dysfunction via reperfusion injury. The protective effect and mechanism behind Po2 cycling in skeletal muscle during reoxygenation have yet to be fully elucidated. We hypothesize that Po2 cycling effectively increases muscle fatigue resistance through reactive oxygen species (ROS), protein kinase B (Akt), extracellular signal-regulated kinase (ERK), and certain mitochondrial channels during reoxygenation. Using a dihydrofluorescein fluorescent probe, we detected the production of ROS in mouse diaphragmatic skeletal muscle in real time under confocal microscopy. Muscles treated with Po2 cycling displayed significantly attenuated ROS levels (n = 5; P ROS, Akt, ERK, as well as chemical stimulators to close mitochondrial ATP-sensitive potassium channel (KATP) or open mitochondrial permeability transition pore (mPTP). All these blockers or stimulators abolished improved muscle function with Po2 cycling treatment. This current investigation has discovered a correlation between KATP and mPTP and the Po2 cycling pathway in diaphragmatic skeletal muscle. Thus we have identified a unique signaling pathway that may involve ROS, Akt, ERK, and mitochondrial channels responsible for Po2 cycling protection during reoxygenation conditions in the diaphragm. Copyright © 2015 the American Physiological Society.

Effects of seed density and proximity to refuge habitat on seed predation rates for a rare and a common Lupinus species.

Science.gov (United States)

Pardini, Eleanor A; Patten, Melissa V; Knight, Tiffany M

2017-03-01

Biotic interactions such as seed predation can play a role in explaining patterns of abundance among plant species. The effect of seed predation will depend on how the strength of predation differs across species and environments, and on the degree to which seed loss at one life-cycle phase increases fitness at another phase. Few studies have simultaneously quantified predispersal and postdispersal predation in co-occurring rare and common congeners, despite the value of estimating both for understanding causes of rarity. We quantified predispersal seed predation on the rare, herbaceous species Lupinus tidestromii (Fabaceae) and its common, shrubby congener L. chamissonis across multiple years in the same community. We experimentally measured postdispersal seed predation at two seed densities and locations near or far from an exotic grass housing high densities of deer mice ( Peromyscus maniculatus ), their primary, native seed predator. The common L. chamissonis had the lowest predispersal seed predation of the two lupine species, potentially because of its height: its high racemes received less predation than those low to the ground. By contrast, the same species experienced higher postdispersal seed predation, and at predators traveled long distances away from refuge habitat to consume their seeds. Across both plant species, mice preferentially predated high-density seed sources. Our results show differences in the magnitude and direction of seed predation between the species across different life-cycle phases. We demonstrated possible roles of proximity to refuge habitat, seed density, and seed size in these patterns. Congeneric comparisons would benefit from a comprehensive framework that considers seed predation across different life-cycle phases and the environmental context of predation. © 2017 Botanical Society of America.

Ursolic Acid-enriched herba cynomorii extract induces mitochondrial uncoupling and glutathione redox cycling through mitochondrial reactive oxygen species generation: protection against menadione cytotoxicity in h9c2 cells.

Science.gov (United States)

Chen, Jihang; Wong, Hoi Shan; Ko, Kam Ming

2014-01-27

Herba Cynomorii (Cynomorium songaricum Rupr., Cynomoriaceae) is one of the most commonly used 'Yang-invigorating' tonic herbs in Traditional Chinese Medicine (TCM). An earlier study in our laboratory has demonstrated that HCY2, an ursolic acid-enriched fraction derived from Herba Cynomorii, increased mitochondrial ATP generation capacity (ATP-GC) and induced mitochondrial uncoupling as well as a cellular glutathione response, thereby protecting against oxidant injury in H9c2 cells. In this study, we demonstrated that pre-incubation of H9c2 cells with HCY2 increased mitochondrial reactive oxygen species (ROS) generation in these cells, which is likely an event secondary to the stimulation of the mitochondrial electron transport chain. The suppression of mitochondrial ROS by the antioxidant dimethylthiourea abrogated the HCY2-induced enhancement of mitochondrial uncoupling and glutathione reductase (GR)-mediated glutathione redox cycling, and also protected against menadione-induced cytotoxicity. Studies using specific inhibitors of uncoupling protein and GR suggested that the HCY2-induced mitochondrial uncoupling and glutathione redox cycling play a determining role in the cytoprotection against menadione-induced oxidant injury in H9c2 cells. Experimental evidence obtained thus far supports the causal role of HCY2-induced mitochondrial ROS production in eliciting mitochondrial uncoupling and glutathione antioxidant responses, which offer cytoprotection against oxidant injury in H9c2 cells.

Creeping of hysteresis cycles; Reptation des cycles d'hysteresis

Energy Technology Data Exchange (ETDEWEB)

Neel, L [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires; Faculte des Sciences de Grenoble, 38 (France)

1959-07-01

Creeping consists of a kind of progressive translation of dissymmetric ferromagnetic hysteresis cycles as a function of the order number of the cycle. It is interpreted here by means of a probable coupling field, the existence of which is connected to a statistical conception of the distribution of the elementary regions. (author) [French] La reptation consiste en une sorte de translation progressive des cycles d'hysteresis ferromagnetiques dissymetriques en fonction du numero d'ordre du cycle. L'auteur l'interprete au moyen d'un champ aleatoire de couplage dont l'existence est liee a une conception statistique de la distribution des domaines elementaires. (auteur)

Glacial cycles

DEFF Research Database (Denmark)

Kaufmann, R. K.; Juselius, Katarina

We use a statistical model, the cointegrated vector autoregressive model, to assess the degree to which variations in Earth's orbit and endogenous climate dynamics can be used to simulate glacial cycles during the late Quaternary (390 kyr-present). To do so, we estimate models of varying complexity...... and compare the accuracy of their in-sample simulations. Results indicate that strong statistical associations between endogenous climate variables are not enough for statistical models to reproduce glacial cycles. Rather, changes in solar insolation associated with changes in Earth's orbit are needed...... to simulate glacial cycles accurately. Also, results suggest that non-linear 10 dynamics, threshold effects, and/or free oscillations may not play an overriding role in glacial cycles....

Fungal parasitism: life cycle, dynamics and impact on cyanobacterial blooms.

Directory of Open Access Journals (Sweden)

Mélanie Gerphagnon

Full Text Available Many species of phytoplankton are susceptible to parasitism by fungi from the phylum Chytridiomycota (i.e. chytrids. However, few studies have reported the effects of fungal parasites on filamentous cyanobacterial blooms. To investigate the missing components of bloom ecosystems, we examined an entire field bloom of the cyanobacterium Anabaena macrospora for evidence of chytrid infection in a productive freshwater lake, using a high resolution sampling strategy. A. macrospora was infected by two species of the genus Rhizosiphon which have similar life cycles but differed in their infective regimes depending on the cellular niches offered by their host. R. crassum infected both vegetative cells and akinetes while R. akinetum infected only akinetes. A tentative reconstruction of the developmental stages suggested that the life cycle of R. crassum was completed in about 3 days. The infection affected 6% of total cells (and 4% of akinètes, spread over a maximum of 17% of the filaments of cyanobacteria, in which 60% of the cells could be parasitized. Furthermore, chytrids may reduce the length of filaments of Anabaena macrospora significantly by "mechanistic fragmentation" following infection. All these results suggest that chytrid parasitism is one of the driving factors involved in the decline of a cyanobacteria blooms, by direct mortality of parasitized cells and indirectly by the mechanistic fragmentation, which could weaken the resistance of A. macrospora to grazing.

The glutathione cycle: Glutathione metabolism beyond the γ-glutamyl cycle.

Science.gov (United States)

Bachhawat, Anand Kumar; Yadav, Shambhu

2018-04-17

Glutathione was discovered in 1888, over 125 years ago. Since then, our understanding of various functions and metabolism of this important molecule has grown over these years. But it is only now, in the last decade, that a somewhat complete picture of its metabolism has emerged. Glutathione metabolism has till now been largely depicted and understood by the γ-glutamyl cycle that was proposed in 1970. However, new findings and knowledge particularly on the transport and degradation of glutathione have revealed that many aspects of the γ-glutamyl cycle are incorrect. Despite this, an integrated critical analysis of the cycle has never been undertaken and this has led to the cycle and its errors perpetuating in the literature. This review takes a careful look at the γ-glutamyl cycle and its shortcomings and presents a "glutathione cycle" that captures the current understanding of glutathione metabolism. © 2018 IUBMB Life, 2018. © 2018 International Union of Biochemistry and Molecular Biology.

[Cycling in Zagreb].

Science.gov (United States)

Matos, Stipan; Krapac, Ladislav; Krapac, Josip

2007-01-01

Cycling in Zagreb, as means of urban transport inside and outside the city, has a bright past, hazy presence but a promising future. Every day, aggressive citizens who lack urban traffic culture mistreat many cyclists but also many pedestrians. Sedentary way of living, unhealthy eating habits and inadequate recreation would surely be reduced if Zagreb had a network of cycling tracks (190 cm) or lanes (80 cm). Main city roads were constructed at the beginning of the 20th century. Today, the lack of cycling tracks is particularly evident in terms of missing connections between northern and southern parts of the city. Transportation of bikes in public vehicles, parking of bikes as well as cycling along the foot of the mountains Medvednica and Zumberacko gorje is not adequately organized. Better organization is necessary not only because of the present young generation but also because of the young who will shortly become citizens of the EU, where cycling is enormously popular. Cycling tourism is not known in Zagreb, partly due to inadequate roads. The surroundings of Zagreb are more suitable for cycling tourism and attractive brochures and tourist guides offer information to tourists on bikes. Professional, acrobatic and sports cycling do not have a tradition in Zagreb and in Croatia. The same holds true for recreational cycling and indoor exercise cycling. The authors discuss the impact of popularization of cycling using print and electronic media. The role of district and local self-government in the construction and improvement of traffic roads in Zagreb is very important. It is also significant for the implementation of legal regulations that must be obeyed by all traffic participants in order to protect cyclists, the most vulnerable group of traffic participants besides passengers. Multidisciplinary action of all benevolent experts would surely increase safety and pleasure of cycling in the city and its surroundings. This would also help reduce daily stress and

Signatures of natural selection between life cycle stages separated by metamorphosis in European eel

DEFF Research Database (Denmark)

Pujolar, J.M.; Jacobsen, M.W.; Bekkevold, Dorte

2015-01-01

Species showing complex life cycles provide excellent opportunities to study the genetic associations between life cycle stages, as selective pressures may differ before and after metamorphosis. The European eel presents a complex life cycle with two metamorphoses, a first metamorphosis from larvae...... into glass eels (juvenile stage) and a second metamorphosis into silver eels (adult stage). We tested the hypothesis that different genes and gene pathways will be under selection at different life stages when comparing the genetic associations between glass eels and silver eels. Results: We used two sets...... of markers to test for selection: first, we genotyped individuals using a panel of 80 coding-gene single nucleotide polymorphisms (SNPs) developed in American eel; second, we investigated selection at the genome level using a total of 153,423 RAD-sequencing generated SNPs widely distributed across the genome...

