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Sample records for australis root secreted

  1. Phragmites australis root secreted phytotoxin undergoes photo-degradation to execute severe phytotoxicity

    PubMed Central

    Rudrappa, Thimmaraju; Choi, Yong Seok; Levia, Delphis F; Legates, David R; Lee, Kelvin H

    2009-01-01

    Our study organism, Phragmites australis (common reed), is a unique invader in that both native and introduced lineages are found coexisting in North America. This allows one to make direct assessments of physiological differences between these different subspecies and examine how this relates to invasiveness. Recent efforts to understand plant invasive behavior show that some invasive plants secrete a phytotoxin to ward-off encroachment by neighboring plants (allelopathy) and thus provide the invaders with a competitive edge in a given habitat. Here we show that a varying climatic factor like ultraviolet (UV) light leads to photo-degradation of secreted phytotoxin (gallic acid) in P. australis rhizosphere inducing higher mortality of susceptible seedlings. The photo-degraded product of gallic acid (hereafter GA), identified as mesoxalic acid (hereafter MOA), triggered a similar cell death cascade in susceptible seedlings as observed previously with GA. Further, we detected the biological concentrations of MOA in the natural stands of exotic and native P. australis. Our studies also show that the UV degradation of GA is facilitated at an alkaline pH, suggesting that the natural habitat of P. australis may facilitate the photo-degradation of GA. The study highlights the persistence of the photo-degraded phytotoxin in the P. australis's rhizosphere and its inhibitory effects against the native plants. PMID:19816146

  2. Suppression of native Melaleuca ericifolia by the invasive Phragmites australis through allelopathic root exudates.

    PubMed

    Uddin, Md Nazim; Robinson, Randall William; Caridi, Domenic; Al Harun, Md Abdullah Yousuf

    2014-03-01

    Invasive plants are a great threat to the conservation of natural ecosystems and biodiversity. Allelopathy as a mechanism for invasion of plants such as Phragmites australis, one of the most aggressive invaders, has the potential to suppress neighboring plant species. Allelopathic interference, through root exudates of P. australis on native Melaleuca ericifolia, was investigated to find out the underlying invasion mechanisms. Germination and growth effects of P. australis on M. ericifolia were studied in the greenhouse using potting mix both with and without activated carbon, and a combination of single and repeated cuttings of P. australis as the management tool. P. AUSTRALIS had significant negative effects on germination and growth of M. ericifolia by inhibiting germination percentage, maximum root length and plant height, biomass, stem diameter, and number of growth points with little effect on leaf physiology. Activated carbon (AC) in turn moderately counteracted these effects. The cutting of P. australis shoots significantly reduced the suppressive effects on M. ericifolia compared to the addition of AC to soil. Furthermore, significant changes in soil such as pH, electrical conductivity, osmotic potential, phenolics, and dehydrogenase activity were identified among cutting treatments with little variation between AC treatments. The results demonstrated that allelopathy through root exudates of P. australis had relatively low contribution in suppressing M. ericifolia in comparison to other competitive effects. Management tools combining repeated cutting of P. australis shoots with AC treatments may assist partly in the restoration of native ecosystems invaded by P. australis.

  3. Bioactive chemical constituents from the root bark of Morus australis.

    PubMed

    Liao, Yu-Ren; Kuo, Ping-Chung; Tsai, Wei-Jern; Huang, Guan-Jhong; Lee, Kuo-Hsiung; Wu, Tian-Shung

    2017-01-15

    Two new pyranoflavonoids, morustralins A (1) and B (2), a new natural benzene derivative, one benzenoid (Z)-1-hydroxy-4-(2-nitroethenyl)benzene (3), and thirty known compounds were isolated and characterized from the root bark of Morus australis. The structures of the new compounds were established from spectroscopic and spectrometric analyses. Ten isolates (1-10) were examined for inhibitory effects on adenosine diphosphate (ADP)-, arachidonic acid (AA)-, and platelet-aggregating factor (PAF)-induced platelet aggregation. Among the tested compounds, compound 3 displayed the most significant inhibition of ADP- and AA-induced platelet aggregation with IC50 values of 9.76±5.54 and 9.81±2.7μM, respectively. In addition, eight purified compounds (3-10) were examined for inhibition of nitric oxide (NO) production in RAW 264.7 cells and six compounds (3-8) displayed significant inhibitory effects with IC50 values ranging from 2.1±0.3 to 6.3±0.6μM. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Short term uptake and transport process for metformin in roots of Phragmites australis and Typha latifolia.

    PubMed

    Cui, H; Hense, B A; Müller, J; Schröder, P

    2015-09-01

    Metformin (MET) as an emerging contaminant has been detected in surface water and wastewater in numerous countries, due to insufficient retention in classical waste water treatment plants. In order to characterize the uptake of the compound during phytotreatment of waste water, a short term Pitman chamber experiment was carried out to assess the characteristics of MET uptake and transport by roots. Three different concentrations (0.5, 1.0 and 2.0 mmol L(-)(1)) were applied to cattail (Typha latifolia) and reed (Phragmites australis) roots which were used to investigate the uptake mechanism because they are frequently utilized in phytoremediation. In addition, quinidine was used as an inhibitor to assess the role of organic cation transporters (OCTs) in the uptake of MET by T. latifolia. The transport process of MET is different from carbamazepine (CBZ) and caffeine (CFN). In both T. latifolia and P. australis, the uptake processes were independent of initial concentrations. Quinidine, a known inhibitor of organic cation transporters, can significantly affect MET uptake by T. latifolia roots with inhibition ratios of 70-74%. Uptake into the root could be characterized by a linear model with R(2) values in the range of 0.881-0.999. Overall, the present study provides evidence that MET is taken up by plant roots and has the potential for subsequent translocation. OCTs could be one of the important pathways for MET uptake into the plant. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Accelerated biodegradation of pyrene and benzo[a]pyrene in the Phragmites australis rhizosphere by bacteria-root exudate interactions.

    PubMed

    Toyama, Tadashi; Furukawa, Tetsuya; Maeda, Noritaka; Inoue, Daisuke; Sei, Kazunari; Mori, Kazuhiro; Kikuchi, Shintaro; Ike, Michihiko

    2011-02-01

    We investigated the biodegradation of pyrene and benzo[a]pyrene in Phragmites australis rhizosphere sediment. We collected P. australis plants, rhizosphere sediments, and unvegetated sediments from natural aquatic sites and conducted degradation experiments using sediments spiked with pyrene or benzo[a]pyrene. Accelerated removal of pyrene and benzo[a]pyrene was observed in P. australis rhizosphere sediments with plants, whereas both compounds persisted in unvegetated sediments without plants and in autoclaved rhizosphere sediments with sterilized plants, suggesting that the accelerated removal resulted largely from biodegradation by rhizosphere bacteria. Initial densities of pyrene-utilizing bacteria were substantially higher in the rhizosphere than in unvegetated sediments, but benzo[a]pyrene-utilizing bacteria were not detected in rhizosphere sediments. Mycobacterium gilvum strains isolated from rhizosphere sediments utilized pyrene aerobically as a sole carbon source and were able to degrade benzo[a]pyrene when induced with pyrene. Phragmites australis root exudates containing phenolic compounds supported growth as a carbon source for the one Mycobacterium strain tested, and induced benzo[a]pyrene-degrading activity of the strain. The stimulatory effect on benzo[a]pyrene biodegradation and the amounts of phenolic compounds in root exudates increased when P. australis was exposed to pyrene. Our results show that Mycobacterium-root exudate interactions can accelerate biodegradation of pyrene and benzo[a]pyrene in P. australis rhizosphere sediments. © 2010 Elsevier Ltd. All rights reserved.

  6. Influence of season and salinity on the exudation of aliphatic low molecular weight organic acids (ALMWOAs) by Phragmites australis and Halimione portulacoides roots

    NASA Astrophysics Data System (ADS)

    Rocha, A. Cristina S.; Almeida, C. Marisa R.; Basto, M. Clara P.; Vasconcelos, M. Teresa S. D.

    2015-01-01

    Plant roots have the ability to produce and secrete substances, such as aliphatic low molecular weight organic acids (ALMWOAs), into the rhizosphere. This phenomenon occurs for several purposes, for instance, the detoxification of pollutants. Nevertheless, knowledge about the exudation of such substances from marsh plants roots is still scarce. This work aimed at studying: 1) the ability of marsh plants, freshly collected in estuarine marshes, to liberate ALMWOAs into the surrounding medium and 2) the influence of the physiological cycle of these plants on the exudation of those substances. In vitro experiments were carried out, in different seasons, with Phragmites australis and Halimione portulacoides (two marsh plants widely distributed in Europe). Root exudates were collected in freshwater to which plant specimens, in different physiological stages, were exposed. Both marsh plants were capable of liberating oxalic and citric acids into the surrounding medium. Formic acid was also released by P. australis roots and acetic acid by H. portulacoides. There was a seasonal effect on the liberation of ALMWOAs by both plant roots. Marked changes were registered in the nature and levels of the ALMWOAs liberated and such changes depended upon the season in which the specimens were collected. In growing season, a significantly higher liberation of oxalic and citric acids (and acetic acid but only in H. portulacoides case) was observed. For P. australis, formic acid was only found in the decaying stage (autumn and winter). The nature of the medium (in particular, salinity) was a feature conditioning the exudation of ALMWOAs. Both plants were shown to contribute for the presence of ALMWOAs in marsh rhizosediments (some ALMWOAs were found in pore waters extracted). The nature and extent of this contribution will be however dependent upon plants' physiological stage, in addition to plant species. Therefore, these features should be taken into consideration in the event of

  7. Synchrotron X-ray microfluorescence measurement of metal distributions in Phragmites australis root system in the Yangtze River intertidal zone

    DOE PAGES

    Feng, Huan; Zhang, Weiguo; Qian, Yu; ...

    2016-06-15

    This paper investigates the distributions of Br, Ca, Cl, Cr, Cu, K, Fe, Mn, Pb, Ti, V and Zn in Phragmites australis root system and the function of Fe nanoparticles in scavenging metals in the root epidermis using synchrotron X-ray microfluorescence, synchrotron transmission X-ray microscope measurement and synchrotron X-ray absorption near-edge structure techniques. The purpose of this study is to understand the mobility of metals in wetland plant root systems after their uptake from rhizosphere soils. Phragmites australis samples were collected in the Yangtze River intertidal zone in July 2013. The results indicate that Fe nanoparticles are present in themore » root epidermis and that other metals correlate significantly with Fe, suggesting that Fe nanoparticles play an important role in metal scavenging in the epidermis.« less

  8. Synchrotron X-ray microfluorescence measurement of metal distributions in Phragmites australis root system in the Yangtze River intertidal zone.

    PubMed

    Feng, Huan; Zhang, Weiguo; Qian, Yu; Liu, Wenliang; Yu, Lizhong; Yoo, Shinjae; Wang, Jun; Wang, Jia Jun; Eng, Christopher; Liu, Chang Jun; Tappero, Ryan

    2016-07-01

    This study investigates the distributions of Br, Ca, Cl, Cr, Cu, K, Fe, Mn, Pb, Ti, V and Zn in Phragmites australis root system and the function of Fe nanoparticles in scavenging metals in the root epidermis using synchrotron X-ray microfluorescence, synchrotron transmission X-ray microscope measurement and synchrotron X-ray absorption near-edge structure techniques. The purpose of this study is to understand the mobility of metals in wetland plant root systems after their uptake from rhizosphere soils. Phragmites australis samples were collected in the Yangtze River intertidal zone in July 2013. The results indicate that Fe nanoparticles are present in the root epidermis and that other metals correlate significantly with Fe, suggesting that Fe nanoparticles play an important role in metal scavenging in the epidermis.

  9. Manganese and copper in the root plaque of Phragmites australis (cav. ) trin. ex steudel

    SciTech Connect

    St-Cyr, L.; Crowder, A.A. )

    1990-04-01

    Manganese and copper were found in the iron oxide plaque on roots of Phragmites australis collected at six sampling sites in southern Quebec and Ontario, Canada. Manganese concentration in the plaque, like that of Fe, is correlated with Mn-bound-to-carbonates fraction of the soil/sediment. The Fe:Mn ratio of the plaque resemble the same ratio of Fe:Mn-bound-to-carbonates in the substrate. The ratio changes with environmental conditions, increasing with percentage of water and decreasing with pH. Plants located near flowing water accumulate more Mn (and Fe) in the plaque than plants in other habitats through the summer. Copper concentration in the plaque than plants in other habitats through the summer. Copper concentration in the plaque is pH-dependent and is positively correlated with the amount of Fe and Mn of the plaque, but appears to be related more closely to Mn.

  10. Aluminium and Phosphate Uptake by Phragmites australis: the Role of Fe, Mn and Al Root Plaques

    PubMed Central

    BATTY, LESLEY C.; BAKER, ALAN J. M.; WHEELER, BRYAN D.

    2002-01-01

    Aluminium, a potentially phytotoxic metal, is an important constituent of many mine water discharges but has largely been neglected in the literature. The behaviour of this element in the rhizosphere of the wetland plant Phragmites australis was investigated in the laboratory in the presence and absence of Mn and Fe root plaques. Electron microscopy and chemical extraction techniques were utilized to determine the physico‐chemical properties of the plaques and any association of Al. Both Mn and Fe plaques occurred as amorphous coatings on root surfaces with uneven distributions. Al was not adsorbed onto the surface of either plaque type but formed a separate phosphate deposit closely resembling the Fe and Mn plaques. Phosphorus was also found to be adsorbed to the surface of the Fe plaques (but not the Mn plaques). Both mechanisms were found to immobilize P at the root surface but this did not significantly reduce the concentration of P in aerial plant tissues that was sufficient to ensure adequate growth. PMID:12096805

  11. Archaeal communities associated with roots of the common reed (Phragmites australis) in Beijing Cuihu Wetland.

    PubMed

    Liu, Yin; Li, Hong; Liu, Qun Fang; Li, Yan Hong

    2015-05-01

    The richness, phylogeny and composition of archaeal community associated with the roots of common reed (Phragmites australis) growing in the Beijing Cuihu Wetland, China was investigated using a 16S rDNA library. In total, 235 individual sequences were collected, and a phylogenetic analysis revealed that 69.4 and 11.5 % of clones were affiliated with the Euryarchaeota and the Crenarchaeota, respectively. In Euryarchaeota, the archaeal community was dominated by species in following genera: Methanobacterium in the order Methanobacteriales (60.7 %); Methanoregula and Methanospirillum in the order Methanomicrobiales (20.2 %), and Methanomethylovorans, Methanosarcina and Methanosaeta in the order Methanosarcinales (17.2 %). Of 27 sequences assigned to uncultured Crenarchaeota, 22 were grouped into Group 1.3, and five grouped into Group 1.1b. Hence, the archaeal communities associated with reed roots are largely involved in methane production, and, to a lesser extent, in ammonia oxidization. Quantification of the archaeal amoA gene indicated that ammonia oxidizing archaea were more numerous in the rhizosphere soil than in the root tissue or surrounding water. A total of 19.1 % of the sequences were unclassified, suggesting that many unidentified archaea are probably involved in the reed wetland ecosystem.

  12. Comparison of the diversity of root-associated bacteria in Phragmites australis and Typha angustifolia L. in artificial wetlands.

    PubMed

    Li, Yan Hong; Zhu, Jing Nan; Liu, Qun Fang; Liu, Yin; Liu, Min; Liu, Lei; Zhang, Qiang

    2013-08-01

    Common reed (Phragmites australis) and narrow-leaved cattail (Typha angustifolia L.) are two plant species used widely in artificial wetlands constructed to treat wastewater. In this study, the community structure and diversity of root-associated bacteria of common reed and narrow-leaved cattail growing in the Beijing Cuihu Wetland, China, were investigated using 16S rDNA library and PCR-denaturing gradient gel electrophoresis methods. Root-associated bacterial diversity was higher in common reed than in narrow-leaved cattail. In both plant species, the dominant root-associated bacterial species were Alpha, Beta and Gamma Proteobacteria, including the genera Aeromonas, Hydrogenophaga, Ideonella, Uliginosibacterium and Vogesella. Acidobacteria, Actinobacteria, Nitrospirae and Spirochaetes were only found in the roots of common reed. Comparing the root-associated bacterial communities of reed and cattail in our system, many more species of bacteria related involved in the total nitrogen cycle were observed in reed versus cattail, while species involved in total phosphorus and organic matter removal were mainly found in cattail. Although we cannot determine their nutrient removal capacity separately, differences in the root-associated bacterial communities may be an important factor contributing to the differing water purification effects mediated by T. angustifolia and P. australis wetlands. Thus, further work describing the ecosystem functions of these bacterial species is needed, in order to fully understand how effective common reed- and narrow-leaved cattail-dominated wetlands are for phytoremediation.

  13. Developmental and nutritional regulation of isoflavone secretion from soybean roots.

    PubMed

    Sugiyama, Akifumi; Yamazaki, Yumi; Yamashita, Kazuaki; Takahashi, Seiji; Nakayama, Toru; Yazaki, Kazufumi

    2015-01-01

    Isoflavones play important roles in plant-microbe interactions in rhizospheres. Soybean roots secrete daidzein and genistein to attract rhizobia. Despite the importance of isoflavones in plant-microbe interactions, little is known about the developmental and nutritional regulation of isoflavone secretion from soybean roots. In this study, soybeans were grown in hydroponic culture, and isoflavone contents in tissues, isoflavone secretion from the roots, and the expression of isoflavone conjugates hydrolyzing beta-glucosidase (ICHG) were investigated. Isoflavone contents did not show strong growth-dependent changes, while secretion of daidzein from the roots dramatically changed, with higher secretion during vegetative stages. Coordinately, the expression of ICHG also peaked at vegetative stages. Nitrogen deficiency resulted in 8- and 15-fold increases in secretion of daidzein and genistein, respectively, with no induction of ICHG. Taken together, these results suggest that large amounts of isoflavones were secreted during vegetative stages via the hydrolysis of (malonyl)glucosides with ICHG.

  14. Synchrotron X-ray microfluorescence measurement of metal distributions in Phragmites australis root system in the Yangtze River intertidal zone

    SciTech Connect

    Feng, Huan; Zhang, Weiguo; Qian, Yu; Liu, Wenliang; Yu, Lizhong; Yoo, Shinjae; Wang, Jun; Wang, Jia-Jun; Eng, Christopher; Liu, Chang-Jun; Tappero, Ryan

    2016-06-15

    This study investigates the distributions of Br, Ca, Cl, Cr, Cu, K, Fe, Mn, Pb, Ti, V and Zn inPhragmites australisroot system and the function of Fe nanoparticles in scavenging metals in the root epidermis using synchrotron X-ray microfluorescence, synchrotron transmission X-ray microscope measurement and synchrotron X-ray absorption near-edge structure techniques. The purpose of this study is to understand the mobility of metals in wetland plant root systems after their uptake from rhizosphere soils.Phragmites australissamples were collected in the Yangtze River intertidal zone in July 2013. The results indicate that Fe nanoparticles are present in the root epidermis and that other metals correlate significantly with Fe, suggesting that Fe nanoparticles play an important role in metal scavenging in the epidermis.

  15. Synchrotron X-ray microfluorescence measurement of metal distributions in Phragmites australis root system in the Yangtze River intertidal zone

    SciTech Connect

    Feng, Huan; Zhang, Weiguo; Qian, Yu; Liu, Wenliang; Yu, Lizhong; Yoo, Shinjae; Wang, Jun; Wang, Jia -Jun; Eng, Christopher; Liu, Chang -Jun; Tappero, Ryan

    2016-06-15

    This paper investigates the distributions of Br, Ca, Cl, Cr, Cu, K, Fe, Mn, Pb, Ti, V and Zn in Phragmites australis root system and the function of Fe nanoparticles in scavenging metals in the root epidermis using synchrotron X-ray microfluorescence, synchrotron transmission X-ray microscope measurement and synchrotron X-ray absorption near-edge structure techniques. The purpose of this study is to understand the mobility of metals in wetland plant root systems after their uptake from rhizosphere soils. Phragmites australis samples were collected in the Yangtze River intertidal zone in July 2013. The results indicate that Fe nanoparticles are present in the root epidermis and that other metals correlate significantly with Fe, suggesting that Fe nanoparticles play an important role in metal scavenging in the epidermis.

  16. Synchrotron X-ray microfluorescence measurement of metal distributions in Phragmites australis root system in the Yangtze River intertidal zone

    SciTech Connect

    Feng, Huan; Zhang, Weiguo; Qian, Yu; Liu, Wenliang; Yu, Lizhong; Yoo, Shinjae; Wang, Jun; Wang, Jia -Jun; Eng, Christopher; Liu, Chang -Jun; Tappero, Ryan

    2016-06-15

    This paper investigates the distributions of Br, Ca, Cl, Cr, Cu, K, Fe, Mn, Pb, Ti, V and Zn in Phragmites australis root system and the function of Fe nanoparticles in scavenging metals in the root epidermis using synchrotron X-ray microfluorescence, synchrotron transmission X-ray microscope measurement and synchrotron X-ray absorption near-edge structure techniques. The purpose of this study is to understand the mobility of metals in wetland plant root systems after their uptake from rhizosphere soils. Phragmites australis samples were collected in the Yangtze River intertidal zone in July 2013. The results indicate that Fe nanoparticles are present in the root epidermis and that other metals correlate significantly with Fe, suggesting that Fe nanoparticles play an important role in metal scavenging in the epidermis.

  17. Root-secreted malic acid recruits beneficial soil bacteria.

    PubMed

    Rudrappa, Thimmaraju; Czymmek, Kirk J; Paré, Paul W; Bais, Harsh P

    2008-11-01

    Beneficial soil bacteria confer immunity against a wide range of foliar diseases by activating plant defenses, thereby reducing a plant's susceptibility to pathogen attack. Although bacterial signals have been identified that activate these plant defenses, plant metabolites that elicit rhizobacterial responses have not been demonstrated. Here, we provide biochemical evidence that the tricarboxylic acid cycle intermediate L-malic acid (MA) secreted from roots of Arabidopsis (Arabidopsis thaliana) selectively signals and recruits the beneficial rhizobacterium Bacillus subtilis FB17 in a dose-dependent manner. Root secretions of L-MA are induced by the foliar pathogen Pseudomonas syringae pv tomato (Pst DC3000) and elevated levels of L-MA promote binding and biofilm formation of FB17 on Arabidopsis roots. The demonstration that roots selectively secrete L-MA and effectively signal beneficial rhizobacteria establishes a regulatory role of root metabolites in recruitment of beneficial microbes, as well as underscores the breadth and sophistication of plant-microbial interactions.

  18. Kin recognition: another biological function for root secretions.

    PubMed

    Biedrzycki, Meredith L; Bais, Harsh P

    2010-04-01

    In the past, studies have shown that plants do indeed have the ability to recognize other plants in their surroundings based on relatedness and identity. Although, mechanisms for these recognitions have been proposed, to date, one has not been supported. In our recent work, we showed that Arabidopsis plants distinguish self/non self or kin/stranger plants through secretion and by recognition of root secretions. Additionally, we show that this kin response can be eliminated through treatment with a root secretion inhibitor and that the kin recognition response is robust through several Arabidopsis accessions. We hope that this study can promote the understanding of root secretion and its numerous roles in rhizosphere communications.

  19. Secretion of momilactone A from rice roots to the rhizosphere.

    PubMed

    Kato-Noguchi, Hisashi; Ino, Takeshi; Ota, Katsumi

    2008-05-05

    The secretion levels of momilactone A from rice (Oryza sativa L.) seedlings of eight cultivars into the rhizosphere were compared with the endogenous momilactone A concentrations in their shoots and roots. All rice cultivars contained momilactone A in the shoots and roots, and concentrations differed among the cultivars. Momilactone A was also found in all culture solutions in which the rice seedlings were grown, and the concentrations differed among the cultivars. The momilactone A concentrations in the culture solutions were reflected in the momilactone A concentrations in the shoots. These results suggest that all rice cultivars may produce momilactome A and secrete momilactone A into the culture solutions. The secretion levels of momilactone A may be more dependent on their capacities for momilactone A production in the shoots than on their capacities for momilactone A transportation from the shoots into the environment via the roots. As momilactone A acts as an antimicrobial and allelopathic agent, the secretion of momilactone A into the rice rhizosphere may provide a competitive advantage for root establishment through local suppression of soil microorganisms and inhibition of the growth of competing plant species.

  20. Synchrotron micro-scale measurement of metal distributions in Phragmites australis and Typha latifolia root tissue from an urban brownfield site.

    PubMed

    Feng, Huan; Qian, Yu; Gallagher, Frank J; Zhang, Weiguo; Yu, Lizhong; Liu, Changjun; Jones, Keith W; Tappero, Ryan

    2016-03-01

    Liberty State Park in New Jersey, USA, is a "brownfield" site containing various levels of contaminants. To investigate metal uptake and distributions in plants on the brownfield site, Phragmites australis and Typha latifolia were collected in Liberty State Park during the growing season (May-September) in 2011 at two sites with the high and low metal loads, respectively. The objective of this study was to understand the metal (Fe, Mn, Cu, Pb and Zn) concentration and spatial distributions in P. australis and T. latifolia root systems with micro-meter scale resolution using synchrotron X-ray microfluorescence (μXRF) and synchrotron X-ray computed microtomography (μCMT) techniques. The root structure measurement by synchrotron μCMT showed that high X-ray attenuation substance appeared in the epidermis. Synchrotron μXRF measurement showed that metal concentrations and distributions in the root cross-section between epidermis and vascular tissue were statistically different. Significant correlations were found between metals (Cu, Mn, Pb and Zn) and Fe in the epidermis, implying that metals were scavenged by Fe oxides. The results from this study suggest that the expression of metal transport and accumulation within the root systems may be element specific. The information derived from this study can improve our current knowledge of the wetland plant ecological function in brownfield remediation. Copyright © 2015. Published by Elsevier B.V.

  1. Synchrotron micro-scale measurement of metal distributions in Phragmites australis and Typha latifolia root tissue from an urban brownfield site

    DOE PAGES

    Feng, Huan; Qian, Yu; Gallagher, Frank J.; ...

    2015-11-01

    Liberty State Park in New Jersey, USA, is a “brownfield” site containing various levels of contaminants. To investigate metal uptake and distributions in plants on the brownfield site, Phragmites australis and Typha latifolia were collected in Liberty State Park during the growing season (May–September) in 2011 at two sites with the high and low metal loads, respectively. The objective of this study was to understand the metal (Fe, Mn, Cu, Pb and Zn) concentration and spatial distributions in P. australis and T. latifolia root systems with micro-meter scale resolution using synchrotron X-ray microfluorescence (μXRF) and synchrotron X-ray computed microtomography (μCMT)more » techniques. The root structure measurement by synchrotron μCMT showed that high X-ray attenuation substance appeared in the epidermis. Synchrotron μXRF measurement showed that metal concentrations and distributions in the root cross-section between epidermis and vascular tissue were statistically different. Significant correlations were found between metals (Cu, Mn, Pb and Zn) and Fe in the epidermis, implying that metals were scavenged by Fe oxides. The results from this study suggest that the expression of metal transport and accumulation within the root systems may be element specific. The information derived from this study can improve our current knowledge of the wetland plant ecological function in brownfield remediation.« less

  2. Root tip-dependent, active riboflavin secretion by Hyoscyamus albus hairy roots under iron deficiency.

    PubMed

    Higa, Ataru; Miyamoto, Erika; ur Rahman, Laiq; Kitamura, Yoshie

    2008-04-01

    Hyoscyamus albus hairy roots with/without an exogenous gene (11 clones) were established by inoculation of Agrobacterium rhizogenes. All clones cultured under iron-deficient condition secreted riboflavin from the root tips into the culture medium and the productivity depended on the number and size of root tips among the clones. A decline of pH was observed before riboflavin production and root development. By studying effects of proton-pump inhibitors, medium acidification with external organic acid, and riboflavin addition upon pH change and riboflavin productivity, we indicate that riboflavin efflux is not directly connected to active pH reduction, and more significantly active riboflavin secretion occurs as a response to an internal requirement in H. albus hairy roots under iron deficiency.

  3. Studies on the Secretion of Maize Root Cap Slime

    PubMed Central

    Paull, Robert E.; Johnson, Clarence M.; Jones, Russell L.

    1975-01-01

    The secreted slime from root cap cells of corn (Zea mays, cv. SX-17) was studied. Production of slime by excised root tips is stimulated by the addition of 40 mM sucrose or fucose and half-strength Hoagland's solution to the incubation medium. Secreted slime was recovered from aqueous solution by precipitation with ethanol. The polymer has a molecular weight greater than 2 × 10−6 daltons and a density of 1.63 g cm−3. Protein is not present in material purified by density gradient centrifugation with cesium chloride. Fucose (39%) and galactose (30%) are the principle neutral sugars found in the purified polymer. Galacturonic and glucuronic acids, arabinose, xylose, mannose, and glucose are also present. PMID:16659291

  4. Arbuscular mycorrhizal fungus modulates the phytotoxicity of Cd via combined responses of enzymes, thiolic compounds, and essential elements in the roots of Phragmites australis.

    PubMed

    Huang, Xiaochen; Wang, Li; Ma, Fang

    2017-11-01

    The positive effects of arbuscular mycorrhizal (AM) fungi on host plants under heavy metal (HM) stress conditions have been widely recognized. HMs are known to induce phytotoxicity through 1) the production of reactive oxygen species (ROS), 2) the direct interaction with thiol groups or 3) the competition with essential elements. However, how AM fungus inoculation can affect defense mechanisms against cadmium (Cd) stress, which can regulate and alleviate the phytotoxicity via different pathways, is still unclear. We hypothesized that one or some factors in each pathway of phytotoxicity were involved in detoxifying Cd by inoculating with AM fungus. In this study, the involvements of enzymes, thiolic compounds, and divalent essential elements in the roots of Phragmites australis (Cav.) Trin. ex Steud. were assessed. In addition, we also worked to elucidate the significant factors among three possible pathways involved in biosynthesis with AM fungus inoculation, using principal component analysis (PCA). The results presented here indicate that AM symbiosis can result in a marked tolerance to Cd via accumulating Cd with a shorter exposure treatment time, and obvious fluorescence in the roots was also observed. The decrease in phytotoxicity was mainly accomplished by changes in superoxide dismutase (SOD), catalase (CAT), non-protein thiols (NPT), calcium (Ca), manganese (Mn), and copper (Cu). These results provide comprehensive insights for elucidating the defense mechanisms by which inoculation with AM fungus has beneficial roles in helping P. australis cope with the deleterious effects of Cd. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Aurora Australis

    NASA Image and Video Library

    Video of the Aurora Australis taken by the crew of Expedition 29 on board the International Space Station. This sequence of shots was taken September 17, 2011 from 17:22:27 to 17:45:12 GMT, on an a...

  6. Root parasitic plant Orobanche aegyptiaca and shoot parasitic plant Cuscuta australis obtained Brassicaceae-specific strictosidine synthase-like genes by horizontal gene transfer

    PubMed Central

    2014-01-01

    Background Besides gene duplication and de novo gene generation, horizontal gene transfer (HGT) is another important way of acquiring new genes. HGT may endow the recipients with novel phenotypic traits that are important for species evolution and adaption to new ecological niches. Parasitic systems expectedly allow the occurrence of HGT at relatively high frequencies due to their long-term physical contact. In plants, a number of HGT events have been reported between the organelles of parasites and the hosts, but HGT between host and parasite nuclear genomes has rarely been found. Results A thorough transcriptome screening revealed that a strictosidine synthase-like (SSL) gene in the root parasitic plant Orobanche aegyptiaca and the shoot parasitic plant Cuscuta australis showed much higher sequence similarities with those in Brassicaceae than with those in their close relatives, suggesting independent gene horizontal transfer events from Brassicaceae to these parasites. These findings were strongly supported by phylogenetic analysis and their identical unique amino acid residues and deletions. Intriguingly, the nucleus-located SSL genes in Brassicaceae belonged to a new member of SSL gene family, which were originated from gene duplication. The presence of introns indicated that the transfer occurred directly by DNA integration in both parasites. Furthermore, positive selection was detected in the foreign SSL gene in O. aegyptiaca but not in C. australis. The expression of the foreign SSL genes in these two parasitic plants was detected in multiple development stages and tissues, and the foreign SSL gene was induced after wounding treatment in C. australis stems. These data imply that the foreign genes may still retain certain functions in the recipient species. Conclusions Our study strongly supports that parasitic plants can gain novel nuclear genes from distantly related host species by HGT and the foreign genes may execute certain functions in the new hosts

  7. Genetics, novel weapons and rhizospheric microcosmal signaling in the invasion of Phragmites australis

    PubMed Central

    Rudrappa, Thimmaraju

    2008-01-01

    Chemical communication and perception strategies between plants are highly sophisticated but are only partly understood. Among the different interactions, the suppressive interaction of a class of chemicals released by one plant through root exudates against the neighbouring plants (allelopathy) have been implicated in the invasiveness of many exotic weedy species. Phragmites australis (common reed) is one of the dominant colonizers of the North American wetland marshes and exhibits invasive behavior by virtually replacing the entire native vegetation in its niche. Recently, by adopting a systematic bioassay driven approach we elucidated the role of root derived allelopathy as one of the important mechanisms by which P. australis exerts its invasive behavior. Additionally, our recent preliminary data indicates the involvement of rhizobacterial signaling in the invasive success of P. australis. A better understanding of biochemical weaponry used by P. australis will aid scientists and technologists in addressing the impact of root secretions in invasiveness of weedy species and thus promote a more informed environmental stewardship. PMID:19516974

  8. Aurora Australis

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Red and Green colors predominate in this view of the Aurora Australis photographed from the Space Shuttle Discovery (STS-39) in May 1991 at the peak of the last geomagnetic maximum. The payload bay and tail of the shuttle can be seen on the left hand side of the picture. Auroras are caused when high-energy electrons pour down from the Earth's magnetosphere and collide with atoms. Red aurora occurs from 200 km to as high as 500 km altitude and is caused by the emission of 6300 Angstrom wavelength light from oxygen atoms. Green aurora occurs from about 100 km to 250 km altitude and is caused by the emission of 5577 Angstrom wavelength light from oxygen atoms. The light is emitted when the atoms return to their original unexcited state. At times of peaks in solar activity, there are more geomagnetic storms and this increases the auroral activity viewed on Earth and by astronauts from orbit.

  9. Functional Role of Bacteria from Invasive Phragmites australis in Promotion of Host Growth.

    PubMed

    Soares, M A; Li, H-Y; Kowalski, K P; Bergen, M; Torres, M S; White, J F

    2016-08-01

    We hypothesize that bacterial endophytes may enhance the competitiveness and invasiveness of Phragmites australis. To evaluate this hypothesis, endophytic bacteria were isolated from P. australis. The majority of the shoot meristem isolates represent species from phyla Firmicutes, Proteobacteria, and Actinobacteria. We chose one species from each phylum to characterize further and to conduct growth promotion experiments in Phragmites. Bacteria tested include Bacillus amyloliquefaciens A9a, Achromobacter spanius B1, and Microbacterium oxydans B2. Isolates were characterized for known growth promotional traits, including indole acetic acid (IAA) production, secretion of hydrolytic enzymes, phosphate solubilization, and antibiosis activity. Potentially defensive antimicrobial lipopeptides were assayed for through application of co-culturing experiments and mass spectrometer analysis. B. amyloliquefaciens A9a and M. oxydans B2 produced IAA. B. amyloliquefaciens A9a secreted antifungal lipopeptides. Capability to promote growth of P. australis under low nitrogen conditions was evaluated in greenhouse experiments. All three isolates were found to increase the growth of P. australis under low soil nitrogen conditions and showed increased absorption of isotopic nitrogen into plants. This suggests that the Phragmites microbes we evaluated most likely promote growth of Phragmites by enhanced scavenging of nitrogenous compounds from the rhizosphere and transfer to host roots. Collectively, our results support the hypothesis that endophytic bacteria play a role in enhancing growth of P. australis in natural populations. Gaining a better understanding of the precise contributions and mechanisms of endophytes in enabling P. australis to develop high densities rapidly could lead to new symbiosis-based strategies for management and control of the host.

  10. Functional role of bacteria from invasive Phragmites australis in promotion of host growth

    USGS Publications Warehouse

    Soares, M. A.; Li, H-Y; Kowalski, Kurt P.; Bergen, M.; Torres, M. S.; White, J. F.

    2016-01-01

    We hypothesize that bacterial endophytes may enhance the competitiveness and invasiveness of Phragmites australis. To evaluate this hypothesis, endophytic bacteria were isolated from P. australis. The majority of the shoot meristem isolates represent species from phyla Firmicutes, Proteobacteria, and Actinobacteria. We chose one species from each phylum to characterize further and to conduct growth promotion experiments in Phragmites. Bacteria tested include Bacillus amyloliquefaciens A9a, Achromobacter spanius B1, and Microbacterium oxydans B2. Isolates were characterized for known growth promotional traits, including indole acetic acid (IAA) production, secretion of hydrolytic enzymes, phosphate solubilization, and antibiosis activity. Potentially defensive antimicrobial lipopeptides were assayed for through application of co-culturing experiments and mass spectrometer analysis. B. amyloliquefaciens A9a and M. oxydans B2 produced IAA. B. amyloliquefaciens A9a secreted antifungal lipopeptides. Capability to promote growth of P. australis under low nitrogen conditions was evaluated in greenhouse experiments. All three isolates were found to increase the growth of P. australis under low soil nitrogen conditions and showed increased absorption of isotopic nitrogen into plants. This suggests that the Phragmites microbes we evaluated most likely promote growth of Phragmites by enhanced scavenging of nitrogenous compounds from the rhizosphere and transfer to host roots. Collectively, our results support the hypothesis that endophytic bacteria play a role in enhancing growth of P. australis in natural populations. Gaining a better understanding of the precise contributions and mechanisms of endophytes in enabling P. australis to develop high densities rapidly could lead to new symbiosis-based strategies for management and control of the host.

  11. Root-secreted nicotianamine from Arabidopsis halleri facilitates zinc hypertolerance by regulating zinc bioavailability.

    PubMed

    Tsednee, Munkhtsetseg; Yang, Shun-Chung; Lee, Der-Chuen; Yeh, Kuo-Chen

    2014-10-01

    Hyperaccumulators tolerate and accumulate extraordinarily high concentrations of heavy metals. Content of the metal chelator nicotianamine (NA) in the root of zinc hyperaccumulator Arabidopsis halleri is elevated compared with nonhyperaccumulators, a trait that is considered to be one of the markers of a hyperaccumulator. Using metabolite-profiling analysis of root secretions, we found that excess zinc treatment induced secretion of NA in A. halleri roots compared with the nonhyperaccumulator Arabidopsis thaliana. Metal speciation analysis further revealed that the secreted NA forms a stable complex with Zn(II). Supplying NA to a nonhyperaccumulator species markedly increased plant zinc tolerance by decreasing zinc uptake. Therefore, NA secretion from A. halleri roots facilitates zinc hypertolerance through forming a Zn(II)-NA complex outside the roots to achieve a coordinated zinc uptake rate into roots. Secretion of NA was also found to be responsible for the maintenance of iron homeostasis under excess zinc. Together our results reveal root-secretion mechanisms associated with hypertolerance and hyperaccumulation. © 2014 American Society of Plant Biologists. All Rights Reserved.

  12. Synchrotron micro-scale measurement of metal distributions in Phragmites australis and Typha latifolia root tissue from an urban brownfield site

    SciTech Connect

    Feng, Huan; Qian, Yu; Gallagher, Frank J.; Zhang, Weiguo; Yu, Lizhong; Liu, Chang -Jun; Jones, Keith W.; Tappero, Ryan

    2015-11-01

    Liberty State Park in New Jersey, USA, is a “brownfield” site containing various levels of contaminants. To investigate metal uptake and distributions in plants on the brownfield site, Phragmites australis and Typha latifolia were collected in Liberty State Park during the growing season (May–September) in 2011 at two sites with the high and low metal loads, respectively. The objective of this study was to understand the metal (Fe, Mn, Cu, Pb and Zn) concentration and spatial distributions in P. australis and T. latifolia root systems with micro-meter scale resolution using synchrotron X-ray microfluorescence (μXRF) and synchrotron X-ray computed microtomography (μCMT) techniques. The root structure measurement by synchrotron μCMT showed that high X-ray attenuation substance appeared in the epidermis. Synchrotron μXRF measurement showed that metal concentrations and distributions in the root cross-section between epidermis and vascular tissue were statistically different. Significant correlations were found between metals (Cu, Mn, Pb and Zn) and Fe in the epidermis, implying that metals were scavenged by Fe oxides. The results from this study suggest that the expression of metal transport and accumulation within the root systems may be element specific. The information derived from this study can improve our current knowledge of the wetland plant ecological function in brownfield remediation.

  13. Production and secretion of a heterologous protein by turnip hairy roots with superiority over tobacco hairy roots.

    PubMed

    Huet, Yoann; Ekouna, Jean-Pierre Ele; Caron, Aurore; Mezreb, Katiba; Boitel-Conti, Michèle; Guerineau, François

    2014-01-01

    A fully contained and efficient heterologous protein production system was designed using Brassica rapa rapa (turnip) hairy roots. Two expression cassettes containing a cauliflower mosaic virus (CaMV) 35S promoter with a duplicated enhancer region, an Arabidopsis thaliana sequence encoding a signal peptide and the CaMV polyadenylation signal were constructed. One cassette was used to express the green fluorescent protein (GFP)-encoding gene in hairy roots grown in flasks. A stable and fast-growing hairy root line secreted GFP at >120 mg/l culture medium. GFP represented 60 % of the total soluble proteins in the culture medium. Turnip hairy roots retained sustainable growth and stable GFP production over 3 years. These results were superior to those obtained using tobacco hairy roots.

  14. Induced root-secreted phenolic compounds as a belowground plant defense

    PubMed Central

    Burlat, Vincent; Schurr, Ulrich; Röse, Ursula SR

    2010-01-01

    Rhizosphere is the complex place of numerous interactions between plant roots, microbes and soil fauna. Whereas plant interactions with aboveground organisms are largely described, unravelling plant belowground interactions remains challenging. Plant root chemical communication can lead to positive interactions with nodulating bacteria, mycorriza or biocontrol agents or to negative interactions with pathogens or root herbivores. A recent study1 suggested that root exudates contribute to plant pathogen resistance via secretion of antimicrobial compounds. These findings point to the importance of plant root exudates as belowground signalling molecules, particularly in defense responses. In our report,2 we showed that under Fusarium attack the barley root system launched secretion of phenolic compounds with antimicrobial activity. The secretion of de novo biosynthesized t-cinnamic acid induced within 2 days illustrates the dynamic of plant defense mechanisms at the root level. We discuss the costs and benefits of induced defense responses in the rhizosphere. We suggest that plant defense through root exudation may be cultivar dependent and higher in wild or less domesticated varieties. PMID:20699651

  15. The involvement of glucose-6-phosphatase in mucilage secretion by root cap cells of Zea mays

    NASA Technical Reports Server (NTRS)

    Moore, R.; McClelen, C. E.

    1985-01-01

    In order to determine the involvement of glucose-6-phosphatase in mucilage secretion by root cap cells, we have cytochemically localized the enzyme in columella and peripheral cells of root caps of Zea mays. Glucose-6-phosphatase is associated with the plasmalemma and cell wall of columella cells. As columella cells differentiate into peripheral cells and begin to produce and secrete mucilage, glucose-6-phosphatase staining intensifies and becomes associated with the mucilage and, to a lesser extent, the cell wall. Cells being sloughed from the cap are characterized by glucose-6-phosphatase staining being associated with the vacuole and plasmalemma. These changes in enzyme localization during cellular differentiation in root caps suggest that glucose-6-phosphatase is involved in the production and/or secretion of mucilage by peripheral cells of Z. mays.

  16. The involvement of glucose-6-phosphatase in mucilage secretion by root cap cells of Zea mays

    NASA Technical Reports Server (NTRS)

    Moore, R.; McClelen, C. E.

    1985-01-01

    In order to determine the involvement of glucose-6-phosphatase in mucilage secretion by root cap cells, we have cytochemically localized the enzyme in columella and peripheral cells of root caps of Zea mays. Glucose-6-phosphatase is associated with the plasmalemma and cell wall of columella cells. As columella cells differentiate into peripheral cells and begin to produce and secrete mucilage, glucose-6-phosphatase staining intensifies and becomes associated with the mucilage and, to a lesser extent, the cell wall. Cells being sloughed from the cap are characterized by glucose-6-phosphatase staining being associated with the vacuole and plasmalemma. These changes in enzyme localization during cellular differentiation in root caps suggest that glucose-6-phosphatase is involved in the production and/or secretion of mucilage by peripheral cells of Z. mays.

