Sample records for acoel isodiametra pulchra

  1. Characterization of the stem cell system of the acoel Isodiametra pulchra

    PubMed Central

    2009-01-01

    Background Tissue plasticity and a substantial regeneration capacity based on stem cells are the hallmark of several invertebrate groups such as sponges, cnidarians and Platyhelminthes. Traditionally, Acoela were seen as an early branching clade within the Platyhelminthes, but became recently positioned at the base of the Bilateria. However, little is known on how the stem cell system in this new phylum is organized. In this study, we wanted to examine if Acoela possess a neoblast-like stem cell system that is responsible for development, growth, homeostasis and regeneration. Results We established enduring laboratory cultures of the acoel Isodiametra pulchra (Acoela, Acoelomorpha) and implemented in situ hybridization and RNA interference (RNAi) for this species. We used BrdU labelling, morphology, ultrastructure and molecular tools to illuminate the morphology, distribution and plasticity of acoel stem cells under different developmental conditions. We demonstrate that neoblasts are the only proliferating cells which are solely mesodermally located within the organism. By means of in situ hybridisation and protein localisation we could demonstrate that the piwi-like gene ipiwi1 is expressed in testes, ovaries as well as in a subpopulation of somatic stem cells. In addition, we show that germ cell progenitors are present in freshly hatched worms, suggesting an embryonic formation of the germline. We identified a potent stem cell system that is responsible for development, homeostasis, regeneration and regrowth upon starvation. Conclusions We introduce the acoel Isodiametra pulchra as potential new model organism, suitable to address developmental questions in this understudied phylum. We show that neoblasts in I. pulchra are crucial for tissue homeostasis, development and regeneration. Notably, epidermal cells were found to be renewed exclusively from parenchymally located stem cells, a situation known only from rhabditophoran flatworms so far. For further comparison, it will be important to analyse the stem cell systems of other key-positioned understudied taxa. PMID:20017953

  2. Mesodermal Gene Expression in the Acoel Isodiametra pulchra Indicates a Low Number of Mesodermal Cell Types and the Endomesodermal Origin of the Gonads

    PubMed Central

    Chiodin, Marta; Børve, Aina; Berezikov, Eugene; Ladurner, Peter; Martinez, Pedro; Hejnol, Andreas

    2013-01-01

    Acoelomorphs are bilaterally symmetric small marine worms that lack a coelom and possess a digestive system with a single opening. Two alternative phylogenetic positions of this group within the animal tree are currently debated. In one view, Acoelomorpha is the sister group to all remaining Bilateria and as such, is a morphologically simple stepping stone in bilaterian evolution. In the other, the group is a lineage within the Deuterostomia, and therefore, has derived a simple morphology from a more complex ancestor. Acoels and the closely related Nemertodermatida and Xenoturbellida, which together form the Acoelomorpha, possess a very limited number of cell types. To further investigate the diversity and origin of mesodermal cell types we describe the expression pattern of 12 orthologs of bilaterian mesodermal markers including Six1/2, Twist, FoxC, GATA4/5/6, in the acoel Isodiametra pulchra. All the genes are expressed in stem cells (neoblasts), gonads, and at least subsets of the acoel musculature. Most are expressed in endomesodermal compartments of I. pulchra developing embryos similar to what has been described in cnidarians. Our molecular evidence indicates a very limited number of mesodermal cell types and suggests an endomesodermal origin of the gonads and the stem cell system. We discuss our results in light of the two prevailing phylogenetic positions of Acoelomorpha. PMID:23405161

  3. Posterior regeneration in Isodiametra pulchra (Acoela, Acoelomorpha)

    PubMed Central

    2013-01-01

    Introduction Regeneration is a widespread phenomenon in the animal kingdom, but the capacity to restore damaged or missing tissue varies greatly between different phyla and even within the same phylum. However, the distantly related Acoelomorpha and Platyhelminthes share a strikingly similar stem-cell system and regenerative capacity. Therefore, comparing the underlying mechanisms in these two phyla paves the way for an increased understanding of the evolution of this developmental process. To date, Isodiametra pulchra is the most promising candidate as a model for the Acoelomorpha, as it reproduces steadily under laboratory conditions and is amenable to various techniques, including the silencing of gene expression by RNAi. In order to provide an essential framework for future studies, we report the succession of regeneration events via the use of cytochemical, histological and microscopy techniques, and specify the total number of cells in adult individuals. Results Isodiametra pulchra is not capable of regenerating a new head, but completely restores all posterior structures within 10 days. Following amputation, the wound closes via the contraction of local muscle fibres and an extension of the dorsal epidermis. Subsequently, stem cells and differentiating cells invade the wound area and form a loosely delimited blastema. After two days, the posterior end is re-patterned with the male (and occasionally the female) genital primordium being apparent. Successively, these primordia differentiate into complete copulatory organs. The size of the body and also of the male and female copulatory organs, as well as the distance between the copulatory organs, progressively increase and by nine days copulation is possible. Adult individuals with an average length of 670 ?m consist of approximately 8100 cells. Conclusion Isodiametra pulchra regenerates through a combination of morphallactic and epimorphic processes. Existing structures are “re-modelled” and provide a framework onto which newly differentiating cells are added. Growth proceeds through the intercalary addition of structures, mirroring the embryonic and post-embryonic development of various organ systems. The suitability of Isodiametra pulchra for laboratory techniques, the fact that its transcriptome and genome data will soon be available, as well as its small size and low number of cells, make it a prime candidate subject for research into the cellular mechanisms that underlie regeneration in acoelomorphs. PMID:24160844

  4. ACOEL on CORAL A COmponent Requirement and Abstraction Language

    E-print Network

    Leavens, Gary T.

    ACOEL on CORAL A COmponent Requirement and Abstraction Language An Extended Abstract Vugranam C. Sreedhar IBM TJ Watson Research Center Hawthorne, NY 10532 sreedhar@watson.ibm.com ABSTRACT CORAL is a language for specifying properties of ACOEL, a component-oriented extensional language. The design of CORAL

  5. Graptemys pulchra Baur 1893: Alabama Map Turtle

    USGS Publications Warehouse

    Lovich, Jeffrey E.; Godwin, James C.; McCoy, C.J.

    2014-01-01

    The Alabama Map Turtle, Graptemys pulchra (Family Emydidae), is a moderately large riverine species endemic to the Mobile Bay drainage system of Alabama, Georgia, and Mississippi. Sexual size dimorphism is pronounced, with adult females (carapace length [CL] to 273 mm) attaining more than twice the size of adult males (CL to 117 mm). The species is an inhabitant of relatively large, swift creeks and rivers, often with wide sandbars. Stream sections open to the sun and with abundant basking sites in the form of logs and brush are preferred. Six to seven clutches of 4–7 eggs are laid each year on river sandbars. Although the species is locally abundant, populations are threatened by habitat destruction, declines in their prey base, commercial collection, and vandalism. It is listed as a Species of Special Concern in Alabama.

  6. Molecular Architecture of Muscles in an Acoel and Its Evolutionary Implications

    PubMed Central

    CHIODIN, MARTA; ACHATZ, JOHANNES G.; WANNINGER, ANDREAS; MARTINEZ, PEDRO

    2011-01-01

    We have characterized the homologs of an actin, a troponin I, and a tropomyosin gene in the acoel Symsagittifera roscoffensis. These genes are expressed in muscles and most likely coexpressed in at least a subset of them. In addition, and for the first time for Acoela, we have produced a species-specific muscular marker, an antibody against the tropomyosin protein. We have followed tropomyosin gene and protein expression during postembryonic development and during the posterior regeneration of amputated adults, showing that preexisting muscle fibers contribute to the wound closure. The three genes characterized in this study interact in the striated muscles of vertebrates and invertebrates, where troponin I and tropomyosin are key regulators of the contraction of the sarcomere. S. roscoffensis and all other acoels so far described have only smooth muscles, but the molecular architecture of these is the same as that of striated fibers of other bilaterians. Given the proposed basal position of acoels within the Bilateria, we suggest that sarcomeric muscles arose from a smooth muscle type, which had the molecular repertoire of striated musculature already in place. We discuss this model in a broad comparative perspective. PMID:21538843

  7. Molecular architecture of muscles in an acoel and its evolutionary implications.

    PubMed

    Chiodin, Marta; Achatz, Johannes G; Wanninger, Andreas; Martinez, Pedro

    2011-09-15

    We have characterized the homologs of an actin, a troponin I, and a tropomyosin gene in the acoel Symsagittifera roscoffensis. These genes are expressed in muscles and most likely coexpressed in at least a subset of them. In addition, and for the first time for Acoela, we have produced a species-specific muscular marker, an antibody against the tropomyosin protein. We have followed tropomyosin gene and protein expression during postembryonic development and during the posterior regeneration of amputated adults, showing that preexisting muscle fibers contribute to the wound closure. The three genes characterized in this study interact in the striated muscles of vertebrates and invertebrates, where troponin I and tropomyosin are key regulators of the contraction of the sarcomere. S. roscoffensis and all other acoels so far described have only smooth muscles, but the molecular architecture of these is the same as that of striated fibers of other bilaterians. Given the proposed basal position of acoels within the Bilateria, we suggest that sarcomeric muscles arose from a smooth muscle type, which had the molecular repertoire of striated musculature already in place. We discuss this model in a broad comparative perspective. PMID:21538843

  8. Centaurea solstitialis Invasion Success Is Influenced by Nassella pulchra Size

    Microsoft Academic Search

    Kimberly J. Reever Morghan; Kevin J. Rice

    2005-01-01

    Replacement of perennial grasses with non-native annual grasses in California's Central Valley grasslands and foot- hills has increased deep soil water availability. Yellow starthistle (Centaurea solstitialis), a deep-rooted invasive thistle, can use this water to invade annual grasslands. Native perennial bunchgrasses, such as Purple needlegrass (Nassella pulchra), also use deep soil water, so there is an overlap in resource use

  9. The chimerical and multifaceted marine acoel Symsagittifera roscoffensis: from photosymbiosis to brain regeneration

    PubMed Central

    Bailly, Xavier; Laguerre, Laurent; Correc, Gaëlle; Dupont, Sam; Kurth, Thomas; Pfannkuchen, Anja; Entzeroth, Rolf; Probert, Ian; Vinogradov, Serge; Lechauve, Christophe; Garet-Delmas, Marie-José; Reichert, Heinrich; Hartenstein, Volker

    2014-01-01

    A remarkable example of biological engineering is the capability of some marine animals to take advantage of photosynthesis by hosting symbiotic algae. This capacity, referred to as photosymbiosis, is based on structural and functional complexes that involve two distantly unrelated organisms. These stable photosymbiotic associations between metazoans and photosynthetic protists play fundamental roles in marine ecology as exemplified by reef communities and their vulnerability to global changes threats. Here we introduce a photosymbiotic tidal acoel flatworm, Symsagittifera roscoffensis, and its obligatory green algal photosymbiont, Tetraselmis convolutae (Lack of the algal partner invariably results in acoel lethality emphasizing the mandatory nature of the photosymbiotic algae for the animal's survival). Together they form a composite photosymbiotic unit, which can be reared in controlled conditions that provide easy access to key life-cycle events ranging from early embryogenesis through the induction of photosymbiosis in aposymbiotic juveniles to the emergence of a functional “solar-powered” mature stage. Since it is possible to grow both algae and host under precisely controlled culture conditions, it is now possible to design a range of new experimental protocols that address the mechanisms and evolution of photosymbiosis. S. roscoffensis thus represents an emerging model system with experimental advantages that complement those of other photosymbiotic species, in particular corals. The basal taxonomic position of S. roscoffensis (and acoels in general) also makes it a relevant model for evolutionary studies of development, stem cell biology and regeneration. Finally, it's autotrophic lifestyle and lack of calcification make S. roscoffensis a favorable system to study the role of symbiosis in the response of marine organisms to climate change (e.g., ocean warming and acidification). In this article we summarize the state of knowledge of the biology of S. roscoffensis and its algal partner from studies dating back over a century, and provide an overview of ongoing research efforts that take advantage of this unique system. PMID:25324833

  10. A cultivable acoel species from the Mediterranean, Aphanostoma pisae sp. nov. (Acoela, Acoelomorpha).

    PubMed

    Zauchner, Thomas; Salvenmoser, Willi; Egger, Bernhard

    2015-01-01

    Aphanostoma pisae sp. nov. is an interstitial acoel found at the coast of the Liguric Sea in Pisa (Tuscany, Italy). It belongs to the large family Isodiametridae, characterised by a male copulatory organ with a cylindrical shape and non-anastomising longitudinal muscle fibers. It is the first recognised species of Aphanostoma in the Mediterranean and it can occur in great abundance at its type locality (several hundred specimens in a spoonful of sand). A. pisae has been cultured in the laboratory for several years with diatoms for food. The embryonic development lasts for just under two days at 20 °C.        We provide a description of the new species using live observations, light and electron microscopy of sagittal sections and stainings of the filamentous actin and the serotonergic nervous system, and we discuss and update the genus diagnoses of the genera Aphanostoma and Praeconvoluta. PMID:25947519

  11. Electron microscopy of flatworms standard and cryo-preparation methods.

    PubMed

    Salvenmoser, Willi; Egger, Bernhard; Achatz, Johannes G; Ladurner, Peter; Hess, Michael W

    2010-01-01

    Electron microscopy (EM) has long been indispensable for flatworm research, as most of these worms are microscopic in dimension and provide only a handful of characters recognizable by eye or light microscopy. Therefore, major progress in understanding the histology, systematics, and evolution of this animal group relied on methods capable of visualizing ultrastructure. The rise of molecular and cellular biology renewed interest in such ultrastructural research. In the light of recent developments, we offer a best-practice guide for users of transmission EM and provide a comparison of well-established chemical fixation protocols with cryo-processing methods (high-pressure freezing/freeze-substitution, HPF/FS). The organisms used in this study include the rhabditophorans Macrostomum lignano, Polycelis nigra and Dugesia gonocephala, as well as the acoel species Isodiametra pulchra. PMID:20869529

  12. Lipoxygenase inhibitory activity of Cuspidaria pulchra and isolated compounds.

    PubMed

    Alvarenga, Tavane A; Bertanha, Camila S; de Oliveira, Pollyanna F; Tavares, Denise C; Gimenez, Valéria M M; Silva, Márcio L A; Cunha, Wilson R; Januário, Ana H; Pauletti, Patrícia M

    2015-06-01

    This work evaluated the in vitro inhibitory activity of the crude ethanolic extract from the aerial parts of Cuspidaria pulchra (Cham.) L.G. Lohmann against 15-lipoxygenase (15-LOX). The bioassay-guided fractionation of the n-butanol fraction, which displayed the highest activity, led to the isolation of three compounds: caffeoylcalleryanin (1), verbascoside (2) and 6-hydroxyluteolin-7-O-?-glucoside (3). Assessment of the ability of the isolated compounds to inhibit 15-LOX revealed that compounds 1, 2 and 3 exerted strong 15-LOX inhibitory activity; IC50 values were 1.59, 1.76 and 2.35 ?M respectively. The XTT assay showed that none of the isolated compounds seemed to be significantly toxic. PMID:25428032