Insight into the role of cetaceans in the life cycle of the tetraphyllideans (Platyhelminthes: Cestoda).

Science.gov (United States)

Aznar, F J; Agustí, C; Littlewood, D T J; Raga, J A; Olson, P D

2007-02-01

Four types of tetraphyllidean larvae infect cetaceans worldwide: two plerocercoids differing in size, 'small' (SP) and 'large' (LP), and two merocercoids referred to as Phyllobothrium delphini and Monorygma grimaldii. The latter merocercoid larvae parasitize marine mammals exclusively and exhibit a specialised cystic structure. Adult stages are unknown for any of the larvae and thus the role of cetaceans in the life cycle of these species has been a long-standing problem. The SP and LP forms are thought to be earlier stages of P. delphini and M. grimaldii that are presumed to infect large pelagic sharks that feed on cetaceans. A molecular analysis of the D2 variable region of the large subunit ribosomal DNA gene based on several individuals of each larval type collected from three Mediterranean species of cetaceans showed consistent and unique molecular signatures for each type regardless of host species or site of infection. The degree of divergence suggested that LP, P. delphini and M. grimaldii larvae may represent separate species, whereas SP may be conspecific with M. grimaldii. In all host species, individuals of SP accumulated in the gut areas in which the lymphoid tissue was especially developed. We suggest therefore that these larvae use the lymphatic system to migrate to the abdominal peritoneum and mesenteries where they develop into forms recognizable as M. grimaldii. The plerocercoid stage of P. delphini remains unknown. In a partial phylogenetic tree of the Tetraphyllidea, all larvae formed a clade that included a representative of the genus Clistobothrium, some species of which parasitize sharks such as the great white which is known to feed on cetaceans. A bibliographic examination of tetraphyllidean infections in marine mammals indicated that these larvae are acquired mostly offshore. In summary, the evidence suggests that cetaceans play a significant role in the life cycle of these larvae. In addition, it seems clear that cetaceans act as natural

Optimizing anaerobic growth rate and fermentation kinetics in Saccharomyces cerevisiae strains expressing Calvin-cycle enzymes for improved ethanol yield

NARCIS (Netherlands)

Papapetridis, I.; Goudriaan, M.; De Keijzer, Nikita A.; van den Broek, M.A.; van Maris, A.J.A.; Pronk, J.T.

2018-01-01

Background: Reduction or elimination of by-product formation is of immediate economic relevance in fermentation processes for industrial bioethanol production with the yeast Saccharomyces cerevisiae. Anaerobic cultures of wild-type S. cerevisiae require formation of glycerol to maintain the

The seminiferous epithelial cycle and microanatomy of the koala (Phascolarctos cinereus) and southern hairy-nosed wombat (Lasiorhinus latifrons) testis.

Science.gov (United States)

Oishi, Motoharu; Takahashi, Mei; Amasaki, Hajime; Janssen, Tina; Johnston, Stephen D

2013-03-01

The koala (Phascolarctos cinereus) and southern hairy-nosed wombat (Lasiorhinus latifrons) are iconic Australian fauna that share a close phylogenetic relationship but there are currently no comparative studies of the seminiferous epithelial cell or testicular microanatomy of either species. Koala and wombat spermatozoa are unusual for marsupials as they possess a curved stream-lined head and lateral neck insertion that superficially is similar to murid spermatozoa; the koala also contains Sertoli cells with crystalloid inclusions that closely resemble the Charcot-Bottcher crystalloids described in human Sertoli cells. Eighteen sexually mature koalas and four sexually mature southern hairy-nosed (SHN) wombats were examined to establish base-line data on quantitative testicular histology. Dynamics of the seminiferous epithelial cycle in the both species consisted of eight stages of cellular association similar to that described in other marsupials. Both species possessed a high proportion of the pre-meiotic (stages VIII, I - III; koala - 62.2 ± 1.7% and SHN wombat - 66.6 ± 2.4%) when compared with post-meiotic stages of the seminiferous cycle. The mean diameters of the seminiferous tubules found in the koalas and the SHN wombats were 227.8 ± 6.1 and 243.5 ± 3.9 μm, respectively. There were differences in testicular histology between the species including the koala possessing (i) a greater proportion of Leydig cells, (ii) larger Sertoli cell nuclei, (iii) crystalloids in the Sertoli cell cytoplasm, (iv) a distinctive acrosomal granule during spermiogenesis and (v) a highly eosinophilic acrosome. An understanding of the seminiferous epithelial cycle and microanatomy of testis is fundamental for documenting normal spermatogenesis and testicular architecture; recent evidence of orchitis and epididymitis associated with natural chlamydial infection in the koala suggest that this species might be useful as an experimental model for understanding Chlamydia

Using molt cycles to categorize the age of tropical birds: an integrative new system

Science.gov (United States)

Jared D. Wolfe; Thomas B. Ryder; Peter Pyle

2010-01-01

Accurately differentiating age classes is essential for the long-term monitoring of resident New World tropical bird species. Molt and plumage criteria have long been used to accurately age temperate birds, but application of temperate age-classification models to the Neotropics has been hindered because annual life-cycle events of tropical birds do not always...

Beta-mangostin from Cratoxylum arborescens activates the intrinsic apoptosis pathway through reactive oxygen species with downregulation of the HSP70 gene in the HL60 cells associated with a G0/G1 cell-cycle arrest.

Science.gov (United States)

Omer, Fatima Abdelmutaal Ahmed; Hashim, Najihah Binti Mohd; Ibrahim, Mohamed Yousif; Dehghan, Firouzeh; Yahayu, Maizatulakmal; Karimian, Hamed; Salim, Landa Zeenelabdin Ali; Mohan, Syam

2017-11-01

Xanthones are phytochemical compounds found in a number of fruits and vegetables. Characteristically, they are noted to be made of diverse properties based on their biological, biochemical, and pharmacological actions. Accordingly, the apoptosis mechanisms induced by beta-mangostin, a xanthone compound isolated from Cratoxylum arborescens in the human promyelocytic leukemia cell line (HL60) in vitro, were examined in this study. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was done to estimate the cytotoxicity effect of β-mangostin on the HL60 cell line. Acridine orange/propidium iodide and Hoechst 33342 dyes and Annexin V tests were conducted to detect the apoptosis features. Caspase-3 and caspase-9 activities; reactive oxygen species; real-time polymerase chain reaction for Bcl-2, Bax, caspase-3, and caspase-9 Hsp70 genes; and western blot for p53, cytochrome c, and pro- and cleavage-caspase-3 and caspase-9 were assessed to examine the apoptosis mechanism. Cell-cycle analysis conducted revealed that β-mangostin inhibited the growth of HL60 at 58 µM in 24 h. The administration of β-mangostin with HL60 caused cell morphological changes related to apoptosis which increased the number of early and late apoptotic cells. The β-mangostin-catalyzed apoptosis action through caspase-3, caspase-7, and caspase-9 activation overproduced reactive oxygen species which downregulated the expression of antiapoptotic genes Bcl-2 and HSP70. Conversely, the expression of the apoptotic genes Bax, caspase-3, and caspase-9 were upregulated. Meanwhile, at the protein level, β-mangostin activated the formation of cleaved caspase-3 and caspase-9 and also upregulated the p53. β-mangostin arrested the cell cycle at the G 0 /G 1 phase. Overall, the results for β-mangostin showed an antiproliferative effect in HL60 via stopping the cell cycle at the G 0 /G 1 phase and prompted the intrinsic apoptosis pathway.

Diameter characterization of timber species in primary forests of Cerro Murrucucu

International Nuclear Information System (INIS)

Villa G, Ana Maria

2006-01-01

This study in Cerro Murrucucu forests establishes the minimum fell diameter (DMC) and its fell cycle (C). It classifies the forest in 1 (Iess damaged) and 2 (severely damaged). Ten species were selected by means of the importance Value Index (IVI) and the DMC was determined. C was estimated through the times of step method. Pentaclethra macroloba showed the highest IVI (21.5% and 21.09% for forests 1 and 2, respectively). In spite of the deterioration of forest 2 the species still showed highest importance. In forest 1 an equilibrium can be deduced, whereas in forest 2 most of the considered species show instability. The DMC for forests 1 and 2 were 30 and 20 cm respectively, indicating extractive activities are deteriorating the latest. C was 51.8 years

Analysis of redox relationships in the plant cell cycle: determinations of ascorbate, glutathione and poly (ADPribose)polymerase (PARP) in plant cell cultures.

Science.gov (United States)

Foyer, Christine H; Pellny, Till K; Locato, Vittoria; De Gara, Laura

2008-01-01

Reactive oxygen species (ROS) and low molecular weight antioxidants, such as glutathione and ascorbate, are powerful signaling molecules that participate in the control of plant growth and development, and modulate progression through the mitotic cell cycle. Enhanced reactive oxygen species accumulation or low levels of ascorbate or glutathione cause the cell cycle to arrest and halt progression especially through the G1 checkpoint. Plant cell suspension cultures have proved to be particularly useful tools for the study of cell cycle regulation. Here we provide effective and accurate methods for the measurement of changes in the cellular ascorbate and glutathione pools and the activities of related enzymes such poly (ADP-ribose) polymerase during mitosis and cell expansion, particularly in cell suspension cultures. These methods can be used in studies seeking to improve current understanding of the roles of redox controls on cell division and cell expansion.

Cycle to Cycle Variation Study in a Dual Fuel Operated Engine

KAUST Repository

Pasunurthi, Shyamsundar

2017-03-28

The standard capability of engine experimental studies is that ensemble averaged quantities like in-cylinder pressure from multiple cycles and emissions are reported and the cycle to cycle variation (CCV) of indicated mean effective pressure (IMEP) is captured from many consecutive combustion cycles for each test condition. However, obtaining 3D spatial distribution of all the relevant quantities such as fuel-air mixing, temperature, turbulence levels and emissions from such experiments is a challenging task. Computational Fluid Dynamics (CFD) simulations of engine flow and combustion can be used effectively to visualize such 3D spatial distributions. A dual fuel engine is considered in the current study, with manifold injected natural gas (NG) and direct injected diesel pilot for ignition. Multiple engine cycles in 3D are simulated in series like in the experiments to investigate the potential of high fidelity RANS simulations coupled with detailed chemistry, to accurately predict the CCV. Cycle to cycle variation (CCV) is expected to be due to variabilities in operating and boundary conditions, in-cylinder stratification of diesel and natural gas fuels, variation in in-cylinder turbulence levels and velocity flow-fields. In a previous publication by the authors [1], variabilities in operating and boundary conditions are incorporated into several closed cycle simulations performed in parallel. Stochastic variations/stratifications of fuel-air mixture, turbulence levels, temperature and internal combustion residuals cannot be considered in such closed cycle simulations. In this study, open cycle simulations with port injection of natural gas predicted the combined effect of the stratifications on the CCV of in-cylinder pressure. The predicted Coefficient of Variation (COV) of cylinder pressure is improved compared to the one captured by closed cycle simulations in parallel.