  17. Molecular farming in tobacco hairy roots by triggering the secretion of a pharmaceutical antibody.

    PubMed

    Häkkinen, Suvi T; Raven, Nicole; Henquet, Maurice; Laukkanen, Marja-Leena; Anderlei, Tibor; Pitkänen, Juha-Pekka; Twyman, Richard M; Bosch, Dirk; Oksman-Caldentey, Kirsi-Marja; Schillberg, Stefan; Ritala, Anneli

    2014-02-01

    Recombinant pharmaceutical proteins expressed in hairy root cultures can be secreted into the medium to improve product homogeneity and to facilitate purification, although this may result in significant degradation if the protein is inherently unstable or particularly susceptible to proteases. To address these challenges, we used a design of experiments approach to develop an optimized induction protocol for the cultivation of tobacco hairy roots secreting the full-size monoclonal antibody M12. The antibody yield was enhanced 30-fold by the addition of 14 g/L KNO3 , 19 mg/L 1-naphthaleneacetic acid and 1.5 g/L of the stabilizing agent polyvinylpyrrolidone. Analysis of hairy root cross sections revealed that the optimized medium induced lateral root formation and morphological changes in the inner cortex and pericycle cells, indicating that the improved productivity was at least partially based on the enhanced efficiency of antibody secretion. We found that 57% of the antibody was secreted, yielding 5.9 mg of product per liter of induction medium. Both the secreted and intracellular forms of the antibody could be isolated by protein A affinity chromatography and their functionality was confirmed using vitronectin-binding assays. Glycan analysis revealed three major plant complex-type glycans on both forms of the antibody, although the secreted form was more homogeneous due to the predominance of a specific glycoform. Tobacco hairy root cultures therefore offer a practical solution for the production of homogeneous pharmaceutical antibodies in containment. © 2013 Wiley Periodicals, Inc.

  18. Defective secretion of mucilage is the cellular basis for agravitropism in primary roots of Zea mays cv. Ageotropic

    NASA Technical Reports Server (NTRS)

    Miller, I.; Moore, R.

    1990-01-01

    Root caps of primary, secondary, and seminal roots of Z. mays cv. Kys secrete large amounts of mucilage and are in close contact with the root all along the root apex. These roots are strongly graviresponsive. Secondary and seminal roots of Z. mays cv. Ageotropic are also strongly graviresponsive. Similarly, their caps secrete mucilage and closely appress the root all along the root apex. However, primary roots of Z. mays cv. Ageotropic are non-responsive to gravity. Their caps secrete negligible amounts of mucilage and contact the root only at the extreme apex of the root along the calyptrogen. These roots become graviresponsive when their tips are coated with mucilage or mucilage-like materials. Peripheral cells of root caps of roots of Z. mays cv. Kys contain many dictyosomes associated with vesicles that migrate to and fuse with the plasmalemma. Root-cap cells of secondary and seminal (i.e. graviresponsive) roots of Z. mays cv. Ageotropic are similar to those of primary roots of Z. mays cv. Kys. However, root-cap cells of primary (i.e. non-graviresponsive) roots of Z. mays cv. Ageotropic have distended dictyosomal cisternae filled with an electron-dense, granular material. Large vesicles full of this material populate the cells and apparently do not fuse with the plasmalemma. Taken together, these results suggest that non-graviresponsiveness of primary roots of Z. mays cv. Ageotropic results from the lack of apoplastic continuity between the root and the periphery of the root cap. This is a result of negligible secretion of mucilage by cells along the edge of the root cap which, in turn, appears to be due to the malfunctioning of dictyosomes in these cells.

  19. Defective secretion of mucilage is the cellular basis for agravitropism in primary roots of Zea mays cv. Ageotropic

    NASA Technical Reports Server (NTRS)

    Miller, I.; Moore, R.

    1990-01-01

    Root caps of primary, secondary, and seminal roots of Z. mays cv. Kys secrete large amounts of mucilage and are in close contact with the root all along the root apex. These roots are strongly graviresponsive. Secondary and seminal roots of Z. mays cv. Ageotropic are also strongly graviresponsive. Similarly, their caps secrete mucilage and closely appress the root all along the root apex. However, primary roots of Z. mays cv. Ageotropic are non-responsive to gravity. Their caps secrete negligible amounts of mucilage and contact the root only at the extreme apex of the root along the calyptrogen. These roots become graviresponsive when their tips are coated with mucilage or mucilage-like materials. Peripheral cells of root caps of roots of Z. mays cv. Kys contain many dictyosomes associated with vesicles that migrate to and fuse with the plasmalemma. Root-cap cells of secondary and seminal (i.e. graviresponsive) roots of Z. mays cv. Ageotropic are similar to those of primary roots of Z. mays cv. Kys. However, root-cap cells of primary (i.e. non-graviresponsive) roots of Z. mays cv. Ageotropic have distended dictyosomal cisternae filled with an electron-dense, granular material. Large vesicles full of this material populate the cells and apparently do not fuse with the plasmalemma. Taken together, these results suggest that non-graviresponsiveness of primary roots of Z. mays cv. Ageotropic results from the lack of apoplastic continuity between the root and the periphery of the root cap. This is a result of negligible secretion of mucilage by cells along the edge of the root cap which, in turn, appears to be due to the malfunctioning of dictyosomes in these cells.

  20. PIN2 is required for the adaptation of Arabidopsis roots to alkaline stress by modulating proton secretion

    PubMed Central

    Xu, Weifeng; Jia, Liguo; Shi, Weiming; Zhang, Jianhua

    2012-01-01

    Soil alkalinity is a widespread environmental problem that limits agricultural productivity. The hypothesis that an auxin-regulated proton secretion by plasma membrane H+-ATPase plays an important role in root adaption to alkaline stress was studied. It was found that alkaline stress increased auxin transport and PIN2 (an auxin efflux transporter) abundance in the root tip of wild-type Arabidopsis plants (WT). Compared with WT roots, the pin2 mutant roots exhibited much reduced plasma membrane H+-ATPase activity, root elongation, auxin transport, and proton secretion under alkaline stress. More importantly, roots of the pks5 mutant (PKS5, a protein kinase) lacking PIN2 (a pks5/pin2 double mutant) lost the previous higher proton-secretion capacity and higher elongation rate of primary roots under alkaline stress. By using Arabidopsis natural accessions with a high proton-secretion capacity, it was found that their PIN2 transcription abundance is positively related to the elongation rate of the primary root and proton-secretion capacity under alkaline stress. Taken together, our results confirm that PIN2 is involved in the PKS5-mediated signalling cascade under alkaline-stress and suggest that PIN2 is required for the adaptation of roots to alkaline stress by modulating proton secretion in the root tip to maintain primary root elongation. PMID:23002434

  1. Production and secretion of recombinant thaumatin in tobacco hairy root cultures.

    PubMed

    Pham, Ngoc Bich; Schäfer, Holger; Wink, Michael

    2012-04-01

    Production of recombinant proteins in plant cell or organ cultures and their secretion into the plant cell culture medium simplify the purification procedure and increase protein yield. In this study, the sweet-tasting protein thaumatin I was expressed and successfully secreted from tobacco hairy root cultures. The presence of an ER signal peptide appears to be crucial for the secretion of thaumatin: without an ER signal peptide, no thaumatin was detectable in the spent medium, whereas inclusion of the ER signal peptide calreticulin fused to the N terminus of thaumatin led to the secretion of thaumatin into the spent medium of hairy root cultures at concentrations of up to 0.21 mg/L. Extracellular thaumatin levels reached a maximum after 30 days (stationary phase) and the subsequent decline was linked to the rapid increase of proteases in the medium. Significant amounts of thaumatin were trapped in the apoplastic space of the root cells. The addition of polyvinylpyrrolidone and sodium chloride into the culture medium led to an increase of extracellular thaumatin amounts up to 1.4 and 2.63 mg/L, respectively. Thaumatin production compares well with yields from other transgenic plants, so that tobacco hairy roots can be considered an alternative production platform of thaumatin. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Effects of liming on potential oxalate secretion and iron chelation of beech ectomycorrhizal root tips.

    PubMed

    Rineau, François; Garbaye, Jean

    2010-08-01

    Liming is used to counteract forest decline induced by soil acidification. It consists of Ca and Mg input to forest soil and not only restores tree mineral nutrition but also modifies the availability of nutrients in soil. Ectomycorrhizal (ECM) fungi are involved in mineral nutrient uptake by trees and can recover them through dissolution of mineral surface. Oxalate and siderophore secretion are considered as the main agents of mineral weathering by ECMs. Here, we studied the effects of liming on the potential oxalate secretion and iron complexation by individual beech ECM root tips. Results show that freshly excised Lactarius subdulcis root tips from limed plots presented a high potential oxalate exudation of 177 μM tip(-1) h(-1). As this ECM species distribution is very dense, it is likely that, in the field, oxalate concentrations in the vicinity of its clusters could be very high. This points out that not only extraradical mycelium but also ECM root tips of certain species can contribute significantly to mineral weathering. Nonmetric multidimensional scaling (NMDS) separated potential oxalate production by ECM root tips in limed and untreated plots, and this activity was mainly driven by L. subdulcis ECMs, but NMDS on potential activity of iron mobilization by ECM root tips did not show a difference between limed and untreated plots. As the mean oxalate secretion did not significantly correlated with the mean iron mobilization by ECM morphotype, we conclude that iron complexation was due to either other organic acids or to siderophores.

  3. Abscisic acid accumulation modulates auxin transport in the root tip to enhance proton secretion for maintaining root growth under moderate water stress.

    PubMed

    Xu, Weifeng; Jia, Liguo; Shi, Weiming; Liang, Jiansheng; Zhou, Feng; Li, Qianfeng; Zhang, Jianhua

    2013-01-01

    Maintenance of root growth is essential for plant adaptation to soil drying. Here, we tested the hypothesis that auxin transport is involved in mediating ABA's modulation by activating proton secretion in the root tip to maintain root growth under moderate water stress. Rice and Arabidopsis plants were raised under a hydroponic system and subjected to moderate water stress (-0.47 MPa) with polyethylene glycol (PEG). ABA accumulation, auxin transport and plasma membrane H(+)-ATPase activity at the root tip were monitored in addition to the primary root elongation and root hair density. We found that moderate water stress increases ABA accumulation and auxin transport in the root apex. Additionally, ABA modulation is involved in the regulation of auxin transport in the root tip. The transported auxin activates the plasma membrane H(+)-ATPase to release more protons along the root tip in its adaption to moderate water stress. The proton secretion in the root tip is essential in maintaining or promoting primary root elongation and root hair development under moderate water stress. These results suggest that ABA accumulation modulates auxin transport in the root tip, which enhances proton secretion for maintaining root growth under moderate water stress.

  4. Enhancement of ginsenoside biosynthesis and secretion by Tween 80 in Panax ginseng hairy roots.

    PubMed

    Liang, Yanlong; Wu, Jianjun; Li, Yao; Li, Jian; Ouyang, Yong; He, Zhi; Zhao, Shoujing

    2015-01-01

    We evaluated the effect of Tween 80 permeabilization on ginsenoside secretion in Panax ginseng hairy roots. Tween 80 (1.2%, w/v) had no significant effect on hairy root vitality. After a 25-day treatment with Tween 80, approximately 76% of the total ginsenosides was released into the surrounding medium. In the case of control, the ginsenosides secreted into the medium were negligible. Furthermore, when compared with control, the level of total ginsenosides was enhanced by approximately threefold under Tween treatment. Additionally, secretion of the typical ginsenoside monomers including Rb1 , Rg1 , and Re was analyzed, indicating that the most of them were released into the medium. Moreover, it was observed that dammarenediol synthase, a key enzyme involved in ginsenoside biosynthesis, was upregulated at both gene expression and enzyme activity levels. The expression of genes CYP716A47 and CYP716A53v2 encoding Cyt P450 enzymes catalyzing the formation of protopanaxadiol from dammarenediol and protopanaxatriol from protopanaxadiol, respectively, was slightly upregulated. These results clearly demonstrated that Tween 80 could act not only as an efficient permeabilizer to enhance ginsenoside secretion from the hairy roots, but also as an elicitor to promote the biosynthesis of ginsenoside.

  5. Cadmium-induced oxalate secretion from root apex is associated with cadmium exclusion and resistance in Lycopersicon esulentum.

    PubMed

    Zhu, Xiao Fang; Zheng, Cheng; Hu, Yi Ting; Jiang, Tao; Liu, Yu; Dong, Ning Yu; Yang, Jian Li; Zheng, Shao Jian

    2011-07-01

    The mechanisms of heavy metal resistance in plants can be classified into internal tolerance and exclusion mechanisms, but exclusion of heavy metals with the help of organic acids secretion has not been well documented. Here we demonstrated the contribution of oxalate secretion to cadmium (Cd) exclusion and resistance in tomato. Different Cd resistance between two tomato cultivars was evaluated by relative root elongation (RRE) and Cd accumulation. Cultivar 'Micro-Tom' showed better growth and lower Cd content in roots than 'Hezuo903' at different Cd concentrations not only in short-term hydroponic experiment but also in long-term hydroponic and soil experiments, indicating that the genotypic difference in Cd resistance is related to the exclusion of Cd from roots. 'Micro-Tom' had greater ability to secrete oxalate, suggesting that oxalate secretion might contribute to Cd resistance. Cd-induced secretion of oxalate was localized to root apex at which the majority of Cd accumulated. Phenylglyoxal, an anion-channel inhibitor, effectively blocked Cd-induced oxalate secretion and aggravated Cd toxicity while exogenous oxalate supply ameliorated Cd toxicity efficiently. These results indicated that the oxalate secreted from the root apex helps to exclude Cd from entering tomato roots, thus contributes to Cd resistance in the Cd-resistant tomato cultivar. © 2011 Blackwell Publishing Ltd.

  6. Root-Secreted Nicotianamine from Arabidopsis halleri Facilitates Zinc Hypertolerance by Regulating Zinc Bioavailability1[W][OPEN

    PubMed Central

    Tsednee, Munkhtsetseg; Yang, Shun-Chung; Lee, Der-Chuen; Yeh, Kuo-Chen

    2014-01-01

    Hyperaccumulators tolerate and accumulate extraordinarily high concentrations of heavy metals. Content of the metal chelator nicotianamine (NA) in the root of zinc hyperaccumulator Arabidopsis halleri is elevated compared with nonhyperaccumulators, a trait that is considered to be one of the markers of a hyperaccumulator. Using metabolite-profiling analysis of root secretions, we found that excess zinc treatment induced secretion of NA in A. halleri roots compared with the nonhyperaccumulator Arabidopsis thaliana. Metal speciation analysis further revealed that the secreted NA forms a stable complex with Zn(II). Supplying NA to a nonhyperaccumulator species markedly increased plant zinc tolerance by decreasing zinc uptake. Therefore, NA secretion from A. halleri roots facilitates zinc hypertolerance through forming a Zn(II)-NA complex outside the roots to achieve a coordinated zinc uptake rate into roots. Secretion of NA was also found to be responsible for the maintenance of iron homeostasis under excess zinc. Together our results reveal root-secretion mechanisms associated with hypertolerance and hyperaccumulation. PMID:25118254

  7. Base to Tip and Long-Distance Transport of Sodium in the Root of Common Reed [Phragmites australis (Cav.) Trin. ex Steud.] at Steady State Under Constant High-Salt Conditions.

    PubMed

    Fujimaki, Shu; Maruyama, Teppei; Suzui, Nobuo; Kawachi, Naoki; Miwa, Eitaro; Higuchi, Kyoko

    2015-05-01

    We analyzed the directions and rates of translocation of sodium ions (Na(+)) within tissues of a salt-tolerant plant, common reed [Phragmites australis (Cav.) Trin. ex Steud.], and a salt-sensitive plant, rice (Oryza sativa L.), under constant high-salt conditions using radioactive (22)Na tracer and a positron-emitting tracer imaging system (PETIS). First, the test plants were incubated in a nutrient solution containing 50 mM NaCl and a trace level of (22)Na for 24 h (feeding step). Then the original solution was replaced with a fresh solution containing 50 mM NaCl but no (22)Na, in which the test plants remained for >48 h (chase step). Non-invasive dynamic visualization of (22)Na distribution in the test plants was conducted during feeding and chase steps with PETIS. Our results revealed that (22)Na was absorbed in the roots of common reed, but not transported to the upper shoot beyond the shoot base. During the chase step, a basal to distal movement of (22)Na was detected within the root tissue over >5 cm with a velocity of approximately 0.5 cm h(-1). On the other hand, (22)Na that was absorbed in the roots of rice was continuously translocated to and accumulated in the whole shoot. We concluded that the basal roots and the shoot base of common reed have constitutive functions of Na(+) exclusion only in the direction of root tips, even under constant high-salt conditions. This function apparently may contribute to the low Na(+) concentration in the upper shoot and high salt tolerance of common reed.

  8. Iron deficiency induces changes in riboflavin secretion and the mitochondrial electron transport chain in hairy roots of Hyoscyamus albus.

    PubMed

    Higa, Ataru; Mori, Yuko; Kitamura, Yoshie

    2010-07-15

    Hyoscyamus albus hairy roots secrete riboflavin under Fe-deficient conditions. To determine whether this secretion was linked to an enhancement of respiration, both riboflavin secretion and the reduction of 2,3,5-triphenyltetrazolium chloride (TTC), as a measure of respiration activity, were determined in hairy roots cultured under Fe-deficient and Fe-replete conditions, with or without aeration. Appreciable TTC-reducing activity was detected at the root tips, at the bases of lateral roots and in internal tissues, notably the vascular system. TTC-reducing activity increased under Fe deficiency and this increase occurred in concert with riboflavin secretion and was more apparent under aeration. Riboflavin secretion was not apparent under Fe-replete conditions. In order to examine which elements of the mitochondrial electron transport chain might be involved, the effects of the respiratory inhibitors, barbiturate, dicoumarol, malonic acid, antimycin, KCN and salicylhydroxamic acid (SHAM) were investigated. Under Fe-deficient conditions, malonic acid affected neither root growth, TTC-reducing activity nor riboflavin secretion, whereas barbiturate and SHAM inhibited only root growth and TTC-reducing activity, respectively, and the other compounds variously inhibited growth and TTC-reducing activity. Riboflavin secretion was decreased, in concert with TTC-reducing activity, by dicoumarol, antimycin and KCN, but not by SHAM. In Fe-replete roots, all inhibitors which reduced riboflavin secretion in Fe-deficient roots showed somewhat different effects: notably, antimycin and KCN did not significantly inhibit TTC-reducing activity and the inhibition by dicoumarol was much weaker in Fe-replete roots. Combined treatment with KCN and SHAM also revealed that Fe-deficient and Fe-replete roots reduced TTC in different ways. A decrease in the Fe content of mitochondria in Fe-deficient roots was confirmed. Overall, the results suggest that, under conditions of Fe deficiency in H

  9. Time lapse - Aurora Australis

    NASA Image and Video Library

    2013-07-05

    ISS040-E-040103 (5 July 2014) --- As the International Space Station was flying at an altitude of 226 nautical miles on July 5 above a point in the southern Indian Ocean near South Africa's Prince Edwards Islands, one of the Expedition 40 crew members photographed this image of Aurora Australis.

  10. Time lapse - Aurora Australis

    NASA Image and Video Library

    2013-07-05

    ISS040-E-040088 (5 July 2014) --- As the International Space Station was flying at an altitude of 226 nautical miles on July 5 above a point in the southern Indian Ocean near South Africa's Prince Edwards Islands, one of the Expedition 40 crew members photographed this image of Aurora Australis.

  11. Characterization of Shikonin Derivative Secretion in Lithospermum erythrorhizon Hairy Roots as a Model of Lipid-Soluble Metabolite Secretion from Plants

    PubMed Central

    Tatsumi, Kanade; Yano, Mariko; Kaminade, Kenta; Sugiyama, Akifumi; Sato, Mayuko; Toyooka, Kiminori; Aoyama, Takashi; Sato, Fumihiko; Yazaki, Kazufumi

    2016-01-01

    Shikonin derivatives are specialized lipophilic metabolites, secreted in abundant amounts from the root epidermal cells of Lithospermum erythrorhizon. Because they have anti-microbial activities, these compounds, which are derivatives of red naphthoquinone, are thought to serve as a chemical barrier for plant roots. The mechanism by which they are secreted from cells is, however, largely unknown. The shikonin production system in L. erythrorhizon is an excellent model for studying the mechanism by which lipophilic compounds are secreted from plant cells, because of the abundant amounts of these compounds produced by L. erythrorhizon, the 0 to 100% inducibility of their production, the light-specific inhibition of production, and the visibility of these products as red pigments. To date, many factors regulating shikonin biosynthesis have been identified, but no mechanism that regulates shikonin secretion without inhibiting biosynthesis has been detected. This study showed that inhibitors of membrane traffic strongly inhibit shikonin secretion without inhibiting shikonin production, suggesting that the secretion of shikonin derivatives into the apoplast utilizes pathways common to the ADP-ribosylation factor/guanine nucleotide exchange factor (ARF/GEF) system and actin filament polymerization, at least in part. These findings provide clues about the machinery involved in secreting lipid-soluble metabolites from cells. PMID:27507975

  12. Physiological and Molecular Analysis of Aluminium-Induced Organic Acid Anion Secretion from Grain Amaranth (Amaranthus hypochondriacus L.) Roots

    PubMed Central

    Fan, Wei; Xu, Jia-Meng; Lou, He-Qiang; Xiao, Chuan; Chen, Wei-Wei; Yang, Jian-Li

    2016-01-01

    Grain amaranth (Amaranthus hypochondriacus L.) is abundant in oxalate and can secrete oxalate under aluminium (Al) stress. However, the features of Al-induced secretion of organic acid anions (OA) and potential genes responsible for OA secretion are poorly understood. Here, Al-induced OA secretion in grain amaranth roots was characterized by ion charomatography and enzymology methods, and suppression subtractive hybridization (SSH) together with quantitative real-time PCR (qRT-PCR) was used to identify up-regulated genes that are potentially involved in OA secretion. The results showed that grain amaranth roots secrete both oxalate and citrate in response to Al stress. The secretion pattern, however, differs between oxalate and citrate. Neither lanthanum chloride (La) nor cadmium chloride (Cd) induced OA secretion. A total of 84 genes were identified as up-regulated by Al, in which six genes were considered as being potentially involved in OA secretion. The expression pattern of a gene belonging to multidrug and toxic compound extrusion (MATE) family, AhMATE1, was in close agreement with that of citrate secretion. The expression of a gene encoding tonoplast dicarboxylate transporter and four genes encoding ATP-binding cassette transporters was differentially regulated by Al stress, but the expression pattern was not correlated well with that of oxalate secretion. Our results not only reveal the secretion pattern of oxalate and citrate from grain amaranth roots under Al stress, but also provide some genetic information that will be useful for further characterization of genes involved in Al toxicity and tolerance mechanisms. PMID:27144562

  13. Rickettsia australis Activates Inflammasome in Human and Murine Macrophages

    PubMed Central

    Smalley, Claire; Bechelli, Jeremy; Rockx-Brouwer, Dedeke; Saito, Tais; Azar, Sasha R.; Ismail, Nahed; Walker, David H.; Fang, Rong

    2016-01-01

    Rickettsiae actively escape from vacuoles and replicate free in the cytoplasm of host cells, where inflammasomes survey the invading pathogens. In the present study, we investigated the interactions of Rickettsia australis with the inflammasome in both mouse and human macrophages. R. australis induced a significant level of IL-1β secretion by human macrophages, which was significantly reduced upon treatment with an inhibitor of caspase-1 compared to untreated controls, suggesting caspase-1-dependent inflammasome activation. Rickettsia induced significant secretion of IL-1β and IL-18 in vitro by infected mouse bone marrow-derived macrophages (BMMs) as early as 8–12 h post infection (p.i.) in a dose-dependent manner. Secretion of these cytokines was accompanied by cleavage of caspase-1 and was completely abrogated in BMMs deficient in caspase-1/caspase-11 or apoptosis-associated speck-like protein containing a caspase activation and recruitment domain (ASC), suggesting that R. australis activate the ASC-dependent inflammasome. Interestingly, in response to the same quantity of rickettsiae, NLRP3-/- BMMs significantly reduced the secretion level of IL-1β compared to wild type (WT) controls, suggesting that NLRP3 inflammasome contributes to cytosolic recognition of R. australis in vitro. Rickettsial load in spleen, but not liver and lung, of R. australis-infected NLRP3-/- mice was significantly greater compared to WT mice. These data suggest that NLRP3 inflammasome plays a role in host control of bacteria in vivo in a tissue-specific manner. Taken together, our data, for the first time, illustrate the activation of ASC-dependent inflammasome by R. australis in macrophages in which NLRP3 is involved. PMID:27362650

  14. Rickettsia australis Activates Inflammasome in Human and Murine Macrophages.

    PubMed

    Smalley, Claire; Bechelli, Jeremy; Rockx-Brouwer, Dedeke; Saito, Tais; Azar, Sasha R; Ismail, Nahed; Walker, David H; Fang, Rong

    2016-01-01

    Rickettsiae actively escape from vacuoles and replicate free in the cytoplasm of host cells, where inflammasomes survey the invading pathogens. In the present study, we investigated the interactions of Rickettsia australis with the inflammasome in both mouse and human macrophages. R. australis induced a significant level of IL-1β secretion by human macrophages, which was significantly reduced upon treatment with an inhibitor of caspase-1 compared to untreated controls, suggesting caspase-1-dependent inflammasome activation. Rickettsia induced significant secretion of IL-1β and IL-18 in vitro by infected mouse bone marrow-derived macrophages (BMMs) as early as 8-12 h post infection (p.i.) in a dose-dependent manner. Secretion of these cytokines was accompanied by cleavage of caspase-1 and was completely abrogated in BMMs deficient in caspase-1/caspase-11 or apoptosis-associated speck-like protein containing a caspase activation and recruitment domain (ASC), suggesting that R. australis activate the ASC-dependent inflammasome. Interestingly, in response to the same quantity of rickettsiae, NLRP3-/- BMMs significantly reduced the secretion level of IL-1β compared to wild type (WT) controls, suggesting that NLRP3 inflammasome contributes to cytosolic recognition of R. australis in vitro. Rickettsial load in spleen, but not liver and lung, of R. australis-infected NLRP3-/- mice was significantly greater compared to WT mice. These data suggest that NLRP3 inflammasome plays a role in host control of bacteria in vivo in a tissue-specific manner. Taken together, our data, for the first time, illustrate the activation of ASC-dependent inflammasome by R. australis in macrophages in which NLRP3 is involved.

  15. Aurora Australis, Sinuous Loop

    NASA Technical Reports Server (NTRS)

    1991-01-01

    This view of the Aurora Australis or Southern Lights (location unknown) shows a sinuous looping band of airglow above the Earth Limb. Calculated to be in the 80 - 120 km altitude region, auroral activity is due to exitation of atomic oxygen in the upper atmosphere by radiation from the van Allen Radiation Belts and is most common above the 65 degree north and south latitude range during the spring and fall of the year.

  16. Aurora Australis, Red Crown

    NASA Technical Reports Server (NTRS)

    1991-01-01

    This view of the Aurora Australis or Southern Lights (location unknown) shows a spiked band of red airglow called a 'Red Crown' above the Earth Limb. Calculated to be in the 80 - 120 km altitude region, auroral activity is due to exitation of atomic oxygen in the upper atmosphere by radiation from the van Allen Radiation Belts and is most common above the 65 degree north and south latitude range during the spring and fall of the year.

  17. Phragmites australis response to Cu in terms of low molecular weight organic acids (LMWOAs) exudation: Influence of the physiological cycle

    NASA Astrophysics Data System (ADS)

    Rocha, A. Cristina S.; Almeida, C. Marisa R.; Basto, M. Clara P.; Vasconcelos, M. Teresa S. D.

    2014-06-01

    Plant roots have the ability to produce and secrete substances, such as aliphatic low molecular weight organic acids (ALMWOAs), into the rhizosphere for several purposes, including in response to metal contamination. Despite this, little is yet known about the exudation of such substances from marsh plants roots in response to metal exposure. This work aimed at assessing the influence of the physiological cycle of marsh plants on the exudation of ALMWOAs in response to Cu contamination. In vitro experiments were carried out with Phragmites australis specimens, collected in different seasons. Plant roots were exposed to freshwater contaminated with two different Cu concentrations (67 μg/L and 6.9 mg/L), being the ALMWOAs released by the roots measured. Significant differences (both qualitative and quantitative) were observed during the Phragmites australis life cycle. At growing stage, Cu stimulated the exudation of oxalic and formic acids but no significant stimulation was observed for citric acid. At developing stage, exposure to Cu caused inhibition of oxalic acid exudation whereas citric acid liberation was stimulated but only in the media spiked with the lowest Cu concentration tested. At the decaying stage, no significant variation on oxalic acid was observed, whereas the citric and formic acids release increased as a consequence of the plant exposure to Cu. The physiological cycle of Phragmites australis, and probably also of other marsh plants, is therefore an important feature conditioning plants response to Cu contamination, in terms of ALMWOAs exudation. Hence this aspect should be considered when conducting studies on rhizodeposition involving marsh plants exposed to metals and in the event of using marsh plants for phytoremediation purposes in contaminated estuarine areas.

  18. Characterization of LeMir, a Root-Knot Nematode-Induced Gene in Tomato with an Encoded Product Secreted from the Root1

    PubMed Central

    Brenner, Eric D.; Lambert, Kris N.; Kaloshian, Isgouhi; Williamson, Valerie M.

    1998-01-01

    A tomato gene that is induced early after infection of tomato (Lycopersicon esculentum Mill.) with root-knot nematodes (Meloidogyne javanica) encodes a protein with 54% amino acid identity to miraculin, a flavorless protein that causes sour substances to be perceived as sweet. This gene was therefore named LeMir (L. esculentum miraculin). Sequence similarity places the encoded protein in the soybean trypsin-inhibitor family (Kunitz). LeMir mRNA is found in root, hypocotyl, and flower tissues, with the highest expression in the root. Rapid induction of expression upon nematode infection is localized to root tips. In situ hybridization shows that LeMir is expressed constitutively in the root-cap and root-tip epidermis. The LeMir protein product (LeMir) was produced in the yeast Pichia pastoris for generation of antibodies. Western-blot analysis showed that LeMir expression is up-regulated by nematode infection and by wounding. LeMir is also expressed in tomato callus tissue. Immunoprint analysis revealed that LeMir is expressed throughout the seedling root, but that levels are highest at the root/shoot junction. Analysis of seedling root exudates revealed that LeMir is secreted from the root into the surrounding environment, suggesting that it may interact with soil-borne microorganisms. PMID:9733543

  19. Involvement of the ABCG37 transporter in secretion of scopoletin and derivatives by Arabidopsis roots in response to iron deficiency.

    PubMed

    Fourcroy, Pierre; Sisó-Terraza, Patricia; Sudre, Damien; Savirón, María; Reyt, Guilhem; Gaymard, Frédéric; Abadía, Anunciación; Abadia, Javier; Alvarez-Fernández, Ana; Briat, Jean-François

    2014-01-01

    Studies of Iron (Fe) uptake mechanisms by plant roots have focussed on Fe(III)-siderophores or Fe(II) transport systems. Iron deficency also enhances root secretion of flavins and phenolics. However, the nature of these compounds, their transport outside the roots and their role in Fe nutrition are largely unknown. We used HPLC/ESI-MS (TOF) and HPLC/ESI-MS/MS (ion trap) to characterize fluorescent phenolic-type compounds accumulated in roots or exported to the culture medium of Arabidopsis plants in response to Fe deficiency. Wild-type and mutant plants altered either in phenylpropanoid biosynthesis or in the ABCG37 (PDR9) ABC transporter were grown under standard or Fe-deficient nutrition conditions and compared. Fe deficiency upregulates the expression of genes encoding enzymes of the phenylpropanoid pathway and leads to the synthesis and secretion of phenolic compounds belonging to the coumarin family. The ABCG37 gene is also upregulated in response to Fe deficiency and coumarin export is impaired in pdr9 mutant plants. Therefore it can be concluded that: Fe deficiency induces the secretion of coumarin compounds by Arabidopsis roots; the ABCG37 ABC transporter is required for this secretion to take place; and these compounds improved plant Fe nutrition. © 2013 CNRS. New Phytologist © 2013 New Phytologist Trust.

  20. Bioaccumulation of heavy metals by Phragmites australis cultivated in synthesized substrates.

    PubMed

    Wang, He; Jia, Yongfeng

    2009-01-01

    Accumulation of heavy metals from various oxides with adsorbed cadmium by wetland plant Phragmites australis was studied to evaluate the fate of heavy metals in the sediment of constructed wetlands. Hoagland solution was used as nutrition supply, and single metal oxide with adsorbed cadmium was applied as contaminant to study the accumulation characteristics of cadmium and the substrate metals by P. australis. After 45-d treatment, the bioaccumulation degree in root followed the order: Al(OH)3 > Al2O3 > Fe3O4 > MnO2 > FeOOH. Heavy metals absorbed by P. australis were largely immobilized by the roots with little translocation to aboveground parts.

  1. Molecular Control of Acid Phosphatase Secretion into the Rhizosphere of Proteoid Roots from Phosphorus-Stressed White Lupin1

    PubMed Central

    Miller, Susan Stade; Liu, Junqi; Allan, Deborah L.; Menzhuber, Christopher J.; Fedorova, Maria; Vance, Carroll P.

    2001-01-01

    White lupin (Lupinus albus) grown under P deficiency displays a suite of highly coordinated adaptive responses. Included among these is secretion of copious amounts of acid phosphatase (APase). Although numerous reports document that plants secrete APases in response to P deficiency, little is known of the biochemical and molecular events involved in this process. Here we characterize the secreted APase protein, cDNA, and gene from white lupin. The secreted APase enzyme is a glycoprotein with broad substrate specificity. It is synthesized as a preprotein with a deduced Mr of 52,000 containing a 31-amino acid presequence. Analysis of the presequence predicts that the protein is targeted to outside the cell. The processed protein has a predicted Mr of 49,000 but migrates as a protein with Mr of 70,000 on sodium dodecyl sulfate gels. This is likely due to glycosylation. Enhanced expression is fairly specific to proteoid roots of P-stressed plants and involves enhanced synthesis of both enzyme protein and mRNA. Secreted APase appears to be encoded by a single gene containing seven exons interrupted by six introns. The 5′-upstream putative promoter of the white lupin-secreted APase contains a 50-base pair region having 72% identity to an Arabidopsis APase promoter that is responsive to P deficiency. The white lupin-secreted APase promoter and targeting sequence may be useful tools for genetically engineering important proteins from plant roots. PMID:11598233

  2. Salicylic acid changes the properties of extracellular peroxidase activity secreted from wounded wheat (Triticum aestivum L.) roots.

    PubMed

    Minibayeva, F; Mika, A; Lüthje, S

    2003-05-01

    Wheat ( Triticum aestivum L.) roots released proteins showing peroxidase activity in the apoplastic solution in response to wound stress. Preincubation of excised roots with 1 mM salicylic acid at pH 7.0 enhanced the guaiacol peroxidase activity of the extracellular solution (so-called extracellular peroxidase). The soluble enzymes were partially purified by precipitation with ammonium sulfate followed by size exclusion and ion exchange chromatography. Despite an increase in the total activity of secreted peroxidase induced by pretreatment of excised roots with salicylic acid, the specific activity of the partially purified protein was significantly lower compared to that of the control. Purification of the corresponding proteins by ion exchange chromatography indicates that several isoforms of peroxidase occurred in both control and salicylic acid-treated samples. The activities of the extracellular peroxidases secreted by the salicylic acid-treated roots responded differently to calcium and lectins compared with those from untreated roots. Taken together, our data suggest that salicylic acid changes the isoforms of peroxidase secreted by wounded wheat roots.

  3. Aurora Australis, Red Crown

    NASA Image and Video Library

    1991-05-06

    STS039-23-036 (28 April-6 May 1991) --- A 35mm frame of the Aurora Australis, also known as the Southern Lights, photographed from the Space Shuttle Discovery's flight deck by one of its seven crew members. One of the mission objectives was to measure the spectral and spatial characteristics of auroral emissions. While passing over the sunlit portion of Earth, the crew was able to take a number of photos of the various geographic points on the planet; much of the time on nightside passes was devoted to a thorough study and documentation of auroral displays.

  4. Aurora Australis, Sinuous Loop

    NASA Image and Video Library

    1991-05-06

    STS039-23-020 (28 April-6 May 1991) --- A 35mm frame of the Aurora Australis, also known as the Southern Lights, photographed from Space Shuttle Discovery's flight deck by one of its seven crew members. One of the mission objectives was to measure the spectral and spatial characteristics of auroral emissions. While passing over the sunlighted portion of Earth, the crew was able to take a number of photos of the various geographic points on the planet; much of the time on nightside passes was devoted to a thorough study and documentation of auroral displays.

  5. Effect of phosphorus levels on the protein profiles of secreted protein and root surface protein of rice.

    PubMed

    Shinano, Takuro; Yoshimura, Tomoko; Watanabe, Toshihiro; Unno, Yusuke; Osaki, Mitsuru; Nanjo, Yohei; Komatsu, Setsuko

    2013-11-01

    Plant roots are complicated organs that absorb water and nutrients from the soil. Roots also play an essential role in protecting plants from attack by soil pathogens and develop a beneficial role with some soil microorganisms. Plant-derived rhizosphere proteins (e.g., root secretory proteins and root surface binding proteins) are considered to play important roles in developing mutual relationships in the rhizosphere. In the rhizosphere, where plant roots meet the surrounding environment, it has been suggested that root secretory protein and root surface binding protein are important factors. Furthermore, it is not known how the physiological status of the plant affects the profile of these proteins. In this study, rice plants were grown aseptically, with or without phosphorus nutrition, and proteins were obtained from root bathing solution (designated as root secretory proteins) and obtained using 0.2 M CaCl2 solution (designated as root surface binding proteins). The total number of identified proteins in the root bathing solution was 458, and the number of root surface binding proteins was 256. More than half of the proteins were observed in both fractions. Most of the proteins were categorized as either having signal peptides or no membrane transport helix sites. The functional categorization suggested that most of the proteins seemed to have secretory pathways and were involved in defense/disease-related functions. These characteristics seem to be unique to rhizosphere proteins, and the latter might be part of the plants strategy to defeat pathogens in the soil. The low phosphorus treatment significantly increased the number of pathogenesis-related proteins in the root secretory proteins, whereas the change was small in the case of the root surface binding proteins. The results suggested that the roots are actively and selectively secreting protein into the rhizosphere.

  6. Stability of Chloropyromorphite in Ryegrass Rhizosphere as Affected by Root-Secreted Low Molecular Weight Organic Acids

    PubMed Central

    Wei, Wei; Wang, Yu; Wang, Zheng; Han, Ruiming; Li, Shiyin; Wei, Zhenggui; Zhang, Yong

    2016-01-01

    Understanding the stability of chloropyromorphite (CPY) is of considerable benefit for improving risk assessment and remediation strategies in contaminated water and soil. The stability of CPY in the rhizosphere of phosphorus-deficient ryegrass was evaluated to elucidate the role of root-secreted low molecular weight organic acids (LMWOAs) on the dissolution of CPY. Results showed that CPY treatments significantly reduced the ryegrass biomass and rhizosphere pH. The presence of calcium nitrate extractable lead (Pb) and phosphorus (P) suggested that CPY in the rhizosphere could be bioavailable, because P and Pb uptake by ryegrass potentially provided a significant concentration gradient that would promote CPY dissolution. Pb accumulation and translocation in ryegrass was found to be significantly higher in P-sufficient conditions than in P-deficient conditions. CPY treatments significantly enhanced root exudation of LMWOAs irrigated with P-nutrient solution or P-free nutrient solution. Oxalic acid was the dominant species in root-secreted LMWOAs of ryegrass under P-free nutrient solution treatments, suggesting that root-secreted oxalic acid may be the driving force of root-induced dissolution of CPY. Hence, our work, provides clarifying hints on the role of LMWOAs in controlling the stability of CPY in the rhizosphere. PMID:27494023

  7. Flavins secreted by roots of iron-deficient Beta vulgaris enable mining of ferric oxide via reductive mechanisms.

    PubMed

    Sisó-Terraza, Patricia; Rios, Juan J; Abadía, Javier; Abadía, Anunciación; Álvarez-Fernández, Ana

    2016-01-01

    Iron (Fe) is abundant in soils but generally poorly soluble. Plants, with the exception of Graminaceae, take up Fe using an Fe(III)-chelate reductase coupled to an Fe(II) transporter. Whether or not nongraminaceous species can convert scarcely soluble Fe(III) forms into soluble Fe forms has deserved little attention so far. We have used Beta vulgaris, one among the many species whose roots secrete flavins upon Fe deficiency, to study whether or not flavins are involved in Fe acquisition. Flavins secreted by Fe-deficient plants were removed from the nutrient solution, and plants were compared with Fe-sufficient plants and Fe-deficient plants without flavin removal. Solubilization of a scarcely soluble Fe(III)-oxide was assessed in the presence or absence of flavins, NADH (nicotinamide adenine dinucleotide, reduced form) or plant roots, and an Fe(II) trapping agent. The removal of flavins from the nutrient solution aggravated the Fe deficiency-induced leaf chlorosis. Flavins were able to dissolve an Fe(III)-oxide in the presence of NADH. The addition of extracellular flavins enabled roots of Fe-deficient plants to reductively dissolve an Fe(III)-oxide. We concluded that root-secretion of flavins improves Fe nutrition in B. vulgaris. Flavins allow B. vulgaris roots to mine Fe from Fe(III)-oxides via reductive mechanisms.

  8. Stability of Chloropyromorphite in Ryegrass Rhizosphere as Affected by Root-Secreted Low Molecular Weight Organic Acids.

    PubMed

    Wei, Wei; Wang, Yu; Wang, Zheng; Han, Ruiming; Li, Shiyin; Wei, Zhenggui; Zhang, Yong

    2016-01-01

    Understanding the stability of chloropyromorphite (CPY) is of considerable benefit for improving risk assessment and remediation strategies in contaminated water and soil. The stability of CPY in the rhizosphere of phosphorus-deficient ryegrass was evaluated to elucidate the role of root-secreted low molecular weight organic acids (LMWOAs) on the dissolution of CPY. Results showed that CPY treatments significantly reduced the ryegrass biomass and rhizosphere pH. The presence of calcium nitrate extractable lead (Pb) and phosphorus (P) suggested that CPY in the rhizosphere could be bioavailable, because P and Pb uptake by ryegrass potentially provided a significant concentration gradient that would promote CPY dissolution. Pb accumulation and translocation in ryegrass was found to be significantly higher in P-sufficient conditions than in P-deficient conditions. CPY treatments significantly enhanced root exudation of LMWOAs irrigated with P-nutrient solution or P-free nutrient solution. Oxalic acid was the dominant species in root-secreted LMWOAs of ryegrass under P-free nutrient solution treatments, suggesting that root-secreted oxalic acid may be the driving force of root-induced dissolution of CPY. Hence, our work, provides clarifying hints on the role of LMWOAs in controlling the stability of CPY in the rhizosphere.

  9. Secreted phosphoprotein 24 kD inhibits nerve root inflammation induced by bone morphogenetic protein-2.

    PubMed

    Tian, Haijun; Li, Chen-Shuang; Scott, Trevor P; Montgomery, Scott R; Phan, Kevin; Lao, Lifeng; Zhang, Wei; Li, Yawei; Hayashi, Tetsuo; Takahashi, Shinji; Alobaidaan, Raed; Ruangchainikom, Monchai; Zhao, Ke-Wei; Brochmann, Elsa J; Murray, Samuel S; Wang, Jeffrey C; Daubs, Michael D

    2015-02-01

    Bone morphogenetic protein-2 (BMP-2) has been used to successfully promote spine fusion, but side-effects including nerve inflammation have been observed. To investigate the direct neurotoxic effects of BMP-2 and test the hypotheses that the use of BMP binding proteins, such as secreted phosphoprotein 24 kD (Spp24), can reduce or eliminate these effects. In vitro experiments and in vivo analysis in a rodent model. In vitro, dorsal root ganglion cells were cultured in the presence of BMP-2 with and without Spp24 and calcitonin gene-related peptide and Substance P, markers of neuroinflammation, were measured by immunohistochemistry. In vivo, rats underwent a left-sided laminotomy at L5 to expose the S1 nerve root and were randomized into four different groups according to the intervention at the laminotomy site: collagen sponge only (no BMP-2 or Spp24), BMP-2 in a collagen sponge only, BMP-2 in a collagen sponge+an empty collagen sponge to act as a barrier, and BMP-2 in a collagen sponge+Spp24 in a collagen sponge to act as a barrier. Functional evaluation was done using the Basso, Beattie, and Bresnahan scale and immunohistochemical analyses were performed using calcitonin gene-related peptide and Substance P staining. The neuroinflammatory effects of BMP-2 in vitro were ameliorated by the addition of Spp24. Similarly, in vivo, Spp24 reduced the expression of markers on neuroinflammation in animals treated with BMP-2 and also improved the function after BMP-2 administration. These results confirm that BMP binding proteins have great potential as adjuvant therapies to limit BMP-2 related side-effects in spine surgery. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. A GTPase-Dependent Fine ER Is Required for Localized Secretion in Polarized Growth of Root Hairs1

    PubMed Central

    Qi, Xingyun; Sun, Jiaqi; Zheng, Huanquan

    2016-01-01

    The endoplasmic reticulum (ER) is a cellular network comprising membrane tubules and sheets stretching throughout the cytoplasm. Atlastin GTPases, including Atlastin-1 in mammals and RHD3 in plants, play a role in the generation of the interconnected tubular ER network by promoting the fusion of ER tubules. Root hairs in rhd3 are short and wavy, a defect reminiscent of axon growth in cells with depleted Atlastin-1. However, how a loss in the ER complexity could lead to a defective polarized cell growth of root hairs or neurons remains elusive. Using live-cell imaging techniques, we reveal that, a fine ER distribution, which is found in the subapical zone of growing root hairs of wild-type plants, is altered to thick bundles in rhd3. The localized secretion to the apical dome as well as the apical localization of root hair growth regulator ROP2 is oscillated in rhd3. Interestingly, the shift of ROP2 precedes the shift of localized secretion as well as the fine ER distribution in rhd3. Our live imaging and pharmacologic modification of root hair growth defects in rhd3 suggest that there is interplay between the ER and microtubules in the polarized cell growth of root hairs. We hypothesize that, under the guidance of ROP2, RHD3, together with the action of microtubules, is required for the formation of a fine ER structure in the subapical zone of growing root hairs. This fine ER structure is essential for the localized secretion to the apical dome in polarized cell growth. PMID:27231102

  11. Potential role of Flavobacterial gliding-motility and type IX secretion system complex in root colonization and plant defense.