  13. Chemistry and Antiviral Activity of Arrabidaea pulchra (Bignoniaceae).

    PubMed

    Brandão, Geraldo Célio; Kroon, Erna G; Souza, Danielle E R; Souza Filho, José D; Oliveira, Alaíde Braga

    2013-01-01

    The aim of the present work was to carry out a bioguided isolation of antiviral chemical constituents from an ethanol extract of leaves from Arrabidaea pulchra (Cham.) Sandwith (EEAPL) that had shown in vitro activity in a previous screening using DNA and RNA viruses. The activity of EEPAL was evaluated against the DNA viruses Human herpesvirus 1 (HSV-1) and Vaccinia virus Western Reserve (VACV-WR) as well as against the RNA viruses Murine encephalomyocarditis virus (EMCV), and Dengue virus 2 (DENV-2) by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) colorimetric assay. Cytotoxicity was determined in LLCMK2 and Vero cells and the Selectivity Indexes (SI) were calculated. The most potent effect was observed against DENV-2 (EC50 46.8 ± 1.6 µg mL(-1); SI 2.7). For HSV-1 and VACV-WR EC50 values > 200 µg mL(-1) were determined, while no inhibition of the cytopathic effect was observed with EMCV. Bioguided fractionation of EEAPL by partition between immiscible solvents followed by chromatography over a Sephadex LH20 column afforded two arylpropanoid glycosides, verbascoside (AP 1) and caffeoylcalleryanin (AP 2), along with a terpenoid, ursolic acid (AP 3). AP 1 and AP 3 exhibited similar anti-DENV-2 profiles, with SI values of 3.8 and 3.1, respectively, while AP 2 was the most effective anti-DENV-2 constituent, with a SI of 20.0. Our results show that A. pulchra leaves ethanol extract (EEAPL) affords compounds with antiviral activity, mainly against DENV-2. PMID:23959197

  14. Structure of the central nervous system of a juvenile acoel, Symsagittifera roscoffensis

    PubMed Central

    Cardona, Albert; Martinez, Pedro

    2010-01-01

    The neuroarchitecture of Acoela has been at the center of morphological debates. Some authors, using immunochemical tools, suggest that the nervous system in Acoela is organized as a commissural brain that bears little resemblance to the central, ganglionic type brain of other flatworms, and bilaterians in general. Others, who used histological staining on paraffin sections, conclude that it is a compact structure (an endonal brain; e.g., Raikova 2004; von Graff 1891; Delage Arch Zool Exp Gén 4:109-144, 1886). To address this question with modern tools, we have obtained images from serial transmission electron microscopic sections of the entire hatchling of Symsagittifera roscoffensis. In addition, we obtained data from wholemounts of hatchlings labeled with markers for serotonin and tyrosinated tubulin. Our data show that the central nervous system of a juvenile S. roscoffensis consists of an anterior compact brain, formed by a dense, bilobed mass of neuronal cell bodies surrounding a central neuropile. The neuropile flanks the median statocyst and contains several types of neurites, classified according to their types of synaptic vesicles. The neuropile issues three pairs of nerve cords that run at different dorso-ventral positions along the whole length of the body. Neuronal cell bodies flank the cords, and neuromuscular synapses are abundant. The TEM analysis also reveals different classes of peripheral sensory neurons and provides valuable information about the spatial relationships between neurites and other cell types within the brain and nerve cords. We conclude that the acoel S. roscoffensis has a central brain that is comparable in size and architecture to the brain of other (rhabditophoran) flatworms. PMID:20549514

  15. Reversal of Phototaxis in the Larvæ of Polydora pulchra, Carazzi (Polychæta, Spionidæ)

    Microsoft Academic Search

    M. R. Ranade

    1957-01-01

    REVERSAL of phototaxis has been noted in a number of animals and attributed to fright, hunger and food and other chemical stimuli. The only case known to me in which the direction of phototaxis is determined by the salinity of the environment is provided by the larvæ of Polydora pulchra, Carazzi, previously recorded1 from the plaice ponds at the Marine

  16. Calcium isotope fractionation in coccoliths of cultured Calcidiscus leptoporus, Helicosphaera carteri, Syracosphaera pulchra and Umbilicosphaera foliosa

    Microsoft Academic Search

    Nikolaus Gussone; Gerald Langer; Markus Geisen; Blair A. Steel; Ulf Riebesell

    2007-01-01

    Four species of marine calcifying algae, the coccolithophores Calcidiscus leptoporus, Helicosphaera carteri, Syracosphaera pulchra and Umbilicosphaera foliosa were grown in laboratory cultures under temperatures varying between 14 and 23 °C, and one species, C. leptoporus, under varying [CO32?], ranging from 105 to 219 ?mol\\/kg. Calcium isotope compositions of the coccoliths resemble in both absolute fractionation and temperature sensitivity previous calibrations of marine

  17. Dissociation of Circadian and Circatidal Timekeeping in the Marine Crustacean Eurydice pulchra

    PubMed Central

    Zhang, Lin; Hastings, Michael H.; Green, Edward W.; Tauber, Eran; Sladek, Martin; Webster, Simon G.; Kyriacou, Charalambos P.; Wilcockson, David C.

    2013-01-01

    Summary Background Tidal (12.4 hr) cycles of behavior and physiology adapt intertidal organisms to temporally complex coastal environments, yet their underlying mechanism is unknown. However, the very existence of an independent “circatidal” clock has been disputed, and it has been argued that tidal rhythms arise as a submultiple of a circadian clock, operating in dual oscillators whose outputs are held in antiphase i.e., ?12.4 hr apart. Results We demonstrate that the intertidal crustacean Eurydice pulchra (Leach) exhibits robust tidal cycles of swimming in parallel to circadian (24 hr) rhythms in behavioral, physiological and molecular phenotypes. Importantly, ?12.4 hr cycles of swimming are sustained in constant conditions, they can be entrained by suitable stimuli, and they are temperature compensated, thereby meeting the three criteria that define a biological clock. Unexpectedly, tidal rhythms (like circadian rhythms) are sensitive to pharmacological inhibition of Casein kinase 1, suggesting the possibility of shared clock substrates. However, cloning the canonical circadian genes of E. pulchra to provide molecular markers of circadian timing and also reagents to disrupt it by RNAi revealed that environmental and molecular manipulations that confound circadian timing do not affect tidal timing. Thus, competent circadian timing is neither an inevitable nor necessary element of tidal timekeeping. Conclusions We demonstrate that tidal rhythms are driven by a dedicated circatidal pacemaker that is distinct from the circadian system of E. pulchra, thereby resolving a long-standing debate regarding the nature of the circatidal mechanism. PMID:24076244

  18. Monanchomycalin C, a new pentacyclic guanidine alkaloid from the far-eastern marine sponge Monanchora pulchra.

    PubMed

    Tabakmakher, Ksenya M; Denisenko, Vladimir A; Guzii, Alla G; Dmitrenok, Pavel S; Dyshlovoy, Sergey A; Lee, Hyi-Seung; Makarieva, Tatyana N

    2013-10-01

    A new pentacyclic guanidine alkaloid, monanchomycalin C (1), along with the earlier known ptilomycalin A (2), were isolated from the Far-Eastern marine sponge Monanchora pulchra. The structure of 1 was elucidated using 1D and 2D NMR spectroscopic and ma ss spectrometric da ta. Compounds 1 and 2 exhibited cytotoxic activities against human breast cancer MDA-MB-231 cells with IC50 values of 8.2 microM and 4.3 pM, respectively. PMID:24354184

  19. A new species of Centris ( Centris) (Fabricius) from northeastern Brazil, with taxonomic notes on C. ( C.) pulchra Moure, Oliveira & Viana (Hymenoptera, Apidae)

    PubMed Central

    Mahlmann, Thiago; de Oliveira, Favízia Freitas

    2012-01-01

    Abstract We describe a new species of the bee genus Centris, Centris (Centris) byrsonimae Mahlmann & Oliveira sp. n., whose name has appeared as a nomen nudum in the literature since 1985. Further, a new species group of Centris s.str. is proposed, the pulchra group, based on morphological characters, which comprises the species Centris pulchra Moure, Oliveira & Viana, 2003 and Centris byrsonimae sp. n..Based on information from specimen labels studied and data from the literature, a list of plant species visited by the pulchra group is presented. The male genitalia and hidden metasomal sterna 7 and 8 of Centris pulchra are described for the first time. Typographic errors pertaining to the paratype labels reported in the original description of Centris pulchra are corrected. One female paratype of Centris pulchra is designated herein as a paratype of Centris byrsonimae sp. n. An updated list of species of Centris s.str. from northeastern Brazil is provided including references about geographic distributions as well as an identification key to the pulchra species group. PMID:23459508

  20. Pulchranins B and C, new acyclic guanidine alkaloids from the Far-Eastern marine sponge Monanchora pulchra.

    PubMed

    Makarieva, Tatyana N; Ogurtsova, Ekaterina K; Korolkova, Yuliya V; Andreev, Yaroslav A; Mosharova, Irina V; Tabakmakher, Ksenya M; Guzii, Alla G; Denisenko, Vladimir A; Dmitrenok, Pavel S; Lee, Hyi-Seung; Grishin, Eugene V; Stonik, Valentin A

    2013-09-01

    New marine natural products, pulchranins B and C (2 and 3), were isolated from the marine sponge Monanchora pulchra and their structures were established using NMR and MS analysis. Compounds 2 and 3 were moderately active as inhibitors of TRPV1 (EC50 value of 95 and 183 microM, respectively) and less potent against TRPV3 and TRPA1 receptors. PMID:24273853

  1. Growth rates, biomass and distribution of selected woody plant roots in Burkea africana-Ochna pulchra savanna

    Microsoft Academic Search

    M. C. Rutherford

    1983-01-01

    Woody plants in an African Burkea africana-Ochna pulchra savanna on deep sandy soil were found to have characteristically bimorphic root systems. The shallow lateral root component was often well developed and roots extended up to seven times the extent of the plant canopy in several species. Exponential tapering of lateral roots was found in Terminalia sericea. The wide-ranging roots, together

  2. Induction of metamorphosis in the sea urchin Holopneustes purpurascens by a metabolite complex from the algal host Delisea pulchra.

    PubMed

    Williamson, J E; De Nys, R; Kumar, N; Carson, D G; Steinberg, P D

    2000-06-01

    Most benthic invertebrates have complex life cycles with planktonic larvae that return to the substratum to settle and metamorphose into a benthic stage. Although naturally produced chemical cues have long been thought to be important for the settlement or metamorphosis of invertebrate larvae, few ecologically relevant chemical cues have been clearly identified. The marine echinoid Holopneustes purpurascens has a complex life cycle, with a planktonic, nonfeeding dispersive larva that metamorphoses into a benthic stage that lives in the canopy of subtidal benthic algae such as the red alga Delisea pulchra and the kelp Ecklonia radiata. Recently recruited juveniles are found primarily on D. pulchra, and we hypothesized that this was in response to a chemical cue produced by this alga. Competent larvae metamorphosed in the presence of D. pulchra, or seawater surrounding this alga, but not in response to the presence of E. radiata or its extracts. A cue for metamorphosis was isolated and characterized from D. pulchra and found to be a water-soluble complex of the sugar floridoside and isethionic acid in a 1:1 molar ratio. The floridoside-isethionic acid complex also triggered settlement in H. purpurascens; however, this response was less specific than metamorphosis and was reversible. Larvae of H. purpurascens also metamorphosed in the presence of several other species of red, but not brown or green, algae from their habitat. Floridoside is found only in red algae, suggesting that the floridoside-isethionic acid complex may be acting as a cue for metamorphosis in other red algae as well as in D. pulchra. PMID:10897447

  3. Kaempulchraols A-H, Diterpenoids from the Rhizomes of Kaempferia pulchra Collected in Myanmar.

    PubMed

    Win, Nwet Nwet; Ito, Takuya; Aimaiti, Simayijiang; Imagawa, Hiroshi; Ngwe, Hla; Abe, Ikuro; Morita, Hiroyuki

    2015-05-22

    Eight new diterpenoids, kaempulchraols A-H (1-8), along with five known analogues were isolated from the CHCl3-soluble extract of rhizomes of Kaempferia pulchra of Myanmar. The structures of these compounds were elucidated using extensive spectroscopic techniques including X-ray diffraction analysis. All the isolates were tested for their antiproliferative activity against a panel of five human cancer cell lines (A549, human lung cancer; HeLa, human cervix cancer; PANC-1 and PSN-1, human pancreatic cancer; MDA-MB-231, human breast cancer) and TIG-3, normal human primary fibroblast cells. Kaempulchraol F (6) exhibited weak activity against the human pancreatic PSN-1 cell line with an IC50 value of 12.3 ?M. PMID:25919052

  4. Trees as huge flowers and flowers as oversized floral guides: the role of floral color change and retention of old flowers in Tibouchina pulchra

    PubMed Central

    Brito, Vinícius L. G.; Weynans, Kevin; Sazima, Marlies; Lunau, Klaus

    2015-01-01

    Floral color changes and retention of old flowers are frequently combined phenomena restricted to the floral guide or single flowers in few-flowered inflorescences. They are thought to increase the attractiveness over long distances and to direct nearby pollinators toward the rewarding flowers. In Tibouchina pulchra, a massively flowering tree, the whole flower changes its color during anthesis. On the first day, the flowers are white and on the next 3 days, they change to pink. This creates a new large-scale color pattern in which the white pre-changed flowers contrast against the pink post-changed ones over the entire tree. We describe the spectral characteristics of floral colors of T. pulchra and test bumblebees’ response to this color pattern when viewed at different angles (simulating long and short distances). The results indicated the role of different color components in bumblebee attraction and the possible scenario in which this flower color pattern has evolved. We tested bumblebees’ preference for simulated trees with 75% pink and 25% white flowers resembling the color patterns of T. pulchra, and trees with green leaves and pink flowers (control) in long-distance approach. We also compared an artificial setting with three pink flowers and one white flower (T. pulchra model) against four pink flowers with white floral guides (control) in short-distance approach. Bumblebees spontaneously preferred the simulated T. pulchra patterns in both approaches despite similar reward. Moreover, in short distances, pollinator visits to peripheral, non-rewarding flowers occurred only half as frequently in the simulated T. pulchra when compared to the control. Thefore, this exceptional floral color change and the retention of old flowers in T. pulchra favors the attraction of pollinators over long distances in a deception process while it honestly directs them toward the rewarding flowers at short distances possibly exploring their innate color preferences.

  5. PRELIMINARY GASTROINTESTINAL STUDIES OF METHANOL EXTRACT OF INDIGOFERA PULCHRA WILLD IN RODENTS

    PubMed Central

    Sule, M.I.; Haruna, A. K.; Ilyas, M.; Iliya, I.; Yaro, A. H.; Magaji, M.G.