The influence of day/night cycles on biomass yield and composition of Neochloris oleoabundans.

Science.gov (United States)

de Winter, Lenneke; Cabanelas, Iago Teles Dominguez; Martens, Dirk E; Wijffels, René H; Barbosa, Maria J

2017-01-01

Day/night cycles regulate the circadian clock of organisms to program daily activities. Many species of microalgae have a synchronized cell division when grown under a day/night cycle, and synchronization might influence biomass yield and composition. Therefore, the aim of this study was to study the influence of day/night cycle on biomass yield and composition of the green microalgae Neochloris oleoabundans . Hence, we compared continuous turbidostat cultures grown under continuous light with cultures grown under simulated day/night cycles. Under day/night cycles, cultures were synchronized as cell division was scheduled in the night, whereas under continuous light cell division occurred randomly synchronized cultures were able to use the light 10-15% more efficiently than non-synchronized cultures. Our results indicate that the efficiency of light use varies over the cell cycle and that synchronized cell division provides a fitness benefit to microalgae. Biomass composition under day/night cycles was similar to continuous light, with the exception of starch content. The starch content was higher in cultures under continuous light, most likely because the cells never had to respire starch to cover for maintenance during dark periods. Day/night cycles were provided in a 'block' (continuous light intensity during the light period) and in a 'sine' (using a sine function to simulate light intensities from sunrise to sunset). There were no differences in biomass yield or composition between these two ways of providing light (in a 'block' or in a 'sine'). The biomass yield and composition of N. oleoabundans were influenced by day/night cycles. These results are important to better understand the relations between research done under continuous light conditions and with day/night cycle conditions. Our findings also imply that more research should be done under day/night cycles.

Internal cycle modeling and environmental assessment of multiple cycle consumer products

International Nuclear Information System (INIS)

Tsiliyannis, C.A.

2012-01-01

Highlights: ► Dynamic flow models are presented for remanufactured, reused or recycled products. ► Early loss and stochastic return are included for fast and slow cycling products. ► The reuse-to-input flow ratio (Internal Cycle Factor, ICF) is determined. ► The cycle rate, which is increasing with the ICF, monitors eco-performance. ► Early internal cycle losses diminish the ICF, the cycle rate and performance. - Abstract: Dynamic annual flow models incorporating consumer discard and usage loss and featuring deterministic and stochastic end-of-cycle (EOC) return by the consumer are developed for reused or remanufactured products (multiple cycle products, MCPs), including fast and slow cycling, short and long-lived products. It is shown that internal flows (reuse and overall consumption) increase proportionally to the dimensionless internal cycle factor (ICF) which is related to environmental impact reduction factors. The combined reuse/recycle (or cycle) rate is shown capable for shortcut, albeit effective, monitoring of environmental performance in terms of waste production, virgin material extraction and manufacturing impacts of all MCPs, a task, which physical variables (lifetime, cycling frequency, mean or total number of return trips) and conventional rates, via which environmental policy has been officially implemented (e.g. recycling rate) cannot accomplish. The cycle rate is shown to be an increasing (hyperbolic) function of ICF. The impact of the stochastic EOC return characteristics on total reuse and consumption flows, as well as on eco-performance, is assessed: symmetric EOC return has a small, positive effect on performance compared to deterministic, while early shifted EOC return is more beneficial. In order to be efficient, environmental policy should set higher minimum reuse targets for higher trippage MCPs. The results may serve for monitoring, flow accounting and comparative eco-assessment of MCPs. They may be useful in identifying

A NEW SPECIES OF CYRTOSPIRIFER (BRACHIOPODA FROM THE MIDDLE DEVONIAN OF THE WESTERN SAHARA (NORTHWESTERN AFRICA

Directory of Open Access Journals (Sweden)

MENA SCHEMM-GREGORY

2011-03-01

Full Text Available A new species of Cyrtospirifer is described from the Middle to Upper Givetian of the Western Sahara (Northwest Africa. Cyrtospirifer tindoufensis new species differs in its smaller number and coarser medial and flank plications and equibiconvex shell profile from the other Givetian species of Cyrtospirifer that all occur in Europe and to which the new species probably gives rise. The new implications of the proposed phylogeny of the earliest cyrtospiriferids and their origin from the Western Sahara are discussed. The palaeogeographic distribution of the cyrtospiriferids during the Givetian and Frasnian is shown and its migration ways are described considering the global transgression and regression cycles. 

Modeling the effects of tree species and incubation temperature on soil's extracellular enzyme activity in 78-year-old tree plantations

Science.gov (United States)

Zhou, Xiaoqi; Wang, Shen S. J.; Chen, Chengrong

2017-12-01

Forest plantations have been widely used as an effective measure for increasing soil carbon (C), and nitrogen (N) stocks and soil enzyme activities play a key role in soil C and N losses during decomposition of soil organic matter. However, few studies have been carried out to elucidate the mechanisms behind the differences in soil C and N cycling by different tree species in response to climate warming. Here, we measured the responses of soil's extracellular enzyme activity (EEA) to a gradient of temperatures using incubation methods in 78-year-old forest plantations with different tree species. Based on a soil enzyme kinetics model, we established a new statistical model to investigate the effects of temperature and tree species on soil EEA. In addition, we established a tree species-enzyme-C/N model to investigate how temperature and tree species influence soil C/N contents over time without considering plant C inputs. These extracellular enzymes included C acquisition enzymes (β-glucosidase, BG), N acquisition enzymes (N-acetylglucosaminidase, NAG; leucine aminopeptidase, LAP) and phosphorus acquisition enzymes (acid phosphatases). The results showed that incubation temperature and tree species significantly influenced all soil EEA and Eucalyptus had 1.01-2.86 times higher soil EEA than coniferous tree species. Modeling showed that Eucalyptus had larger soil C losses but had 0.99-2.38 times longer soil C residence time than the coniferous tree species over time. The differences in the residual soil C and N contents between Eucalyptus and coniferous tree species, as well as between slash pine (Pinus elliottii Engelm. var. elliottii) and hoop pine (Araucaria cunninghamii Ait.), increase with time. On the other hand, the modeling results help explain why exotic slash pine can grow faster, as it has 1.22-1.38 times longer residual soil N residence time for LAP, which mediate soil N cycling in the long term, than native coniferous tree species like hoop pine and

Population biology of two rare fern species: long-life and long-lasting stability

Czech Academy of Sciences Publication Activity Database

Bucharová, Anna; Münzbergová, Z.; Tájek, P.

2010-01-01

Roč. 97, č. 8 (2010), s. 1260-1271 ISSN 0002-9122 R&D Projects: GA MŽP SP/2D4/112/08 Institutional research plan: CEZ:AV0Z60050516 Keywords : ferns * life cycle * naturally rare species Subject RIV: EF - Botanics Impact factor: 3.052, year: 2010

Monitoring menstrual cycle, gestation and lactation by measuring urinary oestradiol and progesterone in the captive golden snub-nosed monkey (Rhinopithecus roxellanae).

Science.gov (United States)

Chen, Wei-Zhen; Li, Yue; Yu, Hui-Liang; Yao, Hui; Li, Xiang; Han, Li; Hu, Chang-Min; Xiong, Jia-Jun; Liu, Dong-Ming; Ding, Ming-Xing; Chen, Jian-Guo

2017-06-01

The golden snub-nosed monkey is an endangered species and study of its reproductive physiology is crucial for the species' breeding programs. Urine samples (770) from 5 mature female golden snub-nosed monkeys were collected in the Shengnongjia Nature Reserve between October 2013 and December 2014 to monitor their menstrual cycle, gestation, and lactation. The concentrations of oestradiol (E 2 ) and progesterone (P 4 ) in the samples were measured by Chemiluminescent Microparticle Immunoassay (CMIA), and the hormone concentrations were indexed to creatinine levels to compensate for differences in water content. The results showed that the E 2 and P 4 levels during the breeding season were significantly higher than those during the non-breeding season (Pmean±SEM) with a follicular cycle of 8.33±0.62days and luteal cycle of 15.27±0.83days. In addition, the levels of E 2 and P 4 began to rise on day 14 and day 10 after conception and remained at a high level until parturition. However, the E 2 and P 4 levels during lactation were lower than those during gestation (Pgolden snub-nosed monkeys, which could play an important role in the expansion of this species' population. Copyright © 2017 Elsevier B.V. All rights reserved.

Rapid Ammonia Gas Transport Accounts for Futile Transmembrane Cycling under NH3/NH4+ Toxicity in Plant Roots1[C][W

Science.gov (United States)

Coskun, Devrim; Britto, Dev T.; Li, Mingyuan; Becker, Alexander; Kronzucker, Herbert J.

2013-01-01

Futile transmembrane NH3/NH4+ cycling in plant root cells, characterized by extremely rapid fluxes and high efflux to influx ratios, has been successfully linked to NH3/NH4+ toxicity. Surprisingly, the fundamental question of which species of the conjugate pair (NH3 or NH4+) participates in such fluxes is unresolved. Using flux analyses with the short-lived radioisotope 13N and electrophysiological, respiratory, and histochemical measurements, we show that futile cycling in roots of barley (Hordeum vulgare) seedlings is predominately of the gaseous NH3 species, rather than the NH4+ ion. Influx of 13NH3/13NH4+, which exceeded 200 µmol g–1 h–1, was not commensurate with membrane depolarization or increases in root respiration, suggesting electroneutral NH3 transport. Influx followed Michaelis-Menten kinetics for NH3 (but not NH4+), as a function of external concentration (Km = 152 µm, Vmax = 205 µmol g–1 h–1). Efflux of 13NH3/13NH4+ responded with a nearly identical Km. Pharmacological characterization of influx and efflux suggests mediation by aquaporins. Our study fundamentally revises the futile-cycling model by demonstrating that NH3 is the major permeating species across both plasmalemma and tonoplast of root cells under toxicity conditions. PMID:24134887

Influência do hospedeiro no ciclo e comprovação do ciclo heteroxeno de Anocentor nitens (Neumann, 1897 Host influency on life cycle and comprovation of the heteroxenous cycle of Anocentor nitens (Neumann, 1897

Directory of Open Access Journals (Sweden)

N. M. Serra Freire

1989-01-01

Full Text Available Steers and rabbits were used as experimental hosts for Anocenter nitens during scheduled infections, when ticks were recovered from naturally infected horses. Thus, the influence of the host species on the parasite was evaluated mainly considering parameters related to the engorgement period and pre molting of evolutive stages. It was also observed that almost 5% if the metanymphae and a few more than 1% of metalarvae fall off from the host to molt in the evironment, characterizing cycles in one or more hosts. The heteroxenous cycle is reported for the first time occuring in A. nitens.