    PubMed

    Kolton, Max; Frenkel, Omer; Elad, Yigal; Cytryn, Eddie

    2014-09-01

    Members of the Flavobacterium genus are often highly abundant in the rhizosphere. Nevertheless, the physiological characteristics associated with their enhanced rhizosphere competence are currently an enigma. Flavobacteria possess a unique gliding-motility complex that is tightly associated with a recently characterized Bacteroidetes-specific type IX protein secretion system, which distinguishes them from the rest of the rhizosphere microbiome. We hypothesize that proper functionality of this complex may confer a competitive advantage in the rhizosphere. To test this hypothesis, we constructed mutant and complement root-associated flavobacterial variants with dysfunctional secretion and gliding motility, and tested them in a series of in planta experiments. These mutants demonstrated significantly lower rhizosphere persistence (approximately 10-fold), plant root colonization (approximately fivefold), and seed adhesion capacity (approximately sevenfold) than the wild-type strains. Furthermore, the biocontrol capacity of the mutant strain toward foliar-applied Clavibacter michiganensis was significantly impaired relative to the wild-type strain, suggesting a role of the gliding and secretion complex in plant protection. Collectively, these results provide an initial link between the high abundance of flavobacteria in the rhizosphere and their unique physiology, indicating that the flavobacterial gliding-motility and secretion complex may play a central role in root colonization and plant defense.

  12. Aurora Australis, Seen From Space

    NASA Image and Video Library

    This video of the Aurora Australis was created from a sequence of still shots taken by astronauts on board the International Space Station. The images were acquired on September 11, 2011 as the ISS...

  13. Aurora Australis over Indian Ocean

    NASA Image and Video Library

    Video of the Aurora Australis taken by the crew of Expedition 28 on board the International Space Station. This sequence of shots was taken September 7, 2011 from 17:38:03 to 17:49:15 GMT, from the...

  14. Catechin is a phytotoxin and a pro-oxidant secreted from the roots of Centaurea stoebe

    PubMed Central

    Kaushik, Shail; Biedrzycki, Meredith L; Venkatachalam, Lakshmannan

    2010-01-01

    When applied to the roots of Arabidopsis thaliana, the phytotoxin (±)-catechin triggers a wave of reactive oxygen species (ROS), leading to a cascade of genome-wide changes in gene expression and, ultimately, death of the root system. Biochemical links describing the root secreted phytotoxin, (±)-catechin, represent one of most well studied systems to describe biochemically based negative plant-plant interactions, but of late have also sparked controversies on phytotoxicity and pro-oxidant behavior of (±)-catechin. The studies originating from two labs1–3 maintained that (±)-catechin is not at all phytotoxic but has strong antioxidant activity. The step-wise experiments performed and the highly correlative results reported in the present study clearly indicate that (±)-catechin indeed is phytotoxic against A. thaliana and Festuca idahoensis. Our results show that catechin dissolved in both organic and aqueous phase inflicts phytotoxic activity against both A. thaliana and F. idahoensis. We show that the deviation in results highlighted by the two labs1–3 could be due to different media conditions and a group effect in catechin treated seedlings. We also determined the presence of catechin in the growth medium of C. stoebe to support the previous studies. One of the largest functional categories observed for catechin-responsive genes corresponded to gene families known to participate in cell death and oxidative stress. Our results showed that (±)-catechin treatment to A. thaliana plants resulted in activation of signature cell death genes such as accelerated cell death (acd2) and constitutively activated cell death 1 (cad1). Further, we confirmed our earlier observation of (±)-catechin induced ROS mediated phytotoxicity in A. thaliana. We also provide evidence that (±)-catechin induced ROS could be aggravated in the presence of divalent transition metals. These observations have significant impact on our understanding regarding catechin phytotoxicity and

  15. Catechin is a phytototoxin and a pro-oxidant secreted from the roots of Centaurea stoebe.

    PubMed

    Kaushik, Shail; Bais, Harsh P; Biedrzycki, Meredith L; Venkatachalam, Lakshmannan

    2010-09-01

    When applied to the roots of Arabidopsis thaliana, the phytotoxin (±)-catechin triggers a wave of reactive oxygen species (ROS), leading to a cascade of genome-wide changes in gene expression and, ultimately, death of the root system. Biochemical links describing the root secreted phytotoxin, (±)-catechin, represent one of most well studied systems to describe biochemically based negative plant-plant interactions, but of late have also sparked controversies on phytotoxicity and pro-oxidant behavior of (±)-catechin. The studies originating from two labs ( 1- 3) maintained that (±)-catechin is not at all phytotoxic but has strong antioxidant activity. The step-wise experiments performed and the highly correlative results reported in the present study clearly indicate that (±)-catechin indeed is phytotoxic against A. thaliana and Festuca idahoensis. Our results show that catechin dissolved in both organic and aqueous phase inflict phytotoxic activity against both A. thaliana and F. idahoensis. We show that the deviation in results highlighted by the two labs ( 1- 3) could be due to different media conditions and a group effect in catechin treated seedlings. We also determined the presence of catechin in the growth medium of C. stoebe to support the previous studies. One of the largest functional categories observed for catechin-responsive genes corresponded to gene families known to participate in cell death and oxidative stress. Our results showed that (±)-catechin treatment to A. thaliana plants resulted in activation of signature cell death genes such as accelerated cell death (acd2) and constitutively activated cell death 1 (cad1). Further, we confirmed our earlier observation of (±)-catechin induced ROS mediated phytotoxicity in A. thaliana. We also provide evidence that (±)-catechin induced ROS could be aggravated in the presence of divalent transition metals. These observations have significant impact on our understanding regarding catechin

  16. The corky root rot pathogen Pyrenochaeta lycopersici secretes a proteinaceous inducer of cell death affecting host plants differentially.

    PubMed

    Clergeot, Pierre-Henri; Schuler, Herwig; Mørtz, Ejvind; Brus, Maja; Vintila, Simina; Ekengren, Sophia

    2012-09-01

    Pathogenic isolates of Pyrenochaeta lycopersici, the causal agent of corky root rot of tomato, secrete cell death in tomato 1 (CDiT1), a homodimeric protein of 35 kDa inducing cell death after infiltration into the leaf apoplast of tomato. CDiT1 was purified by fast protein liquid chromatography, characterized by mass spectrometry and cDNA cloning. Its activity was confirmed after infiltration of an affinity-purified recombinant fusion of the protein with a C-terminal polyhistidine tag. CDiT1 is highly expressed during tomato root infection compared with axenic culture, and has a putative ortholog in other pathogenic Pleosporales species producing proteinaceous toxins that contribute to virulence. Infiltration of CDiT1 into leaves of other plants susceptible to P. lycopersici revealed that the protein affects them differentially. All varieties of cultivated tomato (Solanum lycopersicum) tested were more sensitive to CDiT1 than those of currant tomato (S. pimpinellifolium). Root infection assays showed that varieties of currant tomato are also significantly less prone to intracellular colonization of their root cells by hyphae of P. lycopersici than varieties of cultivated tomato. Therefore, secretion of this novel type of inducer of cell death during penetration of the fungus inside root cells might favor infection of host species that are highly sensitive to this molecule.

  17. Spatiotemporal monitoring of the antibiome secreted by Bacillus biofilms on plant roots using MALDI mass spectrometry imaging.

    PubMed

    Debois, Delphine; Jourdan, Emmanuel; Smargiasso, Nicolas; Thonart, Philippe; De Pauw, Edwin; Ongena, Marc

    2014-05-06

    Some soil Bacilli living in association with plant roots can protect their host from infection by pathogenic microbes and are therefore being developed as biological agents to control plant diseases. The plant-protective activity of these bacteria has been correlated with the potential to secrete a wide array of antibiotic compounds upon growth as planktonic cells in isolated cultures under laboratory conditions. However, in situ expression of these antibiotics in the rhizosphere where bacterial cells naturally colonize root tissues is still poorly understood. In this work, we used matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI MSI) to examine spatiotemporal changes in the secreted antibiome of Bacillus amyloliquefaciens developing as biofilms on roots. Nonribosomal lipopeptides such as the plant immunity elicitor surfactin or the highly fungitoxic iturins and fengycins were readily produced albeit in different time frames and quantities in the surrounding medium. Interestingly, tandem mass spectrometry (MS/MS) experiments performed directly from the gelified culture medium also allowed us to identify a new variant of surfactins released at later time points. However, no other bioactive compounds such as polyketides were detected at any time, strongly suggesting that the antibiome expressed in planta by B. amyloliquefaciens does not reflect the vast genetic arsenal devoted to the formation of such compounds. This first dynamic study reveals the power of MALDI MSI as tool to identify and map antibiotics synthesized by root-associated bacteria and, more generally, to investigate plant-microbe interactions at the molecular level.

  18. Genetic elicitation by inducible expression of β-cryptogein stimulates secretion of phenolics from Coleus blumei hairy roots.

    PubMed

    Vuković, Rosemary; Bauer, Nataša; Curković-Perica, Mirna

    2013-02-01

    The accumulation of phenolic compounds in plants is often part of the defense response against stress and pathogen attack, which can be triggered and activated by elicitors. Oomycetal proteinaceous elicitor, β-cryptogein, induces hypersensitive response and systemic acquired resistance against some pathogens. In order to test the effect of endogenously synthesized cryptogein protein on phenolic compounds accumulation in tissue, and secretion into the culture medium, Coleus blumei hairy roots were generated. Agrobacterium rhizogenes was employed to insert synthetic crypt gene, encoding β-cryptogein, under the control of alcohol-inducible promoter. The expression of β-cryptogein, in C. blumei hairy roots, was controlled by application of 1% and 2% ethanol, during 21 days induction period. Ethanol-induced expression of β-cryptogein caused significant decrease of soluble phenolics and rosmarinic acid (RA) in hairy root lines and increase of phenolics, RA and caffeic acid in culture medium. These data suggest that β-cryptogein might be a potential regulatory factor for phenolics secretion from the roots.

  19. Up-regulation of licochalcone A biosynthesis and secretion by Tween 80 in hairy root cultures of Glycyrrhiza uralensis Fisch.

    PubMed

    Zhang, Hai-Chao; Liu, Jing-Mei; Chen, Hai-Min; Gao, Chun-Chun; Lu, Hong-Yu; Zhou, Hua; Li, Yi; Gao, Shan-Lin

    2011-01-01

    We evaluated the effect of Tween 80 as elicitor on licochalcone A from hairy root cultures of Glycyrrhiza uralensis Fisch. After a 15-days treatment with 2% Tween 80, hairy roots still grew well and produced higher levels of licochalcone A and total flavonoids than the control (without treatment). Licochalcone A content and total flavonoid content were 3.103 and 127.095 mg per flask (9- and 11-fold higher), respectively, compared with controls. Secretion of licochalcone A and total flavonoids into the culture medium was remarkably high, up to 98 and 94% of the total production, respectively. The enhanced flavonoid production was associated with elevated mRNA levels and enzyme activities of phenylalanine ammonia-lyase (PAL), 4-coumarate:coenzyme A ligase (4CL), and cinnamate-4-hydroxylase (C4H). These results clearly demonstrated that Tween 80 treatment permeabilized the roots to enhance secretion, but also acted as an efficient elicitor of licochalcone A and total flavonoid production in hairy roots of G. uralensis Fisch.

  20. Metabolism of Ibuprofen by Phragmites australis: Uptake and Phytodegradation.

    PubMed

    He, Yujie; Langenhoff, Alette A M; Sutton, Nora B; Rijnaarts, Huub H M; Blokland, Marco H; Chen, Feiran; Huber, Christian; Schröder, Peter

    2017-04-18

    This study explores ibuprofen (IBP) uptake and transformation in the wetland plant species Phragmites australis and the underlying mechanisms. We grew P. australis in perlite under greenhouse conditions and treated plants with 60 μg/L of IBP. Roots and rhizomes (RR), stems and leaves (SL), and liquid samples were collected during 21 days of exposure. Results show that P. australis can take up, translocate, and degrade IBP. IBP was completely removed from the liquid medium after 21 days with a half-life of 2.1 days. IBP accumulated in RR and was partly translocated to SL. Meanwhile, four intermediates were detected in the plant tissues: hydroxy-IBP, 1,2-dihydroxy-IBP, carboxy-IBP and glucopyranosyloxy-hydroxy-IBP. Cytochrome P450 monooxygenase was involved in the production of the two hydroxy intermediates. We hypothesize that transformation of IBP was first catalyzed by P450, and then by glycosyltransferase, followed by further storage or metabolism in vacuoles or cell walls. No significant phytotoxicity was observed based on relative growth of plants and stress enzyme activities. In conclusion, we demonstrated for the first time that P. australis degrades IBP from water and is therefore a suitable species for application in constructed wetlands to clean wastewater effluents containing IBP and possibly also other micropollutants.

  1. Factors other than root secreted malic acid that contributes toward Bacillus subtilis FB17 colonization on Arabidopsis roots.

    PubMed

    Lakshmanan, Venkatachalam; Bais, Harsh P

    2013-11-01

    The plant growth promoting rhizobacterium (PGPR) Bacillus subtilis FB17 (hereafter FB17) induces resistance against broad pathogen including Pseudomonas syringae pv tomato (PstDC3000). The extent of plant protection by FB17 depends on establishment of root colonization followed by biofilm formation. The general convention dictates that beneficial rhizobacterium may suppress the root innate immune system to establish a robust colonization. However, it is still not well understood which genetic targets FB17 affects in plants to facilitate a symbiotic association. Our recent study, involving whole transcriptome analysis of Arabdiopsis thaliana roots treated with FB17 post 24 h of treatment showed totally 279 genes that were significantly up- or/ downregulated. Further, we found that the mutants for upregulated and downregulated genes post-FB17 colonization showed a differential phenotype for FB17 root colonization. Interestingly, plants mutated in the FB17-responsive genes showed increased Aluminum activated malate transporter (ALMT1) expression under foliar pathogen PstDC3000, infections, indicating the independent functionality of ALMT1 for bacterial recruitment. Taken together this, present study suggests that the establishment of interaction between the plant host and PGPR is a complex phenomenon which is regulated by multiple genetic components.

  2. Factors other than root secreted malic acid that contributes toward Bacillus subtilis FB17 colonization on Arabidopsis roots

    PubMed Central

    Lakshmanan, Venkatachalam; Bais, Harsh P

    2013-01-01

    The plant growth promoting rhizobacterium (PGPR) Bacillus subtilis FB17 (hereafter FB17) induces resistance against broad pathogen including Pseudomonas syringae pv tomato (PstDC3000). The extent of plant protection by FB17 depends on establishment of root colonization followed by biofilm formation. The general convention dictates that beneficial rhizobacterium may suppress the root innate immune system to establish a robust colonization. However, it is still not well understood which genetic targets FB17 affects in plants to facilitate a symbiotic association. Our recent study, involving whole transcriptome analysis of Arabidopsis thaliana roots treated with FB17 post 24 h of treatment showed totally 279 genes that were significantly up- or/ downregulated. Further, we found that the mutants for upregulated and downregulated genes post-FB17 colonization showed a differential phenotype for FB17 root colonization. Interestingly, plants mutated in the FB17-responsive genes showed increased Aluminum activated malate transporter (ALMT1) expression under foliar pathogen PstDC3000, infections, indicating the independent functionality of ALMT1 for bacterial recruitment. Taken together this, present study suggests that the establishment of interaction between the plant host and PGPR is a complex phenomenon which is regulated by multiple genetic components. PMID:24310121

  3. A secreted chitinase-like protein (OsCLP) supports root growth through calcium signaling in Oryza sativa.

    PubMed

    Wu, Jingni; Wang, Yiming; Kim, Sang Gon; Jung, Ki-Hong; Gupta, Ravi; Kim, Joonyup; Park, Younghoon; Kang, Kyu Young; Kim, Sun Tae

    2017-04-12

    Chitinases belong to a conserved protein family and play multiple roles in defense, development, and growth regulation in plants. Here, we identified a secreted chitinase-like protein, OsCLP, which functions in rice growth. A T-DNA insertion mutant of OsCLP (osclp) showed significant retardation of root and shoot growth. A comparative proteomic analysis was carried out using root tissue of wild-type and the osclp mutant to understand the OsCLP-mediated rice growth retardation. Results obtained revealed that proteins related to glycolysis (phosphoglycerate kinase), stress adaption (chaperonin) and calcium signaling (calreticulin and CDPK1) were differentially regulated in osclp roots. Fura-2 molecular probe staining, which is an intracellular calcium indicator, and ICP-MS analysis suggested that the intracellular calcium content was significantly lower in roots of osclp as compared to the wild-type. Exogenous application of Ca(2+) resulted in successful recovery of both primary and lateral root growth in osclp. Moreover, overexpression of OsCLP resulted in improved growth with modified seed shape and starch structure; however, the overall yield remained unaffected. Taken together, our results highlight the involvement of OsCLP in rice growth by regulating the intracellular calcium concentrations.

  4. Heavy metals in sediments and their bioaccumulation in Phragmites australis in the Anzali wetland of Iran

    NASA Astrophysics Data System (ADS)

    Esmaeilzadeh, Marjan; Karbassi, Abdolreza; Moattar, Faramarz

    2016-07-01

    Accumulation of metals in both sediments and Phragmites australis organs was studied. Samples were collected from seven stations located in Anzali wetland, Iran. The samples were analyzed by inductively coupled plasma mass spectrometry (ICP-MS). The results showed that concentration of the studied metals (except As and Cd) were higher in sediments than in P. australis organs. Metal accumulation was found to be significantly ( P <0.05) higher in roots than in above-ground organs of P. australis. The bioaccumulation factor (BAF) and the transfer factor (TF) also verified the highest rate of metal accumulation in roots and their reduced mobility from roots to the above-ground organs. Pearson correlation coefficient showed significant relationships between metal concentrations in sediments and those in plant organs. It should be pointed out that sediment and plant samples exhibited higher metal concentrations in eastern and central parts than in western and southern parts of the wetland. The mean concentrations of all studied elements (except for Fe, V and Al) were higher in these sediment samples than in the Earth's crust and shale. High accumulation of metals in P. australis organs (roots and shoots) is indicative of their high bioavailability in sediments of the wetland. The correlation between metal concentrations in sediments and in P. australis indicates that plant organs are good bioindicators of metal pollution in sediments of Anzali wetland.

  5. Root secreted metabolites and proteins are involved in the early events of plant-plant recognition prior to competition.

    PubMed

    Badri, Dayakar V; De-la-Peña, Clelia; Lei, Zhentian; Manter, Daniel K; Chaparro, Jacqueline M; Guimarães, Rejane L; Sumner, Lloyd W; Vivanco, Jorge M

    2012-01-01

    The mechanism whereby organisms interact and differentiate between others has been at the forefront of scientific inquiry, particularly in humans and certain animals. It is widely accepted that plants also interact, but the degree of this interaction has been constricted to competition for space, nutrients, water and light. Here, we analyzed the root secreted metabolites and proteins involved in early plant neighbor recognition by using Arabidopsis thaliana Col-0 ecotype (Col) as our focal plant co-cultured in vitro with different neighbors [A. thaliana Ler ecotype (Ler) or Capsella rubella (Cap)]. Principal component and cluster analyses revealed that both root secreted secondary metabolites and proteins clustered separately between the plants grown individually (Col-0, Ler and Cap grown alone) and the plants co-cultured with two homozygous individuals (Col-Col, Ler-Ler and Cap-Cap) or with different individuals (Col-Ler and Col-Cap). In particularly, we observed that a greater number of defense- and stress-related proteins were secreted when our control plant, Col, was grown alone as compared to when it was co-cultured with another homozygous individual (Col-Col) or with a different individual (Col-Ler and Col-Cap). However, the total amount of defense proteins in the exudates of the co-cultures was higher than in the plant alone. The opposite pattern of expression was identified for stress-related proteins. These data suggest that plants can sense and respond to the presence of different plant neighbors and that the level of relatedness is perceived upon initial interaction. Furthermore, the role of secondary metabolites and defense- and stress-related proteins widely involved in plant-microbe associations and abiotic responses warrants reassessment for plant-plant interactions.

  6. Root Secreted Metabolites and Proteins Are Involved in the Early Events of Plant-Plant Recognition Prior to Competition

    PubMed Central

    Badri, Dayakar V.; De-la-Peña, Clelia; Lei, Zhentian; Manter, Daniel K.; Chaparro, Jacqueline M.; Guimarães, Rejane L.; Sumner, Lloyd W.; Vivanco, Jorge M.

    2012-01-01

    The mechanism whereby organisms interact and differentiate between others has been at the forefront of scientific inquiry, particularly in humans and certain animals. It is widely accepted that plants also interact, but the degree of this interaction has been constricted to competition for space, nutrients, water and light. Here, we analyzed the root secreted metabolites and proteins involved in early plant neighbor recognition by using Arabidopsis thaliana Col-0 ecotype (Col) as our focal plant co-cultured in vitro with different neighbors [A. thaliana Ler ecotype (Ler) or Capsella rubella (Cap)]. Principal component and cluster analyses revealed that both root secreted secondary metabolites and proteins clustered separately between the plants grown individually (Col-0, Ler and Cap grown alone) and the plants co-cultured with two homozygous individuals (Col-Col, Ler-Ler and Cap-Cap) or with different individuals (Col-Ler and Col-Cap). In particularly, we observed that a greater number of defense- and stress- related proteins were secreted when our control plant, Col, was grown alone as compared to when it was co-cultured with another homozygous individual (Col-Col) or with a different individual (Col-Ler and Col-Cap). However, the total amount of defense proteins in the exudates of the co-cultures was higher than in the plant alone. The opposite pattern of expression was identified for stress-related proteins. These data suggest that plants can sense and respond to the presence of different plant neighbors and that the level of relatedness is perceived upon initial interaction. Furthermore, the role of secondary metabolites and defense- and stress-related proteins widely involved in plant-microbe associations and abiotic responses warrants reassessment for plant-plant interactions. PMID:23056382

  7. Antioxidant response to metal pollution in Phragmites australis from Anzali wetland.

    PubMed

    Esmaeilzadeh, Marjan; Karbassi, Abdolreza; Bastami, Kazem Darvish

    2017-06-15

    This research was conducted to examine variations of antioxidant enzyme activity in Phragmites australis as a biomarker for metals such as As, Pb, Cu, and Cd. Samples of sediment and plants were collected from 7 stations located in Anzali wetland. Biochemical parameters including Catalase, Peroxidase and Ascorbate Peroxidase activity were analyzed in the roots, stems and leaves of P. australis. The obtained results indicated that there were significant differences among activities of antioxidant enzymes in three organs (p<0.05). Antioxidant enzyme activities in the organs for all studied stations were as the following order: stemroot. Overall, significant positive correlations were observed among concentrations of metals in sediments and activities of antioxidant enzymes in P. australis. As a result, it can be concluded from this study that antioxidant enzymes are good biomarkers reflecting metal contamination in sediments of Anzali wetland. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Increased de novo riboflavin synthesis and hydrolysis of FMN are involved in riboflavin secretion from Hyoscyamus albus hairy roots under iron deficiency.

    PubMed

    Higa, Ataru; Khandakar, Jebunnahar; Mori, Yuko; Kitamura, Yoshie

    2012-09-01

    Riboflavin secretion by Hyoscyamus albus hairy roots under Fe deficiency was examined to determine where riboflavin is produced and whether production occurs via an enhancement of riboflavin biosynthesis or a stimulation of flavin mononucleotide (FMN) hydrolysis. Confocal fluorescent microscopy showed that riboflavin was mainly localized in the epidermis and cortex of the root tip and, at the cellular level, in the apoplast. The expressions of three genes involved in the de novo biosynthesis of riboflavin (GTP cyclohydrolase II/3,4-dihydroxy-2-butanone 4-phosphate synthase; 6,7-dimethyl-8-ribityllumazine synthase; riboflavin synthase) were compared between Fe-starved and Fe-replete roots over a time-course of 7 days, using RT-PCR. All three genes were found to be highly expressed over the period 1-7 days in the roots cultured under Fe deficiency. Since riboflavin secretion began to be detected only from 3 days, there was a lag phase observed between the increased transcript accumulations and riboflavin secretion. To determine whether FMN hydrolysis might contribute to the riboflavin secretion in Fe-deficient root cultures, FMN hydrolase activity was determined and was found to be substantially increased after 3 days, when riboflavin secretion became detectable. These results suggested that not only de novo riboflavin synthesis but also the hydrolysis of FMN contributes to riboflavin secretion under conditions of Fe deficiency. Respiration activity was assayed during the time-course, and was also found to be enhanced after 3 days under Fe deficiency, suggesting a possible link with riboflavin secretion. On the other hand, several respiratory inhibitors were found not to affect riboflavin synthase transcript accumulation. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  9. Acceleration of nonylphenol and 4-tert-octylphenol degradation in sediment by Phragmites australis and associated rhizosphere bacteria.

    PubMed

    Toyama, Tadashi; Murashita, Manabu; Kobayashi, Kazutaka; Kikuchi, Shintaro; Sei, Kazunari; Tanaka, Yasuhiro; Ike, Michihiko; Mori, Kazuhiro

    2011-08-01

    We investigated biodegradation of technical nonylphenol (tNP) in Phragmites australis rhizosphere sediment by conducting degradation experiments using sediments spiked with tNP. Accelerated tNP removal was observed in P. australis rhizosphere sediment, whereas tNP persisted in unvegetated sediment without plants and in autoclaved sediment with sterile plants, suggesting that the accelerated tNP removal resulted largely from tNP biodegradation by rhizosphere bacteria. Three bacterial strains, Stenotrophomonas sp. strain IT-1 and Sphingobium spp. strains IT-4 and IT-5, isolated from the rhizosphere were capable of utilizing tNP and 4-tert-octylphenol as a sole carbon source via type II ipso-substitution. Oxygen from P. australis roots, by creating highly oxygenated conditions in the sediment, stimulated cell growth and the tNP-degrading activity of the three strains. Moreover, organic compounds from P. australis roots functioned as carbon and energy sources for two strains, IT-4 and IT-5, supporting cell growth and tNP-degrading activity. Thus, P. australis roots elevated the cell growth and tNP-degrading activity of the three bacterial strains, leading to accelerated tNP removal. These results demonstrate that rhizoremediation of tNP-contaminated sediments using P. australis can be an effective strategy.

  10. Potential of Phragmites australis for the removal of veterinary pharmaceuticals from aquatic media.

    PubMed

    Carvalho, Pedro N; Basto, M Clara P; Almeida, C Marisa R

    2012-07-01

    The potential of Phragmites australis was evaluated for the removal of three veterinary drugs, enrofloxacin (ENR), ceftiofur (CEF) and tetracycline (TET), from aquatic mediums. Results showed that the plant promoted the removal of 94% and 75% of ENR and TET, respectively, from wastewater. Microbial abundance estimation revealed that microorganisms were not a major participant. Occurrence of drugs adsorption to plant roots was observed in small extension. Therefore, main mechanisms occurring were drug removal by plant uptake and/or degradation. Present results demonstrated the potential of P. australis-planted beds to be used for removal of pharmaceuticals from livestock and slaughterhouse industries wastewater. Copyright © 2012 Elsevier Ltd. All rights reserved.

  11. [Effects of Cuscuta australis parasitism on the growth, reproduction and defense of Solidago canadensis].

    PubMed

    Yang, Bei-fen; Du, Le-shan; Li, Jun-min

    2015-11-01

    In order to find out how parasitic Cuscuta australis influences the growth and reproduction of Solidago canadensis, the effects of the parasitism of C. australis on the morphological, growth and reproductive traits of S. canadensis were examined and the relationships between the biomass and the contents of the secondary metabolites were analyzed. The results showed that the parasitism significantly reduced the plant height, basal diameter, root length, root diameter, root biomass, stem biomass, leaf biomass, total biomass, number of inflorescences branches, axis length of inflorescence, and number of inflorescence. In particular, plant height, number of inflorescence and the stem biomass of parasitized S. canadensis were only 1/2, 1/5 and 1/8 of non-parasitized plants, respectively. There was no significant difference of plant height, root length, stem biomass and total biomass between plants parasitized with high and low intensities. But the basal diameter, root volume, leaf biomass, root biomass, the number of inflorescences branches, axis length of inflorescence and number of inflorescence of S. canadensis parasitized with high intensity were significantly lower than those of plants parasitized with low intensity. The parasitism of C. australis significantly increased the tannins content in the root and the flavonoids content in the stem of S. canadensis. The biomass of S. canadensis was significantly negatively correlated with the tannin content in the root and the flavonoids content in the stem. These results indicated that the parasitism of C. australis could inhibit the growth of S. canadensis by changing the resources allocation patterns as well as reducing the resources obtained by S. canadensis.

  12. Pyrolytic Characteristics and Kinetics of Phragmites australis

    PubMed Central

    Zhao, Hui; Yan, Huaxiao; Zhang, Congwang; Liu, Xiaodong; Xue, Yanhui; Qiao, Yingyun; Tian, Yuanyu; Qin, Song

    2011-01-01

    The pyrolytic kinetics of Phragmites australis was investigated using thermogravimetric analysis (TGA) method with linear temperature programming process under an inert atmosphere. Kinetic expressions for the degradation rate in devolatilization and combustion steps have been obtained for P. australis with Dollimore method. The values of apparent activation energy, the most probable mechanism functions, and the corresponding preexponential factor were determined. The results show that the model agrees well with the experimental data and provide useful information for the design of pyrolytic processing system using P. australis as feedstock to produce biofuel. PMID:22007256

  13. [Flavonoids of Cuscuta australis R. Br].

    PubMed

    Guo, H; Li, J

    1997-01-01

    Six flavonoids were isolated from the seed of Cuscuta australis and four of them were identified as kaempferol, quercetin, astragalin and hyperoside. Hyperoside was obtained from this plant for the first time. In comparison with the flavonoids in C. chinensis, it is found that quercetin and its glycoside are the main flavonoids in C. australis. This result suggests that the flavonoids can be used to distinguish these two medicinal materials.

  14. Hydathode trichomes actively secreting water from leaves play a key role in the physiology and evolution of root-parasitic rhinanthoid Orobanchaceae

    PubMed Central

    Světlíková, Petra; Hájek, Tomáš; Těšitel, Jakub

    2015-01-01

    Background and Aims Root hemiparasites from the rhinanthoid clade of Orobanchaceae possess metabolically active glandular trichomes that have been suggested to function as hydathode trichomes actively secreting water, a process that may facilitate resource acquisition from the host plant’s root xylem. However, no direct evidence relating the trichomes to water secretion exists, and carbon budgets associated with this energy-demanding process have not been determined. Methods Macro- and microscopic observations of the leaves of hemiparasitic Rhinanthus alectorolophus were conducted and night-time gas exchange was measured. Correlations were examined among the intensity of guttation, respiration and transpiration, and analysis of these correlations allowed the carbon budget of the trichome activity to be quantified. We examined the intensity of guttation, respiration and transpiration, correlations among which indicate active water secretion. Key Results Guttation was observed on the leaves of 50 % of the young, non-flowering plants that were examined, and microscopic observations revealed water secretion from the glandular trichomes present on the abaxial leaf side. Night-time rates of respiration and transpiration and the presence of guttation drops were positively correlated, which is a clear indicator of hydathode trichome activity. Subsequent physiological measurements on older, flowering plants indicated neither intense guttation nor the presence of correlations, which suggests that the peak activity of hydathodes is in the juvenile stage. Conclusions This study provides the first unequivocal evidence for the physiological role of the hydathode trichomes in active water secretion in the rhinanthoid Orobanchaceae. Depending on the concentration of organic elements calculated to be in the host xylem sap, the direct effect of water secretion on carbon balance ranges from close to neutral to positive. However, it is likely to be positive in the xylem-only feeding

  15. Differences in salinity tolerance of genetically distinct Phragmites australis clones

    PubMed Central

    Achenbach, Luciana; Eller, Franziska; Nguyen, Loc Xuan; Brix, Hans

    2013-01-01

    Different clones of the wetland grass Phragmites australis differ in their morphology and physiology, and hence in their ability to cope with environmental stress. We analysed the responses of 15 P. australis clones with distinct ploidy levels (PLs) (4n, 6n, 8n, 10n, 12n) and geographic origins (Romania, Russia, Japan, Czech Republic, Australia) to step-wise increased salinity (8, 16, 24, 32, 40, 56 and 72 ppt). Shoot elongation rate, photosynthesis and plant part-specific ion accumulation were studied in order to assess if traits associated with salinity tolerance can be related to the genetic background and the geographic origin of the clones. Salt stress affected all clones, but at different rates. The maximum height was reduced from 1860 mm in control plants to 660 mm at 40 ppt salinity. The shoot elongation rate of salt-exposed plants varied significantly between clones until 40 ppt salinity. The light-saturated photosynthesis rate (Pmax) was stimulated by a salinity of 8 ppt, but decreased significantly at higher salinities. The stomatal conductance (gs) and the transpiration rate (E) decreased with increasing salinity. Only three clones survived at 72 ppt salinity, although their rates of photosynthesis were strongly inhibited. The roots and basal leaves of the salt-exposed plants accumulated high concentrations of water-extractable Na+ (1646 and 1004 µmol g−1 dry mass (DM), respectively) and Cl− (1876 and 1400 µmol g−1 DM, respectively). The concentrations of water-extractable Mg2+ and Ca2+ were reduced in salt-exposed plants compared with controls. The variation of all the measured parameters was higher among clones than among PLs. We conclude that the salinity tolerance of distinct P. australis clones varies widely and can be partially attributed to their longitudinal geographic origin, but not to PL. Further investigation will help in improving the understanding of this species' salt tolerance mechanisms and their connection to genetic factors.

  16. Non-targeted profiling of semi-polar metabolites in Arabidopsis root exudates uncovers a role for coumarin secretion and lignification during the local response to phosphate limitation

    PubMed Central

    Ziegler, Jörg; Schmidt, Stephan; Chutia, Ranju; Müller, Jens; Böttcher, Christoph; Strehmel, Nadine; Scheel, Dierk; Abel, Steffen

    2016-01-01

    Plants have evolved two major strategies to cope with phosphate (Pi) limitation. The systemic response, mainly comprising increased Pi uptake and metabolic adjustments for more efficient Pi use, and the local response, enabling plants to explore Pi-rich soil patches by reorganization of the root system architecture. Unlike previous reports, this study focused on root exudation controlled by the local response to Pi deficiency. To approach this, a hydroponic system separating the local and systemic responses was developed. Arabidopsis thaliana genotypes exhibiting distinct sensitivities to Pi deficiency could be clearly distinguished by their root exudate composition as determined by non-targeted reversed-phase ultraperformance liquid chromatography electrospray ionization quadrupole-time-of-flight mass spectrometry metabolite profiling. Compared with wild-type plants or insensitive low phosphate root 1 and 2 (lpr1 lpr2) double mutant plants, the hypersensitive phosphate deficiency response 2 (pdr2) mutant exhibited a reduced number of differential features in root exudates after Pi starvation, suggesting the involvement of PDR2-encoded P5-type ATPase in root exudation. Identification and analysis of coumarins revealed common and antagonistic regulatory pathways between Pi and Fe deficiency-induced coumarin secretion. The accumulation of oligolignols in root exudates after Pi deficiency was inversely correlated with Pi starvation-induced lignification at the root tips. The strongest oligolignol accumulation in root exudates was observed for the insensitive lpr1 lpr2 double mutant, which was accompanied by the absence of Pi deficiency-induced lignin deposition, suggesting a role of LPR ferroxidases in lignin polymerization during Pi starvation. PMID:26685189

  17. Dissection of Bacterial Wilt on Medicago truncatula Revealed Two Type III Secretion System Effectors Acting on Root Infection Process and Disease Development[C][W][OA

    PubMed Central

    Turner, Marie; Jauneau, Alain; Genin, Stéphane; Tavella, Marie-José; Vailleau, Fabienne; Gentzbittel, Laurent; Jardinaud, Marie-Françoise

    2009-01-01

    Ralstonia solanacearum is the causal agent of the devastating bacterial wilt disease, which colonizes susceptible Medicago truncatula via the intact root tip. Infection involves four steps: appearance of root tip symptoms, root tip cortical cell invasion, vessel colonization, and foliar wilting. We examined this pathosystem by in vitro inoculation of intact roots of susceptible or resistant M. truncatula with the pathogenic strain GMI1000. The infection process was type III secretion system dependent and required two type III effectors, Gala7 and AvrA, which were shown to be involved at different stages of infection. Both effectors were involved in development of root tip symptoms, and Gala7 was the main determinant for bacterial invasion of cortical cells. Vessel invasion depended on the host genetic background and was never observed in the resistant line. The invasion of the root tip vasculature in the susceptible line caused foliar wilting. The avrA mutant showed reduced aggressiveness in all steps of the infection process, suggesting a global role in R. solanacearum pathogenicity. The roles of these two effectors in subsequent stages were studied using an assay that bypassed the penetration step; with this assay, the avrA mutant showed no effect compared with the GMI1000 strain, indicating that AvrA is important in early stages of infection. However, later disease symptoms were reduced in the gala7 mutant, indicating a key role in later stages of infection. PMID:19493968

  18. Differential proton secretion in the apical elongation zone caused by gravistimulation is induced by a signal from the root cap.

    PubMed

    Monshausen, G B; Zieschang, H E; Sievers, A

    1996-12-01

    The extracellular proton activity along primary roots of Phleum pratense L. was measured using proton-selective microelectrodes. Removal of the root cap caused a reduction of the proton influx in the transitional region between the meristem and the apical elongation zone of the vertical root and inhibited the development of pH differences between the physically upper and lower flanks of the gravistimulated root. Disruption of the actin filament system of the root with 5 mmol m-3 cytochalasin D did not result in an altered proton flux and pH pattern compared with untreated vertical control roots, but inhibited the gravity-induced development of pH differences between the physically upper and lower root flanks as well as gravitropic curvature. These results provide evidence that pH changes following gravistimulation are induced by a signal transmitted from the root cap and that the actin filament system is involved in the gravity perception/transduction mechanism.

  19. Evaluating the phytoremediation potential of Phragmites australis grown in pentachlorophenol and cadmium co-contaminated soils.

    PubMed

    Hechmi, Nejla; Aissa, Nadhira Ben; Abdenaceur, Hassen; Jedidi, Naceur

    2014-01-01

    Pot-culture experiments were conducted to evaluate the phytoremediation potential of a wetland plant species, Phragmites australis in cadmium (Cd) and pentachlorophenol (PCP) co-contaminated soil under glasshouse conditions for 70 days. The treatments included Cd (0, 5 and 50 mg kg(-1)) without or with PCP (50 and 250 mg kg(-1)). The results showed that growth of P. australis was significantly influenced by interaction of Cd and PCP, decreasing with either Cd or PCP additions. Plant biomass was inhibited and reduced by the rate of 89 and 92% in the low and high Cd treatments and by 20 and 40% in the low and high PCP treatments compared to the control. The mixture of low Cd and low PCP lessened Cd toxicity to plants, resulting in improved plant growth (by 144%). Under the joint stress of the two contaminants, the ability of Cd uptake and translocation by P. australis was weak, and the BF and TF values were inferior to 1.0. A low proportion of the metal is found aboveground in comparison to roots, indicating a restriction on transport upwards and an excluding effect on Cd uptake. Thus, P. australis cannot be useful for phytoextraction. The removal rate of PCP increased significantly (70%) in planted soil. Significant positive correlations were found between the DHA and the removal of PCP in planted soils which implied that plant root exudates promote the rhizosphere microorganisms and enzyme activity, thereby improving biodegradation of PCP. Based on results, P. australis cannot be effective for phytoremediation of soil co-contaminated with Cd and PCP. Further, high levels of pollutant hamper and eventually inhibit plant growth. Therefore, developing supplementary methods (e.g. exploring the partnership of plant-microbe) for either enhancing (phytoextraction) or reducing the bioavailability of contaminants in the rhizosphere (phytostabilization) as well as plant growth promoting could significantly improve the process of phytoremediation in co-contaminated soil.

  20. Genome Sequence of Photobacterium halotolerans MELD1, with Mercury Reductase (merA), Isolated from Phragmites australis.

    PubMed

    Mathew, Dony Chacko; Mathew, Gincy Marina; Gicana, Ronnie Gicaraya; Huang, Chieh-Chen

    2015-06-04

    Here, we present the whole-genome sequence of Photobacterium halotolerans strain, MELD1, isolated from the roots of a terrestrial plant Phragmites australis grown in soil heavily contaminated with mercury and dioxin. The genome provides further insight into the adaptation of bacteria to the toxic environment from where it was isolated.

  1. Phospholipase dzeta2 drives vesicular secretion of auxin for its polar cell-cell transport in the transition zone of the root apex.

    PubMed

    Mancuso, Stefano; Marras, Anna Maria; Mugnai, Sergio; Schlicht, Markus; Zársky, Viktor; Li, Gang; Song, Li; Xue, Hong-Wei; Baluska, Frantisek

    2007-07-01

    Auxin (IAA) is versatile signalling molecule of plants, currently classified as plant hormone. But there are data suggesting that auxin is acting also as plant-specific morphogen, electric-responses inducing transmitter, and as general signalling molecule used for plant-bacteria communication. Our previous data revealed that auxin is associated with secretory endosomes and also highly enriched within cell walls of cells active in transcellular auxin transport. Our present data, based on in vivo non-invasive auxin flux recordings, reveal that auxin is secreted out of synaptic-like domains specialized for efflux of auxin in root apex cells highly active in polar cell-cell transport of auxin. We obtained both genetic and pharmacological evidence that phospholipase Dzeta2 drives vesicular secretion of auxin for its polar transcellular transport in the transition zone of the root apex. Secretion of auxin via secretory vesicles has far-reaching consequences not only for our understanding of cell-cell auxin transport but also for plant sciences as a whole.

  2. Phospholipase Dζ2 Drives Vesicular Secretion of Auxin for Its Polar Cell-Cell Transport in the Transition Zone of the Root Apex

    PubMed Central

    Mancuso, Stefano; Marras, Anna Maria; Mugnai, Sergio; Schlicht, Markus; Žársky, Viktor; Li, Gang; Song, Li; Xue, Hong-Wei

    2007-01-01

    Auxin (IAA) is versatile signalling molecule of plants, currently classified as plant hormone. But there are data suggesting that auxin is acting also as plant-specific morphogen, electric-responses inducing transmitter, and as general signalling molecule used for plant-bacteria communication. Our previous data revealed that auxin is associated with secretory endosomes and also highly enriched within cell walls of cells active in transcellular auxin transport. Our present data, based on in vivo non-invasive auxin flux recordings, reveal that auxin is secreted out of synaptic-like domains specialized for efflux of auxin in root apex cells highly active in polar cell-cell transport of auxin. We obtained both genetic and pharmacological evidence that phospholipase Dζ2 drives vesicular secretion of auxin for its polar transcellular transport in the transition zone of the root apex. Secretion of auxin via secretory vesicles has far-reaching consequences not only for our understanding of cell-cell auxin transport but also for plant sciences as a whole. PMID:19516994

  3. Exogenous melatonin affects photosynthesis in characeae Chara australis.

    PubMed

    Lazár, Dušan; Murch, Susan J; Beilby, Mary J; Al Khazaaly, Sabah

    2013-03-01

    Melatonin was found in the fresh water characeae Chara australis. The concentrations (~4 μg/g of tissue) were similar in photosynthesizing cells, independent of their position on the plant and rhizoids (roots) without chloroplasts. Exogenous melatonin, added at 10 μM to the artificial pond water, increased quantum yield of photochemistry of photosystem II by 34%. The increased efficiency appears to be due to the amount of open reaction centers of photosystem II, rather than increased efficiency of each reaction center. More open reaction centers reflect better functionality of all photosynthetic transport chain constituents. We suggest that melatonin protection against reactive oxygen species covers not only chlorophyll, but also photosynthetic proteins in general.