    2010-01-01

    In this study, the effect of the methanol extract of Indigofera pulchra Willd. (Papillionaceae) was investigated against castor oil induced diarrheoa. Its effects on perfused isolated rabbit jejunum and guinea pig ileum were also evaluated. The extract produced a dose-dependent protection against the castor oil-induced diarrheoa in mice with the highest protection (100%), obtained at 200 mgkg?1 comparable to that of loperamide (5 mgkg?1), a standard antidiarrhoeal drug. The extract (0.4 – 6.4 mgml?1) produced a concentration relaxation of the rabbit jejunum. However, no observable effect was noticed when the guinea pig ileum was treated. The extract blocked the contractile effect of acetylcholine (2 × 10?8 gml?1) and histamine (4 × 10?7 gml?1) on both rabbit jejunum and guinea pig ileum. Phytochemical screening revealed the presence of flavonoids, tannins, saponins and steroids. The intraperitoneal median lethal dose (LD50) value for the extract was found to be 2154.0 mgkg?1. The results obtained revealed that the extract possesses pharmacologically active compounds with gastrointestinal relaxant and antidiarrhoeal activities and may possibly explain the use of the plant in traditional medicine for the treatment of gastrointestinal disorder. PMID:21197141

  6. Urupocidin A: a new, inducing iNOS expression bicyclic guanidine alkaloid from the marine sponge Monanchora pulchra.

    PubMed

    Makarieva, Tatyana N; Ogurtsova, Ekaterina K; Denisenko, Vladimir A; Dmitrenok, Pavel S; Tabakmakher, Ksenya M; Guzii, Alla G; Pislyagin, Evgeny A; Es'kov, Andrey A; Kozhemyako, Valery B; Aminin, Dmitry L; Wang, Yun-Ming; Stonik, Valentin A

    2014-08-15

    Urupocidins A and B (1 and 2), bisguanidine alkaloids with an unprecedented skeleton system, derived from polyketide precursors and containing an unusual N-alkyl-N-hydroxyguanidine moiety, have been isolated from the sponge Monanhora pulchra. The structures of 1 and 2, including absolute configuration, were established using the detailed analysis of 1D and 2D NMR, CD, and mass spectra as well as chemical transformations. Compound 1 increases nitric oxide production in murine macrophages via inducing iNOS expression. PMID:25092065

  7. Rapid Development of Microsatellite Markers with 454 Pyrosequencing in a Vulnerable Fish, the Mottled Skate, Raja pulchra

    PubMed Central

    Kang, Jung-Ha; Park, Jung-Youn; Jo, Hyun-Su

    2012-01-01

    The mottled skate, Raja pulchra, is an economically valuable fish. However, due to a severe population decline, it is listed as a vulnerable species by the International Union for Conservation of Nature. To analyze its genetic structure and diversity, microsatellite markers were developed using 454 pyrosequencing. A total of 17,033 reads containing dinucleotide microsatellite repeat units (mean, 487 base pairs) were identified from 453,549 reads. Among 32 loci containing more than nine repeat units, 20 primer sets (62%) produced strong PCR products, of which 14 were polymorphic. In an analysis of 60 individuals from two R. pulchra populations, the number of alleles per locus ranged from 1–10, and the mean allelic richness was 4.7. No linkage disequilibrium was found between any pair of loci, indicating that the markers were independent. The Hardy–Weinberg equilibrium test showed significant deviation in two of the 28 single-loci after sequential Bonferroni’s correction. Using 11 primer sets, cross-species amplification was demonstrated in nine related species from four families within two classes. Among the 11 loci amplified from three other Rajidae family species; three loci were polymorphic. A monomorphic locus was amplified in all three Rajidae family species and the Dasyatidae family. Two Rajidae polymorphic loci amplified monomorphic target DNAs in four species belonging to the Carcharhiniformes class, and another was polymorphic in two Carcharhiniformes species. PMID:22837688

  8. Genomes and Virulence Factors of Novel Bacterial Pathogens Causing Bleaching Disease in the Marine Red Alga Delisea pulchra

    PubMed Central

    Fernandes, Neil; Case, Rebecca J.; Longford, Sharon R.; Seyedsayamdost, Mohammad R.; Steinberg, Peter D.; Kjelleberg, Staffan; Thomas, Torsten

    2011-01-01

    Nautella sp. R11, a member of the marine Roseobacter clade, causes a bleaching disease in the temperate-marine red macroalga, Delisea pulchra. To begin to elucidate the molecular mechanisms underpinning the ability of Nautella sp. R11 to colonize, invade and induce bleaching of D. pulchra, we sequenced and analyzed its genome. The genome encodes several factors such as adhesion mechanisms, systems for the transport of algal metabolites, enzymes that confer resistance to oxidative stress, cytolysins, and global regulatory mechanisms that may allow for the switch of Nautella sp. R11 to a pathogenic lifestyle. Many virulence effectors common in phytopathogenic bacteria are also found in the R11 genome, such as the plant hormone indole acetic acid, cellulose fibrils, succinoglycan and nodulation protein L. Comparative genomics with non-pathogenic Roseobacter strains and a newly identified pathogen, Phaeobacter sp. LSS9, revealed a patchy distribution of putative virulence factors in all genomes, but also led to the identification of a quorum sensing (QS) dependent transcriptional regulator that was unique to pathogenic Roseobacter strains. This observation supports the model that a combination of virulence factors and QS-dependent regulatory mechanisms enables indigenous members of the host alga's epiphytic microbial community to switch to a pathogenic lifestyle, especially under environmental conditions when innate host defence mechanisms are compromised. PMID:22162749

  9. Establishing the redox potential of Tibouchina pulchra (Cham.) Cogn., a native tree species from the Atlantic Rain Forest, in the vicinity of an oil refinery in SE Brazil.

    PubMed

    Esposito, Marisia Pannia; Domingos, Marisa

    2014-04-01

    The present study aimed to establish the seasonal variations in the redox potential ranges of young Tibouchina pulchra plants growing in the Cubatão region (SE Brazil) under varying levels of oxidative stress caused by air pollutants. The plants were exposed to filtered air (FA) and non-filtered air (NFA) in open-top chambers installed next to an oil refinery in Cubatão during six exposure periods of 90 days each, which included the winter and summer seasons. After exposure, several analyses were performed, including the foliar concentrations of ascorbic acid and glutathione in its reduced (AsA and GSH), total (totAA and totG) and oxidized forms (DHA and GSSG); their ratios (AsA/totAA and GSH/totG); the enzymatic activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT) and glutathione reductase (GR); and the content of malondialdehyde (MDA). The range of antioxidant responses in T. pulchra plants varied seasonally and was stimulated by high or low air pollutant concentrations and/or air temperatures. Glutathione and APX were primarily responsible for increasing plant tolerance to oxidative stress originating from air pollution in the region. The high or low air temperatures mainly affected enzymatic activity. The content of MDA increased in response to increasing ozone concentration, thus indicating that the pro-oxidant/antioxidant balance may not have been reached. PMID:24407781

  10. The redifferentiation of nutritive cells in galls induced by Lepidoptera on Tibouchina pulchra (Cham.) Cogn. reveals predefined patterns of plant development.

    PubMed

    Vecchi, Claudia; Menezes, Nanuza Luiza; Oliveira, Denis Coelho; Ferreira, Bruno Garcia; Isaias, Rosy Mary Santos

    2013-12-01

    Insect galls may present nutritive tissues with distinct cytological features related to the order of the gall inducer. Galling Lepidoptera larvae chew plant cells and induce the redifferentiation of parenchymatic cells into nutritive ones. The nutritive cells in the galls induced by a microlepidoptera on the leaves of Tibouchina pulchra (Cham.) Cogn. (Melastomataceae) are organelle-rich, with developed Golgi apparatus, endoplasmic reticulum, ribosomes, polyribosomes, mitochondria, plastids, and one great central or several fragmented vacuoles. The nonobservance of the nuclei in the nutritive cells deserves special attention, and confers a similarity between the nutritive cells and the vascular conductive ones. The great amount of rough endoplasmic reticulum, ribosomes, polyribosomes, and mitochondria is indicative of the high metabolic status of these cells. They are vascular cambium-like, with high protein synthesis and lipid storage. The proteins are essential to enzymatic metabolism, and secondarily, to larvae nutrition, similarly to the lipid droplets which confer energetic profile to these nutritive cells. The living enucleated cells receive mRNA from their neighbor ones, which may support the high metabolic profile of endoplasmic reticulum and ribosomes observed in galls. Thus, the nutritive cells are stimulated by the galling larvae activity, generating a new cell type, whose redifferentiation includes a mix of intrinsic and common plant pathways. PMID:23779213

  11. Physiological responses of the tropical tree Tibouchina pulchra Cogn under the influence of combustion of crude oil and natural gas at an oil refinery.

    PubMed

    Silva, Daiane T; Moraes, Regina M

    2013-04-01

    A refinery located on the slopes of a mountain range in the city of Cubatão (SE-Brazil) is the main source of sulfur dioxide (SO(2)) in the region. For this reason, the refinery replaced a system in which energy was produced from crude oil combustion in boilers with a system of energy and vapor co-generation in a thermoelectric power plant fueled by natural gas. The aim of this study was to investigate the responses of Tibouchina pulchra to the fuel switching. Saplings planted in pots were distributed throughout monitoring sites around the polluting source (sites I, II, III and IV) and in a site (V) far from emissions. Changes on the plants responses occur along the three fuel switching phases. During the last phase, increased carbon assimilation (Asat) and decreased stomatal conductance (gs) were observed in plants growing in sites II and III; as a consequence, intrinsic water use efficiency (iWUE) increased. However, the increase in Asat did not promote growth increase suggesting that changes at the refinery did not result in better air quality, but only in a change in the main contaminants. PMID:23352657

  12. Determination of five flavonoids in different parts of Fordia cauliflora by ultra performance liquid chromatography/triple-quadrupole mass spectrometry and chemical comparison with the root of Millettia pulchra var. laxior

    PubMed Central

    2013-01-01

    Background The root of Fordia cauliflora Hemsl (FC) has long been used in southern China for the treatment of rheumatism, bruises, dementia in children, and valetudinarianism. However, sometimes it is mixed with other parts. And it has always been confused with the root of Millettia pulchra (Benth.) Kurz var. laxior (Dunn) Z. Wei (MP) by the local people. The chemical differences between the two ethnic drugs are not clear until now. The aim of this study is to develop a precise and accurate method to characterize and quantify multiple chemical components of FC, which is helpful for the quality evaluation and identification of FC. Results A method coupling ultra performance liquid chromatography (UPLC) with triple-quadrupole mass spectrometry (QqQ-MS) was first developed for simultaneous determination of five flavonoids in different parts of FC and the root of MP, based on a UPLC-diode array detection (DAD) fingerprint method. All calibration curves showed good linearity (R2>0.99) within test ranges. The overall LOD and LOQ were lower than 2.5 ng/mL and 5.0 ng/mL, respectively. The RSDs for intra- and inter-day of five analytes were less than 2.83% and 3.04%, respectively. Recovery studies for the quantified compounds were found to be within the range 93.6-99.8% with RSD less than 5.73%. The results suggest that the root, traditionally used medicinal part, yields the highest flavanoid content in FC. Pachycarin A, 3?,4?-dimethoxy(2??,3??:7,8) furanoflavone, karanjachromene and isoderricin A can be used to differentiate between FC and MP samples. Conclusions The present method is specific, precise and reliable, and is suitable for characterizing and quantifying multiple chemical components of FC. PMID:23870070

  13. Body colors and algal distribution in the acoel flatworm Convolutriloba longifissura: histology and ultrastructure.

    PubMed

    Hirose, Euichi; Hirose, Mamiko

    2007-12-01

    Convolutriloba longifissura is a red flatworm with white dots that harbors unicellular green algae within its body. The red pigment of the flatworm that is present in round cells is soluble in ethanol or acetone, whereas the white pigment contained in the crystalline (retractile) platelets of amoeboid-shaped cells is soluble in 1% NH4OH. These two types of pigment cells form the body coloration and are probably involved in light protection of the algal symbionts, as many algal cells are distributed beneath the body wall and some are in the highly vacuolated parenchyma. The ultrastructural features of these cells suggest a close relationship with Tetraselmis spp. The morphology of sagittocysts within the mantle is also described by means of scanning and transmission electron microscopy. PMID:18271640

  14. Nassella pulchra Survival and Water Relations Depend More on Site Productivity Than on

    E-print Network

    Fehmi, Jeffrey S.

    from fifteen 900-cm2 clipped quadrats on each site in May 1998. Taeni- atherum caput-medusae and Bromus hordeaceus domi- nated the selected low productivity site (2,423 kg/ha). Taeniatherum caput-medusae dominated

  15. The effects of oxalates produced by Salsola tragus on the phosphorus nutrition of Stipa pulchra

    Microsoft Academic Search

    J. P. Cannon; E. B. Allen; M. F. Allen; L. M. Dudley; J. J. Jurinak

    1995-01-01

    Oxalic acid is produced by some species of plants and mycorrhizal fungi and it may solubilize unavailable soil phosphorus (P) bound by cations (Ca++, Al++, Fe+++). Field and greenhouse experiments were conducted to show whether oxalate produced by the annual Salsola tragus or added oxalic acid would solubilize P from the inorganic-bound soil P pool, making it available for uptake

  16. Mating systems and interfertility of swamp milkweed (Asclepias incarnata ssp. incarnata and ssp. pulchra)

    Microsoft Academic Search

    CHRISTOPHER T. IVEY; SARA R. LIPOW; Robert Wyatt

    1999-01-01

    We investigated the breeding system and interfertility of both subspecies of Asclepias incarnata. We performed hand-pollinations in the glasshouse to compare fruit-set from self- vs. cross-pollinations and to assess interfertility in crosses between the subspecies. We also used horizontal starch-gel electrophoresis to infer mating-system parameters from open-pollinated progeny arrays in three natural populations over two consecutive years. Plants of ssp.

  17. Ecological Applications, 00(0), 0000, pp. 000000 0000 by the Ecological Society of America

    E-print Network

    Rice, Kevin

    the impact of an invasive thistle (Centaurea solstitialis) on a native perennial bunchgrass (Nassella pulchra. solstitialis performance and ameliorated its negative effect on N. pulchra growth and reproduction. Higher water availability resulted in a stronger negative effect of C. solstitialis on N. pulchra in both

  18. California Department of Transportation New Technology and Research Program

    E-print Network

    Brown, Cynthia S.

    of four perennial grasses native to California (Elymus glaucus, Hordeum brachyantherum ssp. brachyantherum, Hordeum brachyantherum ssp. californicum and Nassella pulchra). Soil decompaction generally benefited

  19. Radial Dispersion of Neighbors and the Small-Scale Competitive Impact of Two Annual Grasses on a Native Perennial Grass

    Microsoft Academic Search

    Jeffrey S. Fehmi; Kevin J. Rice; Emilio A. Laca

    2004-01-01

    In California's Mediterranean type grasslands, native perennial grasses such as Nassella pulchra are surrounded by introduced annual species and these annuals are thought to have displaced natives through much of their range. Amongst other invaders, two grasses Lolium multiflorum and Bromus hordeaceus, commonly dominate portions of the grassland with potential for N. pulchra restoration. We hypothesized that competitor species differences

  20. Epidemiology of Powedery Mildew on Flowering Dogwood in Tennessee

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Powdery mildew, caused by Erysiphe pulchra (syn. Microsphaera pulchra) is an important disease on flowering dogwood (Cornus florida) in the Eastern United States. Temporal progress of powdery mildew on flowering dogwood cultivars with different levels of resistance was investigated in the field in 2...