Cycle to Cycle Variation Study in a Dual Fuel Operated Engine

KAUST Repository

Pasunurthi, Shyamsundar; Jupudi, Ravichandra; Wijeyakulasuriya, Sameera; Gubba, Sreenivasa Rao; Im, Hong G.; Jaasim, Mohammed; Primus, Roy; Klingbeil, Adam; Finney, Charles

2017-01-01

The standard capability of engine experimental studies is that ensemble averaged quantities like in-cylinder pressure from multiple cycles and emissions are reported and the cycle to cycle variation (CCV) of indicated mean effective pressure (IMEP

Remote sensing of California estuaries: Monitoring climate change and invasive species

Science.gov (United States)

Mulitsch, Melinda Jennifer

above ground distribution in response to El Nino and La Nina cycles. We used SMA to analyze 2002 AVIRIS imagery. Overall accuracy was 80.94%. 1994-1996 AVIRIS imagery was analyzed to determine the distribution of species and to relate changes to annual rainfall data. Based on the known salinity tolerances, the spatial distribution and zonation of these species respond to salinity stresses resulting from the El Nino and La Nina cycles.

Breathing of heliospheric structures triggered by the solar-cycle activity

Directory of Open Access Journals (Sweden)

K. Scherer

Full Text Available Solar wind ram pressure variations occuring within the solar activity cycle are communicated to the outer heliosphere as complicated time-variabilities, but repeating its typical form with the activity period of about 11 years. At outer heliospheric regions, the main surviving solar cycle feature is a periodic variation of the solar wind dynamical pressure or momentum flow, as clearly recognized by observations of the VOYAGER-1/2 space probes. This long-periodic variation of the solar wind dynamical pressure is modeled here through application of appropriately time-dependent inner boundary conditions within our multifluid code to describe the solar wind – interstellar medium interaction. As we can show, it takes several solar cycles until the heliospheric structures adapt to an average location about which they carry out a periodic breathing, however, lagged in phase with respect to the solar cycle. The dynamically active heliosphere behaves differently from a static heliosphere and especially shows a historic hysteresis in the sense that the shock structures move out to larger distances than explained by the average ram pressure. Obviously, additional energies are pumped into the heliosheath by means of density and pressure waves which are excited. These waves travel outwards through the interface from the termination shock towards the bow shock. Depending on longitude, the heliospheric sheath region memorizes 2–3 (upwind and up to 6–7 (downwind preceding solar activity cycles, i.e. the cycle-induced waves need corresponding travel times for the passage over the heliosheath. Within our multifluid code we also adequately describe the solar cycle variations in the energy distributions of anomalous and galactic cosmic rays, respectively. According to these results the distribution of these high energetic species cannot be correctly described on the basis of the actually prevailing solar wind conditions.

Key words. Interplanetary

Graphene and maghemite composites based supercapacitors delivering high volumetric capacitance and extraordinary cycling stability

International Nuclear Information System (INIS)

Zhang, Haitao; Zhang, Xiong; Lin, He; Wang, Kai; Sun, Xianzhong; Xu, Nansheng; Li, Chen; Ma, Yanwei

2015-01-01

Metal oxides (like MnO 2 , Fe 2 O 3 , and Co 3 O 4 , etc) based supercapacitors have disadvantages, such as low volumetric capacitance for thick-film electrodes, or short cycling life because a Faradaic process involves chemical changes of state of the reactant species. In the present work, we report that supercapacitors based on reduced graphene oxide and maghemite (γ-Fe 2 O 3 ) composites (GγM) exhibit superior performance. GγM electrodes with average electrode thickness up to ∼60 μm have a high volumetric capacitance of 230 F cm −3 , together with an outstanding electrode package density of 1.44 g cm −3 . Particularly, the GγM electrodes have excellent cycling performance of ∼90% capacitance retention over 100,000 galvanostatic charge–discharge cycles or voltage floating at 0.9 V for 300 h. No detectable change in phase and an effective inhibition of γ-Fe 2 O 3 refinement after cycle-life test are confirmed by X-ray diffraction and transmission electron microscopy

Effects of increased solar ultraviolet radiation on biogeochemical cycles

International Nuclear Information System (INIS)

Zepp, R.G.; Callaghan, T.V.; Erickson, D.J.

1995-01-01

Increases in solar UV radiation could affect terrestrial and aquatic biogeochemical cycles thus altering both sources and sinks of greenhouse and chemically important trace gases (e.g., carbon dioxide (CO2), carbon monoxide (CO), carbonyl sulfide (COS). In terrestrial ecosystems, increased UV-B could modify both the production and decomposition of plant matter with concomitant changes in the uptake and release of atmospherically important trace gases. Decomposition processes can be accelerated when UV-B photodegrades surface litter, or retarded when the dominant effect involves changes in the chemical composition of living tissues that reduce the biodegradability of buried litter. These changes in decomposition can affect microbial production of CO2 and other trace gases and also may affect the availability of nutrients essential for plant growth. Primary production can be reduced by enhanced UV-B, but the effect is variable between species and even cultivars of some crops. Likewise, the effects of enhanced UV-B on photoproduction of CO from plant matter is species-dependent and occurs more efficiently from dead than from living matter. Aquatic ecosystems studies in several different locations have shown that reductions in current levels of solar UV-B result in enhanced primary production, and Antarctic experiments under the ozone hole demonstrated that primary production is inhibited by enhanced UV-B. In addition to its effects on primary production, solar UV radiation can reduce bacterioplankton growth in the upper ocean with potentially important effects on marine biogeochemical cycles. Decomposition processes can be retarded when bacterial activity is suppressed by enhanced UV-B radiation or stimulated when solar UV radiation photodegrades aquatic dissolved organic matter. Photodegradation of DOM results in loss of UV absorption and formation of dissolved inorganic carbon, CO, and organic substrates that are readily mineralized or taken up by aquatic

Restriction point control of the mammalian cell cycle via the cyclin E/Cdk2:p27 complex.

NARCIS (Netherlands)

Conradie, R.; Bruggeman, F.J.; Ciliberto, A.; Csikasz-Nagby, A.; Novak, B.; Westerhoff, H.V.; Snoep, J.L.

2010-01-01

Numerous top-down kinetic models have been constructed to describe the cell cycle. These models have typically been constructed, validated and analyzed using model species (molecular intermediates and proteins) and phenotypic observations, and therefore do not focus on the individual model processes

Nature of vegetative cycle in Phytophthora parasitica Dastur and palmivora (BUTLER) BUTLER

International Nuclear Information System (INIS)

Le Grand-Pernot, Francoise; Pellegrin, F.

1976-01-01

Up to now, neither cytological nor genetical studies have clearly demonstrated the 'ploidy' degree of somatic nuclei in different species of Phytophthora. Two complementary studies, using biological effect of γ rays upon zoospores, and microspectrophotometric techniques measuring relative amount of DNA by nucleus in zoospores or in hyphae, allowed to demonstrate diploid nature of the vegetative phase in P. palmivora (BUTLER) BUTLER and P. parasitica DASTUR cycles [fr

The Hamburg oceanic carbon cycle circulation model. Cycle 1

International Nuclear Information System (INIS)

Maier-Reimer, E.; Heinze, C.

1992-02-01

The carbon cycle model calculates the prognostic fields of oceanic geochemical carbon cycle tracers making use of a 'frozen' velocity field provided by a run of the LSG oceanic circulation model (see the corresponding manual, LSG=Large Scale Geostrophic). The carbon cycle model includes a crude approximation of interactions between sediment and bottom layer water. A simple (meridionally diffusive) one layer atmosphere model allows to calculate the CO 2 airborne fraction resulting from the oceanic biogeochemical interactions. (orig.)

The female reproductive cycle of the neotropical snake Atractus pantostictus (Fernandes and Puorto, 1993) from south-eastern Brazil.

Science.gov (United States)

de Resende, F C; Nascimento, L B

2015-06-01

Data on reproductive activity of fossorial species are limited because the specimens are difficult to be observed and captured. Here in, we present the reproductive cycle of female Atractus pantostictus, a fossorial neotropical species, and the sexual maturity of males and females in south-eastern Brazil. The female reproductive cycle of A. pantostictus is seasonal, with vitellogenic follicles being found from September to April and eggs in November, February, March and April with the number varying between two and four. Spermatozoa were found in the lumen of the glandular and non-glandular uterus in females collected during the rainy season. Sperm storage tubules were found in the posterior infundibulum of the females, where the storage of sperm occurs for a short time. The storage may occur because mating and ovulation are dissociated. © 2014 Blackwell Verlag GmbH.

Colaspis caligula, a new species found in association with Vitis vinifera (L.) crops in Argentina (Coleoptera: Chrysomelidae).

Science.gov (United States)

Agrain, Federico A; Cabrera, Nora; Holgado, Miriam G; Vicchi, Franco R

2016-09-05

Some species of Colaspis Fabricius are well-known pests of several crops in Argentina. In this contribution, we describe a new species within this genus: Colaspis caligula n. sp., found in association with Vitis vinifera (Linnaeus) crops. We provide descriptions and illustrations of the mature larva, pupa and adult, as well as notes on its diagnostic characters, life cycle, and the damages produced to the plants.

Future fuel cycles

International Nuclear Information System (INIS)

Archinoff, G.H.