  4. Exogenous melatonin affects photosynthesis in characeae Chara australis

    PubMed Central

    Lazár, Dušan; Murch, Susan J.; Beilby, Mary J.; Al Khazaaly, Sabah

    2013-01-01

    Melatonin was found in the fresh water characeae Chara australis. The concentrations (~4 μg/g of tissue) were similar in photosynthesizing cells, independent of their position on the plant and rhizoids (roots) without chloroplasts. Exogenous melatonin, added at 10 μM to the artificial pond water, increased quantum yield of photochemistry of photosystem II by 34%. The increased efficiency appears to be due to the amount of open reaction centers of photosystem II, rather than increased efficiency of each reaction center. More open reaction centers reflect better functionality of all photosynthetic transport chain constituents. We suggest that melatonin protection against reactive oxygen species covers not only chlorophyll, but also photosynthetic proteins in general. PMID:23299331

  5. A comparison of trace metal bioaccumulation and distribution in Typha latifolia and Phragmites australis: implication for phytoremediation.

    PubMed

    Klink, Agnieszka

    2017-02-01

    The aims of the present investigation were to reveal various trace metal accumulation abilities of two common helophytes Typha latifolia and Phragmites australis and to investigate their potential use in the phytoremediation of environmental metal pollution. The concentrations of Fe, Mn, Zn, Cu, Cd, Pb and Ni were determined in roots, rhizomes, stems and leaves of both species studied as well as in corresponding water and bottom sediments from 19 sites selected within seven lakes in western Poland (Leszczyńskie Lakeland). The principal component and classification analysis showed that P. australis leaves were correlated with the highest Mn, Fe and Cd concentrations, but T. latifolia leaves with the highest Pb, Zn and Cu concentrations. However, roots of the P. australis were correlated with the highest Mn, Fe and Cu concentrations, while T. latifolia roots had the highest Pb, Zn and Cd concentrations. Despite the differences in trace metal accumulation ability between the species studied, Fe, Cu, Zn, Pb and Ni concentrations in the P. australis and T. latifolia exhibited the following accumulation scheme: roots > rhizomes > leaves > stems, while Mn decreased in the following order: root > leaf > rhizome > stem. The high values of bioaccumulation factors and low values of translocation factors for Zn, Mn, Pb and Cu indicated the potential application of T. latifolia and P. australis in the phytostabilisation of contaminated aquatic ecosystems. Due to high biomass of aboveground organs of both species, the amount of trace metals stored in these organs during the vegetation period was considerably high, despite of the small trace metals transport.

  6. Hydathode trichomes actively secreting water from leaves play a key role in the physiology and evolution of root-parasitic rhinanthoid Orobanchaceae.

    PubMed

    Světlíková, Petra; Hájek, Tomáš; Těšitel, Jakub

    2015-07-01

    Root hemiparasites from the rhinanthoid clade of Orobanchaceae possess metabolically active glandular trichomes that have been suggested to function as hydathode trichomes actively secreting water, a process that may facilitate resource acquisition from the host plant's root xylem. However, no direct evidence relating the trichomes to water secretion exists, and carbon budgets associated with this energy-demanding process have not been determined. Macro- and microscopic observations of the leaves of hemiparasitic Rhinanthus alectorolophus were conducted and night-time gas exchange was measured. Correlations were examined among the intensity of guttation, respiration and transpiration, and analysis of these correlations allowed the carbon budget of the trichome activity to be quantified. We examined the intensity of guttation, respiration and transpiration, correlations among which indicate active water secretion. Guttation was observed on the leaves of 50 % of the young, non-flowering plants that were examined, and microscopic observations revealed water secretion from the glandular trichomes present on the abaxial leaf side. Night-time rates of respiration and transpiration and the presence of guttation drops were positively correlated, which is a clear indicator of hydathode trichome activity. Subsequent physiological measurements on older, flowering plants indicated neither intense guttation nor the presence of correlations, which suggests that the peak activity of hydathodes is in the juvenile stage. This study provides the first unequivocal evidence for the physiological role of the hydathode trichomes in active water secretion in the rhinanthoid Orobanchaceae. Depending on the concentration of organic elements calculated to be in the host xylem sap, the direct effect of water secretion on carbon balance ranges from close to neutral to positive. However, it is likely to be positive in the xylem-only feeding holoparasites of the genus Lathraea, which is closely

  7. Auxin secretion by Bacillus amyloliquefaciens FZB42 both stimulates root exudation and limits phosphorus uptake in Triticum aestivum

    PubMed Central

    2014-01-01

    Background The use of auxin-producing rhizosphere bacteria as agricultural products promises increased root production and therefore greater phosphate (Pi) uptake. Whilst such bacteria promote root production in vitro, the nature of the bacteria-plant interaction in live soil, particularly concerning any effects on nutrient uptake, are not known. This study uses Bacillus amyloliquefaciens FZB42, an auxin-producing rhizobacterium, as a dressing on Triticum aestivum seeds. It then examines the effects on root production, Pi uptake, Pi-related gene expression and organic carbon (C) exudation. Results Seed treatment with B. amyloliquefaciens FZB42 increased root production at low environmental Pi concentrations, but significantly repressed root Pi uptake. This coincided with an auxin-mediated reduction in expression of the Pi transporters TaPHT1.8 and TaPHT1.10. Applied exogenous auxin also triggered an increase in root C exudation. At high external Pi concentrations, root production was promoted by B. amyloliquefaciens FZB42, but Pi uptake was unaffected. Conclusions We conclude that, alongside promoting root production, auxin biosynthesis by B. amyloliquefaciens FZB42 both re-models Pi transporter expression and elevates organic C exudation. This shows the potential importance of rhizobacterial-derived auxin following colonisation of root surfaces, and the nature of this bacteria-plant interaction in soil. PMID:24558978

  8. Soil as levels and bioaccumulation in Suaeda salsa and Phragmites australis wetlands of the Yellow River Estuary, China.

    PubMed

    Wang, Junjing; Bai, Junhong; Gao, Zhaoqin; Lu, Qiongqiong; Zhao, Qingqing

    2015-01-01

    Little information is available on As contamination dynamics in the soil-plant systems of wetlands. Total arsenic (As) in soil and plant samples from Suaeda salsa and Phragmites australis wetlands was measured in the Yellow River Estuary (YRE) in summer and autumn of 2007 to investigate the seasonal changes in As concentrations in different wetlands. The results showed that soil As levels greatly exceeded the global and regional background values. As levels in soil and the roots and stems of both types of plants were much higher in summer than in autumn, whereas leaf As showed higher level in autumn. Soil sulfur was the main factor influencing As levels in Suaeda salsa wetlands, whereas soil porosity was the most important factor for Phragmites australis wetlands. The contamination factor (CF) showed moderately to considerably polluted levels of As in both wetland soils. Plant roots and leaves of Suaeda salsa had higher As concentrations and biological concentration factors (BCFs) than stems, while the leaves and stems of Phragmites australis showed higher As levels and BCFs than roots. Compared to Phragmites australis, Suaeda salsa generally showed higher translocation factor (TF), while TF values for both plant species were higher in summer than in autumn.

  9. Soil As Levels and Bioaccumulation in Suaeda salsa and Phragmites australis Wetlands of the Yellow River Estuary, China

    PubMed Central

    Wang, Junjing; Bai, Junhong; Gao, Zhaoqin; Lu, Qiongqiong; Zhao, Qingqing

    2015-01-01

    Little information is available on As contamination dynamics in the soil-plant systems of wetlands. Total arsenic (As) in soil and plant samples from Suaeda salsa and Phragmites australis wetlands was measured in the Yellow River Estuary (YRE) in summer and autumn of 2007 to investigate the seasonal changes in As concentrations in different wetlands. The results showed that soil As levels greatly exceeded the global and regional background values. As levels in soil and the roots and stems of both types of plants were much higher in summer than in autumn, whereas leaf As showed higher level in autumn. Soil sulfur was the main factor influencing As levels in Suaeda salsa wetlands, whereas soil porosity was the most important factor for Phragmites australis wetlands. The contamination factor (CF) showed moderately to considerably polluted levels of As in both wetland soils. Plant roots and leaves of Suaeda salsa had higher As concentrations and biological concentration factors (BCFs) than stems, while the leaves and stems of Phragmites australis showed higher As levels and BCFs than roots. Compared to Phragmites australis, Suaeda salsa generally showed higher translocation factor (TF), while TF values for both plant species were higher in summer than in autumn. PMID:25685781

  10. Aurora Australis as seen from STS-62

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Aurora Australis or southern lights as seen from STS-62. The multi-hued shafts of light, extending upward to 200 miles above the Earth's surface, are caused by beams of energetic electrons colliding with the oxygen and nitrogen in the Earth's upper atmosphere.

  11. STS-47 view of the Aurora Australis

    NASA Image and Video Library

    1992-09-20

    STS047-20-015 (12-20 Sept. 1992) --- This 35mm frame represents one of the more spectacular views of Aurora Australis, photographed by the crew. The crew observed and photographed a great deal of auroral activity from the Earth-orbiting Space Shuttle Endeavour during the eight-day Spacelab-J mission.

  12. Accumulation and Secretion of Coumarinolignans and other Coumarins in Arabidopsis thaliana Roots in Response to Iron Deficiency at High pH

    PubMed Central

    Sisó-Terraza, Patricia; Luis-Villarroya, Adrián; Fourcroy, Pierre; Briat, Jean-François; Abadía, Anunciación; Gaymard, Frédéric; Abadía, Javier; Álvarez-Fernández, Ana

    2016-01-01

    Root secretion of coumarin-phenolic type compounds has been recently shown to be related to Arabidopsis thaliana tolerance to Fe deficiency at high pH. Previous studies revealed the identity of a few simple coumarins occurring in roots and exudates of Fe-deficient A. thaliana plants, and left open the possible existence of other unknown phenolics. We used HPLC-UV/VIS/ESI-MS(TOF), HPLC/ESI-MS(ion trap) and HPLC/ESI-MS(Q-TOF) to characterize (identify and quantify) phenolic-type compounds accumulated in roots or secreted into the nutrient solution of A. thaliana plants in response to Fe deficiency. Plants grown with or without Fe and using nutrient solutions buffered at pH 5.5 or 7.5 enabled to identify an array of phenolics. These include several coumarinolignans not previously reported in A. thaliana (cleomiscosins A, B, C, and D and the 5′-hydroxycleomiscosins A and/or B), as well as some coumarin precursors (ferulic acid and coniferyl and sinapyl aldehydes), and previously reported cathecol (fraxetin) and non-cathecol coumarins (scopoletin, isofraxidin and fraxinol), some of them in hexoside forms not previously characterized. The production and secretion of phenolics were more intense when the plant accessibility to Fe was diminished and the plant Fe status deteriorated, as it occurs when plants are grown in the absence of Fe at pH 7.5. Aglycones and hexosides of the four coumarins were abundant in roots, whereas only the aglycone forms could be quantified in the nutrient solution. A comprehensive quantification of coumarins, first carried out in this study, revealed that the catechol coumarin fraxetin was predominant in exudates (but not in roots) of Fe-deficient A. thaliana plants grown at pH 7.5. Also, fraxetin was able to mobilize efficiently Fe from a Fe(III)-oxide at pH 5.5 and pH 7.5. On the other hand, non-catechol coumarins were much less efficient in mobilizing Fe and were present in much lower concentrations, making unlikely that they could play a

  13. Metabolic Control of Anaerobic Glycolysis (Overexpression of Lactate Dehydrogenase in Transgenic Tomato Roots Supports the Davies-Roberts Hypothesis and Points to a Critical Role for Lactate Secretion.

    PubMed

    Rivoal, J.; Hanson, A. D.

    1994-11-01

    Roots of all plants examined so far have the potential for both ethanol and lactate fermentation. A short burst of lactate fermentation usually occurs when plant tissues are transferred from normoxic to anoxic conditions. According to the Davies-Roberts hypothesis, the consequent pH drop both initiates ethanol fermentation and blocks further production of lactate by inhibiting lactate dehydrogenase (LDH). However, the role of LDH in this pH control mechanism is still a matter of debate. To perturb the control system in a defined way, a barley LDH cDNA under the control of the cauliflower mosaic virus 35S promoter was introduced into tomato (Lycopersicon esculentum Mill. cv VFMT) using Agrobacterium rhizogenes. The transgenic root clones expressed up to 50 times the LDH activity of controls. The fermentative metabolism of these clones was compared using roots grown previously in normoxic conditions or roots given a 3-d hypoxic pretreatment. During the transition from normoxia to anoxia, lactate accumulation was no faster and no more extensive in transgenic roots than in controls. Similarly, during prolonged anoxia the flux of 14C from [U-14C] glucose to lactate and ethanol was not modified by the expression of the transgene. However, in both transgenic and control roots, hypoxic pretreatment increased the flux to lactate and promoted lactate export to the medium. These results show that LDH has a very low flux control coefficient for lactate fermentation, consistent with the Davies-Roberts hypothesis. Moreover, they suggest that lactate secretion exerts major control over long-term lactate glycolysis in vivo.

  14. Fe plaque-related aquatic uranium retention via rhizofiltration along a redox-state gradient in a natural Phragmites australis Trin ex Steud. wetland.

    PubMed

    Wang, Weiqing; Gert Dudel, E

    2017-05-01

    Studies have revealed that the rhizofiltration is a feasible plant-based technology for aquatic metal/metalloid removal. However, the performance of aquatic U retention via rhizofiltration has not been fully revealed yet. In this study, a field investigation was conducted in a Phragmites australis Trin ex Steud. dominated wetland to estimate the efficiency of Fe plaque (IP)-assisted U rhizofiltration, with redox-state gradient (-179 to 220 mV) and low aquatic U level (66.7 to 92.0 μg l(-1)). The U concentrations were determined in soil, root, and aboveground biomass of P. australis. The IP on root surface was extracted via DCB extraction procedure. The bio-concentration factor (BCF) was applied to evaluate the aquatic U transfer capacity from root to above ground biomass of P. australis. The result suggested that root of P. australis was highly effective for aquatic U uptake via rhizofiltration (BCF 1025 to 1556). It also benefited the real U accumulation in aboveground biomass of P. australis (up to 0.4 mg m(-2)) and related plant-water-soil U recycling. The IP and associated microbial community in rhizosphere was effective mediator for aquatic U retention on root surface (BCF 1162 to 847). The IP-assisted aquatic U rhizofiltration was significantly promoted in relatively reductive environment. It was benefited by the enhanced root uptake of Fe due to lower oxidizers (e.g., DO and NO3(-)) availability. On the other hand, the competitive adsorption effect from co-existing IP-affinitive elements (e.g., As) also possibly impaired the real capacity of IP-assisted aquatic U rhizofiltration via P. australis.

  15. Transcriptional profiling of arbuscular mycorrhizal roots exposed to high levels of phosphate reveals the repression of cell cycle-related genes and secreted protein genes in Rhizophagus irregularis.

    PubMed

    Sugimura, Yusaku; Saito, Katsuharu

    2017-02-01

    The development of arbuscular mycorrhiza (AM) is strongly suppressed under high-phosphate (Pi) conditions. To investigate AM fungal responses during the suppression of AM by high Pi, we performed an RNA-seq analysis of Rhizophagus irregularis colonizing Lotus japonicus roots at different levels of Pi (20, 100, 300, and 500 μM). AM fungal colonization decreased markedly under high-Pi conditions. In total, 163 fungal genes were differentially expressed among the four Pi treatments. Among these genes, a cell cycle-regulatory gene, cyclin-dependent kinase CDK1, and several DNA replication- and mitosis-related genes were repressed under high-Pi conditions. More than 20 genes encoding secreted proteins were also downregulated by high-Pi conditions, including the strigolactone-induced putative secreted protein 1 gene that enhances AM fungal colonization. In contrast, the expression of genes related to aerobic respiration and transport in R. irregularis were largely unaffected. Our data suggest that high Pi suppresses the expression of genes associated with fungal cell cycle progression or that encode secreted proteins that may be required for intercellular hyphal growth and arbuscule formation. However, high Pi has little effect on the transcriptional regulation of the primary metabolism or transport in preformed fungal structures.

  16. Salt marsh macrophyte Phragmites australis strategies assessment for its dominance in mercury-contaminated coastal lagoon (Ria de Aveiro, Portugal).

    PubMed

    Anjum, Naser A; Ahmad, Iqbal; Válega, Mónica; Pacheco, Mário; Figueira, Etelvina; Duarte, Armando C; Pereira, Eduarda

    2011-08-01

    The dominance of a plant species in highly metal-contaminated areas reflects its tolerance or adaptability potential to these scenarios. Hence, plants with high adaptability and/or tolerance to exceptionally high metal-contaminated scenarios may help protect environmental degradation. The present study aimed to assess the strategies adopted by common reed, Phragmites australis for its dominance in highly mercury-contaminated Ria de Aveiro coastal lagoon (Portugal). Both plant samples and the sediments vegetated by monospecific stand of Phragmites australis were collected in five replicates from mercury-free (reference) and contaminated sites during low tide between March 2006 and January 2007. The sediments’ physico-chemical traits, plant dry mass, uptake, partitioning, and transfer of mercury were evaluated during growing season (spring, summer, autumn, and winter) of P. australis. Redox potential and pH of the sediment around roots were measured in situ using a WTW-pH 330i meter. Dried sediments were incinerated for 4 h at 500°C for the estimation of organic matter whereas plant samples were oven-dried at 60°C till constant weight for plant dry mass determination. Mercury concentrations in sediments and plant parts were determined by atomic absorption spectrometry with thermal decomposition, using an advanced mercury analyzer (LECO 254) and maintaining the accuracy and precision of the analytical methodologies. In addition, mercury bioaccumulation and translocation factors were also determined to differentiate the accumulation of mercury and its subsequent translocation to plant parts in P. australis. P. australis root exhibited the highest mercury accumulation followed by rhizome and leaves during the reproductive phase (autumn). During the same phase, P. australis exhibited ≈5 times less mercury-translocation factor (0.03 in leaf) when compared with the highest mercury bioaccumulation factor for root (0.14). Moreover, seasonal variations differentially

  17. Zinc isotopic fractionation in Phragmites australis in response to toxic levels of zinc

    PubMed Central

    Caldelas, Cristina; Dong, Shuofei; Araus, José Luis; Jakob Weiss, Dominik

    2011-01-01

    Stable isotope signatures of Zn have shown great promise in elucidating changes in uptake and translocation mechanisms of this metal in plants during environmental changes. Here this potential was tested by investigating the effect of high Zn concentrations on the isotopic fractionation patterns of Phragmites australis (Cav.) Trin. ex Steud. Plants were grown for 40 d in a nutritive solution containing 3.2 μM (sufficient) or 2 mM (toxic) Zn. The Zn isotopic composition of roots, rhizomes, shoots, and leaves was analysed. Stems and leaves were sampled at different heights to evaluate the effect of long-distance transport on Zn fractionation. During Zn sufficiency, roots, rhizomes, and shoots were isotopically heavy (δ66ZnJMC Lyon=0.2‰) while the youngest leaves were isotopically light (–0.5‰). During Zn excess, roots were still isotopically heavier (δ66Zn=0.5‰) and the rest of the plant was isotopically light (up to –0.5‰). The enrichment of heavy isotopes at the roots was attributed to Zn uptake mediated by transporter proteins under Zn-sufficient conditions and to chelation and compartmentation in Zn excess. The isotopically lighter Zn in shoots and leaves is consistent with long-distance root to shoot transport. The tolerance response of P. australis increased the range of Zn fractionation within the plant and with respect to the environment. PMID:21193582

  18. Bioaccumulation of selected metals in bivalves (Unionidae) and Phragmites australis inhabiting a municipal water reservoir.

    PubMed

    Rzymski, Piotr; Niedzielski, Przemysław; Klimaszyk, Piotr; Poniedziałek, Barbara

    2014-05-01

    Urbanization can considerably affect water reservoirs by, inter alia, input, and accumulation of contaminants including metals. Located in the course of River Cybina, Maltański Reservoir (Western Poland) is an artificial shallow water body built for recreation and sport purposes which undergoes restoration treatment (drainage) every 4 years. In the present study, we demonstrate an accumulation of nine metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Zn) in water, sediment, three bivalve species (Anodonta anatina, Anodonta cygnea, Unio tumidus), and macrophyte Phragmites australis collected before complete drainage in November 2012. The mean concentrations of metals in the sediment, bivalves, and P. australis (roots and leaves) decreased in the following order: Fe > Mn > Zn > Cu > Cr > Ni > Pb > Co > Cd. A considerably higher bioconcentration of metals was observed in samples collected from the western and southern sites which undergo a higher degree of human impact. Sediments were found to be a better indicator of metal contamination than water samples. Interspecific differences in levels of metal accumulation were found between investigated unionids. U. tumidus accumulated higher levels of Cr, positively correlated with ambient concentrations, predisposing this species as a potential bioindicator of this metal in aquatic environments. On the other hand, species of Anodonta genus demonstrated higher accumulation of Cu and Cd. Positive correlations were found between Pb content in the sediments and tissues of all three bivalve species. In P. australis, metals were largely retained in roots except for Cd and Pb for which higher concentrations were found in leaves suggesting additional absorption of these metals from aerial sources. P. australis and bivalve from the Maltański Reservoir may be a potential source of toxic metals for animals feeding upon them and contribute to further contamination in the food chain.

  19. Aurora Australis, Spiked, Sinuous Green Airglow

    NASA Technical Reports Server (NTRS)

    1991-01-01

    This distant view of the Aurora Australis or Southern Lights (location unknown) shows a spiked and sinuous band of green airglow above the Earth Limb. Calculated to be in the 80 - 120 km altitude region, auroral activity is due to exitation of atomic oxygen in the upper atmosphere by radiation from the van Allen Radiation Belts and is most common above the 65 degree north and south latitude range during the spring and fall of the year.

  20. Aurora Australis, Spiked, Sinuous Green Airglow

    NASA Technical Reports Server (NTRS)

    1991-01-01

    This distant view of the Aurora Australis or Southern Lights (location unknown) shows a spiked and sinuous band of green airglow above the Earth Limb. Calculated to be in the 80 - 120 km altitude region, auroral activity is due to exitation of atomic oxygen in the upper atmosphere by radiation from the van Allen Radiation Belts and is most common above the 65 degree north and south latitude range during the spring and fall of the year.

  1. [A Contrastive Study on Salt-alkaline Resistance and Removal Efficiency of Nitrogen and Phosphorus by Phragmites australis and Typha angustifolia in Coastal Estuary Area].

    PubMed

    Chen, You-yuan; Sun, Ping; Chen, Guang-lin; Wang, Ning-ning

    2015-04-01

    The salt and alkali contents were so high that the ecological landscape was depressed in water body of a coastal estuary area. Screening some plants which could not only tolerate saline-alkaline but also effectively remove nitrogen and phosphorus was therefore in urgent need. The tolerance range and removal rate of nitrogen and phosphorus by Phragmites australis and Typha angustifolia under salt and pH stress were investigated by hydroponic experiments. The results showed that Phragmites australis could tolerate at least 10 per thousand salinity and pH 8.5, while Typha angustifolia tolerated 7.5 per thousand salinity and pH 8.0. Combined with the change of the growth and physiological indexes (relative conductivity, proline, chlorophyll and root activity), the salt resistance of Phragmites australis was stronger than that of Typha angustifolia. Under salt stress, the removal rate of ammonia nitrogen of Phragmites australis was higher. The removal rates of nitrate nitrogen and phosphorus of Typha angustifolia were 2.5% and 7.3% higher than those of Phragmites australis in average, respectively, because of the high biomass of Typha angustifolias. The total nitrogen removal rate was equivalent. Under pH stress, the removal rate of ammonia nitrogen and total phosphorus of Phragmites australis was a little higher than that of Typha angustifolia. However, Typha angustifolia had a higher removal rate of total nitrogen, which was 8.2% higher than that of Phragmites australis. All the analysis showed that both Phragmites australis and Typha angustifolia could be used as alternative plants to grow and remove nitrogen and phosphorus in the high salt-alkaline water body in coastal estuary area.

  2. Root and bacterial secretions regulate the interaction between plants and PGPR leading to distinct plant growth promotion effects

    USDA-ARS?s Scientific Manuscript database

    Plant growth-promoting rhizobacteria (PGPR) have garnered interest in agriculture due to their ability to influence the growth and production of host plants. ATP-binding cassette (ABC) transporters play important roles in plant-microbe interactions by modulating plant root exudation. The present stu...

  3. Ailanthus Altissima and Phragmites Australis for chromium removal from a contaminated soil.

    PubMed

    Ranieri, Ezio; Fratino, Umberto; Petrella, Andrea; Torretta, Vincenzo; Rada, Elena Cristina

    2016-08-01

    The comparative effectiveness for hexavalent chromium removal from irrigation water, using two selected plant species (Phragmites australis and Ailanthus altissima) planted in soil contaminated with hexavalent chromium, has been studied in the present work. Total chromium removal from water was ranging from 55 % (Phragmites) to 61 % (Ailanthus). After 360 days, the contaminated soil dropped from 70 (initial) to 36 and 41 mg Cr/kg (dry soil), for Phragmites and Ailanthus, respectively. Phragmites accumulated the highest amount of chromium in the roots (1910 mg Cr/kg(dry tissue)), compared with 358 mg Cr/kg(dry tissue) for Ailanthus roots. Most of chromium was found in trivalent form in all plant tissues. Ailanthus had the lowest affinity for Cr(VI) reduction in the root tissues. Phragmites indicated the highest chromium translocation potential, from roots to stems. Both plant species showed good potentialities to be used in phytoremediation installations for chromium removal.

  4. [Neurite-stimulating effect of Hirudo medicinalis salivary gland secreting factors in organotypic culture of the dorsal root ganglia].

    PubMed

    Chalisova, N I; Baskova, I P; Zavalova, L L; Pennijainen, V A

    2001-06-01

    Effects of destabilise, bdellin, bdellin A, eglin were investigated in organotypic tissue culture of dorsal root ganglia (DRG) of 10-11-day old chick embryos. Native destabilase and bdellin A, bdellin B and eglin are more active inducing a more intensive neurite growth in DRG as compared with the control. A neurite-stimulating effect of the drug "pyjavit" seems to be associated with destabilase, bdellins and eglin neurite-stimulating activity.

  5. Mycorrhizal compatibility and symbiotic reproduction of Gavilea australis, an endangered terrestrial orchid from south Patagonia.

    PubMed

    Fracchia, Sebastián; Aranda-Rickert, Adriana; Flachsland, Eduardo; Terada, Graciela; Sede, Silvana

    2014-11-01

    Gavilea australis is a terrestrial orchid endemic from insular south Argentina and Chile. Meeting aspects of mycorrhizal fungi identity and compatibility in this orchid species is essential for propagation and conservation purposes. These knowledge represent also a first approach to elucidate the mycorrhizal specificity of this species. In order to evaluate both the mycorrhizal compatibility and the symbiotic seed germination of G. australis, we isolated and identified its root endophytic fungal strains as well as those from two sympatric species: Gavilea lutea and Codonorchis lessonii. In addition, we tested two other strains isolated from allopatric terrestrial orchid species from central Argentina. All fungal strains formed coilings and pelotons inside protocorms and promoted, at varying degrees, seed germination, and protocorm development until seedlings had two to three leaves. These results suggest a low mycorrhizal specificity of G. australis and contribute to a better knowledge of the biology of this orchid as well as of other sympatric Patagonian orchid species, all of them currently under serious risk of extinction.

  6. Dynamics of the dayside Aurora Australis

    NASA Astrophysics Data System (ADS)

    McEwen, D. J.; Sivjee, G. G.; Azeem, S. I.

    2010-01-01

    Current dayside optical studies of Aurora Australis from the Amundsen-Scott Research Station at the South Pole (74 degrees magnetic latitude) show some striking differences from optical results reported from Svalbard. A 6-channel meridian scanning photometer operating during the past three austral winters shows, in particular, the 630 nm emission is much lower, on average, than the Arctic dayside aurora and very weak on some days. The 558 nm intensity is higher relative to 630 nm suggesting the incoming electrons have a higher average energy. There are notable differences in auroral forms, giving further evidence of asymmetries in the two dayside ovals.

  7. Aurora Australis, Spiked, Sinuous Green Airglow

    NASA Image and Video Library

    1991-05-06

    STS039-25-006 (28 April-6 May 1991) --- A 35mm frame of the Aurora Australis, also known as the Southern Lights, photographed from the Space Shuttle Discovery's flight deck by one of its seven crew members. One of the mission objectives was to measure the spectral and spatial characteristics of auroral emissions. While passing over the sunlighted portion of Earth, the crew was able to take a number of photos of the various geographic points on the planet; much of the time on nightside passes was devoted to a thorough study and documentation of auroral displays.

  8. Sterols from the Green Alga Ulva australis.

    PubMed

    Li, Guo-Liang; Guo, Wei-Jie; Wang, Guang-Bao; Wang, Rong-Rong; Hou, Yu-Xue; Liu, Kun; Liu, Yang; Wang, Wei

    2017-09-28

    Three new sterols, (24R)-5,28-stigmastadiene-3β,24-diol-7-one (1), (24S)-5,28-stigmastadiene-3β,24-diol-7-one (2), and 24R and 24S-vinylcholesta-3β,5α,6β,24-tetraol (3), together with three known sterols (4-6) were isolated from the green alga Ulva australis. The structures of the new compounds (1-3) were elucidated through 1D and 2D nuclear magnetic resonance spectroscopy as well as mass spectrometry. Compounds 4-6 were identified as isofucoterol (4), 24R,28S and 24S,28R-epoxy-24-ethylcholesterol (5), and (24S)-stigmastadiene-3β,24-diol (6) on the basis of spectroscopic data analyses and comparison with those reported in the literature. Compounds 4-6 were isolated from U. australis for the first time. These compounds, together with the previously isolated secondary metabolites of this alga, were investigated for their inhibitory effects on human recombinant aldose reductase in vitro. Of the compounds, 24R,28S and 24S,28R-epoxy-24-ethylcholesterol (5), 1-O-palmitoyl-3-O-(6'-sulfo-α-d-quinovopyranosyl) glycerol, (2S)-1-O-palmitoyl-3-O-[α-d-galactopyranosyl(1→2)β-d-galactopyranosyl] glycerol, 4-hydroxybenzoic acid, 4-hydroxyphenylacetic acid, and 8-hydroxy-(6E)-octenoic acid weakly inhibited the enzyme, while the three new sterols, 1-3, were almost inactive.

  9. Structural constituents of the seagrass Posidonia australis.

    PubMed

    Torbatinejad, Nour Mohammad; Annison, Geoffrey; Rutherfurd-Markwick, Kay; Sabine, John R

    2007-05-16

    Large amounts of seagrass, Posidonia australis, wash onto beaches in South Australia each year, causing substantial environmental problems. It was of interest to assess the potential for an economic use of this seagrass-such as for animal nutrition. Structural constituents of P. australis (green, freshly deposited, and both washed and unwashed samples from dried deposits on the beach) were examined and compared. Glucose, galactose, and mannose were the dominant sugars (>10 g kg-1 of dry matter) in the soluble fraction of nonstarch polysaccharides in all seagrass forms. The content of the insoluble constituents of the nonstarch polysaccharides was significantly higher than soluble nonstarch polysaccharide constituents (P < 0.01). Data showed that the major constituents of the Posidonia cell wall are cellulose and lignin (190-209 and 145-154 g kg-1, respectively). The crude protein content of Posidonia ranged from 54 to 61 g kg-1. Results showed no biologically significant compositional differences between the four different forms of seagrass tested. Dry, unwashed seagrass, which is readily available in large quantities and easily harvested, may have potential as a foodstuff for ruminant animals.

  10. Root Hairs

    PubMed Central

    Grierson, Claire; Nielsen, Erik; Ketelaarc, Tijs; Schiefelbein, John

    2014-01-01

    Roots hairs are cylindrical extensions of root epidermal cells that are important for acquisition of nutrients, microbe interactions, and plant anchorage. The molecular mechanisms involved in the specification, differentiation, and physiology of root hairs in Arabidopsis are reviewed here. Root hair specification in Arabidopsis is determined by position-dependent signaling and molecular feedback loops causing differential accumulation of a WD-bHLH-Myb transcriptional complex. The initiation of root hairs is dependent on the RHD6 bHLH gene family and auxin to define the site of outgrowth. Root hair elongation relies on polarized cell expansion at the growing tip, which involves multiple integrated processes including cell secretion, endomembrane trafficking, cytoskeletal organization, and cell wall modifications. The study of root hair biology in Arabidopsis has provided a model cell type for insights into many aspects of plant development and cell biology. PMID:24982600

  11. Evaluation of the functional roles of fungal endophytes of Phragmites australis from high saline and low saline habitats

    USGS Publications Warehouse

    Soares, Marcos Antonio; Li, Hai-Yan; Kowalski, Kurt P.; Bergen, Marshall; Torres, Monica S.; White, James F.

    2016-01-01

    Non-native Phragmites australis decreases biodiversity and produces dense stands in North America. We surveyed the endophyte communities in the stems, leaves and roots of collections of P. australis obtained from two sites with a low and high salt concentration to determine differences in endophyte composition and assess differences in functional roles of microbes in plants from both sites. We found differences in the abundance, richness and diversity of endophytes between the low saline collections (18 species distributed in phyla Ascomycota, Basidiomycota and Stramenopiles (Oomycota); from orders Dothideales, Pleosporales, Hypocreales, Eurotiales, Cantharellales and Pythiales; Shannon H = 2.639; Fisher alpha = 7.335) and high saline collections (15 species from phylum Ascomycota; belonging to orders Pleosporales, Hypocreales, Diaporthales, Xylariales and Dothideales; Shannon H = 2.289; Fisher alpha = 4.181). Peyronellaea glomerata, Phoma macrostoma and Alternaria tenuissima were species obtained from both sites. The high salt endophyte community showed higher resistance to zinc, mercury and salt stress compared to fungal species from the low salt site. These endophytes also showed a greater propensity for growth promotion of rice seedlings (a model species) under salt stress. The results of this study are consistent with the ‘habitat-adapted symbiosis hypothesis’ that holds that endophytic microbes may help plants adapt to extreme habitats. The capacity of P. australis to establish symbiotic relationships with diverse endophytic microbes that enhance its tolerance to abiotic stresses could be a factor that contributes to its invasiveness in saline environments. Targeting the symbiotic associates of P. australis could lead to more sustainable control of non-native P. australis.

  12. Allelopathy and resource competition: the effects of Phragmites australis invasion in plant communities.

    PubMed

    Uddin, Md Nazim; Robinson, Randall William

    2017-12-01

    Phragmites australis, a ubiquitous wetland plant, has been considered one of the most invasive species in the world. Allelopathy appears to be one of the invasion mechanisms, however, the effects could be masked by resource competition among target plants. The difficulty of distinguishing allelopathy from resource competition among plants has hindered investigations of the role of phytotoxic allelochemicals in plant communities. This has been addressed via experiments conducted in both the greenhouse and laboratory by growing associated plants, Melaleuca ericifolia, Rumex conglomeratus, and model plant, Lactuca sativa at varying densities with the allelopathic plant, P. australis, its litter and leachate of P. australis litter. This study investigated the potential interacting influences of allelopathy and resource competition on plant growth-density relationships. In greenhouse, the root exudates mediated effects showed the strongest growth inhibition of M. ericifolia at high density whereas litter mediated results revealed increased growth at medium density treatments compared to low and high density. Again, laboratory experiments related to seed germination and seedling growth of L. sativa and R. conglomeratus exhibited phytotoxicity decreased showing positive growth as plant density increased and vice versa. Overall, the differential effects were observed among experiments but maximum individual plant biomass and some other positive effects on plant traits such as root and shoot length, chlorophyll content occurred at an intermediate density. This was attributed to the sharing of the available phytotoxin among plants at high densities which is compatible to density-dependent phytotoxicity model. The results demonstrated that plant-plant interference is the combined effect of allelopathy and resource competition with many other factors but this experimental design, target-neighbor mixed-culture in combination of plant grown at varying densities with varying

  13. Maghemite nanoparticles and ferrous sulfate for the stimulation of iron plaque formation and arsenic immobilization in Phragmites australis.

    PubMed

    Pardo, Tania; Martínez-Fernández, Domingo; de la Fuente, Carlos; Clemente, Rafael; Komárek, Michael; Bernal, M Pilar

    2016-12-01

    Wetland plants are considered as suitable biofilters for the removal of metal(loid)s and other contaminants from waters and wastewaters, due to their ability to accumulate and retain the contaminants in their roots. The iron plaque (IP) on the root surface influences the metal(loid)s retention processes. The stimulation of the IP development on roots of Phragmites australis by the external supply of a novel synthetic nanomaterial (nanomaghemite, nFe2O3) and FeSO4 (alone or in combination) was studied. An hydroponic experiment was carried out to evaluate the iron plaque formation after external iron addition, as well as their influence on arsenic immobilization capacity. Microscopic and spectroscopic techniques were utilized to assess the distribution of Fe and As in the roots. The addition of Fe stimulated the generation of the IP, especially when FeSO4 was involved. The nanoparticles alone were not efficient with regard to IP formation or As adsorption, even though they adhered to the root surface and did not enter into epithelial root cells. The combination of FeSO4 and nFe2O3 was the most effective treatment for improving the As removal capacity, and it seems to be an effective way to enhance the rhizofiltration potential of P. australis in As contaminated (waste)waters. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. R Coronae Australis: A Cosmic Watercolour

    NASA Astrophysics Data System (ADS)

    2010-06-01

    This magnificent view of the region around the star R Coronae Australis was created from images taken with the Wide Field Imager (WFI) at ESO's La Silla Observatory in Chile. R Coronae Australis lies at the heart of a nearby star-forming region and is surrounded by a delicate bluish reflection nebula embedded in a huge dust cloud. The image reveals surprising new details in this dramatic area of sky. The star R Coronae Australis lies in one of the nearest and most spectacular star-forming regions. This portrait was taken by the Wide Field Imager (WFI) on the MPG/ESO 2.2-metre telescope at the La Silla Observatory in Chile. The image is a combination of twelve separate pictures taken through red, green and blue filters. This image shows a section of sky that spans roughly the width of the full Moon. This is equivalent to about four light-years at the distance of the nebula, which is located some 420 light-years away in the small constellation of Corona Australis (the Southern Crown). The complex is named after the star R Coronae Australis, which lies at the centre of the image. It is one of several stars in this region that belong to the class of very young stars that vary in brightness and are still surrounded by the clouds of gas and dust from which they formed. The intense radiation given off by these hot young stars interacts with the gas surrounding them and is either reflected or re-emitted at a different wavelength. These complex processes, determined by the physics of the interstellar medium and the properties of the stars, are responsible for the magnificent colours of nebulae. The light blue nebulosity seen in this picture is mostly due to the reflection of starlight off small dust particles. The young stars in the R Coronae Australis complex are similar in mass to the Sun and do not emit enough ultraviolet light to ionise a substantial fraction of the surrounding hydrogen. This means that the cloud does not glow with the characteristic red colour seen in

  15. Flavobacterium phragmitis sp. nov., an endophyte of reed (Phragmites australis).

    PubMed

    Liu, Min; Li, Yan Hong; Liu, Yang; Zhu, Jing Nan; Liu, Qun Fang; Liu, Yin; Gu, Jin Gang; Zhang, Xiao Xia; Li, Chun Li

    2011-11-01

    A Gram-staining-negative bacterium, designated strain BLN2(T), was isolated from within the roots of reeds (Phragmites australis) in Beijing Cuihu Wetland (China) and characterized using a polyphasic taxonomic approach. The cells were yellow-pigmented, rod-shaped, strictly aerobic and devoid of flagella, but showed gliding motility. Strain BLN2(T) produced yellow, translucent, circular and convex colonies, with optimal growth at 30 °C and pH 7.0. The major respiratory quinone was menaquinone 6 (MK-6) and the predominant fatty acids were iso-C(15 : 0), summed feature 3 (comprising C(16 : 1)ω7c and/or C(16 : 1)ω6c), C(16 : 0) 3-OH, C(16 : 0,) iso-C(17 : 0) 3-OH and iso-C(15 : 0) 3-OH. The G+C content of the genomic DNA was 34.8 mol%. The 16S rRNA gene sequence analysis showed that strain BLN2(T) belonged to the genus Flavobacterium and was most closely related to Flavobacterium anhuiense CGMCC 1.6859(T) (97.0 % sequence similarity). The DNA-DNA relatedness between strain BLN2(T) and F. anhuiense CGMCC 1.6859(T) was 25.7 %. Based on the phenotypic data and phylogenetic inference presented, it is concluded that strain BLN2(T) represents a novel species within the genus Flavobacterium, for which the name Flavobacterium phragmitis sp. nov. is proposed. The type strain is BLN2(T) ( = DSM 23314(T) = CGMCC 1.10370(T)).

  16. Effects of vegetative-periodic-induced rhizosphere variation on the uptake and translocation of metals in Phragmites australis (Cav.) Trin ex. Steudel growing in the Sun Island Wetland.

    PubMed

    Wu, Jieting; Wang, Li; Ma, Fang; Yang, Jixian; Li, Shiyang; Li, Zhe

    2013-05-01

    To evaluate the vegetative periodic effect of rhizosphere on the patterns of metal bioaccumulation, the concentrations of Mg, K, Ca, Mn, Zn, Fe, Cu, Cr, Ni, Cd and Pb in the corresponding rhizosphere soil and tissues of Phragmites australis growing in the Sun Island wetland (Harbin, China) were compared. The concentrations of Zn, Fe, Cu, Cr, Ni, Cd and Pb in roots were higher than in shoots, suggesting that roots are the primary accumulation organs for these metals and there exists an exclusion strategy for metal tolerance. In contrast, the rest of the metals showed an opposite trend, suggesting that they were not restricted in roots. Harvesting would particularly be an effective method to remove Mn from the environment. The concentrations of metals in shoots were generally higher in autumn than in summer, suggesting that Ph. australis possesses an efficient root-to-shoot translocation system, which is activated at the end of the growing season and allows more metals into the senescent tissues. Furthermore, metal bioaccumulation of Ph. australis was affected by vegetative periodic variation through the changing of physicochemical and microbial conditions. The rhizospheric microbial characteristics were significantly related to the concentrations of Mg, K, Zn, Fe and Cu, suggesting that microbial influence on metal accumulation is specific and selective, not eurytopic.

  17. Aurora Australis as seen from STS-62

    NASA Image and Video Library

    1994-03-05

    STS062-58-025 (4-18 March) --- This photo shows the aurora australis or souther lights. The multi-hued shafts of light, extending upward to 200 miles above the earth's surface, are caused by beams of energetic electrons colliding with the oxygen and nitrogen in the earth's upper atmosphere. The strong red glow occurs at the highest altitude where the air is least dense and composed mostly of oxygen. At lower altitudes, the greater density favors the green color, also produced by atomic oxygen. Sometimes at the bottom (the lowest altitude of the aurora) a pink border is produced by nitrogen. The aurora usually can be seen only in Arctic regions. However, because of the tilt of the magnetic axis of the space shuttle mission orbits. One of these regions is over eastern North American, and the second one is south of Australia. Since most shuttle launches occur in daytime, the North American region is in daylight, and the only auroras that can be seen are usually in the Southern Hemisphere.

  18. Removal of Cu, Zn, Pb, and Cr from Yangtze Estuary Using the Phragmites australis Artificial Floating Wetlands.

    PubMed

    Huang, Xiaofeng; Zhao, Feng; Yu, Gao; Song, Chao; Geng, Zhi; Zhuang, Ping

    2017-01-01

    Contamination of heavy metals would threaten the water and soil resources; phytoremediation can be potentially used to remediate metal contaminated sites. We constructed the Phragmites australis artificial floating wetlands outside the Qingcaosha Reservoir in the Yangtze Estuary. Water characteristic variables were measured in situ by using YSI Professional Pro Meter. Four heavy metals (copper, zinc, lead, and chromium) in both water and plant tissues were determined. Four heavy metals in estuary water were as follows: 0.03 mg/Kg, 0.016 mg/Kg, 0.0015 mg/Kg, and 0.004 mg/Kg. These heavy metals were largely retained in the belowground tissues of P. australis. The bioaccumulation (BAF) and translation factor (TF) value of four heavy metals were affected by the salinity, temperature, and dissolved oxygen. The highest BAF of each metal calculated was as follows: Cr (0.091 in winter) > Cu (0.054 in autumn) > Pb (0.016 in summer) > Zn (0.011 in summer). Highest root-rhizome TF values were recorded for four metals: 6.450 for Cu in autumn, 2.895 for Zn in summer, 7.031 for Pb in autumn, and 2.012 for Cr in autumn. This indicates that the P. australis AFW has potential to be used to protect the water of Qingcaosha Reservoir from heavy metal contamination.