  1. Back in time: a new systematic proposal for the Bilateria

    Microsoft Academic Search

    Pere Martinez; Jordi Paps; Marta Riutort

    2009-01-01

    Conventional wisdom suggests that bilateral organisms arose from ancestors that were radially, rather than bilaterally, symmetrical and, therefore, had a single body axis and no mesoderm. The two main hypotheses on how this transformation took place consider either a simple organism akin to the planula larva of extant cnidarians or the acoel Platyhelminthes (planuloid-acoeloid theory), or a rather complex organism

  2. AQUATIC BIOLOGY Vol. 14: 277281, 2012

    E-print Network

    Benayahu, Yehuda

    exclu- sively marine worms (Hooge & Tyler 2005). They are a morphologically varied group of soft-bodied worms (Hooge et al. 2002) lacking a gut cavity and pro- tonephridia (Tyler 2003). Acoels have been spe- cies that are epibenthic, epiphytic (Hooge & Tyler 2006) and epizoic on live coral colonies

  3. Neo-Latin News

    E-print Network

    Kallendorf, Craig, et al.

    2007-01-01

    religiosum): Carmina Nasonis laudas cultumque Tibullum Lucanusque tibi Vergiliusque placent. Sed mallem Davidis cantus psalmique placerent et Salomoniacae Musa pudica lyrae. Non bene nempe tuo concordat Naso cucullo detonsumque odit pulchra Corinna caput...

  4. UNCORRECTED 2 Arbuscular mycorrhizal assemblages in native plant roots change

    E-print Network

    Bruns, Tom

    of invasion by Bromus tectorum into long-term plots dominated by either of two native 21 grasses, Hilaria plant communities composed of exotic (Avena barbata, Bromus hordeaceus) and 19 native (Nassella pulchra

  5. Variation in resource availability changes the impact of invasive thistles on native bunchgrasses.

    PubMed

    Morghan, Kimberly J Reever; Rice, Kevin J

    2006-04-01

    The threat posed by invasive nonnative plants to native plant populations is one of the largest challenges facing both conservation biology and restoration ecology. California has been highly impacted by invaders, although many relict stands of native plants are found on shallow, rocky soils with limited resources. The abiotic conditions of these sites may strongly influence the performance of an invasive plant and its effect on resident native species. In addition, the maturity of native plants in these sites may modulate an invader's impact; larger, well-established plants may be better able to resist invaders. In this study we examined how the impact of an invasive thistle (Centaurea solstitialis) on a native perennial bunchgrass (Nassella pulchra) changed in response to variation in soil depth, soil water availability, and bunchgrass maturity. We measured plant performance in terms of survival, growth, reproduction, and predawn water potential. We found that soil depth, water availability, and bunchgrass maturity acted in concert to influence the impact of the invasive thistle on the native bunchgrass. Both species performed better in deep soils, especially during dry years. The combination of shallow soil and low water availability reduced C. solstitialis performance and ameliorated its negative effect on N. pulchra growth and reproduction. Higher water availability resulted in a stronger negative effect of C. solstitialis on N. pulchra in both shallow and deep soils. However, as N. pulchra matured and increased in size, we saw a steady decline in C. solstitialis growth and reproductive output. Higher water availability increased the performance of C. solstitialis in shallow soils. C. solstitialis may thus have a stronger impact on N. pulchra and be more able to invade relict stands of N. pulchra in shallow soils during high-rainfall years. However, established stands of N. pulchra appear to be more resistant to invasion by C. solstitialis as N. pulchra plants grow older and larger. PMID:16711042

  6. Coexistence and interference between a native perennial grass and non-native annual grasses in California

    Microsoft Academic Search

    Jason G. Hamilton; Claus Holzapfel; Bruce E. Mahall

    1999-01-01

    Little is known about the potential for coexistence between native and non-native plants after large-scale biological invasions.\\u000a Using the example of native perennial bunchgrasses and non-native annual grasses in California grasslands, we sought to determine\\u000a the effects of interference from non-native grasses on the different life stages of the native perennial bunchgrass Nassella pulchra. Further, we asked whether N. pulchra

  7. Determination of total sulfur in lichens and plants by combustion-infrared analysis. [Medicago sativa L. ; Vitis labruscana Bailey; Festuca sp. ; Fraxinum pennsylvanica Marsh. ; Paremelia chlorochroa Tuck. ; P. sulcata Tayl. ; Juniperus scopulorum Sarg. ; Artemisia tridentata Nuttl; Lycopersicum esculentum Mill. ; Triticum compactum Host; Agropyron smithii Rydb. ; Salix pulchra Cham

    SciTech Connect

    Jackson, L.L.; Engleman, E.E.; Peard, J.L.

    1985-01-01

    Sulfur was determined in plants and lichens by combustion of the sample and infrared detection of evolved sulfur dioxide using an automated sulfur analyzer. Vanadium pentaoxide was used as a combustion accelerator. Pelletization of the sample prior to combustion was not found to be advantageous. Washing studies showed that leaching of sulfur was not a major factor in the sample preparation. The combustion-IR analysis usually gave higher sulfur content than the turbidimetric analysis as well as shorter analysis time. Relative standard deviations of less than 7% were obtained by the combustion-IR technique when sulfur levels in plant material range from 0.05 to 0.70%. Determination of sulfur in National Bureau of Standards botanical reference materials showed good agreement between the combustion-IR technique and other instrumental procedures. Seven NBS botanical reference materials were analyzed.

  8. The Acoela: on their kind and kinships, especially with nemertodermatids and xenoturbellids (Bilateria incertae sedis).

    PubMed

    Achatz, Johannes G; Chiodin, Marta; Salvenmoser, Willi; Tyler, Seth; Martinez, Pedro

    2013-06-01

    Acoels are among the simplest worms and therefore have often been pivotal in discussions of the origin of the Bilateria. Initially thought primitive because of their "planula-like" morphology, including their lumenless digestive system, they were subsequently dismissed by many morphologists as a specialized clade of the Platyhelminthes. However, since molecular phylogenies placed them outside the Platyhelminthes and outside all other phyla at the base of the Bilateria, they became the focus of renewed debate and research. We review what is currently known of acoels, including information regarding their morphology, development, systematics, and phylogenetic relationships, and put some of these topics in a historical perspective to show how the application of new methods contributed to the progress in understanding these animals. Taking all available data into consideration, clear-cut conclusions cannot be made; however, in our view it becomes successively clearer that acoelomorphs are a "basal" but "divergent" branch of the Bilateria. PMID:24098090

  9. Impact assessment of an invasive flatworm, Convoluta convoluta, in the Southern Gulf of Maine

    Microsoft Academic Search

    Jarrett Byrnes; Jon D. Witman

    2003-01-01

    Convoluta convoluta (Abildgaard 1806) is a small (2–3 mm long) acoellous turbellarian flatworm from Europe that has invaded the Gulf of Maine within the last 5 years. Although it has been reported in densities of up to 19 individuals\\/cm2, its ecological impact remains unknown. In its native habitat, it consumes harpacticoid copepods and primary settling mussels <0.5-mm shell length. This

  10. Induction of settlement of larvae of the sea urchin Holopneustes purpurascens by histamine from a host alga.

    PubMed

    Swanson, Rebecca L; Williamson, Jane E; de Nys, Rocky; Kumar, Naresh; Bucknall, Martin P; Steinberg, Peter D

    2004-06-01

    Larvae of the Australian sea urchin Holopneustes purpurascens are induced to settle and metamorphose (termed settlement herein) by a water-soluble compound produced by the red alga Delisea pulchra, the main host plant of new recruits. The settlement cue for H. purpurascens had previously been identified as a floridoside-isethionic acid complex, and this paper presents new evidence correcting that finding. The actual settlement cue produced by D. pulchra was isolated from the polar extract by cation-exchange chromatography and identified as histamine, using one- and two-dimensional nuclear magnetic resonance spectrometry. The chemical identity of the cue was confirmed by gas chromatography-mass spectrometry (GC-MS) and matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry. Synthetic histamine and histamine at 4.5 microM isolated from D. pulchra both induced rapid settlement in 80%-100% of the larvae of H. purpurascens. Lower concentrations of histamine (0.9-2.3 micro M) induced larval settlement, but this response varied from 0%-90%. The histamine content of two host plants of H. purpurascens--D. pulchra and Ecklonia radiata--and of four other common species was quantified using GC-MS. D. pulchra had the highest histamine content, which is consistent with H. purpurascens recruiting to this species. Histamine was also detected in the seawater surrounding these host algae. This is the first time that a settlement cue has been quantified in the habitat of a marine organism. PMID:15198942

  11. Environmental Microbiology (2001) 3(11), 731736 Brief report

    E-print Network

    Wood, Thomas K.

    2001-01-01

    -sensing disrupter (5Z)-4-bromo-5-(bro- momethylene)-3-butyl-2(5H)-furanone (furanone) of the alga Delisea pulchra by 55%, reduced the number of water channels and decreased the percentage of live cells by 87 recognize the appro- priate environmental signals, they differentiate into swarming cells (which

  12. Differential Gene Expression Shows Natural Brominated Furanones Interfere With the

    E-print Network

    Wood, Thomas K.

    disrupter (5Z)-4-bromo- 5-(bromomethylene)-3-butyl-2(5H)-furanone (furanone) of the alga Delisea pulchra. Thomas,2 Thomas K. Wood1 1 Departments of Chemical Engineering and Molecular & Cell Biology, University increases with cell density, the binding of AIs to the cellular receptors will trigger downstream genes

  13. Mortality of exotic and native seeds in invaded and uninvaded habitats

    Microsoft Academic Search

    John L. Orrock; Jessica L. Hoisington-López

    2009-01-01

    We examined seed survival in exotic- and native-dominated grasslands by placing seeds of a once-pervasive native grass species, Nassella pulchra, and two of the most common, widespread exotic grass species, Avena fatua and Bromus hordeaceus, in mesh bags in the field for 3 months. Compared to germination of unexposed seeds not placed in the field, exotic species experienced an approximately

  14. Morphological and Physiological Response of Five California Native Grass Species to Moderate Salt Spray: Implications for Landscape Irrigation with Reclaimed Water

    Microsoft Academic Search

    Kimberley A. M. Hunter; Lin Wu

    2005-01-01

    Five California native perennial grass species including Melica californica (California melic), Nasella pulchra (purple needlegrass), Sporobolus airoides (alkali sacaton), Muhlenbergia rigens (deergrass), and Deschampsia caespitosa (California hairgrass) were examined for their response to salt spray. Vegetatively propagated plants were sprinkler irrigated with deionized water, 500 mg L and 1500 mg L sodium chloride (NaCl) under greenhouse conditions for 20 weeks.

  15. Apparent competition with an exotic plant reduces native plant establishment.

    PubMed

    Orrock, John L; Witter, Martha S; Reichman, O J

    2008-04-01

    Biological invasions can change ecosystem function, have tremendous economic costs, and impact human health; understanding the forces that cause and maintain biological invasions is thus of immediate importance. A mechanism by which exotic plants might displace native plants is by increasing the pressure of native consumers on native plants, a form of indirect interaction termed "apparent competition." Using experimental exclosures, seed addition, and monitoring of small mammals in a California grassland, we examined whether exotic Brassica nigra increases the pressure of native consumers on a native bunchgrass, Nassella pulchra. Experimental plots were weeded to focus entirely on indirect effects via consumers. We demonstrate that B. nigra alters the activity of native small-mammal consumers, creating a gradient of consumption that dramatically reduces N. pulchra establishment. Previous work has shown that N. pulchra is a strong competitor, but that it is heavily seed limited. By demonstrating that consumer pressure is sufficient to curtail establishment, our work provides a mechanism for this seed limitation and suggests that, despite being a good competitor, N. pulchra cannot reestablish close to B. nigra within its old habitats because exotic-mediated consumption preempts direct competitive exclusion. Moreover, we find that apparent competition has a spatial extent, suggesting that consumers may dictate the rate of invasion and the area available for restoration, and that nonspatial studies of apparent competition may miss important dynamics. PMID:18481540

  16. Ecology, 89(4), 2008, pp. 11681174 2008 by the Ecological Society of America

    E-print Network

    Orrock, John

    , and monitoring of small mammals in a California grassland, we examined whether exotic Brassica nigra increases invasion; Brassica nigra; California (USA) grassland; consumers; granivory; herbivory; Nassella pulchra to focus entirely on indirect effects via consumers. We demonstrate that B. nigra alters the activity

  17. Radial Dispersion of Neighbors and the Small-Scale Competitive Impact of Two Annual Grasses on a

    E-print Network

    Rice, Kevin

    . Amongst other invaders, two grasses Lolium multiflorum and Bromus hordeaceus, commonly dominate portions on these sites. Lolium multiflorum and B. hordeaceus were planted in 20 cm diameter circular plots at a constant. The presence of L. multiflorum was associated with a decrease in N. pulchra survival compared with plots

  18. Compensatory growth and competitive ability of an invasive weed are enhanced by soil fungi and native neighbours

    Microsoft Academic Search

    Ragan M. Callaway; Beth Newingham; Cathy A. Zabinski; Bruce E. Mahall

    2001-01-01

    Compensatory responses to herbivory by invasive weeds may foil attempts to arrest their spread with biological controls. We conducted an experiment to study the effects of defoliation and soil fungi on interactions between Centaurea melitensis, an invasive annual from Eurasia, and Nassella pulchra, a native Californian bunchgrass. Defoliation of C. melitensis reduced its final biomass in all species-fungicide treatments, except

  19. SOIL FUNGI AND THE EFFECTS OF AN INVASIVE FORB ON GRASSES: NEIGHBOR IDENTITY MATTERS

    Microsoft Academic Search

    Ragan M. Callaway; Bruce E. Mahall; Chris Wicks; Joel Pankey; Catherine Zabinski

    2003-01-01

    We studied the effects of soil fungi on interactions between Centaurea mel- itensis, an exotic invasive weed in central California, and two co-occurring grasses, Nassella pulchra and Avena barbata. The fungicide benomyl reduced the abundance of arbuscular mycorrhizal (AM) fungi in plant roots but did not affect non-AM fungi. Centaurea plants grown alone were .50% smaller with the resident microbial

  20. DEVELOPMENT OF POWDERY MILDEW ON RESISTANT AND SUSCEPTIBLE DOGWOOD CULTIVARS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Differences in resistance to powdery mildew were observed on detached leaf disks of six flowering dogwood lines inoculated with conidia of Erysiphe pulchra. Significant differences (P < 0.02) in germinated conidia with branched hyphae, infection efficiency, latent period and sporulation were detect...

  1. Results of Surveys for Special Status Reptiles at the Site 300 Facilities of Lawrence Livermore National Laboratory

    SciTech Connect

    Woollett, J J

    2008-09-18

    The purpose of this report is to present the results of a live-trapping and visual surveys for special status reptiles at the Site 300 Facilities of Lawrence Livermore National Laboratory (LLNL). The survey was conducted under the authority of the Federal recovery permit of Swaim Biological Consulting (PRT-815537) and a Memorandum of Understanding issued from the California Department of Fish and Game. Site 300 is located between Livermore and Tracy just north of Tesla road (Alameda County) and Corral Hollow Road (San Joaquin County) and straddles the Alameda and San Joaquin County line (Figures 1 and 2). It encompasses portions of the USGS 7.5 minute Midway and Tracy quadrangles (Figure 2). Focused surveys were conducted for four special status reptiles including the Alameda whipsnake (Masticophis lateralis euryxanthus), the San Joaquin Whipsnake (Masticophis Hagellum ruddock), the silvery legless lizard (Anniella pulchra pulchra), and the California horned lizard (Phrynosoma coronanum frontale).