1980-01-01

A fuel cycle must offer both financial and resource savings if it is to be considered for introduction into Ontario's nuclear system. The most promising alternative CANDU fuel cycles are examined in the context of both of these factors over a wide range of installed capacity growth rates and economic assumptions, in order to determine which fuel cycle, or cycles, should be introduced, and when. It is concluded that the optimum path for the long term begins with the prompt introduction of the low-enriched-uranium fuel cycle. For a wide range of conditions, this cycle remains the optimum throughout the very long term. Conditions of rapid nuclear growth and very high uranium price escalation rates warrant the supersedure of the low-enriched-uranium cycle by either a plutonium-topped thorium cycle or plutonium recycle, beginning between 2010 and 2025. It is also found that the uranium resource position is sound in terms of both known resources and production capability. Moreover, introduction of the low-enriched-uranium fuel cycle and 1250 MWe reactor units will assure the economic viability of nuclear power until at least 2020, even if uranium prices increase at a rate of 3.5% above inflation. The interrelationship between these two conclusions lies in the tremendous incentive for exploration which will occur if the real uranium price escalation rate is high. From a competitive viewpoint, nuclear power can withstand increases in the price of uranium. However, such increases will likely further expand the resource base, making nuclear an even more reliable energy source. (auth)

On the potential of plant species invasion influencing bio-geomorphologic landscape formation in salt marshes

NARCIS (Netherlands)

Schwarz, C.; Ysebaert, T.; Vandenbruwaene, W.; Temmerman, S.; Zhang, L.; Herman, P.

2016-01-01

Species invasions are known to change biotic and abiotic ecosystem characteristics such as community structure, cycling of materials and dynamics of rivers. However, their ability to alter interactions between biotic and abiotic ecosystem components, in particular bio-geomorphic feedbacks and the

Life Cycle Management

DEFF Research Database (Denmark)

Bey, Niki

2018-01-01

This chapter gives an overview of Life Cycle Management (LCM)—a discipline that deals with the managerial tasks related to practicing sustainable development in an organisation . Just as Life Cycle Assessment, LCM advocates the life cycle perspective , and it applies this perspective in decision...

BWROPT: A multi-cycle BWR fuel cycle optimization code

Energy Technology Data Exchange (ETDEWEB)

Ottinger, Keith E.; Maldonado, G. Ivan, E-mail: Ivan.Maldonado@utk.edu

2015-09-15

Highlights: • A multi-cycle BWR fuel cycle optimization algorithm is presented. • New fuel inventory and core loading pattern determination. • The parallel simulated annealing algorithm was used for the optimization. • Variable sampling probabilities were compared to constant sampling probabilities. - Abstract: A new computer code for performing BWR in-core and out-of-core fuel cycle optimization for multiple cycles simultaneously has been developed. Parallel simulated annealing (PSA) is used to optimize the new fuel inventory and placement of new and reload fuel for each cycle considered. Several algorithm improvements were implemented and evaluated. The most significant of these are variable sampling probabilities and sampling new fuel types from an ordered array. A heuristic control rod pattern (CRP) search algorithm was also implemented, which is useful for single CRP determinations, however, this feature requires significant computational resources and is currently not practical for use in a full multi-cycle optimization. The PSA algorithm was demonstrated to be capable of significant objective function reduction and finding candidate loading patterns without constraint violations. The use of variable sampling probabilities was shown to reduce runtime while producing better results compared to using constant sampling probabilities. Sampling new fuel types from an ordered array was shown to have a mixed effect compared to random new fuel type sampling, whereby using both random and ordered sampling produced better results but required longer runtimes.

Influence of moisture regime and tree species composition on nitrogen cycling dynamics in hardwood forests of Mammoth Cave National Park, Kentucky, USA

Science.gov (United States)

Eric S. Fabio; Mary A. Arthur; Charles C. Rhoades

2009-01-01

Understanding how natural factors interact across the landscape to influence nitrogen (N) cycling is an important focus in temperate forests because of the great inherent variability in these forests. Site-specific attributes, including local topography, soils, and vegetation, can exert important controls on N processes and retention. Seasonal monitoring of N cycling...

Behavioral and endocrine characteristics of the reproductive cycle in wild muriqui monkeys, Brachyteles arachnoides.

Science.gov (United States)

Strier, K B; Ziegler, T E

1997-01-01

The analysis of fecal ovarian steroids provides a powerful noninvasive method to obtain insights into ovulatory cycles, gestation length, and the timing of sexual interactions relative to the periovulatory period in wild primates. Techniques developed to collect and assay feces from free-ranging muriqui monkeys (Brachyteles arachnoides) for estradiol and progesterone yield the first explicit reproductive data on this species, and provide the first opportunity to evaluate the timing of observed copulations with muriqui ovarian cycles. Hormonal profiles from seven females indicate average cycle lengths of 21.0 +/- 5.4 days (n = 20). Females conceived after 3-6 ovulatory cycles. Gestation length averaged 216.4 +/- 1.5 days for the five females for which conception cycles were sampled. Discrete copulation periods spanned an average of 2.1 +/- 1.2 days (n = 29), with intervals between these concentrated periods of copulations averaging 15.6 +/- 6.7 days (n = 20). There were no significant differences among females in cycle lengths, copulation period lengths, or copulation interval lengths. Ejaculation was visible following 71.8 +/- 26.7% of copulations during the females preovulatory periods. All females copulated outside the periovulatory period. The proportion of copulation days outside the periovulatory period was slightly greater (p = 0.08) for primiparous females (64.8 +/- 28.3%) than for multiparous females (28.7 +/- 19.7%).

Divergence in male cricket song and female preference functions in three allopatric sister species.

Science.gov (United States)

Hennig, Ralf Matthias; Blankers, Thomas; Gray, David A

2016-05-01

Multivariate female preference functions for male sexual signals have rarely been investigated, especially in a comparative context among sister species. Here we examined male signal and female preference co-variation in three closely related, but allopatric species of Gryllus crickets and quantified male song traits as well as female preferences. We show that males differ conspicuously in either one of two relatively static song traits, carrier frequency or pulse rate; female preference functions for these traits also differed, and would in combination enhance species discrimination. In contrast, the relatively dynamic song traits, chirp rate and chirp duty cycle, show minimal divergence among species and relatively greater conservation of female preference functions. Notably, among species we demonstrate similar mechanistic rules for the integration of pulse and chirp time scales, despite divergence in pulse rate preferences. As these are allopatric taxa, selection for species recognition per se is unlikely. More likely sexual selection combined with conserved properties of preference filters enabled divergent coevolution of male song and female preferences.

Modeling the effects of tree species and incubation temperature on soil's extracellular enzyme activity in 78-year-old tree plantations

Directory of Open Access Journals (Sweden)

X. Zhou

2017-12-01

Full Text Available Forest plantations have been widely used as an effective measure for increasing soil carbon (C, and nitrogen (N stocks and soil enzyme activities play a key role in soil C and N losses during decomposition of soil organic matter. However, few studies have been carried out to elucidate the mechanisms behind the differences in soil C and N cycling by different tree species in response to climate warming. Here, we measured the responses of soil's extracellular enzyme activity (EEA to a gradient of temperatures using incubation methods in 78-year-old forest plantations with different tree species. Based on a soil enzyme kinetics model, we established a new statistical model to investigate the effects of temperature and tree species on soil EEA. In addition, we established a tree species–enzyme–C∕N model to investigate how temperature and tree species influence soil C∕N contents over time without considering plant C inputs. These extracellular enzymes included C acquisition enzymes (β-glucosidase, BG, N acquisition enzymes (N-acetylglucosaminidase, NAG; leucine aminopeptidase, LAP and phosphorus acquisition enzymes (acid phosphatases. The results showed that incubation temperature and tree species significantly influenced all soil EEA and Eucalyptus had 1.01–2.86 times higher soil EEA than coniferous tree species. Modeling showed that Eucalyptus had larger soil C losses but had 0.99–2.38 times longer soil C residence time than the coniferous tree species over time. The differences in the residual soil C and N contents between Eucalyptus and coniferous tree species, as well as between slash pine (Pinus elliottii Engelm. var. elliottii and hoop pine (Araucaria cunninghamii Ait., increase with time. On the other hand, the modeling results help explain why exotic slash pine can grow faster, as it has 1.22–1.38 times longer residual soil N residence time for LAP, which mediate soil N cycling in the long term, than native

Oxygen-18 as a tool for studying photorespiration. Oxygen uptake and incorporation into glycolate, glycine and serine

International Nuclear Information System (INIS)

Gerster, R.; Dimon, B.; Tournier, P.; Peybernes, A.

1977-01-01

The intensity of photosynthesis and photorespiration has been determined by measuring 16 O 2 evolvement and 18 O 2 uptake on algae and leaves. In the case of algae, there is still an important oxygen uptake even when ribulose diphosphate oxygenase is inhibited by 10 -3 M cyanide. Oxygen-18 incorporation into glycolate, glycine and serine of photorespiring algae and leaves exposed to atmospheres containing 18 O 2 has also been measured. Only one of the two atoms present in molecular oxygen was incorporated into the carboxyl group of the glycolate excreted from algae; the rate of 18 O incorporation was important (65 to 80% according to experimental conditions), even in the presence of 10 -3 M cyanide. Thus, oxidation of ribulose diphosphate is not the sole reaction leading to 18 O glycolate synthesis. In the case of maize, there was a rapid and important 18 O incorporation into the carboxyl group of glycine and serine, the kinetics of which was determined as a function of CO 2 presence in the atmosphere. These results suggest that photorespiration is also operating in C 4 species. Furthermore, in vitro experiments showed that phosphorylated ceto-acids of the Calvin cycle were very sensitive to H 2 O 2 ; the corresponding reaction can explain O 2 uptake and 18 O labelling of glycolate. (author)

Metabolic analysis of the soil microbe Dechloromonas aromatica str. RCB: indications of a surprisingly complex life-style and cryptic anaerobic pathways for aromatic degradation

Directory of Open Access Journals (Sweden)

Feil Helene

2009-08-01

Full Text Available Abstract Background Initial interest in Dechloromonas aromatica strain RCB arose from its ability to anaerobically degrade benzene. It is also able to reduce perchlorate and oxidize chlorobenzoate, toluene, and xylene, creating interest in using this organism for bioremediation. Little physiological data has been published for this microbe. It is considered to be a free-living organism. Results The a priori prediction that the D. aromatica genome would contain previously characterized "central" enzymes to support anaerobic aromatic degradation of benzene proved to be false, suggesting the presence of novel anaerobic aromatic degradation pathways in this species. These missing pathways include the benzylsuccinate synthase (bssABC genes (responsible for fumarate addition to toluene and the central benzoyl-CoA pathway for monoaromatics. In depth analyses using existing TIGRfam, COG, and InterPro models, and the creation of de novo HMM models, indicate a highly complex lifestyle with a large number of environmental sensors and signaling pathways, including a relatively large number of GGDEF domain signal receptors and multiple quorum sensors. A number of proteins indicate interactions with an as yet unknown host, as indicated by the presence of predicted cell host remodeling enzymes, effector enzymes, hemolysin-like proteins, adhesins, NO reductase, and both type III and type VI secretory complexes. Evidence of biofilm formation including a proposed exopolysaccharide complex and exosortase (epsH are also present. Annotation described in this paper also reveals evidence for several metabolic pathways that have yet to be observed experimentally, including a sulphur oxidation (soxFCDYZAXB gene cluster, Calvin cycle enzymes, and proteins involved in nitrogen fixation in other species (including RubisCo, ribulose-phosphate 3-epimerase, and nif gene families, respectively. Conclusion Analysis of the D. aromatica genome indicates there is much to be

Sulfur cycle

Digital Repository Service at National Institute of Oceanography (India)

LokaBharathi, P.A.