  19. Removal of Cu, Zn, Pb, and Cr from Yangtze Estuary Using the Phragmites australis Artificial Floating Wetlands

    PubMed Central

    Zhao, Feng; Yu, Gao; Song, Chao; Geng, Zhi

    2017-01-01

    Contamination of heavy metals would threaten the water and soil resources; phytoremediation can be potentially used to remediate metal contaminated sites. We constructed the Phragmites australis artificial floating wetlands outside the Qingcaosha Reservoir in the Yangtze Estuary. Water characteristic variables were measured in situ by using YSI Professional Pro Meter. Four heavy metals (copper, zinc, lead, and chromium) in both water and plant tissues were determined. Four heavy metals in estuary water were as follows: 0.03 mg/Kg, 0.016 mg/Kg, 0.0015 mg/Kg, and 0.004 mg/Kg. These heavy metals were largely retained in the belowground tissues of P. australis. The bioaccumulation (BAF) and translation factor (TF) value of four heavy metals were affected by the salinity, temperature, and dissolved oxygen. The highest BAF of each metal calculated was as follows: Cr (0.091 in winter) > Cu (0.054 in autumn) > Pb (0.016 in summer) > Zn (0.011 in summer). Highest root-rhizome TF values were recorded for four metals: 6.450 for Cu in autumn, 2.895 for Zn in summer, 7.031 for Pb in autumn, and 2.012 for Cr in autumn. This indicates that the P. australis AFW has potential to be used to protect the water of Qingcaosha Reservoir from heavy metal contamination. PMID:28717650

  20. Copper phytoremediation by a salt marsh plant (Phragmites australis) enhanced by autochthonous bioaugmentation.

    PubMed

    Oliveira, T; Mucha, A P; Reis, I; Rodrigues, P; Gomes, C R; Almeida, C M R

    2014-11-15

    Here we evaluated whether the potential of Phragmites australis to phytoremediate Cu contaminated sediments could be enhanced by bioaugmentation with an autochthonous microorganism consortium (AMC) that is resistant to Cu. Saltmarsh plants with sediment attached to their roots were collected, placed in vessels and kept in greenhouses, under tidal simulation. Sediments were contaminated with Cu and the AMC was added to half of the vessels. After two months, plants accumulated significant amounts of Cu (2-10 times more) in all tissues although in higher amounts (7-10 times more) in belowground structures. AMC addition increased Cu bioavailability (5-10%) in sediments leading to a decrease in belowground structures biomass. However, bioaugmentation increased Cu translocation, with higher amounts (2 times more) of Cu in the plant stems, without significant visual toxicity signs. Therefore, autochthonous bioaugmentation can increase Cu phytoextraction potential of P. australis, which can be a valuable strategy for the recovery and management of moderately impacted estuaries. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Identification, Development, and Release of Insect Biocontrol Agents for the Management of Phragmites australis

    DTIC Science & Technology

    2014-07-01

    it introduced? Why has P. australis become so invasive and how do we measure its spread? The present-day existence of both native North American and...P. australis in North America will encounter a set of unique challenges. Native endemic North American genotypes of P. australis (Saltonstall 2002...associated with invasive P. australis clones (Blossey 2003a). At least two native North American “signature” species, a gall midge, Calamomyia

  2. Effects of transient Phragmites australis removal on brackish marsh greenhouse gas fluxes

    NASA Astrophysics Data System (ADS)

    Martin, Rose M.; Moseman-Valtierra, Serena

    2017-06-01

    Phragmites australis is a common invasive reed of North American coastal marshes, and efforts to control or eradicate it often are included in coastal marsh restoration efforts. While much research has tested impacts of P. australis removal on plant and faunal communities, less is known about biogeochemical responses to P. australis removal. Since coastal marshes are valued for their robust carbon sequestration, understanding the effect of P. australis removal on marsh carbon cycling dynamics is important. Temporary P. australis aboveground biomass clearing conducted as part of a restoration effort provided an opportunity to evaluate changes in fluxes of the greenhouse gases (GHGs) carbon dioxide (CO2) and methane (CH4) during P. australis removal and recovery. In Experiment 1 (2014 growing season), GHG fluxes were compared between a P. australis stand cleared mechanically and recovered within months of initial removal and an uncleared stand in the same marsh system. CO2 uptake increased dramatically in the cleared stand as P. australis regrew, but CH4 emissions remained unchanged, demonstrating that P. australis did not directly contribute to CH4 emission. In Experiment 2 (2015 manipulations), to test mechanisms of P. australis' impact on GHG fluxes, fluxes (light and dark) were compared between unimpacted P. australis plots, cut P. australis plots with litter, and cleared P. australis plots without litter. P. australis cutting (independent of litter removal) resulted in increased CO2 and CH4 emissions. Recovery of P. australis directly drove the rapid recovery of CO2 uptake, and did not increase (and possibly attenuated) CH4 emissions. Results of this study suggest that at this site, P. australis removal, in the absence of native vegetation recovery, may exacerbate GHG emission of coastal marshes in the short term, and that longer-term impacts warrant investigation.

  3. Environmental perspectives of Phragmites australis (Cav.) Trin. Ex. Steudel

    NASA Astrophysics Data System (ADS)

    Srivastava, Jatin; Kalra, Swinder J. S.; Naraian, Ram

    2014-09-01

    Extensive research is being conducted worldwide to find alternative and efficient systems to lessen the impacts of climate change and reduce environmental pollution. The genus Phragmites has proven ability to mitigate the environmental pollution of its surroundings. Common reed ( Phragmites australis (Cav.) Trin. Ex. Steudel), a graminaceous plant of cosmopolitan nature, has been extensively studied especially for the mitigation of environmental contamination. The capability of common reed to grow well at extreme environmental conditions such as elevated CO2 and high temperature is conferred by several factors such as change of carbon trapping mechanism (from C3 to C4 and vice versa), microbial association and biochemical adaptations. P. australis has been a most preferred unique plant system, especially in ecological engineering for improving the quality of wastewater. This paper reviews the current state of knowledge regarding the suitability of Phragmites australis for environmental remediation and summarizes recent advancements in our understanding of this grass.

  4. BOOK REVIEW: European Perceptions of Terra Australis

    NASA Astrophysics Data System (ADS)

    Sterken, Christiaan

    2012-12-01

    Terra Australis - the southern land - has been one of the most widespread concepts in European geography from the sixteenth to the eighteenth century. This book comprises a set of 14 interdisciplinary scholarly contributions that deal with personal perceptions of Terra Australis by cartographers and explorers, and with putting these perceptions in their historical and cultural environments. This book seems, at a first glance, to be very remote from astronomy - and even from the history of astronomy - however, as it also offers an excellent background to Captain James Cook's second voyage to observe the 1769 transit of Venus from Tahiti, it definitely is a work of truly interdisciplinary character. Cook's voyages, in fact, became a model in which key scientists of many nationalities and disciplines traveled together on ships. In these voyages, art, science, technology and political power were centralised and united. The chapters range across history, the visual arts, literature, popular culture, technology, politics and science. Issues of scientific reasoning are raised in the description of how people did think about the south before there even existed a perception of the unknown land - quite comparable to how ancient and early-modern astronomers had their thought about cosmology even before any observational data were available. Several early map systems - like the zonal and T-O maps (medieval world maps with the letter T inside an O representing the lands inside a circle of oceans) - are described, and the description of Roman geography shows the amazing fact that theory and practice were not unified, and existed independently of each other insofar that a real paradox between theory and observation had persisted for a very long time. The maps and charts also exemplify the long-lasting consequences of early modern copy-paste practice: navigators copied original sketch charts of coasts that were previously unknown to them, herewith committing many translation and

  5. Preface: Phragmites australis: A sheep in wolf's clothing?

    USGS Publications Warehouse

    Weinstein, M.P.; Keough, J.R.; Guntenspergen, G.R.; Litvin, S.Y.

    2003-01-01

    A. problem with national priorities for control or prevention of aquatic nuisance species is that we often do not know the full extent of the problem, if there is one. To address this issue, we hosted a technical forum and workshop-Phragmites australis: A Sheep in Wolf's Clothing?--with a focus on new research and critical reviews that address the role of Phragmites as a noxious weed. ... The Workshop helped focus the national effort in new multidisciplinary research to better understand the ecology of P australis and its ecosystem-level effects on the structure and function of coastal wetlands.

  6. Temporal variations of potential fecundity of southern blue whiting (Micromesistius australis australis) in the Southeast Pacific

    NASA Astrophysics Data System (ADS)

    Flores, Andrés; Wiff, Rodrigo; Díaz, Eduardo; Carvajal, Bernardita

    2017-08-01

    Fecundity is a key aspect of fish species reproductive biology because it relates directly to total egg production. Yet, despite such importance, fecundity estimates are lacking or scarce for several fish species. The gravimetric method is the most-used one to estimate fecundity by essentially scaling up the oocyte density to the ovary weight. It is a relatively simple and precise technique, but also time consuming because it requires counting all oocytes in an ovary subsample. The auto-diametric method, on the other hand, is relatively new for estimating fecundity, representing a rapid alternative, because it requires only an estimation of mean oocyte density from mean oocyte diameter. Using the extensive database available from commercial fishery and design surveys for southern blue whiting Micromesistius australis australis in the Southeast Pacific, we compared estimates of fecundity using both gravimetric and auto-diametric methods. Temporal variations in potential fecundity from the auto-diametric method were evaluated using generalised linear models considering predictors from maternal characteristics such as female size, condition factor, oocyte size, and gonadosomatic index. A global and time-invariant auto-diametric equation was evaluated using a simulation procedure based on non-parametric bootstrap. Results indicated there were not significant differences regarding fecundity estimates between the gravimetric and auto-diametric method (p > 0.05). Simulation showed the application of a global equation is unbiased and sufficiently precise to estimate time-invariant fecundity of this species. Temporal variations on fecundity were explained by maternal characteristic, revealing signals of fecundity down-regulation. We discuss how oocyte size and nutritional condition (measured as condition factor) are one of the important factors determining fecundity. We highlighted also the relevance of choosing the appropriate sampling period to conduct maturity studies

  7. Proton-transfer-reaction mass spectrometry as a new tool for real time analysis of root-secreted volatile organic compounds in Arabidopsis.

    PubMed

    Steeghs, Marco; Bais, Harsh Pal; de Gouw, Joost; Goldan, Paul; Kuster, William; Northway, Megan; Fall, Ray; Vivanco, Jorge M

    2004-05-01

    Plant roots release about 5% to 20% of all photosynthetically-fixed carbon, and as a result create a carbon-rich environment for numerous rhizosphere organisms, including plant pathogens and symbiotic microbes. Although some characterization of root exudates has been achieved, especially of secondary metabolites and proteins, much less is known about volatile organic compounds (VOCs) released by roots. In this communication, we describe a novel approach to exploring these rhizosphere VOCs and their induction by biotic stresses. The VOC formation of Arabidopsis roots was analyzed using proton-transfer-reaction mass spectrometry (PTR-MS), a new technology that allows rapid and real time analysis of most biogenic VOCs without preconcentration or chromatography. Our studies revealed that the major VOCs released and identified by both PTR-MS and gas chromatography-mass spectrometry were either simple metabolites, ethanol, acetaldehyde, acetic acid, ethyl acetate, 2-butanone, 2,3,-butanedione, and acetone, or the monoterpene, 1,8-cineole. Some VOCs were found to be produced constitutively regardless of the treatment; other VOCs were induced specifically as a result of different compatible and noncompatible interactions between microbes and insects and Arabidopsis roots. Compatible interactions of Pseudomonas syringae DC3000 and Diuraphis noxia with Arabidopsis roots resulted in the rapid release of 1,8-cineole, a monoterpene that has not been previously reported in Arabidopsis. Mechanical injuries to Arabidopsis roots did not produce 1,8-cineole nor any C6 wound-VOCs; compatible interactions between Arabidopsis roots and Diuraphis noxia did not produce any wound compounds. This suggests that Arabidopsis roots respond to wounding differently from above-ground plant organs. Trials with incompatible interactions did not reveal a set of compounds that was significantly different compared to the noninfected roots. The PTR-MS method may open the way for functional root VOC

  8. Proton-Transfer-Reaction Mass Spectrometry as a New Tool for Real Time Analysis of Root-Secreted Volatile Organic Compounds in Arabidopsis1

    PubMed Central

    Steeghs, Marco; Bais, Harsh Pal; de Gouw, Joost; Goldan, Paul; Kuster, William; Northway, Megan; Fall, Ray; Vivanco, Jorge M.

    2004-01-01

    Plant roots release about 5% to 20% of all photosynthetically-fixed carbon, and as a result create a carbon-rich environment for numerous rhizosphere organisms, including plant pathogens and symbiotic microbes. Although some characterization of root exudates has been achieved, especially of secondary metabolites and proteins, much less is known about volatile organic compounds (VOCs) released by roots. In this communication, we describe a novel approach to exploring these rhizosphere VOCs and their induction by biotic stresses. The VOC formation of Arabidopsis roots was analyzed using proton-transfer-reaction mass spectrometry (PTR-MS), a new technology that allows rapid and real time analysis of most biogenic VOCs without preconcentration or chromatography. Our studies revealed that the major VOCs released and identified by both PTR-MS and gas chromatography-mass spectrometry were either simple metabolites, ethanol, acetaldehyde, acetic acid, ethyl acetate, 2-butanone, 2,3,-butanedione, and acetone, or the monoterpene, 1,8-cineole. Some VOCs were found to be produced constitutively regardless of the treatment; other VOCs were induced specifically as a result of different compatible and noncompatible interactions between microbes and insects and Arabidopsis roots. Compatible interactions of Pseudomonas syringae DC3000 and Diuraphis noxia with Arabidopsis roots resulted in the rapid release of 1,8-cineole, a monoterpene that has not been previously reported in Arabidopsis. Mechanical injuries to Arabidopsis roots did not produce 1,8-cineole nor any C6 wound-VOCs; compatible interactions between Arabidopsis roots and Diuraphis noxia did not produce any wound compounds. This suggests that Arabidopsis roots respond to wounding differently from above-ground plant organs. Trials with incompatible interactions did not reveal a set of compounds that was significantly different compared to the noninfected roots. The PTR-MS method may open the way for functional root VOC

  9. IDENTIFICATION OF RESPIRATORY AND GASTROINTESTINAL PARASITES OF THREE SPECIES OF PINNIPEDS (ARCTOCEPHALUS AUSTRALIS, ARCTOCEPHALUS GAZELLA, AND OTARIA FLAVESCENS) IN SOUTHERN BRAZIL.

    PubMed

    Jacobus, Kristy; Marigo, Juliana; Gastal, Silvia Bainy; Taniwaki, Sueli Akemi; Ruoppolo, Valeria; Catão-Dias, José Luiz; Tseng, Florina

    2016-03-01

    In order to improve understanding of parasitism in South American pinnipeds, respiratory and gastrointestinal samples were collected from 12 Arctocephalus australis (South American fur seal), one Arctocephalus gazella (Antarctic fur seal), and one Otaria flavescens (South American sea lion). Ova and larvae were microscopically identified from fecal samples and respiratory secretions collected from live A. australis undergoing rehabilitation at Centro de Recuperação de Animais Marinhos (CRAM-FURG) in Rio Grande, Rio Grande do Sul, Brazil during June-July 2012. Adult parasites were collected from the lungs and gastrointestinal tracts of animals that died while undergoing treatment or were found dead along the southern Brazil coast. Parasites were identified by polymerase chain reaction and DNA sequencing, microscopic examination, comparison with keys, and histologic examination of tissues. Lung parasites of the Parafilaroides genus (Metastrongyloidea, Filaroididae) were identified at necropsy in both A. australis and A. gazella and gastrointestinal parasites were found in all three species of pinniped studied. Gastrointestinal parasites identified in A. australis included the nematodes Contracaecum sp. and Pseudoterranova cattani, the cestodes Adenocephalus pacificus (previously Diphyllobothrium pacificum), one from the Tetrabothridae family and one undetermined, and the acanthocephalans Corynosoma sp. and Bolbosoma sp.; from A. gazella the nematode Contracaecum sp. and the acanthocephalan Corynosoma sp.; and from O. flavescens the acanthocephalan Corynosoma sp. Ova from fecal samples from A. australis represent ascarid nematodes, Parafilaroides sp., Adenocephalus pacificus, acanthocephalans, and an egg determined either to be a trematode or pseuophyllidean cestode. With limited information surrounding parasitism, these findings are an important contribution to knowledge of the health of Southern Hemisphere pinnipeds.

  10. Aurora Australis view taken by the Expedition 29 crew

    NASA Image and Video Library

    2011-09-18

    ISS029-E-006404 (18 Sept. 2011) --- This is one of a series of night time images photographed by one of the Expedition 29 crew members from the International Space Station. It features Aurora Australis and parts of the southeastern Indian Ocean. Nadir coordinates are 49.42 degrees south latitude and 121.01 degrees east longitude.

  11. Aurora Australis view taken by the Expedition 29 crew

    NASA Image and Video Library

    2011-09-18

    ISS029-E-006406 (18 Sept. 2011) --- This is one of a series of night time images photographed by one of the Expedition 29 crew members from the International Space Station. It features Aurora Australis and parts of the southeastern Indian Ocean. Nadir coordinates are 49.30 degrees south latitude and 121.56 degrees east longitude.

  12. The parasitic plant Cuscuta australis is highly insensitive to abscisic acid-induced suppression of hypocotyl elongation and seed germination.

    PubMed

    Li, Juan; Hettenhausen, Christian; Sun, Guiling; Zhuang, Huifu; Li, Jian-Hong; Wu, Jianqiang

    2015-01-01

    Around 1% of angiosperms are parasitic plants. Their growth and development solely or partly depend on host plants from which they extract water, nutrients, and other molecules using a parasitic plant-specific organ, the haustorium. Strong depletion of nutrients can result in serious growth retardation and in some cases, death of the hosts. The genus Cuscuta (dodder) comprises about 200 holoparasitic species occurring on all continents. Their seedlings have no roots and cotyledons but are only string-like hypocotyls. When they contact suitable host plants, haustoria are formed and thereafter seedlings rapidly develop into vigorously growing branches without roots and leaves. This highly specialized lifestyle suggests that Cuscuta plants likely have unique physiology in development and stress responses. Using germination and seedling growth assays, we show that C. australis seeds and seedlings are highly insensitive to abscisic acid (ABA). Transcriptome analysis and protein sequence alignment with Arabidopsis, tomato, and rice homologs revealed that C. australis most likely consists of only four functional ABA receptors. Given that Cuscuta plants are no longer severely challenged by drought stress, we hypothesize that the ABA-mediated drought resistance pathway in Cuscuta spp. might have had degenerated over time during evolution.

  13. Antioxidant response of Phragmites australis to Cu and Cd contamination.

    PubMed

    Rocha, A Cristina S; Almeida, C Marisa R; Basto, M Clara P; Vasconcelos, M Teresa S D

    2014-11-01

    Metals are known to induce oxidative stress in plant cells. Antioxidant thiolic compounds are known to play an important role in plants׳ defence mechanisms against metal toxicity but, regarding salt marsh plants, their role is still very poorly understood. In this work, the involvement of non-protein thiols (NPT), such as cysteine (Cys), reduced glutathione (GSH), oxidised glutathione (GSSG) and total acid-soluble SH compounds (total thiols), in the tolerance mechanisms of the marsh plant Phragmites australis against Cu and Cd toxicity was assessed. Specimens of this plant, freshly harvested in an estuarine salt marsh, were exposed, for 7 days, to rhizosediment soaked with the respective elutriate contaminated with Cu (0, 10 and 100 mg/L) or Cd (0, 1, 10 mg/L). In terms of NPT production, Cu and Cd contamination induced different responses in P. australis. The content of Cys increased in plant tissue after plant exposure to Cu, whereas Cd contamination led to a decrease in GSSG levels. In general, metal contamination did not cause a significant variation on GSH levels. Both metals influenced, to some extent, the production of other thiolic compounds. Despite the accumulation of considerable amounts of Cu and Cd in belowground tissues, no visible toxicity signs were observed. So, antioxidant thiolic compounds were probably involved in the mechanisms used by P. australis to alleviate metal toxicity. As P. australis is considered suitable for phytostabilising metal-contaminated sediments, understanding its tolerance mechanisms to toxic metals is important to optimise the conditions for applying this plant in phytoremediation procedures. Copyright © 2014 Elsevier Inc. All rights reserved.

  14. Aurora Australis, Spiked and Sinuous Red and Green Airglow

    NASA Technical Reports Server (NTRS)

    1991-01-01

    This view of the Aurora Australis or Southern Lights, in the 80 - 120 km altitude region, (location unknown) shows a spiked and sinuous band of red and green airglow above the Earth Limb and a charged plasma glow around the orbiter. Auroral activity is due to exitation of atomic oxygen in the upper atmosphere by the van Allen Radiation Belts and is most common above the 65 degree north and south latitude range during the spring and fall of the year.

  15. Aurora Australis, Spiked and Sinuous Red and Green Airglow

    NASA Technical Reports Server (NTRS)

    1991-01-01

    In This distant view of the Aurora Australis or Southern Lights (location unknown), a spiked and sinuous band of red and green airglow above the Earth Limb is highlighted by moonglow. Auroral activity is due to exitation of atomic oxygen in the upper atmosphere by radiation from the van Allen Radiation Belts and is most common above the 65 degree north and south latitude range during the spring and fall of the year.

  16. Aurora Australis, Spiked and Sinuous Red and Green Airglow

    NASA Technical Reports Server (NTRS)

    1991-01-01

    In This distant view of the Aurora Australis or Southern Lights (location unknown), a spiked and sinuous band of red and green airglow above the Earth Limb is highlighted by moonglow. Auroral activity is due to exitation of atomic oxygen in the upper atmosphere by radiation from the van Allen Radiation Belts and is most common above the 65 degree north and south latitude range during the spring and fall of the year.

  17. Aurora Australis, Spiked and Sinuous Red and Green Airglow

    NASA Technical Reports Server (NTRS)

    1991-01-01

    This view of the Aurora Australis or Southern Lights, in the 80 - 120 km altitude region, (location unknown) shows a spiked and sinuous band of red and green airglow above the Earth Limb and a charged plasma glow around the orbiter. Auroral activity is due to exitation of atomic oxygen in the upper atmosphere by the van Allen Radiation Belts and is most common above the 65 degree north and south latitude range during the spring and fall of the year.

  18. Aurora Australis view taken by the Expedition 29 crew

    NASA Image and Video Library

    2011-09-17

    ISS029-E-008433 (17 Sept. 2011) --- This is one of a series of night time images photographed by one of the Expedition 29 crew members from the International Space Station. It features Aurora Australis, seen from a point over the southeast Tasman Sea near southern New Zealand. The station was located at 46.65 degrees south latitude and 169.10 degrees east longitude.

  19. The presence of eucalyptol in Artemisia australis validates its use in traditional Hawaiian medicine

    PubMed Central

    Zant, David; Gubler, Daniel A.

    2014-01-01

    Objective To identify the major organic compounds of Artemisia australis (A. australis), a plant used in traditional Hawaiian medicine for the treatment of asthma. Methods The dichloromethane extract of A. australis was analyzed by gas chromatography-mass spectroscopy and major compounds were identified by a National Institute of Standards and Technology library search and confirmed by peak enhancement. Results The major chemical components of A. australis include eucalyptol, borneol, and caryophyllene. Conclusions The presence and biological activity of eucalyptol correlate very well with the usage of this plant in traditional Hawaiian medicine. PMID:25183270

  20. The effects of tannery wastewater on the development of different plant species and chromium accumulation in Phragmites australis.

    PubMed

    Calheiros, Cristina S C; Rangel, António O S S; Castro, Paula M L

    2008-10-01

    Toxicity tests were performed to assess the effect of tannery wastewater with different treatment levels on two wetland plants, Phragmites australis and Typha latifolia, which are frequently used in constructed wetlands (CWs) for water treatment, and thus deepen the knowledge on their capacity to withstand the application of industrial wastewater. Trifolium pratense, a plant generally used as an indicator in toxicity tests, was included as a control. End points measured were germination percentage, shoot length, root elongation, and biomass growth of the plants. When tannery effluent, with a low treatment level, was supplied to the wetland plants germination occurred even at effluent concentrations of 100%, whereas germination of T. pratense was completely inhibited, almost invariably, at effluent concentration of 50%. Higher germination levels were achieved when the plants were exposed to effluent originating from the outlet of constructed wetland pilot units, allowing germination of all tested plants, indicating a significant decrease in its toxicity level. Experiments conducted with the same plants using different growing substrata as the germination matrix, namely expanded clay aggregates (Filtralite MR 3-8 and Filtralite NR 3-8) and two types of sand (fine gravel and standard sand) have shown that higher germination levels were achieved in standard sand and that P. australis was the plant species showing higher germination in all cases, reinforcing the robustness of this plant to environmental stress. The phytoextraction potential of P. australis, was evaluated by subjecting the plant to tannery wastewater supplemented with 50 and 150 mg Cr/L. After 6 weeks of exposure, levels up to 4825, 883, and 627 mg Cr/kg were found in the rhizome, shoot, and leaves, respectively, although phytotoxic signs in the plant were evident. This plant might not be considered a chromium hyperacumulator, but the potential to extract and accumulate this metal on its rhizomes is high.

  1. Sustainable biodegradation of phenolic endocrine-disrupting chemicals by Phragmites australis-rhizosphere bacteria association.

    PubMed

    Toyama, T; Ojima, T; Tanaka, Y; Mori, K; Morikawa, M

    2013-01-01

    The efficacy of two rhizobacteria (Sphingobium fuliginis TIK1 and Sphingobium sp. IT4) of Phragmites australis for the sustainable treatment of water polluted with phenolic endocrine-disrupting chemicals (EDCs) was investigated. Strains TIK1 and IT4 have recently been isolated from Phragmites rhizosphere and shown to degrade various 4-alkylphenols-TIK1 via phenolic ring hydroxylation and meta-cleavage and IT4 via ipso-hydroxylation. The two strains also degraded bisphenol A (BPA), bisphenol B, bisphenol E, bisphenol F, bisphenol P and bisphenol S (BPS). Thus, strains TIK1 and IT4 have wide degradation spectra for phenolic EDCs. The two strains utilized Phragmites root extracts as a sole carbon source and sustainably colonized Phragmites roots, where they degraded phenolic EDCs. In sequencing batch reactor experiments using Phragmites in association with TIK1 or IT4, both associations repeatedly removed phenolic EDCs from polluted secondary effluent water (BPA, BPS, 4-tert-butylphenol, 4-tert-octylphenol and 4-nonylphenol) from polluted secondary effluent water. The results suggest that hydroponic systems using Phragmites-TIK and Phragmites-IT4 associations would be useful for sustainable treatment of polluted waters containing various phenolic EDCs.

  2. Adaptive shoot and root responses collectively enhance growth at optimum temperature and limited phosphorus supply of three herbaceous legume species

    PubMed Central

    Suriyagoda, Lalith D. B.; Ryan, Megan H.; Renton, Michael; Lambers, Hans

    2012-01-01

    Background and Aims Studies on the effects of sub- and/or supraoptimal temperatures on growth and phosphorus (P) nutrition of perennial herbaceous species at growth-limiting P availability are few, and the impacts of temperature on rhizosphere carboxylate dynamics are not known for any species. Methods The effect of three day/night temperature regimes (low, 20/13 °C; medium, 27/20 °C; and high, 32/25 °C) on growth and P nutrition of Cullen cinereum, Kennedia nigricans and Lotus australis was determined. Key Results The highest temperature was optimal for growth of C. cinereum, while the lowest temperature was optimal for K. nigricans and L. australis. At optimum temperatures, the relative growth rate (RGR), root length, root length per leaf area, total P content, P productivity and water-use efficiency were higher for all species, and rhizosphere carboxylate content was higher for K. nigricans and L. australis. Cullen cinereum, with a slower RGR, had long (higher root length per leaf area) and thin roots to enhance P uptake by exploring a greater volume of soil at its optimum temperature, while K. nigricans and L. australis, with faster RGRs, had only long roots (higher root length per leaf area) as a morphological adaptation, but had a higher content of carboxylates in their rhizospheres at the optimum temperature. Irrespective of the species, the amount of P taken up by a plant was mainly determined by root length, rather than by P uptake rate per unit root surface area. Phosphorus productivity was correlated with RGR and plant biomass. Conclusions All three species exhibited adaptive shoot and root traits to enhance growth at their optimum temperatures at growth-limiting P supply. The species with a slower RGR (i.e. C. cinereum) showed only morphological root adaptations, while K. nigricans and L. australis, with faster RGRs, had both morphological and physiological (i.e. root carboxylate dynamics) root adaptations. PMID:22847657

  3. Moving from a regional to a continental perspective of Phragmites australis invasion in North America.

    PubMed

    Kettenring, Karin M; de Blois, Sylvie; Hauber, Donald P

    2012-01-01

    We use a regional comparison of Phragmites australis (common reed) subsp. americanus, P. australis subsp. berlandieri and introduced P. australis (possibly five sublineages) in the Chesapeake Bay, the St Lawrence River, Utah and the Gulf Coast to inform a North American perspective on P. australis invasion patterns, drivers, impacts and research needs. FINDINGS AND RESEARCH NEEDS: Our regional assessments reveal substantial diversity within and between the three main lineages of P. australis in terms of mode of reproduction and the types of environment occupied. For introduced P. australis, the timing of introduction also differed between the regions. Nevertheless, a common finding in these regions reinforces the notion that introduced P. australis is opportunistic and thrives in disturbed habitats. Thus, we expect to see substantial expansion of introduced P. australis with increasing anthropogenic disturbances in each of these regions. Although there have been some studies documenting the negative impacts of introduced P. australis, it also plays a beneficial role in some regions, and in some cases, the purported negative impacts are unproven. There is also a broader need to clarify the genetic and ecological relationships between the different introduced sublineages observed in North America, and their relative competitive ability and potential for admixture. This may be done through regional studies that use similar methodologies and share results to uncover common patterns and processes. To our knowledge, such studies have not been performed on P. australis in spite of the broad attention given to this species. Such research could advance theoretical knowledge on biological invasion by helping to determine the extent to which the patterns observed can be generalized or are sublineage specific or region specific. Given what appears to be sometimes idiosyncratic invasion patterns when interpreted in isolation in the regions that we analysed, it may be time to

  4. Moving from a regional to a continental perspective of Phragmites australis invasion in North America

    PubMed Central

    Kettenring, Karin M.; de Blois, Sylvie; Hauber, Donald P.

    2012-01-01

    Aims We use a regional comparison of Phragmites australis (common reed) subsp. americanus, P. australis subsp. berlandieri and introduced P. australis (possibly five sublineages) in the Chesapeake Bay, the St Lawrence River, Utah and the Gulf Coast to inform a North American perspective on P. australis invasion patterns, drivers, impacts and research needs. Findings and research needs Our regional assessments reveal substantial diversity within and between the three main lineages of P. australis in terms of mode of reproduction and the types of environment occupied. For introduced P. australis, the timing of introduction also differed between the regions. Nevertheless, a common finding in these regions reinforces the notion that introduced P. australis is opportunistic and thrives in disturbed habitats. Thus, we expect to see substantial expansion of introduced P. australis with increasing anthropogenic disturbances in each of these regions. Although there have been some studies documenting the negative impacts of introduced P. australis, it also plays a beneficial role in some regions, and in some cases, the purported negative impacts are unproven. There is also a broader need to clarify the genetic and ecological relationships between the different introduced sublineages observed in North America, and their relative competitive ability and potential for admixture. This may be done through regional studies that use similar methodologies and share results to uncover common patterns and processes. To our knowledge, such studies have not been performed on P. australis in spite of the broad attention given to this species. Such research could advance theoretical knowledge on biological invasion by helping to determine the extent to which the patterns observed can be generalized or are sublineage specific or region specific. Synthesis Given what appears to be sometimes idiosyncratic invasion patterns when interpreted in isolation in the regions that we analysed, it may

  5. A Comparison of the Functional Traits of Common Reed (Phragmites australis) in Northern China: Aquatic vs. Terrestrial Ecotypes

    PubMed Central

    Li, Liping; Han, Wenxuan; Thevs, Niels; Jia, Xiuhong; Ji, Chengjun; Jin, Dongmei; He, Ping; Schmitt, Armin O.; Cirella, Giuseppe Tommaso; Zerbe, Stefan

    2014-01-01

    Common reed (Phragmites australis (Cav.) Trin. ex Steud.) is distributed widely throughout the world with various ecotypes. This research compares the functional traits and biomass allocation patterns of two contrasting reed ecotypes. Twelve pairs of aquatic and terrestrial reed samples were collected in northern China. Significant differences in functional traits between the two reed ecotypes were observed, while biomass allocation patterns of reed organs did not differ significantly except for at the root. The dry matter content (DMC) in the whole of the reed plant, leaf, root, and rhizome was higher; while the specific leaf area (SLA) and specific root length (SRL) were lower in terrestrial versus aquatic reed. The biomass allocation in organs of the two forms of reed was isometric, only root in the terrestrial habitat increased faster with an increase in the whole plant biomass. It can be affirmed that aquatic and terrestrial reed that adapt to different environments generally has distinct leaf and root functional traits but isometric biomass allocation patterns. This suggests different resource acquisition strategies: (1) aquatic reed grows faster with high SLA and SRL and is more responsive to the environment, while (2) terrestrial reed with high DMC grows slower and is less responsive to the adverse environment (e.g. dry soil conditions). PMID:24586505

  6. Phytotoxicity and accumulation of zinc oxide nanoparticles on the aquatic plants Hydrilla verticillata and Phragmites Australis: leaf-type-dependent responses.

    PubMed

    Song, Uhram; Lee, Sunryung

    2016-05-01

    The phytotoxicity and accumulation of zinc oxide nanoparticles (ZnO NPs) on aquatic plant Hydrilla verticillata and Phragmites australis were investigated using mesocosms. The percentage of dissolved Zn in the ZnO NP treatment solutions was measured along with plant shoot growth, antioxidant enzyme activity, chlorophyll content, and Zn content. The dissolution rate of ZnO NPs in Hoagland solution was inversely related to the concentration. The submerged aquatic plant H. verticillata, growth was reduced during the early stages of the experiment when exposed to the highest ZnO NP concentration (1000 mg/L), whereas the emerged aquatic plant P. australis began to show significantly reduced growth after a few weeks. The measurements of chlorophyll content, antioxidant enzyme activity, and Zn accumulation showed that P. australis was adversely affected by NPs and absorbed more Zn than H. verticillata. The results indicated that physiological differences among aquatic plants, such as whether they use leaves or roots for nutrient and water uptake, led to differences in nanoparticle toxicity. Overall, High ZnO NP concentrations caused significant phytotoxicity on aquatic plants, and low concentrations caused unpredictable phytotoxicity. Therefore, the use and disposal of zinc oxide nanoparticles should be carefully monitored.

  7. Role of Rhizophagus irregularis in alleviating cadmium toxicity via improving the growth, micro- and macroelements uptake in Phragmites australis.

    PubMed

    Wang, Li; Huang, Xiaochen; Ma, Fang; Ho, Shih-Hsin; Wu, Jieting; Zhu, Shishu

    2017-02-01

    Arbuscular mycorrhizal (AM) fungi have been used to alleviate heavy metal stress on plant growth and uptake of micro- and macroelements. A greenhouse pot experiment was conducted to verify the effects of AM fungus Rhizophagus irregularis on the growth, physiological characteristics, total Cd, and element uptake of Phragmites australis under different Cd stress (in the range of 0-20 mg L(-1)). The results showed that the symbiosis could effectively alleviate Cd toxicity with greater root biomass, higher photosynthesis rate, and lower levels of malonaldehyde (MDA) and proline than non-mycorrhizal plants could. However, reduced transpiration rate (Tr) and stomatal conductance (g s) indicated R. irregularis protected host plants from Cd stress (≥5 mg L(-1)) via the stomatal closure. Although micro- and macroelements displayed differently in the presence of Cd, higher concentrations were still detected in mycorrhizal plants in contrast to non-mycorrhizal plants. Moreover, step multiple regression significantly demonstrated Pnmax, stem diameter (Sd), and g s were the important factors with regard to total Cd uptake in the symbiosis, but Mn affected to non-mycorrhizal plants. These results suggested R. irregularis could alleviate the competition between Mn and Cd by altering plant physiology. This work clearly demonstrated that R. irregularis can be able to support P. australis growth better even though under high Cd stress (>1 mg L(-1)), suggesting its good potential for practical use in high Cd-contaminated areas.

  8. [Secret medicines].

    PubMed

    Bonnemain, H

    2001-01-01

    Secret medicines had two characteristics: their formula remained unknown and they were prepared by many kinds of people. Before 1728 there were no general laws about these secret medicines but only peculiar rules. From 1728 to 1778, the King edicted rigorous rules in order to limit the number of secret medicines. Between 1778 and 1789, the law became more definite and the Royal Society of Medicine gave advices. The Law of Germinal An-XI forbid secret medicines but since 1805, some compromises took place. Slowly, secret medicines were replaced by pharmaceutics and new set of laws.

  9. Evidence does not support a role for gallic acid in Phragmites australis invasion success.

    PubMed

    Weidenhamer, Jeffrey D; Li, Mei; Allman, Joshua; Bergosh, Robert G; Posner, Mason

    2013-02-01

    Gallic acid has been reported to be responsible for the invasive success of nonnative genotypes of Phragmites australis in North America. We have been unable to confirm previous reports of persistent high concentrations of gallic acid in the rhizosphere of invasive P. australis, and of high concentrations of gallic acid and gallotannins in P. australis rhizomes. The half-life of gallic acid in nonsterile P. australis soil was measured by aqueous extraction of soils and found to be less than 1 day at added concentrations up to 10,000 μg g(-1). Furthermore, extraction of P. australis soil collected in North Carolina showed no evidence of gallic acid, and extractions of both rhizomes and leaves of samples of four P. australis populations confirmed to be of invasive genotype show only trace amounts of gallic acid and/or gallotannins. The detection limits were less than 20 μg gallic acid g(-1) FW in the rhizome samples tested, which is approximately 0.015 % of the minimum amount of gallic acid expected based on previous reports. While the occurrence of high concentrations of gallic acid and gallotannins in some local populations of P. australis cannot be ruled out, our results indicate that exudation of gallic acid by P. australis cannot be a primary, general explanation for the invasive success of this species in North America.

  10. Population size, growth and movements of Anguilla australis in a small lake.

    PubMed

    Jellyman, D J; Crow, S K

    2016-06-01

    To study growth rates, movements and estimate population size of shortfin eels Anguilla australis in a small lake (2·5 ha) near Christchurch, New Zealand, 617 A. australis were tagged with PIT tags. Tag retention was high (95%) and over the seven recapture events spread over 2 years, 55% of tagged A. australis were recaptured. Growth of recaptured A. australis averaged 13·1 mm year(-1) and declined slightly with increasing total length. Distance moved from original capture site increased with increasing time at large. Population estimates of A. australis > 400 mm (susceptible to capture by fyke net) from recaptures of individuals averaged 1451 A. australis, with a biomass of 170 kg ha(-1) . An average of 6·6% of the estimated total population matured as male silver A. australis each year. Results from radio-tracking of four A. australis gave an average nightly foraging area of 2780 m(2) , and there was no apparent preference for inshore movement (within 5-6 m of the shoreline) or offshore movement. Fyke-net efficiency (total catch relative to the estimated total population available to each net) measured over four consecutive nights fishing was 88%. The lack of precision of the shoreline triangulation system used, ±10 m, meant that the positional data were considered too coarse to be used in a proposed novel population estimation technique based on determining population size within foraging areas. © 2016 The Fisheries Society of the British Isles.

  11. Global climate drives southern right whale (Eubalaena australis) population dynamics.

    PubMed

    Leaper, Russell; Cooke, Justin; Trathan, Phil; Reid, Keith; Rowntree, Victoria; Payne, Roger

    2006-06-22

    Sea surface temperature (SST) time-series from the southwest Atlantic and the El Niño 4 region in the western Pacific were compared to an index of annual calving success of the southern right whale (Eubalaena australis) breeding in Argentina. There was a strong relationship between right whale calving output and SST anomalies at South Georgia in the autumn of the previous year and also with mean El Niño 4 SST anomalies delayed by 6 years. These results extend similar observations from other krill predators and show clear linkages between global climate signals and the biological processes affecting whale population dynamics.

  12. Molecular Outflows In the R Coronae Australis Region

    NASA Astrophysics Data System (ADS)

    Knee, Lewis

    2017-06-01

    The low mass star forming region associated with the Corona Australis cloud hosts an embedded culture of young stellar objects (YSOs), many of which drive molecular outflows associated with shock-excited (HH-objct) emission-line objects. CO(1-0) mapping from the SEST and CO(3-2) mapping from JCMT are presented and analyzed in the context of identifying outflows and associating them with known YSOs and HH-objects. This region hosts far more molecular outflows than previously thought and resembles in some respects the "burst" of outflow activity associated with the star forming region NGC1333.

  13. Positive effects of nonnative invasive Phragmites australis on larval bullfrogs.

    PubMed

    Rogalski, Mary Alta; Skelly, David Kiernan

    2012-01-01

    Nonnative Phragmites australis (common reed) is one of the most intensively researched and managed invasive plant species in the United States, yet as with many invasive species, our ability to predict, control or understand the consequences of invasions is limited. Rapid spread of dense Phragmites monocultures has prompted efforts to limit its expansion and remove existing stands. Motivation for large-scale Phragmites eradication programs includes purported negative impacts on native wildlife, a view based primarily on observational results. We took an experimental approach to test this assumption, estimating the effects of nonnative Phragmites australis on a native amphibian. Concurrent common garden and reciprocal transplant field experiments revealed consistently strong positive influences of Phragmites on Rana catesbeiana (North American bullfrog) larval performance. Decomposing Phragmites litter appears to contribute to the effect. Positive effects of Phragmites merit further research, particularly in regions where both Phragmites and R. catesbeiana are invasive. More broadly, the findings of this study reinforce the importance of experimental evaluations of the effects of biological invasion to make informed conservation and restoration decisions.

  14. Positive Effects of Nonnative Invasive Phragmites australis on Larval Bullfrogs

    PubMed Central

    Rogalski, Mary Alta; Skelly, David Kiernan

    2012-01-01

    Background Nonnative Phragmites australis (common reed) is one of the most intensively researched and managed invasive plant species in the United States, yet as with many invasive species, our ability to predict, control or understand the consequences of invasions is limited. Rapid spread of dense Phragmites monocultures has prompted efforts to limit its expansion and remove existing stands. Motivation for large-scale Phragmites eradication programs includes purported negative impacts on native wildlife, a view based primarily on observational results. We took an experimental approach to test this assumption, estimating the effects of nonnative Phragmites australis on a native amphibian. Methodology/Principal Findings Concurrent common garden and reciprocal transplant field experiments revealed consistently strong positive influences of Phragmites on Rana catesbeiana (North American bullfrog) larval performance. Decomposing Phragmites litter appears to contribute to the effect. Conclusions/Significance Positive effects of Phragmites merit further research, particularly in regions where both Phragmites and R. catesbeiana are invasive. More broadly, the findings of this study reinforce the importance of experimental evaluations of the effects of biological invasion to make informed conservation and restoration decisions. PMID:22952976

  15. Phylogeographic analyses and genetic structure illustrate the complex evolutionary history of Phragmites australis in Mexico.

    PubMed

    Colin, Ricardo; Eguiarte, Luis E

    2016-05-01

    Genetic data suggest that three lineages of Phragmites australis are found in North America: the Native North American lineage, the Gulf Coast lineage, and the Invasive lineage. In Mexico, P. australis is a common species, but nothing is known about the distribution or ecology of these lineages. We examined the phylogeography of P. australis to analyze the current geographic distribution of genetic variation, demographic history, and dispersal patterns to better understand its evolutionary history in Mexico. We sampled 427 individuals from 28 populations. We used two noncoding regions of chloroplast DNA to estimate the levels of genetic variation and identified the genetic groups across the species' geographical range in Mexico. We compared the genealogical relationships among haplotypes with those previously reported. A hypothesis of demographic expansion was also tested for the Mexican P. australis lineages. We found 13 new haplotypes native to Mexico that might be undergoing an active process of expansion and diversification. Genealogical analyses provided evidence that two independent lineages of P. australis are present in Mexico. The invasive lineage was not detected with our sampling. Our estimates of population expansions in Mexico ranged from 0.202 to 0.726 mya. Phragmites australis is a native species that has been in Mexico for thousands of years. Genetic data suggest that climatic changes during the Pleistocene played an important role in the demographic expansion of the populations that constitute the different genetic groups of P. australis in Mexico. © 2016 Botanical Society of America.