  2. A CARD-FISH protocol for the identification and enumeration of epiphytic bacteria on marine algae.

    PubMed

    Tujula, Niina A; Holmström, Carola; Mussmann, Marc; Amann, Rudolf; Kjelleberg, Staffan; Crocetti, Gregory R

    2006-06-01

    A CARD-FISH protocol was developed and applied to analyse surface-associated bacteria on the marine algae Ulva lactuca, Delisea pulchra, Corallina officinalis, Amphiroa anceps, Porphyra sp. and Sargassum linearifolium. The combination of Alexa(546)-labelled tyramide as the reporter molecule with SYBR Green II counterstain allowed for superior detection of the hybridised probe fluorescence against plant tissue from which pigment autofluorescence has been reduced. PMID:16216355

  3. Differential physiological responses of two congeneric scleractinian corals to mineral accretion and an electric field

    NASA Astrophysics Data System (ADS)

    Borell, E. M.; Romatzki, S. B. C.; Ferse, S. C. A.

    2010-03-01

    Despite increasing popularity of ‘electric’ reefs as a means for reef restoration, there is a distinct lack of quantitative evidence supporting the alleged benefits of this method. This study investigated the effects of an electric field versus an electric field in combination with a cathode on coral growth (skeletal extension) rates, coral survival, zooxanthella densities, chlorophyll a (chl a) concentrations, and chlorophyll fluorescence of Acropora pulchra and A. yongei. Coral transplants were grown for 4 months under three treatment conditions: (1) on an iron cathode, (2) on bamboo inside an electric field, or (3) on bamboo in the absence of an electric field. Contrary to predictions, coral growth rates of both species were highest inside the electric field and not on the cathode. Except for chl a concentrations, the cathode had a significant adverse effect on all measured variables for A. yongei but not for A. pulchra. Treatment had no effect on the survival of A. pulchra, while mortality rates of A. yongei were significantly higher in the presence of mineral accretion compared to the electric field and control. A. yongei on the cathode featured low zooxanthella densities, depressed electron transport rates (rETR) and maximum quantum yield ( F v/ F m), and reduced growth. By contrast, treatment had no effect on the fluorescence characteristics of A. pulchra, and zooxanthella densities were highest for corals on the cathode, coincident with high growth rates relative to the control. Overall, the data indicate that the proposed benefits of the mineral accretion technology to meet important objectives of reef rehabilitation with regard to colony growth and survival should be considered with caution.

  4. Compensatory growth and competitive ability of an invasive weed are enhanced by soil fungi and native neighbours

    Microsoft Academic Search

    Ragan M. Callaway; A Cathy; Bruce E. Mahall; Evolutionary Biology; Montana State

    Abstract Compensatory,responses to herbivory by invasive weeds may foil attempts to arrest their spread with biological controls. We conducted,an experiment,to study the effects of defoliation and soil fungi on interactions between Centaurea melitensis, an invasive annual from Eurasia, and Nassella pulchra, a native Californian bunchgrass. Defoliation of C. melitensis reduced its final biomass in all species?fungicide treatments, except when C.

  5. Capture and allocation of nitrogen by Quercus douglasii seedlings in competition with annual and perennial grasses

    Microsoft Academic Search

    J. M. Welker; D. R. Gordon; K. J. Rice

    1991-01-01

    Summary  The spatial overlap of woody plant root systems and that of annual or perennial grasses promotes competition for soil-derived\\u000a resources. In this study we examined competition for soil nitrogen between blue oak seedlings and either the annual grassBromus mollis or the perennial grassStipa pulchra under controlled outdoor conditions. Short-term nitrogen competition was quantified by injecting15N at 30 cm depth in

  6. Karyotype and DNA-content evolution in ten species of Crepis (Asteraceae) distributed in Bulgaria

    Microsoft Academic Search

    DESSISLAVA DIMITROVA; JOHANN GREILHUBER

    2000-01-01

    Ten Crepis species from Bulgaria—five perennials (C. viscidula, C. paludosa, C. conyzaefolia, C. bithynica, C. schachtii), four annuals (C. pulchra, C. sancta, C. setosa, C. zacintha) and one biennial (C. biennis)—were analysed karyologically using haematoxylin staining, Feulgen cytophotometry (scanning densitometry and video-based image analysis), and DNA flow cytometry with propidium iodide. All taxa but the biennial are diploids with descending

  7. High resistance of Acropora coral gametes facing copper exposure.

    PubMed

    Puisay, Antoine; Pilon, Rosanne; Hédouin, Laetitia

    2015-02-01

    Pollution by heavy metals remains today an important threat to the health of humans and ecosystems, but there is still a paucity of data on the response of early life stages of key organisms. In this context, the present work assessed the fertilization success rate of two Acropora species (A. cytherea and A. pulchra) from the French Polynesia reefs exposed to six increasing copper concentrations in seawater. The two species showed a relatively high tolerance to copper (4h30-EC50 was 69.4 ± 4.8 ?g L(-1) and 75.4 ± 6.4 ?g L(-1) for A. cytherea and A. pulchra, respectively). As Cu concentration increases, an increasing proportion of deformed embryos was recorded (67.6% and 58.5% for A. cytherea and A. pulchra, respectively, at 220 ?g Cu L(-1)). These results demonstrated thus, that high levels of copper could negatively impair the normal fertilization process of coral gametes and therefore alter the renewal of coral populations. Since the two Acropora species investigated in this study displayed a high resistance to copper, these results should be considered in the context of multiple stressors associated with climate change, where rising temperature or ocean acidification may significantly exacerbate copper toxicity. PMID:25462298

  8. Myogenesis in the basal bilaterian Symsagittifera roscoffensis (Acoela)

    PubMed Central

    Semmler, Henrike; Bailly, Xavier; Wanninger, Andreas

    2008-01-01

    Background In order to increase the weak database concerning the organogenesis of Acoela – a clade regarded by many as the earliest extant offshoot of Bilateria and thus of particular interest for studies concerning the evolution of animal bodyplans – we analyzed the development of the musculature of Symsagittifera roscoffensis using F-actin labelling, confocal laserscanning microscopy, and 3D reconstruction software. Results At 40% of development between egg deposition and hatching short subepidermal fibres form. Muscle fibre development in the anterior body half precedes myogenesis in the posterior half. At 42% of development a grid of outer circular and inner longitudinal muscles is present in the bodywall. New circular muscles either branch off from present fibres or form adjacent to existing ones. The number of circular muscles is higher than that of the longitudinal muscles throughout all life cycle stages. Diagonal, circular and longitudinal muscles are initially rare but their number increases with time. The ventral side bears U-shaped muscles around the mouth, which in addition is surrounded by a sphincter muscle. With the exception of the region of the statocyst, dorsoventral muscles are present along the entire body of juveniles and adults, while adults additionally exhibit radially oriented internal muscles in the anterior tip. Outer diagonal muscles are present at the dorsal anterior tip of the adult. In adult animals, the male gonopore with its associated sexual organs expresses distinct muscles. No specific statocyst muscles were found. The muscle mantles of the needle-shaped sagittocysts are situated along the lateral edges of the animal and in the posterior end close to the male gonopore. In both juveniles and adults, non-muscular filaments, which stain positively for F-actin, are associated with certain sensory cells outside the bodywall musculature. Conclusion Compared to the myoanatomy of other acoel taxa, Symsagittifera roscoffensis shows a very complex musculature. Although data on presumably basal acoel clades are still scarce, the information currently available suggests an elaborated musculature with longitudinal, circular and U-shaped muscles as being part of the ancestral acoel bodyplan, thus increasing the possibility that Urbilateria likewise had a relatively complicated muscular ground pattern. PMID:18803837

  9. Competition and soil resource environment alter plant–soil feedbacks for native and exotic grasses

    PubMed Central

    Larios, Loralee; Suding, Katharine N.

    2015-01-01

    Feedbacks between plants and soil biota are increasingly identified as key determinants of species abundance patterns within plant communities. However, our understanding of how plant–soil feedbacks (PSFs) may contribute to invasions is limited by our understanding of how feedbacks may shift in the light of other ecological processes. Here we assess how the strength of PSFs may shift as soil microbial communities change along a gradient of soil nitrogen (N) availability and how these dynamics may be further altered by the presence of a competitor. We conducted a greenhouse experiment where we grew native Stipa pulchra and exotic Avena fatua, alone and in competition, in soils inoculated with conspecific and heterospecific soil microbial communities conditioned in low, ambient and high N environments. Stipa pulchra decreased in heterospecific soil and in the presence of a competitor, while the performance of the exotic A. fatua shifted with soil microbial communities from altered N environments. Moreover, competition and soil microbial communities from the high N environment eliminated the positive PSFs of Stipa. Our results highlight the importance of examining how individual PSFs may interact in a broader community context and contribute to the establishment, spread and dominance of invaders. PMID:25425557

  10. Revision of Siobla (Hymenoptera, Tenthredinidae) from Japan.

    PubMed

    Shinohara, Akihiko; Wei, Meicai; Niu, Gengyun

    2013-01-01

    The Japanese species of the sawfly genus Siobla Cameron, 1877, are revised and keyed. The following nine species are recognized: S. apicalis Takeuchi, 1929, S. ferox (Smith, 1874), S. hirasana Takeuchi, 1929, S. jucunda (Mocsáry, 1909), S. metallica Takeuchi, 1929, S. sturmii (Klug, 1817), S. japonica, sp. nov., S. pulchra, sp. nov., and S. takeuchii, sp. nov.  Siobla pacifica (Smith, 1874) is synonymized with S. sturmii. Lectotypes are designated for Macrophya ferox Smith, 1874, Macrophya pacifica Smith, 1874, Encarsioneura jucunda Mocsáry, 1909, and Siobla grandis Matsumura, 1912. Previous records of S. ruficornis (Gimmerthal, 1834) and S. villosa Malaise, 1931, from Japan have been found erroneous. Siobla jucunda is newly recorded from Japan.  PMID:25113467

  11. Checklist and Simple Identification Key for Frogs and Toads from District IV of The MADA Scheme, Kedah, Malaysia

    PubMed Central

    Jaafar, Ibrahim; Chai, Teoh Chia; Sah, Shahrul Anuar Mohd; Akil, Mohd Abdul Muin Md.

    2009-01-01

    A survey was conducted to catalogue the diversity of anurans in District IV of the Muda Agriculture Development Authority Scheme (MADA) in Kedah Darul Aman, Malaysia, from July 1996 to January 1997. Eight species of anurans from three families were present in the study area. Of these, the Common Grass Frog (Fejevarya limnocharis) was the most abundant, followed by Mangrove Frog (Fejevarya cancrivora), Long-legged Frog (Hylarana macrodactyla), and Common Toad (Duttaphrynus melanostictus). Puddle Frog (Occidozyga lima), Taiwanese Giant Frog (Hoplobatrachus rugulosus), and Banded Bullfrog (Kaluola pulchra) were rare during the sampling period, and only one Paddy Frog (Hylarana erythraea) was captured. A simple identification key for the anurans of this area is included for use by scientists and laymen alike. PMID:24575178

  12. Ethnobotanical study of some Ghanaian anti-malarial plants.

    PubMed

    Asase, Alex; Oteng-Yeboah, Alfred A; Odamtten, George T; Simmonds, Monique S J

    2005-06-01

    An ethnobotanical study was conducted in the Wechiau Community Hippopotamus Sanctuary area in Ghana, through interviews and quadrate studies, to investigate the range and abundance of species used in the treatment of malaria. Forty-one species belonging to 17 families were encountered during the study. Of the 17 families studied Leguminosae and Anacardiaceae predominated in terms of number of species used to treat malaria. Eight plant species namely, Afraegle paniculata (Rutaceae), Haematostaphis barteri (Anacardiaceae), Indigo era pulchra (Leguminosae), Monanthotaxis sp. (Annonaceae), Ozoroa insignis (Anacardiaceae), Strychnos innocua (Loganiaceae), Strychnos spinosa (Loganiaceae) and Xeroderris stuhlmannii (Leguminosae) have not previously been documented for the treatment of malaria in Ghana. The results are discussed and recommendations made for future research to support the conservation and sustainable harvesting of the species reported to have medicinal properties. PMID:15894138

  13. Long-term coral community records from Lugger Shoal on the terrigenous inner-shelf of the central Great Barrier Reef, Australia

    NASA Astrophysics Data System (ADS)

    Perry, C. T.; Smithers, S. G.; Johnson, K. G.

    2009-12-01

    Long-term (millennial timescale) records of coral community structure can be developed from the analysis of corals preserved in radiometrically dated reef cores. Here, we present such a record (based on six cores) from Lugger Shoal, a turbid zone, nearshore reef on the inner-shelf of the central Great Barrier Reef. Lugger Shoal initiated growth ~800 cal yBP. It is constructed of large in situ Porites bommies, between which a framework of coral rubble (dominated by Acropora pulchra, Montipora mollis, Galaxea fascicularis and Cyphastrea serailia) has accumulated. Reef accretion occurred under conditions of net long-term fine-grained, terrigenous sediment accumulation, and with a coral community dominated throughout by a consistent, but low diversity, suite of coral taxa. This dataset supports recent suggestions that nearshore coral communities that establish themselves under conditions that are already close to the thresholds for coral survival may be resilient to water quality deteriorations associated with human activities.