Microbes, especially bacteria, play an important role in oxidative and reductive cycle of sulfur. The oxidative part of the cycle is mediated by photosynthetic bacteria in the presence of light energy and chemosynthetic forms in the absence of light...

Fast Reactor Fuel Cycle Cost Estimates for Advanced Fuel Cycle Studies

International Nuclear Information System (INIS)

Harrison, Thomas

2013-01-01

Presentation Outline: • Why Do I Need a Cost Basis?; • History of the Advanced Fuel Cycle Cost Basis; • Description of the Cost Basis; • Current Work; • Fast Reactor Fuel Cycle Applications; • Sample Fuel Cycle Cost Estimate Analysis; • Future Work

Comparative gene expression between two yeast species

Directory of Open Access Journals (Sweden)

Guan Yuanfang

2013-01-01

Full Text Available Abstract Background Comparative genomics brings insight into sequence evolution, but even more may be learned by coupling sequence analyses with experimental tests of gene function and regulation. However, the reliability of such comparisons is often limited by biased sampling of expression conditions and incomplete knowledge of gene functions across species. To address these challenges, we previously systematically generated expression profiles in Saccharomyces bayanus to maximize functional coverage as compared to an existing Saccharomyces cerevisiae data repository. Results In this paper, we take advantage of these two data repositories to compare patterns of ortholog expression in a wide variety of conditions. First, we developed a scalable metric for expression divergence that enabled us to detect a significant correlation between sequence and expression conservation on the global level, which previous smaller-scale expression studies failed to detect. Despite this global conservation trend, between-species gene expression neighborhoods were less well-conserved than within-species comparisons across different environmental perturbations, and approximately 4% of orthologs exhibited a significant change in co-expression partners. Furthermore, our analysis of matched perturbations collected in both species (such as diauxic shift and cell cycle synchrony demonstrated that approximately a quarter of orthologs exhibit condition-specific expression pattern differences. Conclusions Taken together, these analyses provide a global view of gene expression patterns between two species, both in terms of the conditions and timing of a gene's expression as well as co-expression partners. Our results provide testable hypotheses that will direct future experiments to determine how these changes may be specified in the genome.

Essays on economic cycles

NARCIS (Netherlands)

Groot, de E.A. (Bert)

2006-01-01

Schumpeter’s line of thought of multiple economic cycles is further investigated. The existence of multiple cycles in economic variables is demonstrated. In basic innovations five different cycles are found. Multiple cycle structures are shown in various macro-economic variables from the United

Nuclear-fuel-cycle education: Module 1. Nuclear fuel cycle overview

International Nuclear Information System (INIS)

Eckhoff, N.D.

1981-07-01

This educational module is an overview of the nuclear-fule-cycle. The overview covers nuclear energy resources, the present and future US nuclear industry, the industry view of nuclear power, the International Nuclear Fuel Cycle Evaluation program, the Union of Concerned Scientists view of the nuclear-fuel-cycle, an analysis of this viewpoint, resource requirements for a model light water reactor, and world nuclear power considerations

On the potential of plant species invasion influencing bio-geomorphologic landscape formation in salt marshes

NARCIS (Netherlands)

Schwarz, Christian; Ysebaert, Tom; Vandenbruwaene, Wouter; Temmerman, Stijn; Zhang, Li Quan; Herman, Peter M.J.

2016-01-01

Species invasions are known to change biotic and abiotic ecosystem characteristics such as community structure, cycling of materials and dynamics of rivers. However, their ability to alter interactions between biotic and abiotic ecosystem components, in particular bio-geomorphic feedbacks and the

Thorium cycles and proliferation

International Nuclear Information System (INIS)

Lovins, A.B.

1979-01-01

This paper analyzes several prevalent misconceptions about nuclear fuel cycles that breed fissile uranium-233 from thorium. Its main conclusions are: U-233, despite the gamma radioactivity of associated isotopes, is a rather attractive material for making fission bombs, and is a credible material for subnational as well as national groups to use for this purpose; (2) pure thorium cycles, which in effect merely substitute U-233 for Pu, would take many decades and much U to establish, and offer no significant safeguards advantage over Pu, cycles; (3) denatured Th-U cycles, which dilute the U-233 with inert U-238 to a level not directly usable in bombs, are not an effective safeguard even against subnational bomb-making; (4) several other features of mixed Th-U cycles are rather unattractive from a safeguards point of view; (5) thus, Th cycles of any kind are not a technical fix for proliferation (national or subnational) and, though probably more safeguardable than Pu cycles, are less so than once-through U cycles that entail no reprocessing; (6) while thorium cycles have some potential technical advantages, including flexibility, they cannot provide major savings in nuclear fuel resources compared to simpler ways of saving neutrons and U; and (7) while advocates of nuclear power may find Th cycles worth exploring, such cycles do not differ fundamentally from U cycles in any of the respects--including safeguards and fuel resources--that are relevant to the broader nuclear debate, and should not be euphorically embraced as if they did

Distribution and ecology of pest fruit fly species in Asia and the Pacific

International Nuclear Information System (INIS)

Allwood, Allan; Vueti, Ema Tora

2003-01-01

Fruit flies belong to the very diverse family Tephritidae, which consists of over 4,500 species distributed in most temperate, sub-tropical and tropical countries. In Asia and the Pacific regions, most of the major pest species belong to two genera. Bactrocera and Dacus. Representatives of Ceratitis occur in southwest Western Australia and the Indian Ocean islands and Carpomya occur in the Indian sub-continent and in Mauritius and Reunion. In the Asian region, 180 species of Bactrocera and 30 species of Dacus have been recorded and in the Australasian and Oceanic region, there are 270 species of Bactrocera and 27 species of Dacus. The diversity of species progressively decreases as the plant/host diversity decreases from west in Indonesia and Papua New Guinea to east in the Polynesian Island countries. The major pest species in the Asian region belong to the dorsalis complex (B. carambolae, B. dorsalis, B. occipitalis, B. philippinensis, B. papayae and B. pyrifoliae) and include other species such as B. cucurbitae, B. zonata, B. latifrons, and others. In the Pacific region, Australia has 100 species of fruit flies. Many Pacific Island countries each have endemic species, several of which are major pests. The factors that impact on populations of fruit flies include host ranges, life cycles, mating and oviposition behavior, dispersal capacity, nutritional, moisture, temperature and light requirements, and competition within and between species. (author)

The importance of kinetics and redox in the biogeochemical cycling of iron in the surface ocean.

Directory of Open Access Journals (Sweden)

Peter L. Croot

2012-06-01

Full Text Available It is now well established that Iron (Fe is a limiting element in many regions of the open ocean. Our current understanding of the key processes which control iron distribution in the open ocean have been largely based on thermodynamic measurements performed under the assumption of equilibrium conditions. Using this equilibrium approach, researchers have been able to detect and quantify organic complexing ligands in seawater and examine their role in increasing the overall solubility of iron. Our current knowledge about iron bioavailability to phytoplankton and bacteria is also based heavily on carefully controlled laboratory studies where it is assumed the chemical species are in equilibrium in line with the free ion association model (FIAM and/or its successor the biotic ligand model (BLM. Similarly most field work on Fe biogeochemistry generally consists of a single profile which is in essence a ‘snap-shot’ in time of the system under investigation. However it is well known that the surface ocean is an extremely dynamic environment and it is unlikely if thermodynamic equilibrium between all the iron species present is ever truly achieved. In sunlit waters this is mostly due to the daily passage of the sun across the sky leading to photoredox processes which alter Fe speciation by cycling between redox states and between inorganic and organic species. Episodic deposition events, are also important perturbations to iron cycling as they bring new iron to the system altering the equilibrium between species and phases. Over the last 20 years the mesoscale iron enrichment experiments (e.g. IronEx I /II, SOIREE, EisenEx, SOFeX, EIFeX, SAGE, SEEDS and SERIES I /II and the FeCycle (I/II experiments have provided the first insights into processes altering iron speciation and distribution which occur over temporal scales of days to weeks. Here we utilize new field data collected in the open ocean on the redox and complexation kinetics of iron in the

The oogenic cycle of the Caspian bent-toed gecko, Cyrtopodion caspium (Squamata: Gekkonidae in Iran

Directory of Open Access Journals (Sweden)

Vida Hojati

2013-07-01

Full Text Available The Caspian bent-toed gecko, Cyrtopodion caspium, is one of the commonest lizards in northern Iran. It is nocturnal, anthropophile and oviparous. In this study, the reproductive cycle of this species was studied by focusing on oogenesis, from April 5 to October 20, 2011. In total, 70 adult females were obtained from Mazandaran, one of the northern provinces of Iran where the climate is temperate. Ovaries were removed and processed for histological and morphometric studies. The results show that oocyte growth starts in late April and ends in August. Mating starts in spring, especially at the beginning of May, with oviposition occurring from late May to mid August. Females lay 1-2 eggs per clutch with the possibility of producing a secondary clutch later in the season. Maximum reproductive activity occurs in May and peaks in June. There was no significant difference between right and left side of reproductive system. With oogenesis occurring from April through July, C. caspium follows an oogenic cycle typical for temperate species.

Drivers of cycling demand and cycling futures in the Danish context

DEFF Research Database (Denmark)

Analysis of the time trend in cycling mode share based on longest possible time series. Logistic regression model of cycling as mode choice as basis for studying ‘driver variables’ contribution to time trend. Describing important vectors of change behind the time trend.......Analysis of the time trend in cycling mode share based on longest possible time series. Logistic regression model of cycling as mode choice as basis for studying ‘driver variables’ contribution to time trend. Describing important vectors of change behind the time trend....

The effect of hydraulic lift on organic matter decomposition, soil nitrogen cycling, and nitrogen acquisition by a grass species.