  16. Soil conditioning effects of Phragmites australis on native wetland plant seedling survival.

    PubMed

    Crocker, Ellen V; Nelson, Eric B; Blossey, Bernd

    2017-08-01

    Interactions between introduced plants and soils they colonize are central to invasive species success in many systems. Belowground biotic and abiotic changes can influence the success of introduced species as well as their native competitors. All plants alter soil properties after colonization but, in the case of many invasive plant species, it is unclear whether the strength and direction of these soil conditioning effects are due to plant traits, plant origin, or local population characteristics and site conditions in the invaded range. Phragmites australis in North America exists as a mix of populations of different evolutionary origin. Populations of endemic native Phragmites australis americanus are declining, while introduced European populations are important wetland invaders. We assessed soil conditioning effects of native and non-native P. australis populations on early and late seedling survival of native and introduced wetland plants. We further used a soil biocide treatment to assess the role of soil fungi on seedling survival. Survival of seedlings in soils colonized by P. australis was either unaffected or negatively affected; no species showed improved survival in P. australis-conditioned soils. Population of P. australis was a significant factor explaining the response of seedlings, but origin (native or non-native) was not a significant factor. Synthesis: Our results highlight the importance of phylogenetic control when assessing impacts of invasive species to avoid conflating general plant traits with mechanisms of invasive success. Both native (noninvasive) and non-native (invasive) P. australis populations reduced seedling survival of competing plant species. Because soil legacy effects of native and non-native P. australis are similar, this study suggests that the close phylogenetic relationship between the two populations, and not the invasive status of introduced P. australis, is more relevant to their soil-mediated impact on other

  17. Vegetative ecological characteristics of restored reed (Phragmites australis) wetlands in the Yellow River Delta, China.

    PubMed

    Wang, Xuehong; Yu, Junbao; Zhou, Di; Dong, Hongfang; Li, Yunzhao; Lin, Qianxin; Guan, Bo; Wang, Yongli

    2012-02-01

    In this study, we compared ecological characteristics of wetland vegetation in a series of restoration projects that were carried out in the wetlands of Yellow River Delta. The investigated characteristics include plant composition structure, species diversity and community similarity in three kinds of Phragmites australis wetlands, i.e. restored P. australis wetlands (R1, R2, R3 and R4: restored in 2002, 2005, 2007 and 2009, respectively), natural P. australis wetland (N) and degraded P. australis wetland (D) to assess the process of wetlands restoration. The coverage of the R1 was 99%, which was similar to natural wetland. Among all studied wetlands, the highest and lowest stem density was observed in R1 and R2, respectively, Plant height and stem diameter show the same trend as N > R2 > R1 > R3 > D > R4. Species diversity of restored P. australis wetlands became closed to natural wetland. Both species richness and Shannon-Wiener index had similar tendency: increased first and then decreased with restored time. The highest species richness and species diversity were observed in R2, while the lowest values of those parameters were found in natural P. australis wetland. Similarity indexes between restored wetlands and natural wetland increased with the restoration time, but they were still less than 50%. The results indicate that the vegetation of P. australis wetlands has experienced a great improvement after several years' restoration, and it is feasible to restored degraded P. australis wetlands by pouring fresh water into those wetlands in the Yellow River Delta. However, it is notable that costal degraded P. australis wetland in this region may take years to decades to reach the status of natural wetland.

  18. The Secrets of Acinetobacter Secretion.

    PubMed

    Weber, Brent S; Kinsella, Rachel L; Harding, Christian M; Feldman, Mario F

    2017-02-16

    Infections caused by the bacterial pathogen Acinetobacter baumannii are a mounting concern for healthcare practitioners as widespread antibiotic resistance continues to limit therapeutic treatment options. The biological processes used by A. baumannii to cause disease are not well defined, but recent research has indicated that secreted proteins may play a major role. A variety of mechanisms have now been shown to contribute to protein secretion by A. baumannii and other pathogenic species of Acinetobacter, including a type II secretion system (T2SS), a type VI secretion system (T6SS), autotransporter, and outer membrane vesicles (OMVs). In this review, we summarize the current knowledge of secretion systems in Acinetobacter species, and highlight their unique aspects that contribute to the pathogenicity and persistence of these emerging pathogens.

  19. Adaptive response of arbuscular mycorrhizal symbiosis to accumulation of elements and translocation in Phragmites australis affected by cadmium stress.

    PubMed

    Huang, Xiaochen; Ho, Shih-Hsin; Zhu, Shishu; Ma, Fang; Wu, Jieting; Yang, Jixian; Wang, Li

    2017-07-15

    Arbuscular mycorrhizal (AM) fungi have been reported to play a central role in improving plant tolerance to cadmium (Cd)-contaminated sites. This is achieved by enhancing both the growth of host plants and the nutritive elements in plants. This study assessed potential regulatory effects of AM symbiosis with regard to nutrient uptake and transport, and revealed different response strategies to various Cd concentrations. Phragmites australis was inoculated with Rhizophagus irregularis in the greenhouse cultivation system, where it was treated with 0-20 mg L(-1) of Cd for 21days to investigate growth parameters, as well as Cd and nutritive element distribution in response to AM fungus inoculation. Mycorrhizal plants showed a higher tolerance, particularly under high Cd-level stress in the substrate. Moreover, our results determined the roots as dominant Cd reservoirs in plants. The AM fungus improved Cd accumulation and saturated concentration in the roots, thus inhibiting Cd uptake to shoots. The observed distributions of nutritive elements and the interactions among these indicated the highest microelement contribution to roots, Ca contributed maximally in leaves, and K and P contributed similarly under Cd stress. In addition, AM fungus inoculation effectively impacted Mn and P uptake and accumulation while coping with Cd toxicity. This study also demonstrated translocation factor from metal concentration (TF) could be a good parameter to evaluate different transportation strategies induced by various Cd stresses in contrast to the bioconcentration factor (BCF) and translocation factor from metal accumulation (TF'). Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Disease protection and allelopathic interactions of seed-transmitted endophytic pseudomonads of invasive reed grass (Phragmites australis)

    USGS Publications Warehouse

    White, James F.; Kingsley, Katheryn I; Kowalski, Kurt P.; Irizarry, Ivelisse; Micci, April; Soares, Marcos Antonio; Bergen, Marshall S.

    2017-01-01

    Background and aimsNon-native Phragmites australis (haplotype M) is an invasive grass that decreases biodiversity and produces dense stands. We hypothesized that seeds of Phragmites carry microbes that improve seedling growth, defend against pathogens and maximize capacity of seedlings to compete with other plants.MethodsWe isolated bacteria from seeds of Phragmites, then evaluated representatives for their capacities to become intracellular in root cells, and their effects on: 1.) germination rates and seedling growth, 2.) susceptibility to damping-off disease, and 3.) mortality and growth of competitor plant seedlings (dandelion (Taraxacum officionale F. H. Wigg) and curly dock (Rumex crispus L.)).ResultsTen strains (of 23 total) were identified and characterized; seven were identified as Pseudomonas spp. Strains Sandy LB4 (Pseudomonas fluorescens) and West 9 (Pseudomonas sp.) entered root meristems and became intracellular. These bacteria improved seed germination in Phragmites and increased seedling root branching in Poa annua. They increased plant growth and protected plants from damping off disease. Sandy LB4 increased mortality and reduced growth rates in seedlings of dandelion and curly dock.ConclusionsPhragmites plants associate with endophytes to increase growth and disease resistance, and release bacteria into the soil to create an environment that is favorable to their seedlings and less favorable to competitor plants.

  1. Catechin secretion and phytotoxicity

    PubMed Central

    Kaushik, Shail

    2010-01-01

    Research indicates that the invasiveness of Centaurea stoebe is attributed to the stronger allelopathic effects on the native North American species than on the related European species, which is one of the unquestionable aspects of the “novel weapons hypothesis (NWH).” Studies originating from controlled to field conditions have shown that C. stoebe utilizes its biochemical potential to exert its invasiveness. The roots of C. stoebe secrete a potent phytotoxin, catechin, which has a detrimental effect on the surrounding plant species. Although, studies on catechin secretion and phytotoxicity represent one of the most well studied systems describing negative plant-plant interactions, it has also sparked controversies lately due to its phytotoxicity dosages and secretion effluxes. Previous reports negate the phytotoxic and pro-oxidant nature of catechin.1–3 In our recent study we have shown that catechin is highly phytotoxic against Arabidopsis thaliana and Festuca idahoensis. We also show that (±) catechin applied to roots of A. thaliana induces reactive oxygen species (ROS) confirming the pro-oxidant nature of catechin. In addition, activation of signature cell death genes such as acd2 and cad1 post catechin treatment in A. thaliana ascertains the phytotoxic nature of catechin. PMID:21057643

  2. Aurora Australis, Spiked and Sinuous Red and Green Airglow

    NASA Image and Video Library

    1991-05-06

    STS039-342-026 (28 April-6 May 1991) --- This view of the Aurora Australis, or Southern Lights, shows a band of airglow above the limb of Earth. Photo experts at NASA studying the mission photography identify the airglow as being in the 80-120 kilometer altitude region and attribute its existence to atomic oxygen (wavelength of 5,577 Angstroms), although other atoms can also contribute. The atomic oxygen airglow is usually most intense at altitudes around 65 degrees north and south latitude, and is most intense in the spring and fall of the year. The aurora phenomena is due to atmospheric oxygen and nitrogen being excited by the particles from the Van Allen Radiation belts which extend between the two geomagnetic poles. The red and green rays appear to extend upward to 200-300 kilometers, much higher than the usual upper limits of about 110 kilometers.

  3. Root rots

    Treesearch

    Kathryn Robbins; Philip M. Wargo

    1989-01-01

    Root rots of central hardwoods are diseases caused by fungi that infect and decay woody roots and sometimes also invade the butt portion of the tree. By killing and decaying roots, root rotting fungi reduce growth, decrease tree vigor, and cause windthrow and death. The most common root diseases of central hardwoods are Armillaria root rot, lnonotus root rot, and...

  4. Moon phase influences the diet of southern Ray's bream Brama australis.

    PubMed

    Horn, P L; Forman, J S; Dunn, M R

    2013-04-01

    Diet composition of the southern Ray's bream Brama australis was examined from stomach contents of 399 specimens sampled by bottom trawl on Chatham Rise to the east of South Island, New Zealand, over 3 years. Prey items were predominantly mesopelagic fishes and crustaceans. Multivariate analysis indicated that moon phase explained more of the diet variability than any other predictor examined. It appears likely that diet composition is influenced by a combination of changes in both tidal flows and illumination. Different combinations of prey were consumed by B. australis at different times of the lunar cycle. An influence of moon phase on feeding by fishes has rarely been reported, but it is likely that moon phase influences the diets of other species that specialize in mesopelagic prey. The most important prey group by mass for B. australis was Myctophidae (primarily Lampanyctodes hectoris), followed by Stomiiformes (primarily Maurolicus australis) and shrimps (Sergestes spp). An ontogenetic shift in diet was observed, from numerical dominance by small crustaceans including amphipods and euphausiids (with some fishes) in smaller (mass <1045 g) B. australis to pelagic teleost prey (with a few larger crustaceans) in larger (>1440 g) B. australis. © 2013 The Authors. Journal of Fish Biology © 2013 The Fisheries Society of the British Isles.

  5. Effects of lead contamination on the clonal propagative ability of Phragmites australis (common reed) grown in wet and dry environments.

    PubMed

    Zhang, N; Zhang, J W; Yang, Y H; Li, X Y; Lin, J X; Li, Z L; Cheng, L Y; Wang, J F; Mu, C S; Wang, A X

    2015-07-01

    Clonal propagation is important for the survival and maintenance of the common reed Phragmites australis. Pot culture experiments were conducted to investigate the effects of lead (Pb) concentration (0, 500, 1500, 3000, 4500 mg·kg(-1) ) and water stress on the clonal reproductive ability of this species. The Pb concentration found in plant organs, in decreasing order, was roots >shoots >rhizomes. There was a negative relationship between the growth of clonal propagative modules (excluding axillary shoot buds) and Pb concentrations, which caused a decrease in biomass, rhizome growth and number of axillary and apical rhizome buds. Daughter axillary shoots exhibited a tolerance strategy, with no significant change in their number; the axillary and apical rhizome buds, daughter apical rhizome shoots and rhizomes exhibited compensatory growth during the late stage of Pb (excluding 4500 mg·kg(-1) ) treatment in a wet environment. Pb applications above 500 mg·kg(-1) reduced these parameters significantly in the drought treatment, except for the number of axillary shoot buds, which did not change. Our results indicate that clonal propagative resistance to Pb contamination can occur via tolerance strategies, compensatory growth and a Pb allocation strategy, enabling these reeds to maintain population stability in wet environments. However, clonal modular growth and reproductive ability were inhibited significantly by the interaction between drought and Pb, which would cause a decline in P. australis populations in a dry environment. Lead concentrations of 4500 and 500 mg·kg(-1) in soils might meet or exceed the Pb tolerance threshold of clonally propagated reeds in wet and dry environments, respectively.

  6. Clathrin in Chara australis: Molecular Analysis and Involvement in Charasome Degradation and Constitutive Endocytosis

    PubMed Central

    Hoepflinger, Marion C.; Hoeftberger, Margit; Sommer, Aniela; Hametner, Christina; Foissner, Ilse

    2017-01-01

    Charasomes are convoluted plasma membrane domains in characean green algae. They are known to form in response to light via secretion of trans-Golgi network (TGN) vesicles and local inhibition of endocytosis. Charasomes are involved in the acidification of their aqueous environment, thereby facilitating photosynthesis-dependent carbon uptake. Charasome formation is reversible to allow cells to adapt to different light conditions. Here, we show that darkness-induced degradation of charasomes involves the formation of coated pits and coated vesicles. The darkness-induced degradation of charasomes can be inhibited by 1–2 μM ikarugamycin (IKA), which is considered to be a specific inhibitor of clathrin-dependent endocytosis. At a much higher concentration (100 μM), IKA also significantly reduces the internalization of styryl dyes, indicating uptake via clathrin-coated vesicles (CV). We are the first to present evidence, based on fine structure investigation, that IKA does not interfere with the formation of clathrin coat, but inhibits the detachment and/or further processing of coated vesicles. Both charasome degradation and constitutive endocytosis are also significantly inhibited by sterol complexing agents (methyl-ß-cyclodextrin and filipin). The absence of an additive effect, when applied together with IKA, suggests that charasome degradation and constitutive endocytosis (measured via styryl dye uptake) is not inhibited due to membrane retrieval via lipid rafts, but due to clathrin coat formation requirement of a specific set of sterols. Analysis of Chara australis clathrin proteins revealed two heavy chains and several light chains with sequence peculiarities, suggesting functional and/or species specific differences. The data obtained indicate that clathrin plays a central role not only in constitutive endocytosis but also in the degradation of charasomes, thereby representing a valuable system for studying targeted exo- and endocytosis. PMID:28184226

  7. Enantioselective uptake, translocation and degradation of the chiral pesticides tebuconazole and imazalil by Phragmites australis.

    PubMed

    Lv, Tao; Carvalho, Pedro N; Casas, Mònica Escolà; Bollmann, Ulla E; Arias, Carlos A; Brix, Hans; Bester, Kai

    2017-10-01

    Phytoremediation of realistic environmental concentrations (10 μg L(-1)) of the chiral pesticides tebuconazole and imazalil by Phragmites australis was investigated. This study focussed on removal dynamics, enantioselective mechanisms and transformation products (TPs) in both hydroponic growth solutions and plant tissues. For the first time, we documented uptake, translocation and metabolisation of these pesticides inside wetland plants, using enantioselective analysis. Tebuconazole and imazalil removal efficiencies from water reached 96.1% and 99.8%, respectively, by the end of the experiment (day 24). Removal from the solutions could be described by first-order removal kinetics with removal rate constants of 0.14 d(-1) for tebuconazole and 0.31 d(-1) for imazalil. Removal of the pesticides from the hydroponic solution, plant uptake, within plant translocation and degradation occurred simultaneously. Tebuconazole and imazalil concentrations inside Phragmites peaked at day 10 and 5d, respectively, and decreased thereafter. TPs of tebuconazole i.e., (5-(4-Chlorophenyl)-2,2-dimethyl-3-(1H-1,2,4-triazol-1-ylmethyl)-1,3-pentanediol and 5-(3-((1H-1,2,4-Triazol-1-yl)methyl)-3-hydroxy-4,4-dimethylpentyl)-2-chlorophenol) were quantified in solution, while the imazalil TPs (α-(2,4-Dichlorophenyl)-1H-imidazole-1-ethanol and 3-[1-(2,4-Dichlorophenyl)-2-(1H-imidazol-1-yl)ethoxy]-1,2-propanediol) were quantified in both solution and plant tissue. Pesticide uptake by Phragmites was positively correlated with evapotranspiration. Pesticide removal from the hydroponic solution was not enantioselective. However, tebuconazole was degraded enantioselectively both in the roots and shoots. Imazalil translocation and degradation inside Phragmites were also enantioselective: R-imazalil translocated faster than S-imazalil. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Remediation of acid mine drainage (AMD)-contaminated soil by Phragmites australis and rhizosphere bacteria.

    PubMed

    Guo, Lin; Cutright, Teresa J

    2014-06-01

    Experiments were conducted to assess the impact of citric acid (CA) and rhizosphere bacteria on metal uptake in Phragmites australis cultured in a spiked acid mine drainage (AMD) soil. Rhizosphere iron-oxidizing bacteria (Fe(II)OB) enhanced the formation of Fe plaque on roots, which decreased the uptake of Fe and Mn. CA inhibited the growth of Fe(II)OB, decreased the formation of metal plaque, raised the metal mobility in soil, and increased the accumulation of metals in all tissues of the reeds. The higher the CA dosage, the more metals accumulated into reeds. The total amount of metals in reeds increased from 7.8 ± 0.5 × 10(-6) mol plant(-1) (Mn), 1.4 ± 0.1 × 10(-3) mol plant(-1) (Fe), and 1.0 ± 0.1 × 10(-4) mol plant(-1) (Al) in spiked soil without CA to 22.2 ± 0.5 × 10(-6) mol plant(-1) (Mn), 3.5 ± 0.06 × 10(-3) mol plant(-1) (Fe), and 5.0 ± 0.2 × 10(-4) mol plant(-1) (Al) in soil added with 33.616 g C6H8O7·H2O for per kilogram soil. CA could be effective at enhancing the phytoremediation of metals from AMD-contaminated soil.

  9. Transplantation as a method for restoring the seagrass Posidonia australis

    NASA Astrophysics Data System (ADS)

    Bastyan, G. R.; Cambridge, M. L.

    2008-08-01

    Transplant trials of the seagrass Posidonia australis were carried out after loss of seagrasses following eutrophication and increased turbidity in two marine inlets on the south coast of Western Australia. A pilot study in Oyster Harbour measured survival and growth in situ for 4 years. Long-term survival rates were high (96-98%), providing plants were anchored into the sediment. All unanchored plants were lost in the first winter. Following the success of the pilot study, a more comprehensive program began 3 years later with over 500 transplant units collected from either actively growing edges of nearby patches (plagiotropic growth form) or within established meadows (orthotropic growth form). Transplant units from edges expanded at a faster rate compared to units from mid-meadow but increases in shoot numbers were similar. Growth rates in the first 2.5 years averaged 10-20 cm yr -1 horizontal rhizome extension, depending on the source of the transplant units, and 4-12 shoots per initial shoot yr -1, depending on the initial shoot number of the transplant unit. After 5 years, shoot numbers of individual transplants were similar to shoot densities recorded for natural meadows, >500 shoots m -2. Approximately, 10% of transplants from mid-meadow flowered in the first year, whereas transplants from edges flowered only after 5 years. Transplant trials were also established in nearby Princess Royal Harbour at a site selected to test the effect of disturbance by bioturbation from large sand-burrowing worms or by sediment erosion. Survival was lower than in Oyster Harbour, 75-89% in areas with bioturbation but only 14% in areas where sediments were eroded. Growth was poor, <1-2 shoots per shoot yr -1 with high shoot mortality, and low rates of increase in rhizome length, <5 cm yr -1. In areas affected by worm bioturbation, there was almost no horizontal expansion of plants because rhizomes grew vertically to keep pace with sediment deposition. This study showed that

  10. Physics and Chemistry of Strongly Irradiated Protostars in Corona Australis

    NASA Astrophysics Data System (ADS)

    Lindberg, J. E.; Jørgensen, J. K.; Bisschop, S.; Sakai, N.; Watanabe, Y.; Yamamoto, S.; Digit Team, Alma Cycle 0 Protostars Team

    2013-10-01

    We have conducted interferometric spectral-line observations with the SMA and APEX of the R CrA region, a star-forming region with a handful of low-mass young stellar objects. We have also conducted single-dish observations of the same spectral lines in 17 young stellar objects in the CrA star-forming region, conducted APEX and ASTE unbiased line surveys of IRS7B, a Class 0/I source in the region, and performed far-infrared continuum mapping with the Herschel Space Observatory. We find unexpectedly high H2CO excitation temperatures in the R CrA region, but also in other protostars in the CrA (Corona Australis) star-forming region. Our models show that the Herbig Be star R CrA is the dominant heat source in this region. Thus, also intermediate-mass stars have large effects on the physical properties in such regions. ALMA observations of H2CO can be used to trace such heating also in more distant regions.

  11. Epidermal ultrastructure of the southern right whale calf (Eubalaena australis).

    PubMed

    Pfeiffer, C J; Rowntree, V J

    1996-04-01

    An ultrastructural analysis by transmission and scanning electron microscopy was carried out on normal epidermis of six southern right whale (Eubalaena australis) calves which stranded over a period of several months at Peninsula Valdes, Argentina. This was undertaken to 1) provide the first normal skin ultrastructural data on this highly endangered species which is known to display skin pathology in some instances, and 2) to elucidate further the integumentary specializations which have developed in diving marine mammals. Southern right whale lipokeratinocytes demonstrated parakeratosis and numerous intracellular lipid bodies, keratin and melanosomes, as reported for other cetacean species, but showed several unique ultrastructural features as well. These included a high prevalence of intranuclear inclusion bodies resembling small fragments of cytoplasmic keratin, and close structural relationship between cytoplasmic lipid droplets and the nucleus. The subcellular morphology supported the concept of possible nuclear import of cytoplasmic keratin and lipid metabolites through enlargements of the nuclear pore complex or other disruptions of the nuclear envelope. The light microscopy and scanning electron microscopy also revealed an irregular contour of the lipokeratinocytes which comprised the thick stratum externum, and surface flaking of the outermost cells which were covered by stubby microvillous-like remnants of intercellular junctions. These results thus suggest that the long-tem aquatic evolution of this cetacean species has resulted in a number of integumentary specializations and that investigation of their submicroscopic cytology may help elucidate the general cell biology of nuclear-cytoplasmic interactions.

  12. Effects of high Zn and Pb concentrations on Phragmites australis (Cav.) Trin. Ex. Steudel: Photosynthetic performance and metal accumulation capacity under controlled conditions.

    PubMed

    Bernardini, A; Salvatori, E; Guerrini, V; Fusaro, L; Canepari, S; Manes, F

    2016-01-01

    The response of Phragmites australis (Cav.) Trin. Ex. Steudel to zinc (Zn) and lead (Pb) was studied separately in two hydroponic tests, during a three weeks experiment. The effects on ecophysiology and biomass partitioning were evaluated during the metal treatments and at the recovery, and total metal content and accumulation capacity in different plant organs were assessed. Zn and Pb had different effects on the overall measured parameters, highlighting different mechanism of action. In particular, Zn concentration was higher in roots and, being a micronutrient, it was translocated into leaves, producing a reduction of assimilation rate, stomatal conductance (-71.9 and -81.3% respect to the control plant respectively), and a strong down regulation of photosystems functionality both at PSII and PSI level. Otherwise, Pb was accumulated mainly in the more lignified tissue such as rhizomes, with slightly effect on gas exchange. Chlorophyll a fluorescence highlighted that Pb inhibits the electron transfer process at the PSI donor side, without recovery after the removal of the metal stress. Despite these physiological limitations, P. australis showed a high capacity to accumulate both metals, and only slight reduction of biomass, being therefore a suitable species for phytoremediation interventions.

  13. Comparative Hepatoprotective Activity of Ethanolic Extracts of Cuscuta australis against Acetaminophen Intoxication in Wistar Rats

    PubMed Central

    Folarin, Rachael O.; Omirinde, Jamiu O.; Bejide, Ronald; Isola, Tajudeen O.; Usende, Levi I.; Basiru, Afisu

    2014-01-01

    This study investigates the comparative hepatoprotective activity of crude ethanol extracts of Cuscuta australis against acetaminophen (APAP) intoxication. Thirty-six rats were randomly divided into six groups of 6 replicates: Group 1 which served as control received water. Group 2 was orally administered 835 mg/kg body wt. of paracetamol on day 8. Groups 3 and 4 were orally administered ethanolic extracts of the seed of Cuscuta australis in doses of 125 mg/kg and 250 mg/kg, respectively, for 7 days and then intoxicated as in Group 2 on the 8th day. Groups 5 and 6 received similar oral doses of Cuscuta australis stem extracts for 7 days and then intoxicated as in Groups 3 and 4. Group 2 rats showed severe periportal hepatic necrosis, significantly elevated serum hepatic injury markers, markedly increased lipid peroxidation, and decreased hepatic antioxidant enzymes activities. Remarkably, Cuscuta australis (seed and stem) extract pretreatments in Groups 3, 4, 5, and 6, most especially, the stem extract pretreatment in Groups 5 and 6, improved better the hepatic histoarchitecture, the hepatocellular, and the oxidative stress injury markers in a dose-dependent manner. Conclusively, ethanol extractions of Cuscuta australis stem appear to protect the liver from acetaminophen intoxication better than the seed counterpart. PMID:27433518

  14. Implications of polyploidy events on the phenotype, microstructure, and proteome of Paulownia australis

    PubMed Central

    Zhai, Xiaoqiao; Deng, Minjie; Zhao, Zhenli; Liu, Wenshan; Cao, Yabing

    2017-01-01

    Polyploidy events are believed to be responsible for increasing the size of plant organs and enhancing tolerance to environmental stresses. Autotetraploid Paulownia australis plants exhibit superior traits compared with their diploid progenitors. Although some transcriptomics studies have been performed and some relevant genes have been revealed, the molecular and biological mechanisms regulating the predominant characteristics and the effects of polyploidy events on P. australis remain unknown. In this study, we compared the phenotypes, microstructures, and proteomes of autotetraploid and diploid P. australis plants. Compared with the diploid plant, the leaves of the autotetraploid plant were longer and wider, and the upper epidermis, lower epidermis, and palisade layer of the leaves were thicker, the leaf spongy parenchyma layer was thinner, the leaf cell size was bigger, and cell number was lower. In the proteome analysis, 3,010 proteins were identified and quantified, including 773 differentially abundant proteins. These results may help to characterize the P. australis proteome profile. Differentially abundant proteins related to cell division, glutathione metabolism, and the synthesis of cellulose, chlorophyll, and lignin were more abundant in the autotetraploid plants. These results will help to enhance the understanding of variations caused by polyploidy events in P. australis. The quantitative real-time PCR results provided details regarding the expression patterns of the proteins at mRNA level. We observed a limited correlation between transcript and protein levels. These observations may help to clarify the molecular basis for the predominant autotetraploid characteristics and be useful for plant breeding in the future. PMID:28273106

  15. Dietary supplementation with purified mulberry (Morus australis Poir) anthocyanins suppresses body weight gain in high-fat diet fed C57BL/6 mice.

    PubMed

    Wu, Tao; Qi, Xueming; Liu, Yan; Guo, Jun; Zhu, Ruiyu; Chen, Wei; Zheng, Xiaodong; Yu, Ting

    2013-11-01

    We present our experiment about adding anthocyanins to the daily food of mice. Three kinds of anthocyanins (cyanidin-3-glucoside, cyanidin-3-rutinoside and pelargonidin-3-glucoside) purified from Chinese mulberry (Morus australis Poir) were evaluated for suppressing body weight gain of the male C57BL/6 mice fed with high-fat diet (HFD). The results from a 12-week experiment show that consumption of purified mulberry anthocyanins (MACN) of 40 or 200mg/kg can significantly inhibit body weight gain, reduce the resistance to insulin, lower the size of adipocytes, attenuate lipid accumulation and decrease the leptin secretion. Thus, dietary supplementation with MACN can protect against body weight gain of the diet-induced obese mice. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. Differences in the removal mechanisms of Undaria pinnatifida and Phragmites australis as biomaterials for lead removal.

    PubMed

    Soto-Rios, Paula Cecilia; Nakano, Kazunori; Leon-Romero, Marco; Aikawa, Yoshio; Arai, Shigeyuki; Nishimura, Osamu

    2015-01-01

    This study offers the opportunity to utilize Undaria pinnatifida and Phragmites australis to remove lead from water in permeable reactive barrier (PRB) technology. Its efficacy was tested using batch experiments and PRB column systems. From the batch experiment results, a higher adsorption capacity was observed for Undaria pinnatifida. Nevertheless, Phragmites australis in the column system efficiently removed lead and the breakthrough occurred at the same time for both biomaterials. To dissipate this difference, a sequential extraction for metal speciation analysis was used for both columns. The results have shown that each biomaterial has a dominant mechanism. Phragmites australis removed lead by physical adsorption, whereas Undaria pinnatifida showed a higher tendency to bind lead due to organic matter, primary and secondary minerals.

  17. Description of the Immature Stages of the Planthopper Lacertinella australis (Hemiptera: Delphacidae)

    PubMed Central

    Batiz, M. F. Rossi; Lenicov, A. M. Marino de Remes

    2014-01-01

    The five immature stages of the planthopper Lacertinella australis (Remes Lenicov and Rossi Batiz) (Hemiptera: Delphacidae: Saccharosydnini) are described and illustrated. The main characters that allowed us to distinguish the various stages were body size, number of tarsomeres and metatibial spines, and number of teeth on the spur. New biological data based on laboratory rearing and field observations showed that L. australis can carry out its biological cycle successfully on the graminaceous pampas grass (Cortaderia spp. Stapf (Poales: Poaceae)). In addition, the efficient rearing in captivity, the high survivorship registered, and overwintering only on this host plant suggests that L. australis is a potential biocontrol agent of this invasive graminaceous weed. This study provides information about the immature stages, including a key for their identification, based on laboratory reared specimens and field observations. PMID:25199992

  18. Accumulation of Metals and Boron in Phragmites australis Planted in Constructed Wetlands Polishing Real Electroplating Wastewater.

    PubMed

    Sochacki, Adam; Guy, Bernard; Faure, Olivier; Surmacz-Górska, Joanna

    2015-01-01

    The concentration of metals (Al, Cu, Fe, Mn, Ni, Zn) and B were determined in the above- and belowground biomass of Phragmites australis collected from the microcosm constructed wetland system used for the polishing of real electroplating wastewater. Translocation factor and bioconcentration factor were determined. Pearson correlation test was used to determine correlation between metal concentration in substrate and above- and belowground parts of Phragmites australis. The obtained results suggested that Phragmites australis did not play a major role as an accumulator of metals. It was observed also that the substrate could have exerted an effect on the translocation of Ni, Cu, Zn and Mn. The analysed concentrations of metals and B in biomass were in the range or even below the concentrations reported in the literature with the exception of Ni. The aboveground biomass was found suitable as a composting input in terms of metals concentrations.

  19. Is the invasion of the common reed, Phragmites australis, into tidal marshes of the eastern US an ecological disaster?

    PubMed

    Weis, Judith S; Weis, Peddrick

    2003-07-01

    Studies of effects of the invasive brackish marsh plant Phragmites australis (common reed) on estuarine biota are reviewed. With few exceptions, most field studies indicate that these P. australis-dominated marshes have diverse and abundant benthic biota, and are utilized by nekton, comparable to Spartina alterniflora marshes. However, larval mummichogs, Fundulus heteroclitus, appear to be reduced in P. australis marshes compared with S. alterniflora marshes. Small epifauna living on plant stems also appear to be denser on S. alterniflora than P. australis stems. Other studies indicate that the detritus produced by decaying P. australis litter provides food value comparable to that of S. alterniflora and that its production enters estuarine food webs. Therefore, the general assumption that these marshes are ecologically "useless" is untrue. This information should be considered by marsh managers when making decisions about restoration projects.

  20. Soil CO2 efflux in an old-growth southern conifer forest (Agathis australis) - magnitude, components and controls

    NASA Astrophysics Data System (ADS)

    Schwendenmann, Luitgard; Macinnis-Ng, Cate

    2016-08-01

    Total soil CO2 efflux and its component fluxes, autotrophic and heterotrophic respiration, were measured in a native forest in northern Aotearoa-New Zealand. The forest is dominated by Agathis australis (kauri) and is on an acidic, clay rich soil. Soil CO2 efflux, volumetric soil water content and soil temperature were measured bi-weekly to monthly at 72 sampling points over 18 months. Trenching and regression analysis was used to partition total soil CO2 efflux into heterotrophic and autotrophic respiration. The effect of tree structure was investigated by calculating an index of local contribution (Ic, based on tree size and distance to the measurement location) followed by correlation analysis between Ic and total soil CO2 efflux, root biomass, litterfall and soil characteristics. The measured mean total soil CO2 efflux was 3.47 µmol m-2 s-1. Autotrophic respiration accounted for 25 % (trenching) or 28 % (regression analysis) of total soil CO2 efflux. Using uni- and bivariate models showed that soil temperature was a poor predictor of the temporal variation in total soil CO2 efflux (< 20 %). In contrast, a stronger temperature sensitivity was found for heterotrophic respiration (around 47 %). We found significant positive relationships between kauri tree size (Ic) and total soil CO2 efflux, root biomass and mineral soil CN ratio within 5-6 m of the sampling points. Using multiple regression analysis revealed that 97 % of the spatial variability in total soil CO2 efflux in this kauri-dominated stand was explained by root biomass and soil temperature. Our findings suggest that biotic factors such as tree structure should be investigated in soil carbon related studies.

  1. Preadaptation and post-introduction evolution facilitate the invasion of Phragmites australis in North America

    PubMed Central

    Guo, Wen-Yong; Lambertini, Carla; Nguyen, Loc Xuan; Li, Xiu-Zhen; Brix, Hans

    2014-01-01

    Compared with non-invasive species, invasive plant species may benefit from certain advantageous traits, for example, higher photosynthesis capacity and resource/energy-use efficiency. These traits can be preadapted prior to introduction, but can also be acquired through evolution following introduction to the new range. Disentangling the origins of these advantageous traits is a fundamental and emerging question in invasion ecology. We conducted a multiple comparative experiment under identical environmental condition with the invasive haplotype M lineage of the wetland grass Phragmites australis and compared the ecophysiological traits of this invasive haplotype M in North America with those of the European ancestor and the conspecific North American native haplotype E lineage, P. australis ssp. americanus. The invasive haplotype M differed significantly from the native North American conspecific haplotype E in several ecophysiological and morphological traits, and the European haplotype M had a more efficient photosynthetic apparatus than the native North American P. australis ssp. americanus. Within the haplotype M lineage, the introduced North American P. australis exhibited different biomass allocation patterns and resource/energy-use strategies compared to its European ancestor group. A discriminant analysis of principal components separated the haplotype M and the haplotype E lineages completely along the first canonical axis, highly related to photosynthetic gas-exchange parameters, photosynthetic energy-use efficiency and payback time. The second canonical axis, highly related to photosynthetic nitrogen use efficiency and construction costs, significantly separated the introduced P. australis in North America from its European ancestor. Synthesis. We conclude that the European P. australis lineage was preadapted to be invasive prior to its introduction, and that the invasion in North America is further stimulated by rapid post-introduction evolution in

  2. Preadaptation and post-introduction evolution facilitate the invasion of Phragmites australis in North America.

    PubMed

    Guo, Wen-Yong; Lambertini, Carla; Nguyen, Loc Xuan; Li, Xiu-Zhen; Brix, Hans

    2014-12-01

    Compared with non-invasive species, invasive plant species may benefit from certain advantageous traits, for example, higher photosynthesis capacity and resource/energy-use efficiency. These traits can be preadapted prior to introduction, but can also be acquired through evolution following introduction to the new range. Disentangling the origins of these advantageous traits is a fundamental and emerging question in invasion ecology. We conducted a multiple comparative experiment under identical environmental condition with the invasive haplotype M lineage of the wetland grass Phragmites australis and compared the ecophysiological traits of this invasive haplotype M in North America with those of the European ancestor and the conspecific North American native haplotype E lineage, P. australis ssp. americanus. The invasive haplotype M differed significantly from the native North American conspecific haplotype E in several ecophysiological and morphological traits, and the European haplotype M had a more efficient photosynthetic apparatus than the native North American P. australis ssp. americanus. Within the haplotype M lineage, the introduced North American P. australis exhibited different biomass allocation patterns and resource/energy-use strategies compared to its European ancestor group. A discriminant analysis of principal components separated the haplotype M and the haplotype E lineages completely along the first canonical axis, highly related to photosynthetic gas-exchange parameters, photosynthetic energy-use efficiency and payback time. The second canonical axis, highly related to photosynthetic nitrogen use efficiency and construction costs, significantly separated the introduced P. australis in North America from its European ancestor. Synthesis. We conclude that the European P. australis lineage was preadapted to be invasive prior to its introduction, and that the invasion in North America is further stimulated by rapid post-introduction evolution in

  3. [Allelopathic interactions between invasive plant Solidago canadensis and native plant Phragmites australis].

    PubMed

    Li, Yu-Zhe; Fan, Jiang-Wen; Yin, Xin; Yang, En-Yi; Wei, Wei; Tian, Zhi-Hui; Da, Liang-Jun

    2011-05-01

    Taking the seeds of invasive plant Solidago canadensis and native plant Phragmites australis from their mono- and co-dominant communities as allelopathic acceptors, this paper analyzed the differences in the seed germination rate and sprout length after treated with five level (12.5, 25, 50, 100, and 200 mg x mL(-1)) S. canadensis and P. australis extracts, aimed to understand the allelopathic interactions between the two species. The 1000-grain weight and seed germination rate under distilled water treatment of the two species in co-dominated community were greater than those in mono-dominant community. Low level (12.5 and 25 mg x mL(-1)) S. canadensi extracts slightly promoted the seed germination rates of S. canadensis in both mono- and co-dominant communities, but high level (50, 100, and 200 mg x mL(-1)) S. canadensi extracts had strong inhibition effect, especially for the S. canadensis in co-dominated community. No significant patterns were observed about the effects of P. australis extract on S. canadensis seed germination. The sprout length of S. canadensis seeds in both mono- and co-dominant communities decreased with increasing level of S. canadensis extract, but decreased in a fluctuation way with increasing level of P. australis extract. After treated with the extracts of P. australis or S. canadensis, the seed germination rate of P. australis in mono-dominant community was significantly greater than that in co-dominant community (P < 0.05), but there was no significant difference between these two extracts.

  4. First artificial hybrid of the eel species Anguilla australis and Anguilla anguilla

    PubMed Central

    2011-01-01

    Background Studies on artificial hybridization of different Anguilla species were conducted recently, i.e. female A. australis with male A. dieffenbachii, and female A. japonica with male A. anguilla. The existence of these artificial hybrids was however not demonstrated by independent genetic methods. Two species - A. anguilla and A. australis - that are phylogenetically close but have different sexual maturation times (12-25 weeks and 6-8 weeks, respectively), were expected to produce favourable hybrids for reproduction studies. Results A modification of the protocol for the reproduction of Anguilla japonica was used to produce eight-day Anguilla australis larvae, with a success rate of 71.4%. Thus ten out of 14 females produced eggs that could be fertilized, and three batches resulted in mass hatching. Hybrid larvae from female A. australis x male A. Anguilla survived for up to seven days post fertilization (dpf). The early development of the hybrid showed typical characteristics of A. anguilla tail pigmentation at 50 hours post fertilization (hpf), indicating expression of genes derived from the father. Conclusions In this paper we describe the first production of hybrid larvae from male A. anguilla and female A. australis and their survival for up to 7 dpf. A species-specific nucleotide difference in the 18 S rDNA gene confirmed that genes from both A. australis and A. anguilla were present in the hybrids. The developmental stages of the hybrid eel embryos and larvae are described using high resolution images. Video footage also indicated a heart beat in 5-dpf larva. PMID:21396126

  5. Can nutrient enrichment influence the invasion of Phragmites australis?

    PubMed

    Uddin, Md Nazim; Robinson, Randall William

    2017-06-22

    Plant invasion and nutrient enrichment because of anthropogenic landscape modifications seriously threaten native plant community diversity in aquatic and wetland ecosystems. It is poorly understood, however, whether these two disturbances interact with the functional identity of recipient native plants to drive community change. We performed combined studies in the fields and greenhouse to examine whether nutrient enrichment may trigger the invasion of Phragmites australis in wetlands through competitive advantage over native Melaleuca ericifolia. Chemical characterizations of rhizosphere water were distinguished in two different nutrient enriched wetlands associated with and without Phragmites over the seasons. Significant changes in rhizosphere water were observed in invaded area compared to uninvaded area at both sites. High nitrogen (NO3(-)), phosphorous (PO4(3-)), dissolved organic carbon, phenolics contents, with low pH were found in invaded areas compared to uninvaded areas. Total biomass of Phragmites was positively regressed with rhizosphere water nitrogen (NO3(-)) and phosphorous (PO4(3-)) content. Nutrient addition significantly enhanced the growth and competitive ability of Phragmites over Melaleuca. In contrast, Melaleuca was significantly less competitive than Phragmites. There was a significantly positive correlation between the growth of Phragmites grown alone and its competitive ability. The findings in greenhouse studies coupled with characteristics of Phragmites and its' rhizosphere chemistry in the nutrient enriched fields suggest that nutrient enrichment may enhance Phragmites invasion through correspondingly increasing growth and maintaining inherent competitive advantages of Phragmites. Nutrient management could limit the vigorous growth of Phragmites in wetlands and thereby reduce invasion through competitive advantages over natives, which might have important management implications for wetland managers. Copyright © 2017. Published by

  6. Structure of the integument of southern right whales, Eubalaena australis.

    PubMed

    Reeb, Desray; Best, Peter Barrington; Kidson, Susan Hillary

    2007-06-01

    Skin (integument) anatomy reflects adaptations to particular environments. It is hypothesized that cetacean (whale) integument will show unique anatomical adaptations to an aquatic environment, particularly regarding differences in temperature, density, and pressure. In this study, the gross and histological structure of the southern right whale integument is described and compared with terrestrial mammals and previous descriptions of mysticete (baleen whale) and odontocete (toothed whale) species. Samples were taken of the integument of 98 free-swimming southern right whales, Eubalaena australis, and examined by both light and electron microscopy. Results show that three epidermal layers are present, with the stratum corneum being parakeratotic in nature. As in bowhead whales, southern right whales possess an acanthotic epidermis and a notably thick hypodermis, with epidermal rods and extensive papillomatosis. However, unlike bowhead whales, southern right whales possess an uninterrupted hypodermal layer. Surprisingly, the integument of balaenids (right and bowhead mysticetes) in general is more like that of odontocetes than that of the more closely related balaenopterids (rorqual mysticetes). Similarities to odontocetes were found specifically in the collagen fibers in a fat-free zone of the reticular dermal layer and the elastic fibers in the dermal and hypodermal layers. Callosities, a distinctive feature of this genus, have a slightly thicker stratum corneum and are usually associated with hairs that have innervated and vascularized follicles. These hairs may function as vibrissae, thus aiding in aquatic foraging by allowing rapid detection of changes in prey density. Although the thick insulatory integument makes right whales bulky and slow-moving, it is an adaptation for living in cold water. Epidermal thickness, presence of epidermal rods, and callosities may act as barriers against mechanical injury from bodily contact with conspecifics or hard surfaces in

  7. Effect of cellulose wastes upon the growth of Phragmites australis.

    PubMed

    Jordan, M; Wilken, D; Gerth, A; Muñoz, O

    2008-01-01

    Growth responses of Phragmites australis (Cav.) Trin. Ex Steud, (reed grass), a helophyte species, were examined under in vitro and greenhouse conditions in the presence of various residues from a Kraft pulp mill. Plant tolerance to solid residues (ashes, dregs, flyashes, grits, primary sludge, and brown stock rejects) was tested in vitro. Solid residues were added separately up to 30% (w/v), as well a liquid residue up to 30% (v/v), to a Murashige and Skoog (1962) sucrose-free nutrient media with (5 mg l(-1)) 6-benzylaminopurine. After 2 mo in vitro, plantlets developed well in the presence of up to 10% solid or liquid wastes, but higher concentrations of either limited growth. This effect was mainly attributed to the plant's uptake and accumulation of various elements such as sodium, iron, copper, manganese, and boron, which are common to these waste types, thus showing an efficient phytoremediation potential. When added to MS media, the concentration of these elements generally decreased in the residual media after 2 mo of culture: the initial sodium, iron, and copper content in the growth media was reduced ca. 10-fold detected; a 5-fold reduction occurred for manganese and boron. In experiments under greenhouse conditions with in vitro propagated plantlets potted in mixtures of a commercial organic soil and residues, significant differences in plant development (plant size and fresh weight increase) were observed in the presence of ashes mixed at levels of 20% and 30%, compared to the control in organic soil. For other solid wastes, plant growth was inhibited as the concentration of each waste increased, causing chlorosis and/or plant necrosis.