  14. Hyposalinity stress compromises the fertilization of gametes more than the survival of coral larvae.

    PubMed

    Hédouin, Laetitia; Pilon, Rosanne; Puisay, Antoine

    2015-03-01

    The life cycle of coral is affected by natural and anthropogenic perturbations occurring in the marine environment. In the context of global changes, it is likely that rainfall events will be more intense and that coastal reefs will be exposed to sudden drops in salinity. Therefore, a better understanding of how corals-especially during the pelagic life stages-are able to deal with declines in salinity is crucial. To fill this knowledge gap, this work investigated how gametes and larva stages of two species of Acropora (Acropora cytherea and Acropora pulchra) from French Polynesia cope with drops in salinity. An analysis of collected results highlights that both Acropora coral gametes displayed the same resistance to salinity changes, with 4h30-ES50 (effective salinity that decrease by 50% the fertilization success after 4h30 exposure) of 26.6 ± 0.1 and 27.5 ± 0.3‰ for A. cytherea and A. pulchra, respectively. This study also revealed that coral gametes were more sensitive to decreases in salinity than larvae, for which significant changes are only observed at 26‰ for A. cytherea after 14 d of exposure. Although rising seawater temperatures and ocean acidification are often perceived as the main threat for the survival of coral reefs, our work indicates that 70% of the gametes could be killed during a single night of spawning by a rainfall event that decreases salinity to 26‰. This suggests that changes in the frequency and intensity of rainfall events associated with climate changes should be taken seriously in efforts to both preserve coral gametes and ensure the persistence and renewal of coral populations. PMID:25562765

  15. Spatial polychaeta habitat potential mapping using probabilistic models

    NASA Astrophysics Data System (ADS)

    Choi, Jong-Kuk; Oh, Hyun-Joo; Koo, Bon Joo; Ryu, Joo-Hyung; Lee, Saro

    2011-06-01

    The purpose of this study was to apply probabilistic models to the mapping of the potential polychaeta habitat area in the Hwangdo tidal flat, Korea. Remote sensing techniques were used to construct spatial datasets of ecological environments and field observations were carried out to determine the distribution of macrobenthos. Habitat potential mapping was achieved for two polychaeta species, Prionospio japonica and Prionospio pulchra, and eight control factors relating to the tidal macrobenthos distribution were selected. These included the intertidal digital elevation model (DEM), slope, aspect, tidal exposure duration, distance from tidal channels, tidal channel density, spectral reflectance of the near infrared (NIR) bands and surface sedimentary facies from satellite imagery. The spatial relationships between the polychaeta species and each control factor were calculated using a frequency ratio and weights-of-evidence combined with geographic information system (GIS) data. The species were randomly divided into a training set (70%) to analyze habitat potential using frequency ratio and weights-of-evidence, and a test set (30%) to verify the predicted habitat potential map. The relationships were overlaid to produce a habitat potential map with a polychaeta habitat potential (PHP) index value. These maps were verified by comparing them to surveyed habitat locations such as the verification data set. For the verification results, the frequency ratio model showed prediction accuracies of 77.71% and 74.87% for P. japonica and P. pulchra, respectively, while those for the weights-of-evidence model were 64.05% and 62.95%. Thus, the frequency ratio model provided a more accurate prediction than the weights-of-evidence model. Our data demonstrate that the frequency ratio and weights-of-evidence models based upon GIS analysis are effective for generating habitat potential maps of polychaeta species in a tidal flat. The results of this study can be applied towards conservation and management initiatives for the macrofauna of tidal flats.

  16. Free-Nematodes in the NW Black Sea meiobenthos - diversity, abundance, distribution and importance as indicator of hypoxic waters

    NASA Astrophysics Data System (ADS)

    Muresan, M.; Gomoiu, M.-T.

    2012-04-01

    The aim of this study performed within EU FP7 Hypox Project was to get deeper knowledge about species of nematodes that could be indicators for stressful biotic conditions as low oxygen concentration due to phenomena of seasonal hypoxia. The Nematodes come from meiobenthos sampling (using a multi corer with 4 tubes, Mark II type, lowered into the sea from R/V "Mare Nigrum" board) performed in May and September 2010 and April 2011 along four transects crossing the Romanian continental shelf from where 87 meiobenthos samples were collected. In the studied area 96 species of nematodes were found. The authors analyzed the nematodes populations' distribution on four profiles: Sf. Gheorghe, Portita, Constanta and Mangalia. The qualitative and quantitative structure of nematodes populations was compared. 41 species were found on Mangalia profile, 47 species on Portita profile, 48 species on Constanta profile and 85 species on Sf. Gheorghe profile. The greatest densities were found on Constanta profile with an average of 369.607indvs/m-2. The most frequent and abundant species were: Sabatieria pulchra, Sabatieria abyssalis, Terschellingia longicaudata, Viscosia cobbi, Axonolaimus ponticus. The species assemblages were assessed for depth gradient distribution, 7 depth intervals being set from 20 to 210 m. The greatest diversity was noted in 61-100 m depth interval, while the lowest between 0-20 m. On the contrary, in terms of density of individuals (indvs/m-2), highest densities were obtained in shallow waters between 21-30 m. As far as the depth increases, the species assemblages change, becoming more favorable to species like Halalaimus ponticus, Metachromadora macrouthera, Halanonchus bullatus, Linhomoneidae species. However, on the first place still remained Sabatieria abyssalis. The vertical distribution of nematodes in sediments was analyzed for the surface layer 0-5 cm and sub-surface layer 5-10 cm, the dominant species in both layers being: Sabatieria pulchra, S. abyssalis, Terschellingia longicaudata, Viscosia cobbi, Axonolaimus ponticus, Metalinhomoeus zosterae, Enoplus euxinus, Eleutherolaimus longus. The density decreases in 5-10 cm layer as compared to 0-5 cm layer. Results show that a dominant nematodes community tolerant to eutrophication conditions, organic loading and hypoxic conditions, made up of species of Sabatieria pulchra, Sabatieria abyssalis, Terschellingia longicaudata etc., is spread throughout the whole investigated area, from the shallow waters to the deepest bottoms at the limit of the metazoan life development. Literature confirms the ubiquitous distribution of these species, often found in areas of low O2 concentration. The taxonomic diversity increases with depth, which may suggest that the nematodes in the Black Sea, under unfavorable conditions, may have an adaptive strategy in response to the lack of resources or in the presence of physiological stress factors.

  17. High resolution paleoceanography of the Guaymas Basin, Gulf of California, during the past 15 000 years

    USGS Publications Warehouse

    Barron, J.A.; Bukry, D.; Bischoff, J.L.

    2004-01-01

    Deep Sea Drilling Project Site 480 (27??54.10???N, 111??39.34???W; 655 m water depth) contains a high resolution record of paleoceanographic change of the past 15 000 years for the Guaymas Basin, a region of very high diatom productivity within the central Gulf of California. Analyses of diatoms and silicoflagellates were completed on samples spaced every 40-50 yr, whereas ICP-AES geochemical analyses were completed on alternate samples (sample spacing 80-100 yr). The B??lling-Aller??d interval (14.6-12.9 ka) (note, ka refers to 1000 calendar years BP throughout this report) is characterized by an increase in biogenic silica and a decline in calcium carbonate relative to surrounding intervals, suggesting conditions somewhat similar to those of today. The Younger Dryas event (12.9-11.6 ka) is marked by a major drop in biogenic silica and an increase in calcium carbonate. Increasing relative percentage contributions of Azpeitia nodulifera and Dictyocha perlaevis (a tropical diatom and silicoflagellate, respectively) and reduced numbers of the silicoflagellate Octactis pulchra are supportive of reduced upwelling of nutrient-rich waters. Between 10.6 and 10.0 ka, calcium carbonate and A. nodulifera abruptly decline at DSDP 480, while Roperia tesselata, a diatom indicative of winter upwelling in the modern-day Gulf, increases sharply in numbers. A nearly coincident increase in the silicoflagellate Dictyocha stapedia suggests that waters above DSDP 480 were more similar to the cooler and slightly more saline waters of the northern Gulf during much of the early and middle parts of the Holocene (???10 to 3.2 ka). At about 6.2 ka a stepwise increase in biogenic silica and the reappearance of the tropical diatom A. nodulifera marks a major change in oceanographic conditions in the Gulf. A winter shift to more northwesterly winds may have occurred at this time along with the onset of periodic northward excursions (El Nin??o-driven?) of the North Equatorial Countercurrent during the summer. Beginning between 2.8 and 2.4 ka, the amplitude of biogenic silica and wt% Fe, Al, and Ti (proxies of terrigenous input) increase, possibly reflecting intensification of ENSO cycles and the establishment of modern oceanographic conditions in the Gulf. Increased numbers of O. pulchra after 2.8 ka suggest enhanced spring upwelling. ?? 2003 Elsevier B.V. All rights reserved.

  18. The Influence Of Water Tracks And Hillslope Position On The Physiology Of The Dominant Plant Species In The Imnavait Creek Watershed, Alaska

    NASA Astrophysics Data System (ADS)

    Griffin, K. L.; Epstein, D. J.; Shapiro, J. B.; Boelman, N. T.; Stieglitz, M.

    2003-12-01

    Within a small arctic tundra watershed located on the north slope of Alaska, we asked if plant abundance and physiological performance are linked to hillslope position by the hydrologic processes controlling nutrient availability. Our prediction was that down slope sites and within water track sites should have the greatest nutrient availability resulting in the highest photosynthetic capacity and productivity. To examine these relationships, two transects were established in the Imnavait Creek watershed, running from the northern ridge crest to a beaded stream. In total, 16 sites, one water track (WT) and one non water track (NWT), from 8 locations, each 100 m apart were examined. At each site, soil moisture, thaw depth, canopy water status (from spectral reflectance) and species diversity were recorded. Chlorophyll fluorescence was used assess the maximum capacity of each species to transport electrons within the photosynthetic membranes of individual leaves (ETRMAX), a variable we expect to reflect both leaf N and general photosynthetic capacity. Significant differences were found within and among the major functional groups of plants growing in the watershed. In the two deciduous shrubs, Betula nana and Salix pulchra, ETRMAX generally decreased down slope but no significant difference were found between the WT and NWT sites. By contrast, ETRMAX in Rubus chamaemors, also a deciduous species, showed an initial decrease at the first two locations, but then remained constant further down slope and between WT and NWT sites. In the evergreen plants, Ledum palustre differed in that the maximum ETRMAX was found at the mid-slope locations while Vaccinium vitis-idaea had a characteristic decrease in ETRMAX down slope, with a large difference between WT and NWT at the first location. The forb Petasites frigidus displayed a unique pattern, with large difference in ETRMAX between WT and NWT at sites 4 and 5, the last two locations at which this species could be found. Finally, the only graminoid species studied, Eriophorum vaginatu, ETRMAX decrease down slope in a linear fashion and had the highest absolute ETRMAX. Additionally leaf gas-exchange was measured in Salix pulchra and leaf N and canopy reflectance was measured at each site. Together, our results demonstrate that while hillsope position has a significant effect on the physiology, growth and diversity of species, the relationships were not as hypothesized. Clearly other ecological, morphological or environmental factors are contributing to the productivity of the watershed and ultimately impacting the biogeochemistry of this important ecosystem.

  19. Characterizing Variation of Isotopic Markers in Northern Alaskan Caribou Forages

    NASA Astrophysics Data System (ADS)

    VanSomeren, L.; Barboza, P. S.; Gustine, D. D.; Parrett, L. S.; Stricker, C. A.

    2013-12-01

    Isotopic markers in feces and tissues are a potential tool for monitoring the importance of feeding areas for migratory herbivores such as caribou (Rangifer tarandus). Many of these techniques are currently limited by gaps in our knowledge of how these isotopic signatures vary over the landscape. We collected seven species of preferred caribou forages along a latitudinal gradient in the summer ranges of the Central Arctic (9 sites) and Teshekpuk Lake (4 sites) caribou herds during 2011 and 2012. We analyzed forages at peak protein content and at the end of the season to characterize temporal, species-specific, and spatial variation in isotopic markers. The availability of C and N was measured by digestion in vitro. Isotopic signatures of digested samples were used to calculate fractionation that would bias the isotopic signature of feces. The range of values for isotopes (all values ‰) of nitrogen (?15N -9.5 - +4.3), and sulfur (?34S -3.6 - +15.5) were greater than those for carbon (?13C -30.5 - -24.9). Small declines in forage ?13C with latitude (Carex aquatilis, Eriophorum vaginatum, Salix pulchra, and S. richardsonii [all P < 0.01]), season (all species except C. bigelowii [all P ? 0.01]), and season x year (S. richardsonii; P = 0.01) were probably associated with changes in water availability. Fractionation of ?13C in early season forages was 0.1 × 1.0 and positively related to C availability (58% × 15%; P < 0.01) with the greatest fractionation for the highly digestible forb Pedicularis langsdorfii (1.43 × 0.44; P < 0.01). Sedges (Carex and Eriophorum) were significantly higher in ?15N than Salix spp. and other dicots (2.0 × 1.1 vs. -2.9 × 2.2; P < 0.01). For Salix spp., ?15N was consistent over the season and between years. Fractionation of ?15N in early season forages was 0.2 × 1.8 and not related to N availability (60% × 17%). For S. pulchra, ?34S may indicate usage of coastal habitats over foothills because ?34S was higher on the coastal plain than in the foothills (11.1 × 3.3 and 3.1 × 2.6; P < 0.01). Isotopic ratios in N and S show the greatest promise for tracking diet and location of migratory caribou whereas the narrow range in ?13C is affected by species, season and location.

  20. Revision, cladistic analysis and biogeography of Typhochlaena C. L. Koch, 1850, Pachistopelma Pocock, 1901 and Iridopelma Pocock, 1901 (Araneae, Theraphosidae, Aviculariinae).

    PubMed

    Bertani, Rogério

    2012-01-01

    Three aviculariine genera endemic to Brazil are revised. Typhochlaena C. L. Koch, 1850 is resurrected, including five species; Pachistopelma Pocock, 1901 includes two species; and Iridopelma Pocock, 1901, six species. Nine species are newly described: Typhochlaena ammasp. n., Typhochlaena costaesp. n., Typhochlaena curumimsp. n., Typhochlaena paschoalisp. n., Pachistopelma bromelicolasp. n., Iridopelma katiaesp. n., Iridopelma marcoisp. n., Iridopelma oliveiraisp. n. and Iridopelma vaninisp. n. Three new synonymies are established: Avicularia pulchra Mello-Leitão, 1933 and Avicularia recifiensis Struchen & Brändle, 1996 are junior synonyms of Pachistopelma rufonigrum Pocock, 1901 syn. n., and Avicularia palmicola Mello-Leitão, 1945 is a junior synonym of Iridopelma hirsutum Pocock, 1901 syn. n.Pachistopelma concolor Caporiacco, 1947 is transferred to Tapinauchenius Ausserer, 1871, making the new combination Tapinauchenius concolor (Caporiacco, 1947)comb. n. Lectotypes are newly designed for Pachistopelma rufonigrum Pocock, 1901 , Iridopelma hirsutum Pocock, 1901 and Pachistopelma concolor Caporiacco, 1947. Cladistic analyses using both equal and implied weights were carried out with a matrix comprising 62 characters and 38 terminal taxa. The chosen cladogram found with X-Pee-Wee and concavity 6 suggests they are monophyletic. All species are keyed and mapped and information on species habitat and area cladograms are presented. Discussion on biogeography and conservation is provided. PMID:23166476

  1. Characterization of fatty acid composition in healthy and bleached corals from Okinawa, Japan

    NASA Astrophysics Data System (ADS)

    Bachok, Zainudin; Mfilinge, Prosper; Tsuchiya, Makoto

    2006-11-01

    Under bleaching conditions, corals lose their symbiotic zooxanthellae, and thus, the ability to synthesize fatty acids (FAs) from photosynthetically derived carbon. This study investigated the lipid content and FA composition in healthy and bleached corals from the Odo reef flat in Okinawa, southern Japan, following a bleaching event. It was hypothesized that the FA composition and abundance would change as algae are lost or die, and possibly microbial abundance would increase in corals as a consequence of bleaching. The lipid content and FA composition of three healthy coral species ( Pavona frondifera, Acropora pulchra, and Goniastrea aspera) and of partially bleached and completely bleached colonies of P. frondifera were examined. The FA composition did not differ among healthy corals, but differed significantly among healthy, partially bleached, and completely bleached specimens of P. frondifera. Completely bleached corals contained significantly lower lipid and total FA content, as well as lower relative amounts of polyunsaturated FAs and higher relative amounts of saturated FAs, than healthy and partially bleached corals. Furthermore, there was a significantly higher relative concentration of monounsaturated FAs and odd-numbered branched FAs in completely bleached corals, indicating an increase in bacterial colonization in the bleached corals.