Science.gov (United States)

Armas, Cristina; Kim, John H; Bleby, Timothy M; Jackson, Robert B

2012-01-01

Hydraulic lift (HL) is the passive movement of water through plant roots, driven by gradients in water potential. The greater soil-water availability resulting from HL may in principle lead to higher plant nutrient uptake, but the evidence for this hypothesis is not universally supported by current experiments. We grew a grass species common in North America in two-layer pots with three treatments: (1) the lower layer watered, the upper one unwatered (HL), (2) both layers watered (W), and (3) the lower layer watered, the upper one unwatered, but with continuous light 24 h a day to limit HL (no-HL). We inserted ingrowth cores filled with enriched-nitrogen organic matter ((15)N-OM) in the upper layer and tested whether decomposition, mineralization and uptake of (15)N were higher in plants performing HL than in plants without HL. Soils in the upper layer were significantly wetter in the HL treatment than in the no-HL treatment. Decomposition rates were similar in the W and HL treatments and lower in no-HL. On average, the concentration of NH(4)(+)-N in ingrowth cores was highest in the W treatment, and NO(3)(-)-N concentrations were highest in the no-HL treatment, with HL having intermediate values for both, suggesting differential mineralization of organic N among treatments. Aboveground biomass, leaf (15)N contents and the (15)N uptake in aboveground tissues were higher in W and HL than in no-HL, indicating higher nutrient uptake and improved N status of plants performing HL. However, there were no differences in total root nitrogen content or (15)N uptake by roots, indicating that HL affected plant allocation of acquired N to photosynthetic tissues. Our evidence for the role of HL in organic matter decomposition and nutrient cycling suggests that HL could have positive effects on plant nutrient dynamics and nutrient turnover.

Assessing Cycling Participation in Australia

Directory of Open Access Journals (Sweden)

Chris Rissel

2013-01-01

Full Text Available Planning and evaluating cycling programs at a national or state level requires accurate measures of cycling participation. However, recent reports of cycling participation have produced very different estimates. This paper examines the reported rates of cycling in five recent population surveys of cycling. Three surveys (one national and two from Sydney asking respondents when they last rode a bicycle generated cycling participation (cycled in the past year estimates of 29.7%, 34.1% and 28.9%. Two other national surveys which asked participants to recall (unprompted any physical activity done for exercise, recreation or sport in the previous 12 months, estimated cycling in the past year as 11.1% and 6.5%. While unprompted recall of cycling as a type of physical activity generates lower estimates of cycling participation than specific recall questions, both assessment approaches produced similar patterns of cycling by age and sex with both approaches indicating fewer women and older adults cycling. The different question styles most likely explain the substantial discrepancies between the estimates of cycling participation. Some differences are to be expected due to sampling variability, question differences, and regional variation in cycling.

Life cycle as a stable trait in the evaluation of diversity of Nostoc from biofilms in rivers.

Science.gov (United States)

Mateo, Pilar; Perona, Elvira; Berrendero, Esther; Leganés, Francisco; Martín, Marta; Golubić, Stjepko

2011-05-01

The diversity within the genus Nostoc is still controversial and more studies are needed to clarify its heterogeneity. Macroscopic species have been extensively studied and discussed; however, the microscopic forms of the genus, especially those from running waters, are poorly known and likely represented by many more species than currently described. Nostoc isolates from biofilms of two Spanish calcareous rivers were characterized comparing the morphology and life cycle in two culture media with different levels of nutrients and also comparing the 16S rRNA gene sequences. The results showed that trichome shape and cellular dimensions varied considerably depending on the culture media used, whereas the characteristics expressed in the course of the life cycle remained stable for each strain independent of the culture conditions. Molecular phylogenetic analysis confirmed the distinction between the studied strains established on morphological grounds. A balanced approach to the evaluation of diversity of Nostoc in the service of autecological studies requires both genotypic information and the evaluation of stable traits. The results of this study show that 16S rRNA gene sequence similarity serves as an important criterion for characterizing Nostoc strains and is consistent with stable attributes, such as the life cycle. © 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

Effects of afforestation and deforestation on the deposition, cycling and leaching of elements

DEFF Research Database (Denmark)

Rasmussen, L.

1998-01-01

forest, its input, cycling, turnover, and possible leaching is of crucial interest for forest management. The input of oxidised forms of nitrogen, together with sulphur, contributes to acidification of forest soils, but internal transformation processes, like nitrification, also contribute....... In parallel, changes in land use and management practice have contributed to changes in the cycling of elements and in soil conditions. Afforestation and deforestation can also change atmospheric dry deposition and the processes controlling the mobility of nutrients and acidifying substances. Different types...... of forest management such as choice of tree species, deforestation by clear-felling or selection forest, fertilization, liming, sludge and compost addition, etc. will influence the leaching of nutrients from forest ecosystems. Since nitrogen is assumed to be the most important macronutrient in European...

Life-cycle cost analysis of adsorption cycles for desalination

KAUST Repository

Thu, Kyaw; Chakraborty, A.; Saha, B.B.; Chun, Won Gee; Ng, K.C.

2010-01-01

This paper presents the thermo-economic analysis of the adsorption desalination (AD) cycle that is driven by low-temperature waste heat from exhaust of industrial processes or renewable sources. The AD cycle uses an adsorbent such as the silica gel

Normal Hematopoietic Progenitor Subsets Have Distinct Reactive Oxygen Species, BCL2 and Cell-Cycle Profiles That Are Decoupled from Maturation in Acute Myeloid Leukemia.

Directory of Open Access Journals (Sweden)

Naeem Khan

Full Text Available In acute myeloid leukemia (AML quiescence and low oxidative state, linked to BCL2 mitochondrial regulation, endow leukemic stem cells (LSC with treatment-resistance. LSC in CD34+ and more mature CD34- AML have heterogeneous immunophenotypes overlapping with normal stem/progenitor cells (SPC but may be differentiated by functional markers. We therefore investigated the oxidative/reactive oxygen species (ROS profile, its relationship with cell-cycle/BCL2 for normal SPC, and whether altered in AML and myelodysplasia (MDS. In control BM (n = 24, ROS levels were highest in granulocyte-macrophage progenitors (GMP and CD34- myeloid precursors but megakaryocyte-erythroid progenitors had equivalent levels to CD34+CD38low immature-SPC although they were ki67high. BCL2 upregulation was specific to GMPs. This profile was also observed for CD34+SPC in MDS-without-excess-blasts (MDS-noEB, n = 12. Erythroid CD34- precursors were, however, abnormally ROS-high in MDS-noEB, potentially linking oxidative stress to cell loss. In pre-treatment AML (n = 93 and MDS-with-excess-blasts (MDS-RAEB (n = 14, immunophenotypic mature-SPC had similar ROS levels to co-existing immature-SPC. However ROS levels varied between AMLs; Flt3ITD+/NPM1wild-type CD34+SPC had higher ROS than NPM1mutated CD34+ or CD34- SPC. An aberrant ki67lowBCL2high immunophenotype was observed in CD34+AML (most prominent in Flt3ITD AMLs but also in CD34- AMLs and MDS-RAEB, suggesting a shared redox/pro-survival adaptation. Some patients had BCL2 overexpression in CD34+ ROS-high as well as ROS-low fractions which may be indicative of poor early response to standard chemotherapy. Thus normal SPC subsets have distinct ROS, cell-cycle, BCL2 profiles that in AML /MDS-RAEB are decoupled from maturation. The combined profile of these functional properties in AML subpopulations may be relevant to differential treatment resistance.

On approximating restricted cycle covers

NARCIS (Netherlands)

Manthey, Bodo

2008-01-01

A cycle cover of a graph is a set of cycles such that every vertex is part of exactly one cycle. An $L$-cycle cover is a cycle cover in which the length of every cycle is in the set $L$. The weight of a cycle cover of an edge-weighted graph is the sum of the weights of its edges. We come close to

Species Diversity and Bird Feed in Residential Complex

Science.gov (United States)

Hadinoto; Suhesti, Eni

2017-12-01

Bird is one component of the ecosystem which has an important role in supporting the occurrence of an organism's life cycle. Therefore, the presence of birds in an area is important, because it can affect the existence and distribution of plant species. The purpose of this study is to calculate the diversity of bird species and identify the source of bird feed in the compound. This study was conducted by field surveys in the residential complex. In addition to the birds as a research object vegetation as habitat / foraging birds were also observed. Data were analyzed by using the bird diversity index, richenes index, bundance index, dominance analysis, analysis of bird distribution and analysis of the level of meeting types, while vegetation will be analyzed based on the type and part of what is eaten by birds. In Pandau Jaya housing complex, found as many as 12 species of birds which consists of seven families. Bird species often present is Cucak Kutilang (Pycnonotus aurigaster) of 20 individuals, Bondol Peking (Lonchura punctulata) 14 individuals and Perkutut Jawa (Geopelia striata) 10 individuals. Bird species diversity (H ‘) in Pandau Jaya housing complex is still relatively moderate with a value of 2.27, while the Evenness Index (E) of 0.91 and Richenes Index (R) of 2.45. Types of vegetation as a food source, among others: mango, guava, cherry, jackfruit, ketapang, coconut, areca, palm, banana, papaya, flowers and grasses.

Nuclear power fuel cycle

International Nuclear Information System (INIS)

Havelka, S.; Jakesova, L.

1982-01-01

Economic problems are discussed of the fuel cycle (cost of the individual parts of the fuel cycle and the share of the fuel cycle in the price of 1 kWh), the technological problems of the fuel cycle (uranium ore mining and processing, uranium isotope enrichment, the manufacture of fuel elements, the building of long-term storage sites for spent fuel, spent fuel reprocessing, liquid and gaseous waste processing), and the ecologic aspects of the fuel cycle. (H.S.)

40 CFR 1065.514 - Cycle-validation criteria for operation over specified duty cycles.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Cycle-validation criteria for operation over specified duty cycles. 1065.514 Section 1065.514 Protection of Environment ENVIRONMENTAL... Over Specified Duty Cycles § 1065.514 Cycle-validation criteria for operation over specified duty...

Benefits of cycle stretchout in pressurized water reactor extended-burnup fuel cycles

International Nuclear Information System (INIS)

Matzie, R.A.; Leung, D.C.; Liu, Y.; Beekmann, R.W.

1981-01-01

Nuclear reactors are inherently capable of operating for a substantial period beyond their nominal end of cycle (EOC) as a result of negative moderator and fuel temperature coefficients and the decrease in xenon poisoning with lower core power levels. This inherent capability can be used to advantage to reduce annual uranium makeup requirements and cycle energy costs by the use of planned EOC stretchout. This paper discusses the fuel utilization efficiency and economics of both the five-batch, extended-burnup cycle and the three-batch, standard-burnup cycle, which can be improved by employing planned EOC (end of cycle) stretchout. 11 refs

Anopheline larval habitats seasonality and species distribution: a prerequisite for effective targeted larval habitats control programmes.