  8. Study on the Salini-adaptation Physiology in Different Ecotypes of Phragmites australis in the Yellow River Delta of China: Osmotica and Their Contribution to the Osmotic Adjustment

    NASA Astrophysics Data System (ADS)

    Zhao, K. F.; Feng, L. T.; Zhang, S. Q.

    1999-08-01

    In the Yellow River Delta, there are four ecotypes of Phragmites australis: freshwater swamp reed; salty-water swamp reed; lower salt-meadow reed and higher salt-meadow reed. The growth status, composition and dominance of the reed community were observed. The organic and inorganic osmotica, osmotic potential and osmotic adjustment ability of reeds were determined. The abundance, coverage, plant height, leaf water content and osmotic potential all decreased with increasing salinity of habitats. K+ and sugars are the main osmotica in lower salinity, while Na+ is the main osmoticum in higher salinity. Na+ contents and the osmotic adjustment abilities of roots are higher than those in leaves. Na/K ratios of reeds varied with salinity levels of habitats, being about 1 in higher salinity. Moreover, the contributions of osmotica to the osmotic adjustment change with salinity, the higher the salinity level, the greater the contribution of inorganic osmotica, but the smaller the contribution of organic osmotica.

  9. Root exudates mediate kin recognition in plants

    PubMed Central

    Biedrzycki, Meredith L; Jilany, Tafari A

    2010-01-01

    Though recent work has demonstrated that plants can recognize species, kin versus strangers, and self/non-self roots, no mechanism for identity recognition in plants has yet been found. Here we examined the role of soluble chemicals in signaling among roots. Utilizing Arabidopsis thaliana, we exposed young seedlings to liquid media containing exudates from siblings, strangers (non-siblings), or only their own exudates. In one experiment, root secretions were inhibited by sodium orthovanadate and root length and number of lateral roots were measured. In a second experiment, responses to siblings, strangers, and their own exudates were measured for several accessions (genotypes), and the traits of length of the longest lateral root and hypocotyl length were also measured. The exposure of plants to the root exudates of strangers induced greater lateral root formation than exposure of plants to sibling exudates. Stranger recognition was abolished upon treatment with the secretion inhibitor. In one experiment, plants exposed to sibling or stranger exudates have shorter roots than plants only exposed to their own exudates. This self/non-self recognition response was not affected by the secretion inhibitor. The results demonstrate that that kin recognition and self/non-self are two separate identity recognition systems involving soluble chemicals. Kin recognition requires active secretion by roots. PMID:20539778

  10. Root exudates mediate kin recognition in plants.

    PubMed

    Biedrzycki, Meredith L; Jilany, Tafari A; Dudley, Susan A; Bais, Harsh P

    2010-01-01

    Though recent work has demonstrated that plants can recognize species, kin versus strangers, and self/non-self roots, no mechanism for identity recognition in plants has yet been found. Here we examined the role of soluble chemicals in signaling among roots. Utilizing Arabidopsis thaliana, we exposed young seedlings to liquid media containing exudates from siblings, strangers (non-siblings), or only their own exudates. In one experiment, root secretions were inhibited by sodium orthovanadate and root length and number of lateral roots were measured. In a second experiment, responses to siblings, strangers, and their own exudates were measured for several accessions (genotypes), and the traits of length of the longest lateral root and hypocotyl length were also measured. The exposure of plants to the root exudates of strangers induced greater lateral root formation than exposure of plants to sibling exudates. Stranger recognition was abolished upon treatment with the secretion inhibitor. In one experiment, plants exposed to sibling or stranger exudates have shorter roots than plants only exposed to their own exudates. This self/non-self recognition response was not affected by the secretion inhibitor. The results demonstrate that that kin recognition and self/non-self are two separate identity recognition systems involving soluble chemicals. Kin recognition requires active secretion by roots.

  11. Desodification from calcareous saline sodic soil through phytoremediation with Phragmites australis (Cav.) Trin. ex Steud. and gypsum.

    PubMed

    Abro, Saeed Akhter; Otho, Aijaz Ali; Bughio, Farooque A; Sahito, Oan Mohammad; Jamali, Abdul Rauf; Mahar, Amanullah

    2017-05-22

    The reclamation of saline sodic soils requires sodium removal and the phytoremediation is one of the proven low-cost, low-risk technologies for reclaiming such soils. However, the role of P. australis in reclaiming saline sodic soil has not been evaluated extensively. The comparative reclaiming role of P. australis and gypsum was evaluated in a column experiment on a sandy clay saline sodic soil with ECe 74.7 dS m(-1), SAR 63.2, Na(+) 361 g kg(-1) and pH 8.46. The gypsum at 100% soil requirement, planting common reed (P. australis) alone, P. australis + gypsum at 50% soil gypsum requirements and leaching (control without plant and gypsum) were four treatments applied. After 11 weeks of incubation, the results showed that all treatments including control significantly reduced pH, EC, exchangeable Na(+) and SAR from the initial values but the control being with least results. The gypsum and P. australis + gypsum were highly effective in salinity (ECe) reduction while, sodicity (SAR) and Na(+) reductions were significantly higher in P. australis + gypsum treatment. The reclamation efficiency in terms of Na(+) (83.4%) and SAR (86.8%) reduction was highest in P. australis + gypsum. It is concluded that phytoremediation is an effective tool to reclaim saline sodic soil.

  12. Hydroponic uptake and distribution of nitrobenzene in Phragmites australis: potential for phytoremediation.

    PubMed

    Song, Yanyu; Song, Changchun; Ju, Songbai; Chai, Junhai; Guo, Jun; Zhao, Quandong

    2010-03-01

    Phragmites australis was grown hydroponically in nutrient solutions containing nitrobenzene to examine the potential for treatment of contaminated waters through phytoremediation. The hydroponic solutions and plant tissue were sampled each day during the five day growth period and tested for nitrobenzene. Plant tissue analysis included both rhizome and shoot sections of the plant. The average half lives and disappearance rate of nitrobenzene in the nutrient solution was 1.85 days and 88.10%, respectively. The levels of nitrobenzene in rhizomes and shoots of Phragmites australis increased with higher exogenous concentrations. For the highest treatment, nitrobenzene measurements in the rhizome tissue were much higher than the plant shoots until the third day. Shoot sections initially showed elevated concentrations and then decreased. This variation is presumably due to the translocation of the target compound from the rhizomes to shoots. Our findings indicate that Phragmites australis removed nitrobenzene from the hydroponic solutions and accumulated the compound within the plant tissue. This activity makes Phragmites australis a good candidate species for the phytoremediation of nitrobenzene contaminated waters.

  13. STS-45 Earth observation of the Aurora Australis or Southern Lights

    NASA Technical Reports Server (NTRS)

    1992-01-01

    STS-45 Earth observation taken onboard Atlantis, Orbiter Vehicle (OV) 104, is of the Aurora Australis or Southern Lights. The green appearing auroral activity engulfs the thin blue line on the Earth's limb. Aurorae were observed and photographed throughout the STS-45 nine-day mission.

  14. STS-45 Earth observation of the Aurora Australis or Southern Lights

    NASA Technical Reports Server (NTRS)

    1992-01-01

    STS-45 Earth observation taken onboard Atlantis, Orbiter Vehicle (OV) 104, is of the Aurora Australis or Southern Lights. The STS-45 crewmembers note the interesting spiralling or corkscrew appearance of this particular sighting. Aurorae were observed and photographed throughout the STS-45 nine-day mission.

  15. STS-45 Earth observation of the Aurora Australis or Southern Lights

    NASA Technical Reports Server (NTRS)

    1992-01-01

    STS-45 Earth observation taken onboard Atlantis, Orbiter Vehicle (OV) 104, is of the Aurora Australis or Southern Lights. The STS-45 crewmembers note the interesting spiralling or corkscrew appearance of this particular sighting. Aurorae were observed and photographed throughout the STS-45 nine-day mission.

  16. Confirmed field hybridization of native and introduced Phragmites australis (Poaceae) in North America.

    PubMed

    Saltonstall, Kristin; Castillo, Hilda E; Blossey, Bernd

    2014-01-01

    Intraspecific hybridization between native and introduced lineages of a species can increase invasiveness and may lead to the decline of native lineages. The introduction of Eurasian Phragmites australis has caused profound changes to wetland habitats across North America, yet evidence for hybridization between native and introduced Phragmites australis in North America is lacking and has puzzled researchers for over a decade. Here we present the first confirmed field hybridization event between the two lineages. Hybrid plants were initially recognized during field surveys by their intermediate morphology and distinct herbivore community. We verified hybrid status using chloroplast DNA haplotypes and microsatellite markers. Confirmed hybrid stems were restricted to one site and displayed morphological characteristics of both native and introduced P. australis. Based on their microsatellite profiles, all samples likely represent a single clone of a first generation hybrid. Sequencing of cpDNA indicates that the maternal parent is from the introduced lineage. Identification of hybrid P. australis in the field is complex and requires multiple characters. All suspected hybrids should be verified using genetic techniques. Preventing the spread of introduced genes and genotypes through North America will require recognition and rapid management response to hybrid plants.

  17. Changes in polyphenols in "Rio Red' grapefruit leaves in response to Elsinoe australis infection

    USDA-ARS?s Scientific Manuscript database

    Sweet orange scab (SOS) is a fungal disease of citrus, which is caused by Elsinoë australis. It affects the aesthetics of the fruit by forming wart-like protruded lesions on the fruit skin, and also affects the leaves, which act as source of inoculum in the orchards. SOS is widespread in the differe...

  18. "Aurora Australis, Airglow, Terminator view taken by the Expedition 29 crew"

    NASA Image and Video Library

    2011-09-18

    ISS029-E-007502 (18 Sept. 2011) --- This is one of a series of night time images photographed by one of the Expedition 29 crew members from the International Space Station. It features Aurora Australis, airglow, and parts of the southeast Indian Ocean. Nadir coordinates are 50.58 degrees south latitude and 138.28 degrees east longitude.

  19. "Aurora Australis, Airglow, Terminator view taken by the Expedition 29 crew"

    NASA Image and Video Library

    2011-09-18

    ISS029-E-007500 (18 Sept. 2011) --- This is one of a series of night time images photographed by one of the Expedition 29 crew members from the International Space Station. It features the Aurora Australis, airglow and parts of the southeastern Indian Ocean. Nadir coordinates are 50.66 degrees south latitude and 137.70 degrees east longitude.

  20. STS-45 Earth observation of the Aurora Australis or Southern Lights

    NASA Image and Video Library

    1992-04-02

    STS-45 Earth observation taken onboard Atlantis, Orbiter Vehicle (OV) 104, is of the Aurora Australis or Southern Lights. The STS-45 crewmembers note the interesting spiralling or corkscrew appearance of this particular sighting. Aurorae were observed and photographed throughout the STS-45 nine-day mission.

  1. Aurora Australis taken from the shuttle Discovery during STS-85 mission

    NASA Image and Video Library

    1997-09-02

    STS085-365-006 (7 - 19 August 1997) --- A 35mm camera with a time exposure was used to record this image of the southern lights or the aurora Australis. The vertical stabilizer of the Space Shuttle Discovery appears in the foreground.

  2. Aurora Australis over the southern Indian ocean view taken by the Expedition 29 crew

    NASA Image and Video Library

    2011-09-17

    ISS029-E-005904 (17 Sept. 2011) --- This is one of a series of night time images photographed by one of the Expedition 29 crew members from the International Space Station. It features Aurora Australis over the southern Indian ocean. Nadir coordinates are 50.16 south latitude and 48.11 degrees east longitude.

  3. STS-45 Earth observation of the Aurora Australis or Southern Lights

    NASA Image and Video Library

    1992-04-02

    STS-45 Earth observation taken onboard Atlantis, Orbiter Vehicle (OV) 104, is of the Aurora Australis or Southern Lights. The green appearing auroral activity engulfs the thin blue line on the Earth's limb. Aurorae were observed and photographed throughout the STS-45 nine-day mission.

  4. STS-45 Earth observation of the Aurora Australis or Southern Lights

    NASA Technical Reports Server (NTRS)

    1992-01-01

    STS-45 Earth observation taken onboard Atlantis, Orbiter Vehicle (OV) 104, is of the Aurora Australis or Southern Lights. The green appearing auroral activity engulfs the thin blue line on the Earth's limb. Aurorae were observed and photographed throughout the STS-45 nine-day mission.

  5. Release of Metals by the Leaves of the Salt Marsh Grasses Spartina alterniflora and Phragmites australis

    NASA Astrophysics Data System (ADS)

    Burke, D. J.; Weis, J. S.; Weis, P.

    2000-08-01

    The perennial grass Spartina alterniflora, common to salt marshes of eastern North America, is known to accumulate metals from marsh sediment and release them into the environment. One pathway by which Spartina alterniflora releases metals is through the excretion of metal-containing salts produced by leaf salt glands. We examined the differential release of metals by Spartina alterniflora and the invasive perennial grass Phragmites australis in an urban marsh ecosystem. Leaching rates were measured by cleaning residues off leaf surfaces under field and controlled laboratory conditions. Leaf residues and leaf tissue were analysed for copper, chromium, lead and zinc by atomic absorption spectrophotometry. Spartina alterniflora was found to release significantly more metal through leaf tissue than Phragmites australis, under both field and laboratory situations. Spartina alterniflora was also found to accumulate significantly more chromium and lead in leaves than Phragmites australis. Therefore, Spartina alterniflora can release larger quantities of metals into the marsh environment than Phragmites australis, through both excretion and leaf deposition.

  6. Effect of Salinity on Common Reed (Phragmites australis) in a Restored Salt Marsh in Rhode Island

    EPA Science Inventory

    Tidal wetlands have undergone extensive degradation throughout the years because of interference with tidal flow from construction, dredging, and invasion of non-native plants such Phragmites australis. In 1956, a 4-lane highway was constructed in Galilee, Rhode Island, USA, cro...

  7. Effect of Salinity on Common Reed (Phragmites australis) in a Restored Salt Marsh in Rhode Island

    EPA Science Inventory

    Tidal wetlands have undergone extensive degradation throughout the years because of interference with tidal flow from construction, dredging, and invasion of non-native plants such Phragmites australis. In 1956, a 4-lane highway was constructed in Galilee, Rhode Island, USA, cro...

  8. EFFECT OF SALINITY ON THE COMMON REED, FRAGMITES AUSTRALIS, IN A RESTORED MARSH

    EPA Science Inventory

    Tidal wetlands have undergone extensive degradation throughout the years because of interference with tidal flow from construction, dredging, and invasion of non-native plants such Phragmites australis. In 1956, a 4-lane highway was constructed in Galilee, Rhode Island, USA, cr...

  9. Location of glycogen in spermatids and spermatozoa of the shipworm, Bankia australis (Teredinidae, Bivalvia, Mollusca).

    PubMed

    Popham, J D; Dickson, M R

    1975-12-18

    The periodic acid-thiocarbohydrazide-silver proteinate technique and alpha-amylase digestion were used to locate glycogen in the spermatids and sperms of the bivalve Bankia australis. Glycogen was found in the middle piece and around the acrosome in spermatozoa, apparently randomly scattered throughout the cytoplasm of young spermatids, and in a cytoplasmic bead in old spermatids.

  10. The fine structure of the oocyte of bankia australis (teredinidae, bivalvia) before and after fertilization.

    PubMed

    Popham, J D

    1975-01-01

    The fine structure of the oocyte of Bankia australis is compared with that of other bivalve oocytes. It was observed that following fertilization, the microvilli changed their spatial organisation and behaviour towards sperm, the cortical granules disappeared in regions of high concentrations of supernumerary sperm, and the mitochondria apparently stated to divide.

  11. Anatomy of nasal complex in the southern right whale, Eubalaena australis (Cetacea, Mysticeti)

    PubMed Central

    Buono, Mónica R; Fernández, Marta S; Fordyce, R Ewan; Reidenberg, Joy S

    2015-01-01

    The nasal region of the skull has undergone dramatic changes during the course of cetacean evolution. In particular, mysticetes (baleen whales) conserve the nasal mammalian pattern associated with the secondary function of olfaction, and lack the sound-producing specializations present in odontocetes (toothed whales, dolphins and porpoises). To improve our understanding of the morphology of the nasal region of mysticetes, we investigate the nasal anatomy, osteology and myology of the southern right whale, Eubalaena australis, and make comparisons with other mysticetes. In E. australis external deflection surfaces around the blowholes appear to divert water off the head, and differ in appearance from those observed in balaenopterids, eschrichtiids and cetotherids. In E. australis the blowholes are placed above hypertrophied nasal soft tissues formed by fat and nasal muscles, a pattern also observed in balaenopterids (rorqual mysticetes) and a cetotherid (pygmy right whale, Caperea marginata). Blowhole movements are due to the action of five nasofacial muscles: dilator naris superficialis, dilator naris profundus, depressor alae nasi, constrictor naris, and retractor alae nasi. The dilator naris profundus found in E. australis has not been previously reported in balaenopterids. The other nasofacial muscles have a similar arrangement in balaenopterids, with minor differences. A novel structure, not reported previously in any mysticete, is the presence of a vascular tissue (rete mirabile) covering the lower nasal passage. This vascular tissue could play a role in warming inspired air, or may engorge to accommodate loss of respiratory space volume due to gas compression from increased pressure during diving. PMID:25440939

  12. EFFECT OF SALINITY ON THE COMMON REED, FRAGMITES AUSTRALIS, IN A RESTORED MARSH

    EPA Science Inventory

    Tidal wetlands have undergone extensive degradation throughout the years because of interference with tidal flow from construction, dredging, and invasion of non-native plants such Phragmites australis. In 1956, a 4-lane highway was constructed in Galilee, Rhode Island, USA, cr...

  13. Phragmites australis and Typha orientalis in removal of pollutant in Taihu Lake, China.

    PubMed

    Tian, Ziqiang; Zheng, Binghui; Liu, Meizhen; Zhang, Zhenyu

    2009-01-01

    Two plant populations of Phragmites australis and Typha orientalis grown in gravel and sediment substrate were studied to assess their capabilities for purifying polluted water in Taihu Lake, China. The substrate displayed most significant effects on the suspended matter (P < 0.01), with the reduction of 76%-87% and 52%-63% for P. australis, and 83%-86% and 45%-62% for T. orientalis in gravel substrate and sediment substrate, respectively. Both species and substrates significantly decreased the N and P concentrations of water body (P < 0.01). P. australis showed higher total N and P concentrations in tissues than T. orientalis and had a greater potential to remove nutrients from the lake. Phosphate was easily to concentrate in the belowground tissues, while nitrate concentration was higher in leaf and stalk. Therefore, harvesting the aboveground tissues could take most of nitrate out of the sediment. The saturate photosynthetic rate (Asat) of P. australis was higher than that of T. orientalis when grown in sediment substrate. But instance water-use-efficiency (WUEi) (A/E) and intrinsic water use efficiency (A/gs) showed the maximum values of two species grown in river water. With significant difference in gs, however, intercellular CO2 concentration (Ci) had no obvious difference in two species which indicated that high Asat value of P. australis might result from the increased carboxylation capacity of the mesophyll, because of the central role of N in photosynthetic enzymes. Our findings suggest that the plants could absorb most of nitrogen in polluted water, while gravel displayed a high capacity for absorbing the suspended matters and phosphate salts. Therefore, biological and physiological pathways for pollutant removal should be integrated.

  14. Classification of retinal ganglion cells in the southern hemisphere lamprey Geotria australis (Cyclostomata).

    PubMed

    Fletcher, Lee Norman; Coimbra, João Paulo; Rodger, Jennifer; Potter, Ian C; Gill, Howard S; Dunlop, Sarah A; Collin, Shaun P

    2014-03-01

    Lampreys are one of two extant representatives of the earliest group of vertebrates, the agnathans or jawless fishes. The single species of the southern hemisphere lamprey family Geotriidae, Geotria australis, possesses the potential for pentachromatic color discrimination opposed to the mono- or dichromacy found in other lampreys. However, little is known of the retinal ganglion cell types that contribute to visual processing in G. australis. A quantitative morphological approach was used to distinguish and describe retinal ganglion cell types in G. australis. The morphology of retinal ganglion cells was revealed by retrograde biocytin labeling from the optic disc. Cells were digitally reconstructed, and somatic area and position and dendritic field size, density, tortuosity, and stratification were subjected to quantitative morphometric analyses. Cluster analysis, in conjunction with similarity profile analysis (SIMPROF), statistically identified five discrete monostratified retinal ganglion cell types, one of which may comprise two subtypes. Two bistratified types were identified separately, including a biplexiform and a bistratified subtype. The use of cluster analysis with SIMPROF provided a robust statistical technique for objectively identifying cell types whose characteristics were similar and significantly different from those of other types and thus provides an objective resolution of the problems posed by "lumpers vs. splitters" when designating cell types. The diversity of retinal ganglion cells suggests that visual information in the lamprey G. australis is processed in parallel streams, as in gnathostomes. These findings, together with the results of previous studies, indicate that the visual system of the lamprey G. australis represents the upper limit of visual complexity in extant agnathans. © 2013 Wiley Periodicals, Inc.

  15. Low densities of epiphytic bacteria from the marine alga Ulva australis inhibit settlement of fouling organisms.

    PubMed

    Rao, Dhana; Webb, Jeremy S; Holmström, Carola; Case, Rebecca; Low, Adrian; Steinberg, Peter; Kjelleberg, Staffan

    2007-12-01

    Bacteria that produce inhibitory compounds on the surface of marine algae are thought to contribute to the defense of the host plant against colonization of fouling organisms. However, the number of bacterial cells necessary to defend against fouling on the plant surface is not known. Pseudoalteromonas tunicata and Phaeobacter sp. strain 2.10 (formerly Roseobacter gallaeciensis) are marine bacteria often found in association with the alga Ulva australis and produce a range of extracellular inhibitory compounds against common fouling organisms. P. tunicata and Phaeobacter sp. strain 2.10 biofilms with cell densities ranging from 10(2) to 10(8) cells cm(-2) were established on polystyrene petri dishes. Attachment and settlement assays were performed with marine fungi (uncharacterized isolates from U. australis), marine bacteria (Pseudoalteromonas gracilis, Alteromonas sp., and Cellulophaga fucicola), invertebrate larvae (Bugula neritina), and algal spores (Polysiphonia sp.) and gametes (U. australis). Remarkably low cell densities (10(2) to 10(3) cells cm(-2)) of P. tunicata were effective in preventing settlement of algal spores and marine fungi in petri dishes. P. tunicata also prevented settlement of invertebrate larvae at densities of 10(4) to 10(5) cells cm(-2). Similarly, low cell densities (10(3) to 10(4)cells cm(-2)) of Phaeobacter sp. strain 2.10 had antilarval and antibacterial activity. Previously, it has been shown that abundance of P. tunicata on marine eukaryotic hosts is low (<1 x 10(3) cells cm(-2)) (T. L. Skovhus et al., Appl. Environ. Microbiol. 70:2373-2382, 2004). Despite such low numbers of P. tunicata on U. australis in situ, our data suggest that P. tunicata and Phaeobacter sp. strain 2.10 are present in sufficient quantities on the plant to inhibit fouling organisms. This strongly supports the hypothesis that P. tunicata and Phaeobacter sp. strain 2.10 can play a role in defense against fouling on U. australis at cell densities that commonly

  16. Low Densities of Epiphytic Bacteria from the Marine Alga Ulva australis Inhibit Settlement of Fouling Organisms▿

    PubMed Central

    Rao, Dhana; Webb, Jeremy S.; Holmström, Carola; Case, Rebecca; Low, Adrian; Steinberg, Peter; Kjelleberg, Staffan

    2007-01-01

    Bacteria that produce inhibitory compounds on the surface of marine algae are thought to contribute to the defense of the host plant against colonization of fouling organisms. However, the number of bacterial cells necessary to defend against fouling on the plant surface is not known. Pseudoalteromonas tunicata and Phaeobacter sp. strain 2.10 (formerly Roseobacter gallaeciensis) are marine bacteria often found in association with the alga Ulva australis and produce a range of extracellular inhibitory compounds against common fouling organisms. P. tunicata and Phaeobacter sp. strain 2.10 biofilms with cell densities ranging from 102 to 108 cells cm−2 were established on polystyrene petri dishes. Attachment and settlement assays were performed with marine fungi (uncharacterized isolates from U. australis), marine bacteria (Pseudoalteromonas gracilis, Alteromonas sp., and Cellulophaga fucicola), invertebrate larvae (Bugula neritina), and algal spores (Polysiphonia sp.) and gametes (U. australis). Remarkably low cell densities (102 to 103 cells cm−2) of P. tunicata were effective in preventing settlement of algal spores and marine fungi in petri dishes. P. tunicata also prevented settlement of invertebrate larvae at densities of 104 to 105 cells cm−2. Similarly, low cell densities (103 to 104cells cm−2) of Phaeobacter sp. strain 2.10 had antilarval and antibacterial activity. Previously, it has been shown that abundance of P. tunicata on marine eukaryotic hosts is low (<1 × 103 cells cm−2) (T. L. Skovhus et al., Appl. Environ. Microbiol. 70:2373-2382, 2004). Despite such low numbers of P. tunicata on U. australis in situ, our data suggest that P. tunicata and Phaeobacter sp. strain 2.10 are present in sufficient quantities on the plant to inhibit fouling organisms. This strongly supports the hypothesis that P. tunicata and Phaeobacter sp. strain 2.10 can play a role in defense against fouling on U. australis at cell densities that commonly occur in situ

  17. Tracking Phragmites Australis Expansion in Bear River Migratory Bird Refuge using AggieAir Aircraft Data

    NASA Astrophysics Data System (ADS)

    Zaman, B.; McKee, M.

    2010-12-01

    This research examines the use of unmanned air vehicles (UAV), a cutting edge technology developed at the Utah Water research lab for acquiring airborne imagery using drones for the assessment of abundance of an invasive species Phragmites australis in a wetland vegetation setup. These UAV’s acquire multispectral data in the visible and near-infrared bands with a spatial resolution of 0.5 meters. The study area is the Bear River Migratory Bird Refuge (MBR) which lies in northern Utah, where the Bear River flows into the northeast arm of the Great Salt Lake. The Refuge protects the marshes found at the mouth of the Bear River; these marshes are the largest freshwater component of the Great Salt Lake ecosystem. A common reed, Phragmites australis, is a tall (1.5-4.0 m) coarse perennial grass found primarily in brackish and freshwater wetlands, growing at or above mean high water. The methodology is to build Bayesian statistical supervised classification model using relevance vector machine (RVM) employing the inexpensive and readily available UAV data. The UAV images of the bird refuge are processed to obtain calibrated reflectance imagery. Thereafter, the isodata clustering algorithm is applied to classify the multispectral imagery into different classes. Using ground sampling of the species, pixels containing the Phragmites australis are deduced. The training set for the supervised RVM classification model is prepared using the deduced pixel values. A separate set of ground sampling points containing the Phragmites australis are kept aside for validation. The distribution of Phragmites australis in the study area as obtained from RVM classification model is compared to the validation set. The RVM model results for tracking of Phragmites are encouraging and the new technique has promising real-time implementation for similar applications.

  18. Cytokinin, auxin and physiological polarity in the aquatic carnivorous plants Aldrovanda vesiculosa and Utricularia australis

    PubMed Central

    Šimura, Jan; Spíchal, Lukáš; Adamec, Lubomír; Pěnčík, Aleš; Rolčík, Jakub; Novák, Ondřej; Strnad, Miroslav

    2016-01-01

    Background and Aims The typical rootless linear shoots of aquatic carnivorous plants exhibit clear, steep polarity associated with very rapid apical shoot growth. The aim of this study was to determine how auxin and cytokinin contents are related to polarity and shoot growth in such plants. Methods The main auxin and cytokinin metabolites in separated shoot segments and turions of two carnivorous plants, Aldrovanda vesiculosa and Utricularia australis, were analysed using ultra-high-performance liquid chromatography coupled with triple quad mass spectrometry. Key Results In both species, only isoprenoid cytokinins were identified. Zeatin cytokinins predominated in the apical parts, with their concentrations decreasing basipetally, and the trans isomer predominated in A. vesiculosa whereas the cis form was more abundant in U australis. Isopentenyladenine-type cytokinins, in contrast, increased basipetally. Conjugated cytokinin metabolites, the O-glucosides, were present at high concentrations in A. vesiculosa but only in minute amounts in U. australis. N9-glucoside forms were detected only in U. australis, with isopentenyladenine-9-glucoside (iP9G) being most abundant. In addition to free indole-3-acetic acid (IAA), indole-3-acetamide (IAM), IAA-aspartate (IAAsp), IAA-glutamate (IAGlu) and IAA-glycine (IAGly) conjugates were identified. Conclusions Both species show common trends in auxin and cytokinin levels, the apical localization of the cytokinin biosynthesis and basipetal change in the ratio of active cytokinins to auxin, in favour of auxin. However, our detailed study of cytokinin metabolic profiles also revealed that both species developed different regulatory mechanisms of active cytokinin content; on the level of their degradation, in U. australis, or in the biosynthesis itself, in the case of A. vesiculosa. Results indicate that the rapid turnover of these signalling molecules along the shoots is essential for maintaining the dynamic balance between the

  19. Infanticide secrets

    PubMed Central

    Barr, Jennieffer A.; Beck, Cheryl T.

    2008-01-01

    ABSTRACT OBJECTIVE To explore thoughts of infanticide that did not lead to the act among mothers with postpartum depression. DESIGN A phenomenologic hermeneutic study in which women were invited to share their experiences of having thoughts of infanticide. SETTING Community setting in a large metropolitan city, Brisbane, Australia. PARTICIPANTS Fifteen women who had been diagnosed as clinically depressed with postpartum onset whose babies were 12 months of age or younger. METHOD Audiotaped, in-depth interviews were transcribed verbatim. Thematic analysis commenced immediately after the first interview, and data collection continued until saturation was achieved. A questioning approach that reflected hermeneutics was facilitated by use of journals by the researchers. MAIN FINDINGS Six themes emerged from the data: imagined acts of infanticide, the experience of horror, distorted sense of responsibility, consuming negativity, keeping secrets, and managing the crisis. CONCLUSION Women who experienced nonpsychotic depression preferred not to disclose their thoughts of infanticide to health professionals, including trusted general practitioners or psychiatrists. These women were more likely to mention their suicidal thoughts than their infanticidal thoughts in order to obtain health care. General practitioners and other health professionals should directly ask about whether a woman has been experiencing thoughts of harming herself or her baby, regardless of the reason why she has presented. PMID:19074717

  20. Interspecific interactions between Phragmites australis and Spartina alterniflora along a tidal gradient in the Dongtan wetland, Eastern China.

    PubMed

    Yuan, Yue; Wang, Kaiyun; Li, Dezhi; Pan, Yu; Lv, Yuanyuan; Zhao, Meixia; Gao, JinJin

    2013-01-01

    The invasive species Spartina alterniora Loisel was introduced to the eastern coast of China in the 1970s and 1980s for the purposes of land reclamation and the prevention of soil erosion. The resulting interspecific competition had an important influence on the distribution of native vegetation, which makes studying the patterns and mechanisms of the interactions between Spartina alterniora Loisel and the native species Phragmites australis (Cav.) Trin ex Steud in this region very important. There have been some researches on the interspecific interactions between P. australis and S. alterniora in the Dongtan wetland of Chongming, east China, most of which has focused on the comparison of their physiological characteristics. In this paper, we conducted a neighbor removal experiment along a tidal gradient to evaluate the relative competitive abilities of the two species by calculating their relative neighbor effect (RNE) index. We also looked at the influence of environmental stress and disturbance on the competitive abilities of the two species by comparing interaction strength (I) among different tidal zones both for P. australis and S. alterniora. Finally, we measured physiological characteristics of the two species to assess the physiological mechanisms behind their different competitive abilities. Both negative and positive interactions were found between P. australis and S. alterniora along the environmental gradient. When the direction of the competitive intensity index for P. australis and S. alterniora was consistent, the competitive or facilitative effect of S. alterniora on P. australis was stronger than that of P. australis on S. alterniora. The interspecific interactions of P. australis and S. alterniora varied with environmental conditions, as well as with the method used, to measure interspecific interactions.

  1. Interspecific Interactions between Phragmites australis and Spartina alterniflora along a Tidal Gradient in the Dongtan Wetland, Eastern China

    PubMed Central

    Yuan, Yue; Wang, Kaiyun; Li, Dezhi; Pan, Yu; Lv, Yuanyuan; Zhao, Meixia; Gao, JinJin

    2013-01-01

    The invasive species Spartina alterniora Loisel was introduced to the eastern coast of China in the 1970s and 1980s for the purposes of land reclamation and the prevention of soil erosion. The resulting interspecific competition had an important influence on the distribution of native vegetation, which makes studying the patterns and mechanisms of the interactions between Spartina alterniora Loisel and the native species Phragmites australis (Cav.) Trin ex Steud in this region very important. There have been some researches on the interspecific interactions between P. australis and S. alterniora in the Dongtan wetland of Chongming, east China, most of which has focused on the comparison of their physiological characteristics. In this paper, we conducted a neighbor removal experiment along a tidal gradient to evaluate the relative competitive abilities of the two species by calculating their relative neighbor effect (RNE) index. We also looked at the influence of environmental stress and disturbance on the competitive abilities of the two species by comparing interaction strength (I) among different tidal zones both for P. australis and S. alterniora. Finally, we measured physiological characteristics of the two species to assess the physiological mechanisms behind their different competitive abilities. Both negative and positive interactions were found between P. australis and S. alterniora along the environmental gradient. When the direction of the competitive intensity index for P. australis and S. alterniora was consistent, the competitive or facilitative effect of S. alterniora on P. australis was stronger than that of P. australis on S. alterniora. The interspecific interactions of P. australis and S. alterniora varied with environmental conditions, as well as with the method used, to measure interspecific interactions. PMID:23342017

  2. Dispersal of Udonella australis (Monogenea: Udonellidae) between caligid copepods Caligus rogercresseyi and Lepeophtheirus mugiloidis on Chilean rock cod.

    PubMed

    Marin, Sandra L; Carvajal, Juan; George-Nascimento, Mario

    2007-04-01

    Udonella australis is a platyhelminth that lives on the surface of the ectoparasite copepods Caligus rogercresseyi and Lepeophtheirus mugiloidis, which coexist on the Chilean rock cod Eleginops maclovinus. The absence of a planktonic oncomiracidium stage in the life cycle of udonellids may limit their dispersal ability. However, the high prevalence and intensity of U. australis on C. rogercresseyi suggest they have developed dispersal strategies to compensate for the lack of a free-living larval stage. The goals of this study were to determine the main dispersal mechanisms of U. australis in 1 copepod species and to compare the dispersal ability of U. australis between 2 different copepod species. Chilean rock cods were infected with female (without udonellids) and male (with and without udonellids) C. rogercresseyi. Other fishes were also infected with this copepod (with U. australis) and with L. mugiloidis (without U. australis). The dispersal of udonellids among copepods occurs through both intraspecific and interspecific processes. The main dispersal mechanism appears to be copepod mating; contact between same-sex individuals is less important. Intraspecific dispersal seems to be more dependent on the number of udonellids per fish than on copepod abundance, as observed for interspecific dispersal.

  3. Chonopeltis australis (Crustacea) male reproductive system morphology; sperm transfer and review of reproduction in Branchiura.

    PubMed

    Neethling, Lourelle Alicia Martins; Avenant-Oldewage, Annemariè

    2015-02-01

    The morphology of the male reproductive system as well as sperm transfer in Branchiura has been described for Dolops ranarum and Argulus japonicus. In this study, the reproductive system and accessory structures are described for male Chonopeltis australis using histology, light microscopy, and scanning electron microscopy. For the first time, we describe sperm transfer by means of a spermatophore in this genus. The internal and external morphology and mechanism of sperm transfer is compared with other Branchiura, where it has been described. The morphology of the reproductive system of C. australis is similar to that of D. ranarum while the accessory structures and the spermatophore produced are similar to that of A. japonicus. A revision of the definition of Branchiura with respect to reproduction is provided. © 2014 Wiley Periodicals, Inc.

  4. Isolation and characterization of collagen from the skin of Brama australis.

    PubMed

    Sionkowska, Alina; Kozłowska, Justyna; Skorupska, Małgorzata; Michalska, Marta

    2015-09-01

    Collagen was extracted from the skin of Brama australis, the fish from warm-water sea. The yield of collagen from skin of B. australis was about 1.5% on a wet weight basis of raw material. The isolated protein was confirmed as collagen by different physico-chemical techniques such as: FTIR, SDS-PAGE, and amino acid analysis. The denaturation temperature (T(d)) of obtained collagen was found to be 24°C, what is promising as an advantage for cosmetic application. According to the electrophoretic pattern, collagen consisted of two different α-chains (α1 and α2) and was classified as type I collagen. Although T(d) of obtained collagen is higher than 20 °C it is still far from T(d) of mammalian collagen.

  5. Genetic ablation of root cap cells in Arabidopsis

    NASA Technical Reports Server (NTRS)

    Tsugeki, R.; Fedoroff, N. V.

    1999-01-01

    The root cap is increasingly appreciated as a complex and dynamic plant organ. Root caps sense and transmit environmental signals, synthesize and secrete small molecules and macromolecules, and in some species shed metabolically active cells. However, it is not known whether root caps are essential for normal shoot and root development. We report the identification of a root cap-specific promoter and describe its use to genetically ablate root caps by directing root cap-specific expression of a diphtheria toxin A-chain gene. Transgenic toxin-expressing plants are viable and have normal aerial parts but agravitropic roots, implying loss of root cap function. Several cell layers are missing from the transgenic root caps, and the remaining cells are abnormal. Although the radial organization of the roots is normal in toxin-expressing plants, the root tips have fewer cytoplasmically dense cells than do wild-type root tips, suggesting that root meristematic activity is lower in transgenic than in wild-type plants. The roots of transgenic plants have more lateral roots and these are, in turn, more highly branched than those of wild-type plants. Thus, root cap ablation alters root architecture both by inhibiting root meristematic activity and by stimulating lateral root initiation. These observations imply that the root caps contain essential components of the signaling system that determines root architecture.

  6. Genetic ablation of root cap cells in Arabidopsis

    NASA Technical Reports Server (NTRS)

    Tsugeki, R.; Fedoroff, N. V.

    1999-01-01

    The root cap is increasingly appreciated as a complex and dynamic plant organ. Root caps sense and transmit environmental signals, synthesize and secrete small molecules and macromolecules, and in some species shed metabolically active cells. However, it is not known whether root caps are essential for normal shoot and root development. We report the identification of a root cap-specific promoter and describe its use to genetically ablate root caps by directing root cap-specific expression of a diphtheria toxin A-chain gene. Transgenic toxin-expressing plants are viable and have normal aerial parts but agravitropic roots, implying loss of root cap function. Several cell layers are missing from the transgenic root caps, and the remaining cells are abnormal. Although the radial organization of the roots is normal in toxin-expressing plants, the root tips have fewer cytoplasmically dense cells than do wild-type root tips, suggesting that root meristematic activity is lower in transgenic than in wild-type plants. The roots of transgenic plants have more lateral roots and these are, in turn, more highly branched than those of wild-type plants. Thus, root cap ablation alters root architecture both by inhibiting root meristematic activity and by stimulating lateral root initiation. These observations imply that the root caps contain essential components of the signaling system that determines root architecture.

  7. Using Transcriptomics to Identify Differential Gene Expression in Response to Salinity among Australian Phragmites australis Clones.

    PubMed

    Holmes, Gareth D; Hall, Nathan E; Gendall, Anthony R; Boon, Paul I; James, Elizabeth A

    2016-01-01

    Common Reed (Phragmites australis) is a frequent component of inland and coastal wetlands in temperate zones worldwide. Ongoing environmental changes have resulted in the decline of this species in many areas and invasive expansion in others. In the Gippsland Lakes coastal waterway system in south-eastern Australia, increasing salinity is thought to have contributed to the loss of fringing P. australis reed beds leading to increased shoreline erosion. A major goal of restoration in this waterway is to address the effect of salinity by planting a genetically diverse range of salt-tolerant P. australis plants. This has prompted an interest in examining the variation in salinity tolerance among clones and the underlying basis of this variation. Transcriptomics is an approach for identifying variation in genes and their expression levels associated with the exposure of plants to environmental stressors. In this paper we present initial results of the first comparative culm transcriptome analysis of P. australis clones. After sampling plants from sites of varied surface water salinity across the Gippsland Lakes, replicates from three clones from highly saline sites (>18 g L(-1) TDS) and three from low salinity sites (<6 g L(-1)) were grown in containers irrigated with either fresh (<0.1 g L(-1)) or saline water (16 g L(-1)). An RNA-Seq protocol was used to generate sequence data from culm tissues from the 12 samples allowing an analysis of differential gene expression. Among the key findings, we identified several genes uniquely up- or down-regulated in clones from highly saline sites when irrigated with saline water relative to clones from low salinity sites. These included the higher relative expression levels of genes associated with photosynthesis and lignan biosynthesis indicative of a greater ability of these clones to maintain growth under saline conditions. Combined with growth data from a parallel study, our data suggests local adaptation of certain clones to

  8. Using Transcriptomics to Identify Differential Gene Expression in Response to Salinity among Australian Phragmites australis Clones

    PubMed Central

    Holmes, Gareth D.; Hall, Nathan E.; Gendall, Anthony R.; Boon, Paul I.; James, Elizabeth A.

    2016-01-01

    Common Reed (Phragmites australis) is a frequent component of inland and coastal wetlands in temperate zones worldwide. Ongoing environmental changes have resulted in the decline of this species in many areas and invasive expansion in others. In the Gippsland Lakes coastal waterway system in south-eastern Australia, increasing salinity is thought to have contributed to the loss of fringing P. australis reed beds leading to increased shoreline erosion. A major goal of restoration in this waterway is to address the effect of salinity by planting a genetically diverse range of salt-tolerant P. australis plants. This has prompted an interest in examining the variation in salinity tolerance among clones and the underlying basis of this variation. Transcriptomics is an approach for identifying variation in genes and their expression levels associated with the exposure of plants to environmental stressors. In this paper we present initial results of the first comparative culm transcriptome analysis of P. australis clones. After sampling plants from sites of varied surface water salinity across the Gippsland Lakes, replicates from three clones from highly saline sites (>18 g L-1 TDS) and three from low salinity sites (<6 g L-1) were grown in containers irrigated with either fresh (<0.1 g L-1) or saline water (16 g L-1). An RNA-Seq protocol was used to generate sequence data from culm tissues from the 12 samples allowing an analysis of differential gene expression. Among the key findings, we identified several genes uniquely up- or down-regulated in clones from highly saline sites when irrigated with saline water relative to clones from low salinity sites. These included the higher relative expression levels of genes associated with photosynthesis and lignan biosynthesis indicative of a greater ability of these clones to maintain growth under saline conditions. Combined with growth data from a parallel study, our data suggests local adaptation of certain clones to salinity

  9. In situ experimental decomposition studies in estuaries: A comparison of Phragmites australis and Fucus vesiculosus

    NASA Astrophysics Data System (ADS)

    Lopes, Marta Lobão; Martins, Patrícia; Ricardo, Fernando; Rodrigues, Ana Maria; Quintino, Victor

    2011-05-01

    The decomposition rates of Phragmites australis and Fucus vesiculosus were experimentally determined in an estuarine system using the leaf-bag technique. The study was conducted in fifteen sites arranged in five areas, extending from freshwater, outside the tidal range, to the marine environment, near the mouth of the estuary. The leaf-bags (5 mm mesh), were set up with 3.0 g of dried substrate, submerged in the experimental sites at day 0 and collected at days 3, 7, 15, 30 and 60, to follow biomass loss. The biomass loss through the leaching phase (day 3) was about 16% for Phragmites australis and 33% for Fucus vesiculosus and was independent of salinity for both substrates. The difference in the remaining biomass between the two species increased with time and the decomposition rates differed along the salinity gradient. For F. vesiculosus, the decomposition rate was highest near the mouth of the estuary, corresponding to the preferential distribution area of the algae, and decreased towards freshwater. For Phragmites australis, the fastest decay was observed in the mid estuary, where Phragmites australis occurs naturally, confirming previous studies. The decomposition rates measured at different time intervals (0-15, 0-30 and 0-60 days) were always higher for the algae and decreased with time for both species. These results indicate that the use of decomposition rates as a measure of ecosystem integrity or quality status in transitional waters will not be straightforward and must take into account, among others, the test species, the study area positioning along the estuarine gradient, and the time interval for the calculation of the decomposition rate.