  2. (5Z)-4-bromo-5-(bromomethylene)-3-butyl-2(5H)-furanone reduces corrosion from Desulfotomaculum orientis.

    PubMed

    Ren, Dacheng; Wood, Thomas K

    2004-05-01

    (5Z)-4-bromo-5-(bromomethylene)-3-butyl-2(5H)-furanone (furanone) from the red marine alga Delisea pulchra was found previously to inhibit the growth, swarming and biofilm formation of Gram-positive bacteria (Ren et al., 2002, Lett Appl Microbiol 34: 293-299). In the present study, the Gram-positive sulphate-reducing bacterium (SRB), Desulfotomaculum orientis, was used to study the inhibition of mild steel corrosion due to the addition of furanone. The weight loss from batch coupon experiments incubated with 40 microg x ml(-1) furanone was reduced fivefold compared with samples that lacked furanone. Analysis of the metal surface with environmental scanning electron microscopy further confirmed the protection afforded by the addition of furanone. In agreement with the corrosion inhibition, most probable number (MPN) analysis showed that 20 and 40 microg x ml(-1) furanone inhibited 58% and 96% of the D. orientis growth respectively. Hence, furanone has the potential to inhibit microbial-induced corrosion related to Gram-positive bacteria. PMID:15049927

  3. A new species of Moennigia (Trichostrongylina: Molineidae) a parasite of Chaetophractus spp. (Xenarthra: Dasypodidae) from Argentina.

    PubMed

    Ezquiaga, María C; Navone, Graciela T

    2014-08-01

    Moennigia celinae n. sp. collected from the small intestine of Chaetophractus vellerosus and Chaetophractus villosus (Xenarthra, Dasypodidae) from Argentina is herein described. This new species belongs to the genus Moennigia because it possesses a short uterus with few eggs, atrophied distal branch of the ovejector, vulva near the anus, and a conical tail. The new species has a synlophe with 17 symmetrical ridges and slight ventro-dorsal orientation. The spicule length:body length ratio is similar to that of the other species parasitic of Dasypodidae; however, Moennigia celinae n. sp. differs from Moennigia pintoi and Moennigia lutzi because the latter lack a gubernaculum, and from Moennigia complexus, Moennigia moennigi, Moennigia filamentosus, Moennigia intrusa, Moennigia littlei, Moennigia pulchra and Moennigia dessetae by the latter having very complex spicules with 2 or 3 points at the distal extremity. Moreover, Moennigia celinae n. sp. differs from Moennigia virilis by the length and shape of its spicules. Moennigia celinae n. sp. can be distinguished from Moennigia travassosi by the shape of the dorsal ray of the caudal bursa. Moennigia celinae n. sp. resembles Moennigia pseudopulchra but the gubernaculum of the latter is V-shaped. This is the second report of a species of Moennigia in Argentina and the first for the genus Chaetophractus. PMID:24552210

  4. Leaves of Lolium multiflorum 'Lema' and tropical tree species as biomonitors of polycyclic aromatic hydrocarbons.

    PubMed

    Rinaldi, Mirian C S; Domingos, Marisa; Dias, Ana P L; Esposito, Jéssica B N; Pagliuso, Josmar D

    2012-05-01

    This study extends the current knowledge regarding the use of plants for the passive accumulation of anthropogenic PAHs that are present in the atmospheric total suspended particles (TSP) in the tropics and sub-tropics. It is of major relevance because the anthropic emissions of TSP containing PAHs are significant in these regions, but their monitoring is still scarce. We compared the biomonitor efficiency of Lolium multiflorum 'Lema' and tropical tree species (Tibouchina pulchra and Psidium guajava 'Paluma') that were growing in an intensely TSP-polluted site in Cubatão (SE Brazil), and established the species with the highest potential for alternative monitoring of PAHs. PAHs present in the TSP indicated that the region is impacted by various emission sources. L. multiflorum showed a greater efficiency for the accumulation of PAH compounds on their leaves than the tropical trees. The linear regression between the logBCF and logKoa revealed that L. multiflorum is an efficient biomonitor of the profile of light and heavy PAHs present in the particulate phase of the atmosphere during dry weather and mild temperatures. The grass should be used only for indicating the PAHs with higher molecular weight in warmer and wetter periods. PMID:22285658

  5. Hybridization of two megacephalic map turtles (testudines: emydidae: Graptemys) in the Choctawhatchee River drainage of Alabama and Florida

    USGS Publications Warehouse

    Godwin, James; Lovich, Jeffrey E.; Ennen, Joshua R.; Kreiser, Brian R.; Folt, Brian; Lechowicz, Chris

    2014-01-01

    Map turtles of the genus Graptemys are highly aquatic and rarely undergo terrestrial movements, and limited dispersal among drainages has been hypothesized to drive drainage-specific endemism and high species richness of this group in the southeastern United States. Until recently, two members of the megacephalic “pulchra clade,” Graptemys barbouri andGraptemys ernsti, were presumed to be allopatric with a gap in both species' ranges in the Choctawhatchee River drainage. In this paper, we analyzed variation in morphology (head and shell patterns) and genetics (mitochondrial DNA and microsatellite loci) from G. barbouri, G. ernsti, and Graptemys sp. collected from the Choctawhatchee River drainage, and we document the syntopic occurrence of those species and back-crossed individuals of mixed ancestry in the Choctawhatchee River drainage. Our results provide a first counter-example to the pattern of drainage-specific endemism in megacephalic Graptemys. Geologic events associated with Pliocene and Pleistocene sea level fluctuations and the existence of paleo-river systems appear to have allowed the invasion of the Choctawhatchee system by these species, and the subsequent introgression likely predates any potential human-mediated introduction.

  6. Morphological variability in tree root architecture indirectly affects coexistence among competitors in the understory.

    PubMed

    Aschehoug, Erik T; Callaway, Ragan M

    2014-07-01

    Interactions between plants can have strong effects on community structure and function. Variability in the morphological, developmental, physiological, and biochemical traits of plants can influence the outcome of plant interactions and thus have important ecological consequences. However, the ecological ramifications of trait variability in plants are poorly understood and have rarely been tested in the field. We experimentally tested the effects of morphological variation in root architecture of Quercus douglasii trees in the field on interactions between understory plants and community composition. Our results indicate that variability among Q. douglasii tree root systems initiates a striking reversal in the competitive effects of dominant understory grass species on a less common species. Trees with a deep-rooted morphology facilitated exotic annual grasses and these annual grasses, in turn, competitively excluded the native perennial bunchgrass, Stipapulchra. In contrast, Q. douglasii trees with shallow-rooted morphologies directly suppressed the growth of exotic annual grasses and indirectly released S. pulchra individuals from competition with these annual grasses. Morphological variation in the root architecture of Q. douglasii created substantial conditionality in the outcomes of competition among species which enhanced the potential for indirect interactions to sustain coexistence and increase community diversity. PMID:25163107

  7. [The pollination of Krameria bahiana B.B. Simpson by bees in the Coastal Sand Plains of Bahia, Brazil].

    PubMed

    Gimenes, Miriam; Lobão, Cybelle da S

    2006-01-01

    The flowers of K. bahiana mainly produce oil as floral resource for their visitors. Oil collecting bees usually show morphological and behavioral adaptation for their collection. This study focused on the analysis of interactions between the flowers of K. bahiana and their visiting bees, aiming for the efficiency of the pollination, in an area of the Coastal Sand Plains of Bahia State, Brazil. From February/2001 to February/2002 and from May to October/2002 observations were accomplished about the phenology and morphology of the plants and the floral visitors' behavior. The flowers of the inflorescences are zigomorphic, small sized, pink and present a pair of petals modified in epithelial elaiophores, which are responsible for the production of oil. These flowers were visited especially by bees of the genus Centris: C. leprieuri Spinola, C. tarsata Smith, C. trigonoides Lepeletier and C. pulchra Moure, Oliveira & Viana. The bees collected only oil in the flowers, by scratching the elaiophores and then transferring it to scopa located on the tibia and basitarsus of the hind legs. During those actions, the bees often contact the reproductive structures of the flowers, resulting in pollination. C. leprieuri was the most frequent bee during this study, thus considered the effective pollinator. Megachile dentipes Vachal also visited the flowers of K. bahiana, collecting only pollen. However, these bees were considered sporadic pollinators because they were not frequent in the flowers of K. bahiana in the months of observation. PMID:17061790

  8. Can methane suppression during digestion of woody and leafy browse compensate for energy costs of detoxification of plant secondary compounds? A test with muskoxen fed willows and birch.

    PubMed

    White, R G; Lawler, J P

    2002-11-01

    Digestion and metabolism of woody and leafy browse requires detoxification of plant secondary compounds that can incur an energy cost. Browse, however, inhibits methane (CH(4)) production and therefore could offset some costs of detoxification. We measured an index of heat increment of feeding (HIFi) and CH(4) production in muskoxen (Ovibos moschatus) given a single test meal (at 10 g/kg BM(0.75)) composed of hay mixed with one of three browse species (Willow: Salix alaxensis, S. pulchra; Birch: Betula nana). Detoxification cost was estimated as HIFi of browse diet-HIFi of hay diet and CH(4) compensation as CH(4) production of hay diet-CH(4) production of browse diet. CH(4) compensation was noted in 47% of 15 trials in which a detoxification cost was evident; six trials were with woody browse and one with leafy browse. Separate controls were responsible for the difference in CH(4) compensation for leafy browse vs. woody browse. Detoxification costs for twigs and leaves of B. nana were underestimated because of their low digestibility. In only one of six treatments was CH(4) compensation documented for B. nana. We conclude that energy saved by CH(4) suppression was small (<6%) compared with detoxification costs. PMID:12443941

  9. Ontogeny of behavioural adaptations in beach crustaceans: some temporal considerations for integrated coastal zone management and conservation

    NASA Astrophysics Data System (ADS)

    Naylor, E.; Kennedy, F.

    2003-10-01

    So-called "typical" behavioural responses of coastal animals to particular stimuli have previously been shown often to vary cyclically in phase with diel or tidal cycles in the environment. Less well-studied are differences in the behaviour of adults and juveniles of the same species at the same time of day or tidal state, or in response to the same stimulus. Experimental studies of such differences in behaviour are reviewed and compared for three species of beach crustaceans, namely, the crab Carcinus maenas, the isopod Eurydice pulchra and the amphipod Orchestoidea tuberculata. Juvenile, but not adult, Carcinus will entrain circatidal rhythmicity after exposure to artificial tidal cycles of immersion/emersion; juvenile, but not adult, Eurydice express pronounced free-running circatidal swimming rhythms at neap tides as well as at springs; and, in Orchestoidea, juveniles and adults express patterns of daily locomotor activity that are complementary, both on the shore and in the laboratory. These ontogenetic differences are discussed in relation to distributional and behavioural differences between adults and juveniles in each species, drawing attention to their adaptive significance and wider implications for coastal management and conservation.

  10. Species composition and seasonal abundance of Chaetognatha in the subtropical coastal waters of Hong Kong

    NASA Astrophysics Data System (ADS)

    Tse, P.; Hui, S. Y.; Wong, C. K.

    2007-06-01

    Species composition, species diversity and seasonal abundance of chaetognaths were studied in Tolo Harbour and the coastal waters of eastern Hong Kong. Tolo Harbour is a semi-enclosed and poorly flushed bay with a long history of eutrophication. It opens into the eastern coast of Hong Kong which is fully exposed to water currents from the South China Sea. Zooplankton samples were collected monthly from July 2003 to July 2005 at six stations. Twenty species of chaetognaths were identified. They included six species of the genus Aidanosagitta ( Aidanosagitta neglecta, Aidanosagitta delicata, Aidanosagitta johorensis, Aidanosagitta regularis, Aidanosagitta bedfordii and Aidanosagitta crassa), four species of the genus Zonosagitta ( Zonosagitta nagae, Zonosagitta bedoti, Zonosagitta bruuni and Zonosagitta pulchra), three species of the genus Ferosagitta ( Ferosagitta ferox, Ferosagitta tokiokai and Ferosagitta robusta) and one species each from the genera Serratosagitta ( Serratosagitta pacifica), Decipisagitta ( Decipisagitta decipiens), Flaccisagitta ( Flaccisagitta enflata), Krohnitta ( Krohnitta pacifica), Mesosagitta ( Mesosagitta minima), Pterosagitta ( Pterosagitta draco) and Sagitta ( Sagitta bipunctata). The most abundant species were Flaccisagitta enflata, A. neglecta and A. delicata. Averaged over the entire study period, the densities of Flaccisagitta enflata, A. neglecta and A. delicata were 9.3, 6.6 and 5.2 ind. m -3, respectively. Overall, these species constituted 39.7%, 28.2% and 22.0% of all chaetognaths collected in the study. Averaged over the entire study, the density of most of the low abundance species was <0.6 ind. m -3. Flaccisagitta enflata occurred throughout the year at all sampling stations. Aidanosagitta neglecta occurred at all sampling stations, but was most common in summer. Aidanosagitta delicata was most common in Tolo Harbour during summer. Tolo Harbour supported larger populations, but fewer species of chaetognaths than the surrounding open waters. These observations suggest that some species of chaetognaths were carried into the coastal waters of Hong Kong by water currents from the South China Sea and established large populations in the productive and poorly flushed waters of Tolo Harbour.

  11. Increasing leaf temperature reduces the suppression of isoprene emission by elevated CO? concentration.

    PubMed

    Potosnak, Mark J; Lestourgeon, Lauren; Nunez, Othon

    2014-05-15

    Including algorithms to account for the suppression of isoprene emission by elevated CO2 concentration affects estimates of global isoprene emission for future climate change scenarios. In this study, leaf-level measurements of isoprene emission were made to determine the short-term interactive effect of leaf temperature and CO2 concentration. For both greenhouse plants and plants grown under field conditions, the suppression of isoprene emission was reduced by increasing leaf temperature. For each of the four different tree species investigated, aspen (Populus tremuloides Michx.), cottonwood (Populus deltoides W. Bartram ex Marshall), red oak (Quercus rubra L.), and tundra dwarf willow (Salix pulchra Cham.), the suppression of isoprene by elevated CO2 was eliminated at increased temperature, and the maximum temperature where suppression was observed ranged from 25 to 35°C. Hypotheses proposed to explain the short-term suppression of isoprene emission by increased CO2 concentration were tested against this observation. Hypotheses related to cofactors in the methylerythritol phosphate (MEP) pathway were consistent with reduced suppression at elevated leaf temperature. Also, reduced solubility of CO2 with increased temperature can explain the reduced suppression for the phosphoenolpyruvate (PEP) carboxylase competition hypothesis. Some global models of isoprene emission include the short-term suppression effect, and should be modified to include the observed interaction. If these results are consistent at longer timescales, there are implications for predicting future global isoprene emission budgets and the reduced suppression at increased temperature could explain some of the variable responses observed in long-term CO2 exposure experiments. PMID:24614154

  12. The effects of 17-methoxyl-7-hydroxy-benzene-furanchalcone on the pressure overload-induced progression of cardiac hypertrophy to cardiac failure.