Directory of Open Access Journals (Sweden)

Eliningaya J Kweka

Full Text Available Larval control is of paramount importance in the reduction of malaria vector abundance and subsequent disease transmission reduction. Understanding larval habitat succession and its ecology in different land use managements and cropping systems can give an insight for effective larval source management practices. This study investigated larval habitat succession and ecological parameters which influence larval abundance in malaria epidemic prone areas of western Kenya.A total of 51 aquatic habitats positive for anopheline larvae were surveyed and visited once a week for a period of 85 weeks in succession. Habitats were selected and identified. Mosquito larval species, physico-chemical parameters, habitat size, grass cover, crop cycle and distance to nearest house were recorded. Polymerase chain reaction revealed that An. gambiae s.l was the most dominant vector species comprised of An.gambiae s.s (77.60% and An.arabiensis (18.34%, the remaining 4.06% had no amplification by polymerase chain reaction. Physico-chemical parameters and habitat size significantly influenced abundance of An. gambiae s.s (P = 0.024 and An. arabiensis (P = 0.002 larvae. Further, larval species abundance was influenced by crop cycle (P≤0.001, grass cover (P≤0.001, while distance to nearest houses significantly influenced the abundance of mosquito species larvae (r = 0.920;P≤0.001. The number of predator species influenced mosquito larval abundance in different habitat types. Crop weeding significantly influenced with the abundance of An.gambiae s.l (P≤0.001 when preceded with fertilizer application. Significantly higher anopheline larval abundance was recorded in habitats in pasture compared to farmland (P = 0.002. When habitat stability and habitat types were considered, hoof print were the most productive followed by disused goldmines.These findings suggest that implementation of effective larval control programme should be targeted with larval

Denatured fuel cycles

International Nuclear Information System (INIS)

Till, C.E.

1979-01-01

This paper traces the history of the denatured fuel concept and discusses the characteristics of fuel cycles based on the concept. The proliferation resistance of denatured fuel cycles, the reactor types they involve, and the limitations they place on energy generation potential are discussed. The paper concludes with some remarks on the outlook for such cycles

Relationship between corrosion and the biological sulfur cycle: A review

Energy Technology Data Exchange (ETDEWEB)

Little, B.J.; Ray, R.I.; Pope, R.K.

2000-04-01

Sulfur and sulfur compounds can produce pitting, crevice corrosion, dealloying, stress corrosion cracking, and stress-oriented hydrogen-induced cracking of susceptible metals and alloys. Even though the metabolic by-products of the biological sulfur cycle are extremely corrosive, there are no correlations between numbers and types of sulfur-related organisms and the probability or rate of corrosion, Determination of specific mechanisms for corrosion caused by microbiologically mediated oxidation and reduction of sulfur and sulfur compounds is complicated by the variety of potential metabolic-energy sources and by-products; the coexistence of reduced and oxidized sulfur species; competing reactions with inorganic and organic compounds; and the versatility and adaptability of microorganisms in biofilms. The microbial ecology of sulfur-rich environments is poorly understood because of the association of aerobes and anaerobes and the mutualism or succession of heterotrophs to autotrophs. The physical scale over which the sulfur cycle influences corrosion varies with the environment. The complete sulfur cycle of oxidation and reduction reactions can take place in macroenvironments, including sewers and polluted harbors, or within the microenvironment of biofilms. In this review, reactions of sulfur and sulfur compounds resulting in corrosion were discussed in the context of environmental processes important to corrosion.

Quantitative analysis of an engineered CO2-fixing Escherichia coli reveals great potential of heterotrophic CO2 fixation.

Science.gov (United States)

Gong, Fuyu; Liu, Guoxia; Zhai, Xiaoyun; Zhou, Jie; Cai, Zhen; Li, Yin

2015-01-01

Production of fuels from the abundant and wasteful CO2 is a promising approach to reduce carbon emission and consumption of fossil fuels. Autotrophic microbes naturally assimilate CO2 using energy from light, hydrogen, and/or sulfur. However, their slow growth rates call for investigation of the possibility of heterotrophic CO2 fixation. Although preliminary research has suggested that CO2 fixation in heterotrophic microbes is feasible after incorporation of a CO2-fixing bypass into the central carbon metabolic pathway, it remains unclear how much and how efficient that CO2 can be fixed by a heterotrophic microbe. A simple metabolic flux index was developed to indicate the relative strength of the CO2-fixation flux. When two sequential enzymes of the cyanobacterial Calvin cycle were incorporated into an E. coli strain, the flux of the CO2-fixing bypass pathway accounts for 13 % of that of the central carbon metabolic pathway. The value was increased to 17 % when the carbonic anhydrase involved in the cyanobacterial carbon concentrating mechanism was introduced, indicating that low intracellular CO2 concentration is one limiting factor for CO2 fixation in E. coli. The engineered CO2-fixing E. coli with carbonic anhydrase was able to fix CO2 at a rate of 19.6 mg CO2 L(-1) h(-1) or the specific rate of 22.5 mg CO2 g DCW(-1) h(-1). This CO2-fixation rate is comparable with the reported rates of 14 autotrophic cyanobacteria and algae (10.5-147.0 mg CO2 L(-1) h(-1) or the specific rates of 3.5-23.7 mg CO2 g DCW(-1) h(-1)). The ability of CO2 fixation was created and improved in E. coli by incorporating partial cyanobacterial Calvin cycle and carbon concentrating mechanism, respectively. Quantitative analysis revealed that the CO2-fixation rate of this strain is comparable with that of the autotrophic cyanobacteria and algae, demonstrating great potential of heterotrophic CO2 fixation.

Edgeworth cycles revisited

International Nuclear Information System (INIS)

Doyle, Joseph; Muehlegger, Erich; Samphantharak, Krislert

2010-01-01

Some gasoline markets exhibit remarkable price cycles, where price spikes are followed by a series of small price declines: a pattern consistent with a model of Edgeworth cycles described by Maskin and Tirole. We extend the model and empirically test its predictions with a new dataset of daily station-level prices in 115 US cities. Consistent with the theory, and often in contrast with previous empirical work, we find the least and most concentrated markets are much less likely to exhibit cycling behavior both within and across cities; areas with more independent convenience-store gas stations are also more likely to cycle. (author)

Variations in the Life Cycle of Anemone patens L. (Ranunculaceae in Wild Populations of Canada

Directory of Open Access Journals (Sweden)

Vladimir Kricsfalusy

2016-06-01

Full Text Available Based on a study of a perennial herb Anemone patens L. (Ranunculaceae in a variety of natural habitats in Saskatchewan, Canada, eight life stages (seed, seedling, juvenile, immature, vegetative, generative, subsenile, and senile are distinguished and characterized in detail. The species ontogenetic growth patterns are investigated. A. patens has a long life cycle that may last for several decades which leads to the formation of compact clumps. The distribution and age of clumps vary substantially in different environments with different levels of disturbance. The plant ontogeny includes the regular cycle with reproduction occurring through seeds. There is an optional subsenile vegetative disintegration at the end of the life span. The following variations in the life cycle of A. patens are identified: with slower development in young age, with an accelerated development, with omission of the generative stage, with retrogression to previous life stages in mature age, and with vegetative dormancy. The range of variations in the life cycle of A. patens may play an important role in maintaining population stability in different environmental conditions and management regimes.

Evolutionary relationships within the Phytophthora cactorum species complex in Europe.

Science.gov (United States)

Pánek, Matěj; Fér, Tomáš; Mráček, Jaroslav; Tomšovský, Michal

2016-01-01

The Phytophthora cactorum species complex in Europe is composed of P. cactorum, Phytophthora hedraiandra, and a hybrid species Phytophthora × serendipita. Evolutionary analyses using the amplified fragment length polymorphism (AFLP) method were carried out on 133 isolates from 19 countries. The AFLP data were complemented by sequence analysis of three genes (ITS region of ribosomal RNA gene, phenolic acid decarboxylase - Pheca I, and Cytochrome oxidase - Cox I), morphometric analysis and cardinal temperature data. The high proportion of clonal genotypes, low gene flow among groups, which was defined by the structure analysis, and low Nei's gene diversity confirms the homothallic life cycle of the groups. On the other hand, the ITS, Cox I and Pheca I sequence data support occasional hybridization between species. The structure K = 5 grouping revealed two groups of hybrid origin (C2 and F). While the C2 group resembles P. × serendipita, the F group includes Finnish isolates characterized by high oogonial abortion rates and slow growth. The morphological characters routinely used in identification of Phytophthora species are not useful for delimitation of species from the P. cactorum complex. Therefore, we discuss the status of P. hedraiandra as a separate species. The epitypification of P. cactorum is proposed. Copyright © 2016 British Mycological Society. Published by Elsevier Ltd. All rights reserved.

First record of multi-species synchronous coral spawning from Malaysia.

Science.gov (United States)

Chelliah, Alvin; Amar, Halimi Bin; Hyde, Julian; Yewdall, Katie; Steinberg, Peter D; Guest, James R

2015-01-01

Knowledge about the timing and synchrony of coral spawning has important implications for both the ecology and management of coral reef ecosystems. Data on the timing of spawning and extent of synchrony, however, are still lacking for many coral reefs, particularly from equatorial regions and from locations within the coral triangle. Here we present the first documentation of a multi-species coral spawning event from reefs around Pulau Tioman, Peninsular Malaysia, a popular diving and tourist destination located on the edge of the coral triangle. At least 8 coral species from 3 genera (Acropora, Montipora and Porites) participated in multi-species spawning over five nights in April 2014, between two nights before and two nights after the full moon. In addition, two Acropora species were witnessed spawning one night prior to the full moon in October 2014. While two of the Acropora species that reproduced in April (A. millepora and A. nasuta) exhibited highly synchronous spawning (100% of sampled colonies), two other common species (A. hyacinthus and A. digitifera) did not contain visible eggs in the majority of colonies sampled (i.e., Malaysia. These data provide further support for the contention that this phenomenon is a feature of all speciose coral assemblages, including equatorial reefs. More research is needed, however, to determine the seasonal cycles and extent of spawning synchrony on these reefs and elsewhere in Malaysia.

Reactive oxygen species production and discontinuous gas exchange in insects

OpenAIRE

Boardman, Leigh; Terblanche, John S.; Hetz, Stefan K.; Marais, Elrike; Chown, Steven L.

2011-01-01

While biochemical mechanisms are typically used by animals to reduce oxidative damage, insects are suspected to employ a higher organizational level, discontinuous gas exchange mechanism to do so. Using a combination of real-time, flow-through respirometry and live-cell fluorescence microscopy, we show that spiracular control associated with the discontinuous gas exchange cycle (DGC) in Samia cynthia pupae is related to reactive oxygen species (ROS). Hyperoxia fails to increase mean ROS produ...