    PubMed

    Huang, Jianchun; Tang, XiaoJun; Liang, Xingmei; Wen, Qingwei; Zhang, Shijun; Xuan, Feifei; Jian, Jie; Lin, Xing; Huang, Renbin

    2014-01-01

    We investigated the effects of 17-methoxyl-7-hydroxy-benzene-furanchalcone (MHBFC), which was isolated from the roots of Millettia pulchra (Benth.) Kurz var. Laxior (Dunn) Z.Wei (Papilionaceae) (MKL), on the progression of cardiac hypertrophy to failure in a rat model of abdominal aortic banding (AAB)-induced pressure overloading. Endothelial dysfunction is central to pressure overload-induced cardiac hypertrophy and failure. It would be useful to clarify whether MHBFC could prevent this dysfunction. The effects of pressure overload were assessed in male Sprague-Dawley rats 6 weeks after AAB using the progression of cardiac hypertrophy to heart failure as the endpoint. The AAB-treated rats exhibited a greater progression to heart failure and had significantly elevated blood pressure, systolic and diastolic cardiac dysfunction, and evidence of left ventricular hypertrophy (LVH). LVH was characterized by increases in the ratios of heart and left ventricular weights to body weight, increased myocyte cross-sectional areas, myocardial and perivascular fibrosis, and elevated cardiac hydroxyproline. These symptoms could be prevented by treatment with MHBFC at daily oral doses of 6 and 12 mg/kg for 6 weeks. The progression to cardiac failure, which was demonstrated by increases in relative lung and right ventricular weights, cardiac function disorders and overexpression of atrial natriuretic peptide (ANP) mRNA, could also be prevented. Furthermore, MHBFC partialy rescued the downregulated nitric oxide signaling system, whereas inhibited the upregulated endothelin signaling system, normalizing the balance between these two systems. MHBFC protected the endothelium and prevented the pressure overload-induced progression of cardiac hypertrophy to cardiac failure. PMID:24622486

  13. Stage-dependent border cell and carbon flow from roots to rhizosphere.

    PubMed

    Odell, Ryan E; Dumlao, Matthew R; Samar, Danial; Silk, Wendy K

    2008-04-01

    Rising CO(2) levels in the atmosphere have drawn attention to the important role of soil in sequestering carbon. This project goal was to quantify soil carbon deposition associated with border cell release and exudation from root growth zones. Carbon was measured with a Carlo Erba C/N analyzer in soil from the rhizosphere of mature grasses and, in separate experiments, in soil collected around root growth zones. Root border cells in "rhizosphere soil" (silica sand) were counted using a compound microscope after soil sonication and extraction with surfactant. For sand-grown Bromus carinatus, Zea mays, and Cucumis sativus, young seedlings (with roots shorter than 2 cm) released thousands of border cells, while older root tips released only hundreds. For a variety of native annual and perennial grasses and invasive annual grasses (Nassella pulchra, B. carinatus, B. diandrus, B. hordeaceus, Vulpia microstachys, Aegilops triuncialis, Lolium multiflorum, Zea mays), the rhizosphere of mature root systems contained between 18 and 32 ?g C g(-1) sand more than that of the unplanted controls. Spatial analysis of the rhizosphere around the cucumber growth zone confirmed C enrichment there. The root tip provided C to the rhizosphere: 4.6 ?g C in front of the growing tip, with the largest deposition, 20.4 ?g C, to the rhizosphere surrounding the apical 3 mm (root cap/meristem). These numbers from laboratory studies represent the maximum C that might be released during flooding in soils. Scaling up from the organ scale to the field requires a growth analysis to quantify root tip distributions in space and time. PMID:21632368

  14. Encyrtidae (Hymenoptera: Chalcidoidea) from the Kingdom of Saudi Arabia.

    PubMed

    Hayat, Mohammad; Ahmad, Zubair; Khan, Farmanur Rehman

    2014-01-01

    This is the first major contribution to the fauna of the family Encyrtidae (Hymenoptera: Chalcidoidea) of the Kingdom of Saudi Arabia. The following new genus and 15 new species are described: Anagyrus azolus Hayat, sp. nov., A. raidahensis Hayat, sp. nov., Arabencyrtus qahtanii Hayat, gen. et sp. nov., Cerchysiella arabia Hayat, sp. nov., C. azeeza Hayat, sp. nov., Cheiloneurus arabiacus Hayat, sp. nov., Leptomastidea abyad Hayat, sp. nov., Mahencyrtus asirensis Hayat, sp. nov., Metaphycus albidus Hayat, sp. nov., Microterys axonis Hayat, sp. nov., Neastymachus bolus Hayat, sp. nov., N. ceelus Hayat, sp. nov., Ooencyrtus likinis Hayat, sp. nov., O. seronis Hayat, sp. nov., Zaomma astera Hayat, sp. nov. The following 27 genera are newly recorded from Saudi Arabia: Achalcerinys Girault, Aphycus Mayr, Apoleptomastix Kerrich, Callipteroma Motschulsky, Cerchysiella Girault, Cerchysius Westwood, Charitopus Foerster, Cheiloneurus Westwood, Coelopencyrtus Timberlake, Copidosoma Ratzeburg, Helegonatopus Perkins, Homalotylus Mayr, Lamennaisia Girault, Leptomastidea Mercet, Leptomastix Foerster, Mahencyrtus Masi, Mayridia Mercet, Microterys Thomson, Neastymachus Girault, Ooencyrtus Ashmead, Paraclausenia Hayat, Prionomastix Mayr, Prochiloneurus Silvestri, Rhopus Foerster, Syrphophagus Ashmead, Tyndarichus Howard, Zaomma Ashmead. The following 27 species are newly recorded from Saudi Arabia: Achalcerinys lindus (Mercet), Anagyrus gracilis (Hayat), A. shahidi Hayat, Aphycus secundus (Mercet), Apoleptomastix bicoloricornis (Girault), Callipteroma sexguttata Motschulsky, C. testacea Motschulsky, Cerchysius ugandensis Kerrich, Charitopus andalusicus Mercet, Cheiloneurus elegans (Dalman), C. quadricolor (Girault), Coelopencyrtus krishnamurtii (Mahdihassan), Comperiella aspidiotiphaga Subba Rao, Copidosoma floridanum (Ashmead), Habrolepis obscura Compere & Annecke, Helegonatopus formosus (Mercet), Homalotylus flaminius (Dalman), Lamennaisia ambigua (Nees), L. nobilis (Nees), Leptomastix dactylopii Howard, L. tsukumiensis Tachikawa, Mayridia pulchra Mercet, Paraclausenia herbicola Hayat, Prochiloneurus aegyptiacus (Mercet), P. pulchellus Silvestri, Rhopus nigroclavatus (Ashmead), Syrphophagus aphidivorus (Mayr). Eleven species belonging to the genera Anagyrus Howard, Charitopus, Helegonatopus, Mayridia, Metaphycus Mercet, Ooencyrtus, Prionomastix, Syrphophagus, and Tyndarichus, were not identified to species for the reasons given in the text. The known species treated in this paper, except for some well known species, are illustrated with suitable figures, and some species are either diagnosed or redescribed.  PMID:24870152

  15. Estimating aboveground biomass of low-stature Arctic shrubs with terrestrial LiDAR

    NASA Astrophysics Data System (ADS)

    Greaves, H.; Vierling, L. A.; Eitel, J.; Boelman, N.; Griffin, K. L.; Magney, T. S.

    2014-12-01

    Arctic tundra ecosystems appear to be responding to rapid climatic warming via changes in vegetation composition and increased woody biomass, which may induce significant shifts in ecosystem structure and function. Although understanding these shifts is important for predicting ecosystem trajectories, establishing methods for quantifying and scaling woody plant biomass in low-stature biomes is challenging. We used LiDAR data from a terrestrial laser scanner (TLS) to estimate harvested biomass and leaf area of two dominant low-stature (<1.5 m) Arctic shrub species (Salix pulchra Cham. and Betula nana L.) in small (0.64 m2) plots. We explored two biomass estimation approaches (volumetric surface differencing and voxel counting) applied to point clouds obtained from either close-range (2 m) or variable-range (<50 m) TLS scans. Relationships between harvested biomass and laser scan metrics were strong for all combinations of approaches. Voxel counting provided a marginally better result than surface differencing for close-range scans (R2 = 0.94 vs 0.92; RMSE = 102 g vs 117 g), while surface differencing proved stronger than voxel counting for variable-range scans (R2 = 0.90 vs 0.79; RMSE = 128 g vs 184 g). Strong relationships between total harvested biomass and total leaf dry mass (R2 = 0.93; RMSE = 13.4 g), and between leaf dry mass and leaf wet area (R2 = 0.99; RMSE = 9.01 cm2) justify estimation of shrub leaf area from TLS-derived shrub biomass. Our results show that rapidly acquired, repeatable terrestrial laser scans taken from multiple distance ranges can be processed using simple algorithms to yield aboveground biomass and leaf area estimates for low-stature shrubs at fine spatial scales (sub-meter to 50 + meters). These data have the fidelity required to monitor small but ecologically meaningful changes in tundra structure, and could be employed as ground reference data for broader scale remote sensing data collection to provide shrub biomass and leaf-area estimates at fine resolution over large spatial extents.

  16. The Regional Geochemistry of Soils and Willow in a Metamorphic Bedrock Terrain, Seward Peninsula, Alaska, 2005, and Its Possible Relation to Moose

    USGS Publications Warehouse

    Gough, L.P.; Lamothe, P.J.; Sanzolone, R.F.; Drew, L.J.; Maier, J.A.K.

    2009-01-01

    In 2005 willow leaves (all variants of Salix pulchra) and A-, B-, and C-horizon soils were sampled at 10 sites along a transect near the Quarry prospect and 11 sites along a transect near the Big Hurrah mine for the purpose of defining the spatial variability of elements and the regional geochemistry of willow and soil over Paleozoic metamorphic rocks potentially high in cadmium (Cd). Willow, a favorite browse of moose (Alces alces), has been shown by various investigators to bioaccumulate Cd. Moose in this region show clinical signs of tooth wear and breakage and are declining in population for unknown reasons. A trace element imbalance in their diet has been proposed as a possible cause for these observations. Cadmium, in high enough concentrations, is one dietary trace element that potentially could produce such symptoms. We report both the summary statistics for elements in willow and soils and the results of an unbalanced, one-way, hierarchical analysis of variance (ANOVA) (general linear model, GLM), which was constructed to measure the geochemical variability in willow (and soil) at various distance scales across the Paleozoic geologic unit high in bioavailable Cd. All of the geochemical data are presented in the Appendices. The two locations are separated by approximately 80 kilometers (km); sites within a location are approximately 0.5 kilometers apart. Duplicate soil samples collected within a site were separated by 0.05 km or slightly less. Results of the GLM are element specific and range from having very little regional variability to having most of their variance at the top (greater than 80 km) level. For willow, a significant proportion of the total variance occurred at the 'between locations' level for ash yield, barium (Ba), Cd, calcium (Ca), cobalt (Co), nickel (Ni), and zinc (Zn). For soils, concentrations of elements in all three soil horizons were similar in that most of the variability in the geochemical data occurred at the 'between locations' and the 'among sites at a location' GLM levels. Most of the variation in concentrations of Cd in soils occurred among sites (separated by 0.5 km) at both locations across all soil horizons and not between the two locations. Cd distribution across the landscape may be due to variation in soil mineralogy, especially the amount of graphite in soil, which has been associated with Cd. Although samples were collected on the same geologic unit, the geochemistry of soils was demonstrated to be uniform with depth but highly variable between locations separated by 80 km. This exploratory study establishes the presence of elevated levels of Cd in willow growing over Paleozoic bedrock in the Seward Peninsula. Further work is needed to definitively link these high Cd levels in willow browse to the health of moose.

  17. Influence of solar activity on the development of calcareous nannofossils from a Middle Holocene costal paleo-ria (SW Portugal)

    NASA Astrophysics Data System (ADS)

    Hernández, Armand; Cachão, Mário; Trigo, Ricardo M.; Conceição Freitas, M.

    2015-04-01

    A 27 m long core was recovered from a present day flat-floored small fluvial valley, tributary of the Mira River (SW Portugal) allowing to span almost the complete Holocene sedimentary sequence directly overlaying Paleozoic schists and greywackes. A high resolution study of its micropaleontological content (Alday et al. 2006) was performed and 5 sedimentary stages were established: i) a coccolith-barren lower fluvial stage; ii) a coccolith intermittent lower estuarine stage; iii) a coccolith rich marine (ria) stage; iv) a coccolith intermittent upper estuarine/lagoonal stage and v) a coccolith-barren upper fluvial stage. The usefulness of calcareous nannofossils as natural tracers of the marine sedimentation contributing with valuable information for environmental reconstructions has been thoroughly demonstrated. Here, we present a high-resolution paleoenvironmental reconstruction from the interpreted marine (ria) section of the core, between 8.8k and 4.8k cal yr BP using most abundant calcareous nannofossils. Factor Analysis retrieved two major factors from the coccolith assemblages. Factor 1 (24% var.) is related to oceanic affinity community (e.g. Gephyrocapsa muellerae, Syracosphaera pulchra and Umbilicosphaera sibogae) whereas Factor 2 (23% var.) is linked to coastal neritic taxa (e.g. Ascidian spicules, Gephyrocapsa oceanica, Coccolithus pelagicus braarudii, Heliscosphaera carteri and Braarudosphaera bigelowii). These scores showed the existence of two episodes (8.8k to 7.4k and 5.8k to 5.2k cal yr BP) of marine colonization inside the paleoecological succession of the Holocene paleo-ria (8.8k and 4.8k cal yr BP). In order to establish the relationship between the solar activity and calcareous nannofossils sedimentation, cyclicity on the studied time series was investigated by performing spectral analysis on Factor 1 (F1) and Factor 2 (F2) scores. F1 score periodogram discloses three significant periodicities (460, 350 and 236-yrs) whereas F2 score periodogram unveils only one significant periodicity (228-yrs). Phases with oceanic influence (downwelling) would be related to 450, 350 and 236-yrs frequencies and the phase with coastal influence (upwelling) would be linked to 228-yrs periodicity. These periodicities fit with previous solar activity reconstructions at millennial-to-centennial scale based on different proxies (Bond et al. 2001, Vaquero et al. 2002, Solanki et al. 2004), which, in turn, are conditioning the earth's climate system. Finally, performed time-frequency analyses on F1 and F2 scores show a higher activity of the 228-yrs periodicity during the whole studied period (spanning between 8.8k and 4.8k cal yr BP) with maximum values between 8k to 7k cal yr BP and 6k to 5k cal yr BP. By contrast, higher periodicities (450, 350 and 236-yrs) would be mainly confined to prior 7.5k cal yrs BP. These results highlight the possibility to use the calcareous nannofossils as indirect proxies of solar activity in cases of ultra-high resolution (centennial) sedimentary sequences. References Alday et al., Estuar Coast Shelf S, 66, 532 (2006). Bond et al., Science, 294, 2130 (2001). Solanki et al., Nature, 431, 1084 (2004). Vaquero et al., Geophys Res Lett, 29, 1997 (2002).