  10. Efficiency of Phragmites australis and Typha latifolia for heavy metal removal from wastewater.

    PubMed

    Kumari, Menka; Tripathi, B D

    2015-02-01

    A cost-effective and promising technology has been demonstrated for the removal of copper (Cu), cadmium (Cd), chromium (Cr), nickel (Ni), iron (Fe), lead (Pb) and zinc (Zn) from urban sewage mixed with industrial effluents within 14 days. With the help of P. australis and T. latifolia grown alone and in combination batch experiments were designed to assess the removal of heavy metals from the wastewater collected from 5 sampling stations. The results revealed that P. australis performed better than T. latifolia for Cu, Cd, Cr, Ni, Fe, Pb and Zn removal, while mixing of the plant species further enhanced the removal of Cu to 78.0±1.2%, Cd to 60.0±1.2%, Cr to 68.1±0.4%, Ni to 73.8±0.6%, Fe to 80.1±0.3%, Pb to 61.0±1.2% and Zn to 61.0±1.2% for wastewater samples from Raj Ghat. Negative correlation coefficients of Cu, Cd, Cr, Ni, Fe, Pb and Zn concentrations in wastewater with the retention time revealed that there was an increase in the heavy metal removal rate with retention time. P. australis showed higher accumulative capacities for Cu, Cd, Cr, Ni and Fe than T. latifolia. P. australis and T. latifolia grown in combination can be used for the removal of Cu, Cd, Cr, Ni, Fe, Pb and Zn from the urban sewage mixed with industrial effluents within 14 days. Copyright © 2014 Elsevier Inc. All rights reserved.

  11. Comparative effects of selenate and selenite on selenium accumulation, morphophysiology, and glutathione synthesis in Ulva australis.

    PubMed

    Schiavon, Michela; Pilon-Smits, Elizabeth A H; Citta, Anna; Folda, Alessandra; Rigobello, Maria Pia; Dalla Vecchia, Francesca

    2016-08-01

    The capacity of Ulva australis Areschoug to tolerate and accumulate selenium (Se) supplied in the form of selenate or selenite was investigated. The macroalga was provided for 3 and 7 days with concentrations of selenate (Na2SeO4) or selenite (Na2SeO3) ranging from 0 to 400 μM. U. australis exhibited the highest ability to accumulate selenium when fed with 100 μM selenate and 200 μM selenite after 7 days, and accumulation values were respectively 25 and 36 ppm Se. At the same concentrations, stimulation of the synthesis of chlorophylls and carotenoids was observed. Elevated doses of selenate or selenite decreased Se accumulation inside algal cells, perhaps through repression of membrane transporters. This effect was more pronounced in thalli cultivated with selenate. There were no morphological and ultrastructural alterations in thalli exposed to Se. However, selenite induced the increase of the oxidized fraction of glutathione (GSSG), perhaps because of its capacity to bind the thiol group of reduced glutathione (GSH). In conclusion, this study highlights the capacity of U. australis to resist to very high concentrations of selenite and selenate, which are normally toxic to other organisms. Also, the lack of bioconcentration in U. australis indicates that this alga does not facilitate delivery of Se in the food chain and remains safe for consumption when it grows in water bodies contaminated with Se. Its potential for the removal of excess Se from water bodies appears limited.

  12. Energy and water balance response of a vegetated wetland to herbicide treatment of invasive Phragmites australis

    NASA Astrophysics Data System (ADS)

    Mykleby, Phillip M.; Lenters, John D.; Cutrell, Gregory J.; Herrman, Kyle S.; Istanbulluoglu, Erkan; Scott, Durelle T.; Twine, Tracy E.; Kucharik, Christopher J.; Awada, Tala; Soylu, Mehmet E.; Dong, Bo

    2016-08-01

    The energy and water balance of a Phragmites australis dominated wetland in south central Nebraska was analyzed to assess consumptive water use and the potential for ;water savings; as a result of vegetation eradication via herbicide treatment. Energy balance measurements were made at the field site for two growing seasons (treated and untreated), including observations of net radiation, heat storage, and sensible heat flux, which was measured using a large-aperture scintillometer. Latent heat flux was calculated as a residual of the energy balance, and comparisons were made between the two growing seasons and with model simulations to examine the relative impacts of vegetation removal and climate variability. Observed ET rates dropped by roughly 32% between the two growing seasons, from a mean of 4.4 ± 0.7 mm day-1 in 2009 (with live vegetation) to 3.0 ± 0.8 mm day-1 in 2010 (with dead P. australis). These results are corroborated by the Agro-IBIS model simulations, and the reduction in ET implies a total ;water savings; of 245 mm over the course of the growing season. The significant decreases in ET were accompanied by a more-than-doubling of sensible heat flux, as well as a ∼60% increase in heat storage due to decreased LAI. Removal of P. australis was also found to cause measurable changes in the local micrometeorology at the wetland. Consistent with the observed increase in sensible heat flux during 2010, warmer, drier, windier conditions were observed in the dead, P. australis section of the wetland, compared to an undisturbed section of live, native vegetation. Modeling results suggest that the elimination of transpiration in 2010 was partially offset by an increase in surface evaporation, thereby reducing the subsequent water savings by roughly 60%. Thus, the impact of vegetation removal depends on the local climate, depth to groundwater, and management decisions related to regrowth of vegetation.

  13. Anatomy of nasal complex in the southern right whale, Eubalaena australis (Cetacea, Mysticeti).

    PubMed

    Buono, Mónica R; Fernández, Marta S; Fordyce, R Ewan; Reidenberg, Joy S

    2015-01-01

    The nasal region of the skull has undergone dramatic changes during the course of cetacean evolution. In particular, mysticetes (baleen whales) conserve the nasal mammalian pattern associated with the secondary function of olfaction, and lack the sound-producing specializations present in odontocetes (toothed whales, dolphins and porpoises). To improve our understanding of the morphology of the nasal region of mysticetes, we investigate the nasal anatomy, osteology and myology of the southern right whale, Eubalaena australis, and make comparisons with other mysticetes. In E. australis external deflection surfaces around the blowholes appear to divert water off the head, and differ in appearance from those observed in balaenopterids, eschrichtiids and cetotherids. In E. australis the blowholes are placed above hypertrophied nasal soft tissues formed by fat and nasal muscles, a pattern also observed in balaenopterids (rorqual mysticetes) and a cetotherid (pygmy right whale, Caperea marginata). Blowhole movements are due to the action of five nasofacial muscles: dilator naris superficialis, dilator naris profundus, depressor alae nasi, constrictor naris, and retractor alae nasi. The dilator naris profundus found in E. australis has not been previously reported in balaenopterids. The other nasofacial muscles have a similar arrangement in balaenopterids, with minor differences. A novel structure, not reported previously in any mysticete, is the presence of a vascular tissue (rete mirabile) covering the lower nasal passage. This vascular tissue could play a role in warming inspired air, or may engorge to accommodate loss of respiratory space volume due to gas compression from increased pressure during diving.

  14. Merluccius tasmanicus Matallanas & Lloris 2006 is a junior synonym of M. australis (Hutton 1872) (Gadiformes: Merluciidae) based on morphological and molecular data.

    PubMed

    Antoni, Mariana Y Deli; Delpiani, Sergio M; Stewart, Andrew L; González-Castro, Mariano; De Astarloa, Juan M Díaz

    2015-05-07

    The high intraspecific variation among and the conservative external morphology of Merluccius spp. have resulted in serious identification difficulties. Four hundred and twenty fresh and preserved specimens of Merluccius were analyzed, including the type series of Merluccius australis, M. tasmanicus and M. hubbsi; specimens of M. hubbsi from Argentina, Brazil and Uruguay, and individuals of M. australis from Argentina and New Zealand were examined. The nomenclatural status of the type specimens of M. australis is discussed and the designation of a lectotype and a paralectotype is proposed. The comparative study of morphology, meristic, traditional and landmark-based morphometry, both external and internal, and through DNA-based Barcoding molecular tools demonstrates that Merluccius tasmanicus is a junior synonym of Merluccius australis. Meristic and morphometric characters of types of M. tasmanicus completely overlap those of M. australis, whereas M. hubbsi show fewer scales along the lateral line, total vertebrae, second dorsal and anal-fin rays. A trend of a longer snout and wider head in M. australis and M. tasmanicus, and larger eyes and longer pelvic fins, in M. hubbsi was observed. While discriminant characters were found in the internal elements (hyomandibula, urohyal and sagitta otolith) between M. hubbsi and M. australis, none were observed between M. australis and those reported for M. tasmanicus. DNA barcoding analyses found no evidence of the existence of other species of Merluccius besides M. hubbsi and M. australis.

  15. Seedling performance of Phragmites australis (Cav.) Trin ex. Steudel in the presence of arbuscular mycorrhizal fungi.

    PubMed

    Wu, J; Ma, F; Wang, L; Yang, J; Huang, X; An, G; Liu, S

    2014-06-01

    Arbuscular mycorrhizal (AM) fungus-plant symbiosis may induce morphological, physiological and/or biochemical changes in the host plants. This study was performed to investigate the effects of AM fungi on Phragmites australis (Cav.) Trin ex. Steudel. Funnelliformis mosseae and Rhizophagus irregularis were chosen as inocula, and detailed attributes related to seedling performance (from seed to five-leaf stage), rhizospheric conditions and micro-organisms were measured and compared. Both of the chosen AM fungal inocula accelerated seed germination and enhanced growth and development, especially in the underground tissues, of seedlings. Specifically, AM fungal colonization improved the photosynthetic efficiency, rhizospheric soil respiration and absorption of certain nutrients in Ph. australis seedlings as well as the rhizospheric microbial metabolic activity and richness in different extents. However, the decreased metabolic diversity suggested that the effects of AM fungi on rhizospheric microbial communities are specific and selective. As a whole, F. mosseae showed greater improvements in the performance of Ph. australis seedlings than R. irregularis. In addition, the potential applications of AM fungi as a 'bio-accelerator', 'biofortifier', and 'bio-enhancer' in phyto-rhizoremediation have been discussed. The main findings could preliminarily reveal the mechanisms behind AM fungus-plant symbioses and could be referred to when optimizing combined phyto-rhizoremediation before practical applications take place. © 2014 The Society for Applied Microbiology.

  16. Intraspecific N and P stoichiometry of Phragmites australis: geographic patterns and variation among climatic regions.

    PubMed

    Hu, Yu-Kun; Zhang, Ya-Lin; Liu, Guo-Fang; Pan, Xu; Yang, Xuejun; Li, Wen-Bing; Dai, Wen-Hong; Tang, Shuang-Li; Xiao, Tao; Chen, Ling-Yun; Xiong, Wei; Song, Yao-Bin; Dong, Ming

    2017-02-24

    Geographic patterns in leaf stoichiometry reflect plant adaptations to environments. Leaf stoichiometry variations along environmental gradients have been extensively studied among terrestrial plants, but little has been known about intraspecific leaf stoichiometry, especially for wetland plants. Here we analyzed the dataset of leaf N and P of a cosmopolitan wetland species, Phragmites australis, and environmental (geographic, climate and soil) variables from literature and field investigation in natural wetlands distributed in three climatic regions (subtropical, temperate and highland) across China. We found no clear geographic patterns in leaf nutrients of P. australis across China, except for leaf N:P ratio increasing with altitude. Leaf N and N:P decreased with mean annual temperature (MAT), and leaf N and P were closely related to soil pH, C:N ratio and available P. Redundancy analysis showed that climate and soil variables explained 62.1% of total variation in leaf N, P and N:P. Furthermore, leaf N in temperate region and leaf P in subtropical region increased with soil available P, while leaf N:P in subtropical region decreased with soil pH. These patterns in P. australis different from terrestrial plants might imply that changes in climate and soil properties can exert divergent effects on wetland and terrestrial ecosystems.

  17. Effects of organochlorines on microbial diversity and community structure in Phragmites australis rhizosphere.

    PubMed

    San Miguel, Angélique; Roy, Julien; Gury, Jérôme; Monier, Armelle; Coissac, Eric; Ravanel, Patrick; Geremia, Roberto A; Raveton, Muriel

    2014-05-01

    This study investigated the impacts of an organochlorine (OC, γ-hexachlorocyclohexane and chlorobenzenes) mixture on microbial communities associated to Phragmites australis rhizosphere. Seventy-eight distinct colony morphotypes were isolated, cultivated and analysed by 16S rDNA sequence analysis. Toxicity tests confirmed sensitivity (e.g. Hevizibacter, Acidovorax) or tolerance (e.g. Bacillus, Aeromonas, Pseudomonas, Sphingomonas) of isolates. Rhizosphere analysis by pyrosequencing showed the microbial adaptation induced by OC exposure. Among the most abundant molecular operational taxonomic units, 80 % appeared to be tolerant (55 % opportunist, 25 % unaffected) and 20 % sensitive. P. australis rhizosphere exposed to OCs was dominated by phylotypes related to α-, β- and γ-Proteobacteria. Specific genera were identified which were previously described as chlorinated organic pollutant degraders: Sphingomonas sp., Pseudomonas sp., Devosia sp. and Sphingobium sp. P. australis could be suitable plants to maintain their rhizosphere active microbial population which can tolerate OCs and potentially improve the OC remediation process in part by biodegradation.

  18. Role of Phragmites australis (common reed) for heavy metals phytoremediation of estuarine sediments.

    PubMed

    Cicero-Fernández, Diego; Peña-Fernández, Manuel; Expósito-Camargo, Jose A; Antizar-Ladislao, Blanca

    2016-01-01

    The ability of Phragmites australis to take up heavy metals (Co, Ni, Mo, Cd, Pb, Cr, Cu, Fe, Mn, Zn, and Hg) and other trace elements (As, Se, Ba), from estuarine sediments was investigated using a pilot plant experimental approach. Bioaccumulation (BCF) and translocation factors (TF) were calculated in vegetative and senescence periods for two populations of P. australis, from contaminated (MIC) and non-contaminated (GAL) estuarine sediments, respectively, both growing in estuarine contaminated sediment (RIA) from ría del Carmen y Boo, Santander Bay, Spain. The highest BCF values were obtained for Ni (0.43), Ba (0.43) Mo (0.36), Cr (0.35), and Cd (0.31) for plants collected from site GAL following the senescence period. The highest BCF values recorded for plants collected from MIC following the senescence period were for Mo (0.22) and Cu (0.22). Following senescence, plants collected from GAL and MIC presented TF>1 for Ni, Mo, Se, and Zn, and in addition plants collected from MIC presented TF>1 for Ba, Cr, and Mn. A substantial increase of Micedo's rhizosphere, six times higher than Galizano's rhizosphere, suggested adaptation to contaminated sediment. The evaluated communities of P. australis demonstrated their suitability for phytoremediation of heavy metals contaminated estuarine sediments.

  19. Intraspecific N and P stoichiometry of Phragmites australis: geographic patterns and variation among climatic regions

    PubMed Central

    Hu, Yu-Kun; Zhang, Ya-Lin; Liu, Guo-Fang; Pan, Xu; Yang, Xuejun; Li, Wen-Bing; Dai, Wen-Hong; Tang, Shuang-Li; Xiao, Tao; Chen, Ling-Yun; Xiong, Wei; Song, Yao-Bin; Dong, Ming

    2017-01-01

    Geographic patterns in leaf stoichiometry reflect plant adaptations to environments. Leaf stoichiometry variations along environmental gradients have been extensively studied among terrestrial plants, but little has been known about intraspecific leaf stoichiometry, especially for wetland plants. Here we analyzed the dataset of leaf N and P of a cosmopolitan wetland species, Phragmites australis, and environmental (geographic, climate and soil) variables from literature and field investigation in natural wetlands distributed in three climatic regions (subtropical, temperate and highland) across China. We found no clear geographic patterns in leaf nutrients of P. australis across China, except for leaf N:P ratio increasing with altitude. Leaf N and N:P decreased with mean annual temperature (MAT), and leaf N and P were closely related to soil pH, C:N ratio and available P. Redundancy analysis showed that climate and soil variables explained 62.1% of total variation in leaf N, P and N:P. Furthermore, leaf N in temperate region and leaf P in subtropical region increased with soil available P, while leaf N:P in subtropical region decreased with soil pH. These patterns in P. australis different from terrestrial plants might imply that changes in climate and soil properties can exert divergent effects on wetland and terrestrial ecosystems. PMID:28233774

  20. Structure and biomechanics of culms of Phragmites australis used for reeds of Japanese wind instrument "hichiriki".

    PubMed

    Kawasaki, Masahiro; Nobuchi, Tadashi; Nakafushi, Yuta; Nose, Masateru; Shiojiri, Makoto

    2015-04-01

    Hichiriki is a traditional Japanese double-reed wind instrument used in Japanese ancient imperial court music, gagaku, which has been performed since the 7th century. The best reeds for hichiriki have been made of culms or stems of Phragmites australis (P. australis) that are harvested from only a limited reed bed at Udono near Kyoto. The aim of this study is to elucidate why the stems from Udono are the best materials for hichiriki reeds. Plant anatomy was examined for choice stems of P. australis grown in different reed beds in Japan as well as morphology, and the local indentation hardness and Young's modulus of tissues on the cross-sections of some representatives of hichiriki reeds were measured. It is concluded that the good stems for hichiriki reeds have an outer diameter of about 11 mm, a wall thickness of about 1 mm and comparatively homogeneous structure where harder materials, such as epidermis, hypodermis, sclerenchymatous cells, and vascular bundle sheaths with hard walls, are orderly deployed with softer materials such as parenchyma cells and vascular bundles. This structure has smaller differences of hardness and Young's modulus between the hard and soft materials in the reed, providing the best music performance. © 2015 Wiley Periodicals, Inc.

  1. Freshwater shrimp (Palaemonetes australis) as a potential bioindicator of crustacean health.

    PubMed

    Webb, Diane

    2011-07-01

    Palaemonetes australis is a euryhaline shrimp found in southwestern Australian estuaries. To determine if P. australis is a suitable bioindicator species for monitoring the health of estuarine biota, they were exposed to measured concentrations of the polycyclic aromatic hydrocarbon, benzo[a]pyrene (B[a]P) at 0.01, 0.1, or 1 ppm for 14 days under laboratory conditions. At the end of exposure the shrimp were sacrificed for biomarker [ethoxycoumarin O-deethylase (ECOD), 8-oxo-dG concentration, and sorbitol dehydrogenase (SDH) activity] analyses. Gender did not appear to influence biomarker responses of the shrimp in this study. ECOD activity was induced in the treatment groups in a linear fashion from three (0.01 ppm) times to 12 (1 ppm) times the negative controls. 8-oxo-dG concentration was reduced three times in treatment groups below the controls suggesting impaired DNA repair pathways. There was no increase in SDH, signifying hepatopancreatic cell damage had not occurred in any treatment group. The response of P. australis to B[a]P exposure indicates that this crustacean is suitable bioindicator species for both laboratory studies and field monitoring. A combination of ECOD and SDH activities and 8-oxo-dG concentration represent a suitable suite of biomarkers for environmental monitoring of the sublethal effects of organic pollution to crustaceans from an estuarine environment.

  2. Composition, uniqueness and variability of the epiphytic bacterial community of the green alga Ulva australis

    PubMed Central

    Burke, Catherine; Thomas, Torsten; Lewis, Matt; Steinberg, Peter; Kjelleberg, Staffan

    2011-01-01

    Green Ulvacean marine macroalgae are distributed worldwide in coastal tidal and subtidal ecosystems. As for many living surfaces in the marine environment, little is known concerning the epiphytic bacterial biofilm communities that inhabit algal surfaces. This study reports on the largest published libraries of near full-length 16S rRNA genes from a marine algal surface (5293 sequences from six samples) allowing for an in-depth assessment of the diversity and phylogenetic profile of the bacterial community on a green Ulvacean alga. Large 16S rRNA gene libraries of surrounding seawater were also used to determine the uniqueness of this bacterial community. The surface of Ulva australis is dominated by sequences of Alphaproteobacteria and the Bacteroidetes, especially within the Rhodobacteriaceae, Sphingomonadaceae, Flavobacteriaceae and Sapropiraceae families. Seawater libraries were also dominated by Alphaproteobacteria and Bacteroidetes sequences, but were shown to be clearly distinct from U. australis libraries through the clustering of sequences into operational taxonomic units and Bray–Curtis similarity analysis. Almost no similarity was observed between these two environments at the species level, and only minor similarity was observed at levels of sequence clustering representing clades of bacteria within family and genus taxonomic groups. Variability between libraries of U. australis was relatively high, and a consistent sub-population of bacterial species was not detected. The competitive lottery model, originally derived to explain diversity in coral reef fishes, may explain the pattern of colonization of this algal surface. PMID:21048801

  3. Hepatoprotective and antioxidant activities of the aqueous extract from the rhizome of Phragmites australis.

    PubMed

    Chen, Song; Ju, Minli; Luo, Yin; Chen, Zhongjian; Zhao, Changpo; Zhou, Yang; Fu, Jie

    2013-01-01

    The rhizome of Phragmites australis has long been used for the treatment of hepatitis in traditional Chinese medicine. In this study, the hepatoprotective and antioxidant activities of an aqueous extract from the rhizome of P. australis (AE-PA) were evaluated. The acute toxicity test in mice showed that AE-PA was nontoxic since a dose of 2000 mg/kg body weight (b.w.) did not cause toxic symptoms or mortality. The prolongation of hexobarbital-induced sleeping time by carbon tetrachloride (CCl4) administration to mice was significantly reduced after pretreatment with AE-PA at 500 mg/kg b.w., proving the protective effect of the extract on microsomal drug-metabolizing enzyme. The oral administration of AE-PA to rats for 5 days before CCl4 intoxication caused a significant decrease in the CCl4-induced elevation of hepatic enzymes activities in serum, such as aspartate aminotransferase, alanine aminotransferase, and lactic acid dehydrogenase. This suggested that AE-PA had good hepatoprotective activity against CCl4-induced liver injury, which was confirmed by pathomorphological examination of the liver. Through evaluation of hydroxyl radical and superoxide anion radical scavenging activities, respectively, it was demonstrated that AE-PA had good antioxidant activity, which possibly contributed to its hepatoprotective activity. More research is needed to study the bio-active compounds in P. australis and to identify the potential hepatoprotective and antioxidant agents.

  4. [Methane emission flux of Zhalong Phragmites australis wetlands in growth season].

    PubMed

    Huang, Pu-Yi; Yu, Hong-Xian; Chai, Long-Hui; Chai, Fang-Ying; Zhang, Wan-Feng

    2011-05-01

    Static chamber/gas chromatogram method was adopted to measure the methane emission flux of Zhalong Phragmites australis wetlands with different water levels in a growth season from May to October, 2009, aimed to understand the methane emission pattern in natural freshwater P. australis wetland in frigid region. During the observation period, the average methane emission flux of test wetlands ranged from -21.18 to 46.15 mg x m(-2) x h(-1), with a mean of 7.67 mg x m(-2) x h(-1). In deep water zone (average water level 100 cm) and shallow water zone (average water level 25 cm), the average methane emission flux was 5.81 and 9.52 mg x m(-2) x h(-1), with a peak in August and July, respectively, and the minimum in October. In summer (from June to July), the methane emission flux in deep water zone was significantly lower than that in shallow water zone; while in spring (May) and autumn (from August to October), a reversed trend was observed. The methane emission flux had a seasonal pattern of summer > autumn > spring, and a diurnal pattern of being the highest at 12:00 and 14:00 and the lowest at 0:00. Temperature and water level were the major factors affecting the methane emission flux in freshwater P. australis wetlands in frigid region.

  5. Bioavailability of adsorbed and coprecipitated Cu, Ni, Pb, and Cd on iron and iron/aluminum hydroxide to Phragmites australis.

    PubMed

    Wang, He; Jia, Yongfeng

    2017-01-01

    The bioavailability of heavy metals strongly depends on their speciation in the environment. Adsorption (ADS) and coprecipitation (CPT) on amorphous metal hydroxides are important processes, controlling the fates of heavy metals in an aqueous environment. This work studied the bioavailability of Cu, Cd, Ni, and Pb adsorbed on and/or coprecipitated with amorphous iron and iron/aluminum mixed hydroxides to the wetland plant Phragmites australis. After a 13-day treatment, there was an apparent uptake of the heavy metals by the plant, and the amount of metal bioaccumulation was measurably different for different association forms (ADS vs. CPT). The bioaccumulation of Cd associated with Fe0.5Al0.5(OH)3 was greater than that with Fe(OH)3; the adsorbed metals were found to be more bioavailable than the coprecipitated forms for most of the treatments while the aging treatment significantly reduced the bioaccumulation of ADS metals. In the single metal treatment, root metal concentrations in the Fe(OH)3 ADS system followed the order Ni (68 mg kg(-1)) > Cu (32 mg kg(-1)) > Cd (28 mg kg(-1)) > Pb (9 mg kg(-1)), while the CPT system followed the order of Cu (30 mg kg(-1)) > Ni (22 mg kg(-1)) > Pb (9 mg kg(-1)) > Cd (7 mg kg(-1)). The order of metal accumulation in a combined metal treatment was similar to that for single metal treatments, but observed Ni concentration declines by 22 and 71 % and Cu and Cd concentrations increase by 30 and 50 % (for CPT and ADS treatments, respectively), while Pb concentrations increased by 30~50 % in both of them. When treated with low-molecular-weight organic acids (LMWOAs), metal desorption, indicative of metal oxide bonding strength and metal bioavailability, was consistent with metal accumulation in the plant.

  6. Effects of oil on internal gas transport, radial oxygen loss, gas films and bud growth in Phragmites australis

    PubMed Central

    Armstrong, Jean; Keep, Rory; Armstrong, William

    2009-01-01

    Background and Aims Oil pollution of wetlands is a world-wide problem but, to date, research has concentrated on its influences on salt marsh rather than freshwater plant communities. The effects of water-borne light oils (liquid paraffin and diesel) were investigated on the fresh/brackish wetland species Phragmites australis in terms of routes of oil infiltration, internal gas transport, radial O2 loss (ROL), underwater gas films and bud growth. Methods Pressure flow resistances of pith cavities of nodes and aerenchyma of leaf sheaths, with or without previous exposure to oil, were recorded from flow rates under applied pressure. Convective flows were measured from living excised culms with oiled and non-oiled nodes and leaf sheaths. The effect of oil around culm basal nodes on ROL from rhizome and root apices was measured polarographically. Surface gas films on submerged shoots with and without oil treatment were recorded photographically. Growth and emergence of buds through water with and without an oil film were measured. Key Results Internodes are virtually impermeable, but nodes of senesced and living culms are permeable to oils which can block pith cavity diaphragms, preventing flows at applied pressures of 1 kPa, natural convective transport to the rhizome, and greatly decreasing ROL to phyllospheres and rhizospheres. Oil infiltrating or covering living leaf sheaths prevents humidity-induced convection. Oil displaces surface gas films from laminae and leaf sheaths. Buds emerge only a few centimetres through oil and die. Conclusions Oil infiltrates the gas space system via nodal and leaf sheath stomata, reducing O2 diffusion and convective flows into the rhizome system and decreasing oxygenation of phyllospheres and rhizospheres; underwater gas exchange via gas films will be impeded. Plants can be weakened by oil-induced failure of emerging buds. Plants will be most at risk during the growing season. PMID:18996951

  7. Phenotypic traits of Phragmites australis clones are not related to ploidy level and distribution range

    PubMed Central

    Achenbach, Luciana; Lambertini, Carla; Brix, Hans

    2012-01-01

    Background and aims Phragmites australis is a wetland grass with high genetic variability, augmented by its cosmopolitan distribution, clonal growth form and large variation in chromosome numbers. Different ploidy levels and ecotypes differ in morphology and ecophysiological traits, and may possess different levels of phenotypic variation. The aim of this study was to quantify the natural variation in ecophysiological characteristics of P. australis, and to explore whether differences in ecophysiological traits can be related to ploidy levels or to the geographic origin of the clones. Methodology Fifteen clones of P. australis from Europe and Asia/Australia, representing five ploidy levels (4x, 6x, 8x, 10x and 12x), were grown in a common garden design for 119 days. Plant growth and light-saturated rate of photosynthesis (Pmax), stomatal conductance (gs), water use efficiency (WUE) and concentrations of photosynthetic pigments and mineral ions in the leaves were measured. Principal results The growth of the plants and most ecophysiological parameters differed significantly between clones. The mean maximum shoot height varied from 0.9 to 1.86 m, Pmax from 9.7 to 27 µmol m−2 s−1, gs from 0.22 to 1.41 mol m−2 s−1 and WUE from 13 to 47 µmol mol−1. The concentrations of chlorophylls did not vary significantly between clones, but the chlorophyll a/b ratio and the concentrations of total carotenoids did. The observed differences were not explained either by the ploidy level per se or by the geographic origin or phylogenetic relationships of the clones. Conclusions Phylogeographic relationships in P. australis on a global scale do not mirror the environment where the adaptations have evolved, and high phenotypic variation among and within clones complicates comparative studies. Future studies aimed at explaining differences in plant behaviour between P. australis populations should be careful in the selection of target genotypes and/or populations, and should

  8. Phenotypic traits of Phragmites australis clones are not related to ploidy level and distribution range.

    PubMed

    Achenbach, Luciana; Lambertini, Carla; Brix, Hans

    2012-01-01

    Phragmites australis is a wetland grass with high genetic variability, augmented by its cosmopolitan distribution, clonal growth form and large variation in chromosome numbers. Different ploidy levels and ecotypes differ in morphology and ecophysiological traits, and may possess different levels of phenotypic variation. The aim of this study was to quantify the natural variation in ecophysiological characteristics of P. australis, and to explore whether differences in ecophysiological traits can be related to ploidy levels or to the geographic origin of the clones. Fifteen clones of P. australis from Europe and Asia/Australia, representing five ploidy levels (4x, 6x, 8x, 10x and 12x), were grown in a common garden design for 119 days. Plant growth and light-saturated rate of photosynthesis (P(max)), stomatal conductance (g(s)), water use efficiency (WUE) and concentrations of photosynthetic pigments and mineral ions in the leaves were measured. The growth of the plants and most ecophysiological parameters differed significantly between clones. The mean maximum shoot height varied from 0.9 to 1.86 m, P(max) from 9.7 to 27 µmol m(-2) s(-1), g(s) from 0.22 to 1.41 mol m(-2) s(-1) and WUE from 13 to 47 µmol mol(-1). The concentrations of chlorophylls did not vary significantly between clones, but the chlorophyll a/b ratio and the concentrations of total carotenoids did. The observed differences were not explained either by the ploidy level per se or by the geographic origin or phylogenetic relationships of the clones. Phylogeographic relationships in P. australis on a global scale do not mirror the environment where the adaptations have evolved, and high phenotypic variation among and within clones complicates comparative studies. Future studies aimed at explaining differences in plant behaviour between P. australis populations should be careful in the selection of target genotypes and/or populations, and should avoid generalizing their findings beyond the genotypes

  9. Cytokinin, auxin and physiological polarity in the aquatic carnivorous plants Aldrovanda vesiculosa and Utricularia australis.

    PubMed

    Šimura, Jan; Spíchal, Lukáš; Adamec, Lubomír; Pěnčík, Aleš; Rolčík, Jakub; Novák, Ondřej; Strnad, Miroslav

    2016-05-01

    The typical rootless linear shoots of aquatic carnivorous plants exhibit clear, steep polarity associated with very rapid apical shoot growth. The aim of this study was to determine how auxin and cytokinin contents are related to polarity and shoot growth in such plants. The main auxin and cytokinin metabolites in separated shoot segments and turions of two carnivorous plants, Aldrovanda vesiculosa and Utricularia australis, were analysed using ultra-high-performance liquid chromatography coupled with triple quad mass spectrometry. In both species, only isoprenoid cytokinins were identified. Zeatin cytokinins predominated in the apical parts, with their concentrations decreasing basipetally, and the trans isomer predominated in A. vesiculosa whereas the cis form was more abundant in U australis. Isopentenyladenine-type cytokinins, in contrast, increased basipetally. Conjugated cytokinin metabolites, the O-glucosides, were present at high concentrations in A. vesiculosa but only in minute amounts in U. australis. N(9)-glucoside forms were detected only in U. australis, with isopentenyladenine-9-glucoside (iP9G) being most abundant. In addition to free indole-3-acetic acid (IAA), indole-3-acetamide (IAM), IAA-aspartate (IAAsp), IAA-glutamate (IAGlu) and IAA-glycine (IAGly) conjugates were identified. Both species show common trends in auxin and cytokinin levels, the apical localization of the cytokinin biosynthesis and basipetal change in the ratio of active cytokinins to auxin, in favour of auxin. However, our detailed study of cytokinin metabolic profiles also revealed that both species developed different regulatory mechanisms of active cytokinin content; on the level of their degradation, in U. australis, or in the biosynthesis itself, in the case of A. vesiculosa Results indicate that the rapid turnover of these signalling molecules along the shoots is essential for maintaining the dynamic balance between the rapid polar growth and development of the apical

  10. Regulation of protein secretion by ... protein secretion?

    PubMed

    Atmakuri, Krishnamohan; Fortune, Sarah M

    2008-09-11

    Mycobacterium tuberculosis (Mtb) requires an alternative protein secretion system, ESX1, for virulence. Recently, Raghavan et al. (2008) reported a new regulatory circuit that may explain how ESX1 activity is controlled during infection. Mtb appears to regulate ESX1 by modulating transcription of associated genes rather than structural components of the secretion system itself.

  11. Root growth

    Treesearch

    Terrell T. Baker; William H. Conner; B. Graeme Lockaby; Marianne K. Burke; John A. Stanturf

    2000-01-01

    While vegetation dynamics of forested floodplains have received considerable attention (Megonigal and others 1997, Mitch and Gosselink 1993), the highly dynamic fine root component of these ecosystems has been primarily ignored. Characterizing fine root growth is a challenging endeavor in any system, but the difficulties are particularly evident in forested floodplains...

  12. Role of plants in nitrogen and sulfur transformations in floating hydroponic root mats: A comparison of two helophytes.

    PubMed

    Saad, Rania A B; Kuschk, Peter; Wiessner, Arndt; Kappelmeyer, Uwe; Müller, Jochen A; Köser, Heinz

    2016-10-01

    Knowledge about the roles helophytes play in constructed wetlands (CWs) is limited, especially regarding their provision of organic rhizodeposits. Here, transformations of inorganic nitrogen and sulfur were monitored in a CW variety, floating hydroponic root mat (FHRM), treating synthetic wastewater containing low concentration of organic carbon. Two helophytes, Phragmites australis and Juncus effusus, were compared in duplicates. Striking differences were found between the FHRM of the two helophytes. Whereas ammonium was removed in all FHRMs to below detection level, total nitrogen of 1.15 ± 0.4 g m(-2) d(-1) was removed completely only in P. australis systems. The mats with J. effusus displayed effective nitrification but incomplete denitrification as 77% of the removed ammonium-nitrogen accumulated as nitrate. Furthermore, the P. australis treatment units showed on average 3 times higher sulfate-S removal rates (1.1 ± 0.45 g m(-2) d(-1)) than the systems planted with J. effusus (0.37 ± 0.29 g m(-2) d(-1)). Since the influent organic carbon was below the stoichiometric requirement for the observed N and S transformation processes, helophytes' organic rhizodeposits apparently contributed to these transformations, while P. australis provided about 6 times higher bioavailable organic rhizodeposits than J. effusus.

  13. Comparative performance of trace element bioaccumulation and biomonitoring in the plant species Typha domingensis, Phragmites australis and Arundo donax.

    PubMed

    Bonanno, Giuseppe

    2013-11-01

    Toxic levels of trace elements in the environment have been reported worldwide over the last few decades, and their increasing concentrations are of the utmost concern because of the adverse effects on human life and ecosystems. Several plant species are able to accumulate trace elements, and may be used for monitoring and remediation of polluted sites. This study compared the capacity of trace element bioaccumulation in three wetland plants distributed worldwide: Typha domingensis, Phragmites australis and Arundo donax. The aims were to identify which species show better potential for removal and monitoring of these elements: Al, As, Cd, Cr, Cu, Hg, Mn, Ni, Pb, Zn. Results showed that all species may be used as biomonitors of trace element contamination in sediment, but only P. australis and A. donax showed also a correlation with water. Overall, T. domingensis and P. australis showed a greater capacity of bioaccumulation as well as a greater efficiency of element removal than A. donax. In particular, T. domingensis and P. australis may be used for Hg phytostabilization, the former acted also as a hyperaccumulator for Hg phytoextraction and as a promising species for As phytostabilization. In contaminated wetlands, the presence of T. domingensis and P. australis may increase the general retention of trace elements, thus, their introduction is recommended for possible actions of phytoremediation and biomonitoring. © 2013 Elsevier Inc. All rights reserved.

  14. [Biomass and carbon storage of Phragmites australis and Spartina alterniflora in Jiuduan Shoal Wetland of Yangtze Estuary, East China].

    PubMed

    Liu, Yu; Li, Xiu-zhen; Yan, Zhong-zheng; Chen, Xiu-zhi; He, Yan-long; Guo, Wen-yong; Sun, Pei-ying

    2013-08-01

    By the methods of field survey and laboratory analysis, an investigation was conducted on the seasonal dynamics of biomass and carbon storage of Phragmites australis and Spartina alterniflora dominated vegetation belts in the Jiuduan Shoal Wetland of Yangtze Estuary, East China in 2010-2012. The organic carbon storage of the biomass (including aboveground part, underground part, and standing litter) of the two plants was the highest in autumn and the lowest in spring. The average carbon storage of the biomass of S. alterniflora per unit area (445.81 g x m(-2)) was much higher than that of P. australis (285.52 g x m(-2)), and the average carbon storage of the standing litter of S. alterniflora (315.28 g x m(-2)) was also higher than that of P. australia (203.15 g x m(-2)). However, the organic carbon storage in the surface soil (0-30 cm) under P. australis community (1048.62 g x m(-2)) was almost as twice times as that under S. alterniflora community (583.33 g x m(-2)). Overall, the carbon accumulation ability of P. australis community (3212.96 g x m(-2)) was stronger than that of the S. alterniflora community (2730.42 g x m(-2)). Therefore, it is of significance to protect the P. australis community in terms of carbon sequestration at the salt marsh.

  15. Enzyme and root activities in surface-flow constructed wetlands.

    PubMed

    Kong, Ling; Wang, Yu-Bin; Zhao, Li-Na; Chen, Zhang-He

    2009-07-01

    Sixteen small-scale wetlands planted with four plant species were constructed for domestic wastewater purification. The objective of this study was to determine the correlations between contaminant removal and soil enzyme activity, root activity, and growth in the constructed wetlands. The results indicated that correlations between contaminant removal efficiency and enzyme activity varied depending on the contaminants. The removal efficiency of NH4+ was significantly correlated with both urease and protease activity in all wetlands, and the removal of total phosphorus and soluble reactive phosphorus was significantly correlated with phosphatase activity in most wetlands, while the removal of total nitrogen, NO3(-) , and chemical oxygen demand (COD) was significantly correlated with enzyme activity only in a few instances. Correlations between soil enzyme activity and root activity varied among species. Activities of all enzymes were significantly correlated with root activity in Vetiveria zizanioides and Phragmites australis wetlands, but not in Hymenocallis littoralis wetlands. Significant correlations between enzyme activity and root biomass and between enzyme activity and root growth were found mainly in Cyperus flabelliformis wetlands. Root activity was significantly correlated with removal efficiencies of all contaminants except NO3(-) and COD in V. zizanioides wetlands. Enzyme activities and root activity showed single-peak seasonal patterns. Activities of phosphatase, urease, and cellulase were significantly higher in the top layer of the substrate than in the deeper layers, and there were generally no significant differences between the deeper layers (deeper than 15 cm).

  16. Peptides and receptors controlling root development.

    PubMed

    Stahl, Yvonne; Simon, Rüdiger

    2012-06-05

    The growth of a plant's root system depends on the continued activity of the root meristem, and the generation of new meristems when lateral roots are initiated. Plants have developed intricate signalling systems that employ secreted peptides and plasma membrane-localized receptor kinases for short- and long-range communication. Studies on growth of the vascular system, the generation of lateral roots, the control of cell differentiation in the root meristem and the interaction with invading pathogens or symbionts has unravelled a network of peptides and receptor systems with occasionally shared functions. A common theme is the employment of conserved modules, consisting of a short signalling peptide, a receptor-like kinase and a target transcription factor, that control the fate and proliferation of stem cells during root development. This review intends to give an overview of the recent advances in receptor and peptide ligand-mediated signalling involved in root development.

  17. Roots and Root Function: Introduction

    USDA-ARS?s Scientific Manuscript database

    A number of current issues related to water management, ecohydrology, and climate change are giving impetus to new research aimed at understanding roots and their functioning. Current areas of research include: use of advanced imaging technologies such as Magnetic Resonance Imaging to observe roots...

  18. Clemacotyle australis (Monogenea: Monocotylidae) from the white-spotted eagle ray Aetobatus narinari (Rajiformes: Myliobatididae) on the Great Barrier Reef: redescription, emended generic diagnosis, and oncomiracidium.

    PubMed

    Beverley-Burton, M; Whittington, I D

    1995-08-01

    Clemacotyle australis Young, 1967 from the branchial cavity of the type host, Aetobatis narinari, is redescribed based on new material from the type locality, Heron Island, Queensland, Australia. The generic diagnosis is emended to include details of the male copulatory complex. Oncomiracidia, hatched from eggs collected from C. australis, are noteworthy in the presence of diffuse pigment throughout the body and haptor.

  19. Archaeal rhizosphere communities differ between the native and invasive lines of the wetland plant phragmites australis (common reed) in a Chesapeake Bay subestuary

    USDA-ARS?s Scientific Manuscript database

    Phragmites australis, a common wetland plant species worldwide, is best known in North America as persistent invasive species. Only in recent decades was a native line, Phragmites australis subsp. americanus, confirmed in North American wetlands. This study investigated whether the two lines suppo...

  20. Characterization of Nops, nodulation outer proteins, secreted via the type III secretion system of NGR234.

    PubMed

    Marie, Corinne; Deakin, William J; Viprey, Virginie; Kopciñska, Joanna; Golinowski, Wladyslaw; Krishnan, Hari B; Perret, Xavier; Broughton, William J

    2003-09-01

    The nitrogen-fixing symbiotic bacterium Rhizobium species NGR234 secretes, via a type III secretion system (TTSS), proteins called Nops (nodulation outer proteins). Abolition of TTSS-dependent protein secretion has either no effect or leads to a change in the number of nodules on selected plants. More dramatically, Nops impair nodule development on Crotalaria juncea roots, resulting in the formation of nonfixing pseudonodules. A double mutation of nopX and nopL, which code for two previously identified secreted proteins, leads to a phenotype on Pachyrhizus tuberosus differing from that of a mutant in which the TTSS is not functional. Use of antibodies and a modification of the purification protocol revealed that NGR234 secretes additional proteins in a TTSS-dependent manner. One of them was identified as NopA, a small 7-kDa protein. Single mutations in nopX and nopL were also generated to assess the involvement of each Nop in protein secretion and nodule formation. Mutation of nopX had little effect on NopL and NopA secretion but greatly affected the interaction of NGR234 with many plant hosts tested. NopL was not necessary for the secretion of any Nops but was required for efficient nodulation of some plant species. NopL may thus act as an effector protein whose recognition is dependent upon the hosts' genetic background.

  1. Differentiation of Cuscuta chinensis and Cuscuta australis by HPLC-DAD-MS analysis and HPLC-UV quantitation.

    PubMed

    He, Xianghui; Yang, Wenzhi; Ye, Min; Wang, Qing; Guo, Dean

    2011-11-01

    Cuscuta chinensis and Cuscuta australis, the two botanical sources of the Chinese herbal medicine Tu-Si-Zi, were distinguished from each other based on qualitative and quantitative chemical analysis. By HPLC‑DAD‑MS, a total of 36 compounds were characterized from these two Cuscuta species, including 14 flavonoids, 17 quinic acid derivatives, and 5 lignans. In addition, HPLC‑UV was applied to determine seven major compounds (6 flavonoids plus chlorogenic acid) in 27 batches of Tu-Si-Zi. The results revealed that the amounts of the three classes of compounds varied significantly between the species. C. australis contained more flavonoids but less quinic acid derivatives and lignans than C. chinensis. Particularly, the amounts of kaempferol and astragalin in C. australis were remarkably higher than in C. chinensis. This finding could be valuable for the quality control of Tu-Si-Zi.

  2. Isolation, cloning, and characterization of a partial novel aro A gene in common reed (Phragmites australis).

    PubMed

    Taravat, Elham; Zebarjadi, Alireza; Kahrizi, Danial; Yari, Kheirollah

    2015-05-01

    Among the essential amino acids, phenylalanine, tryptophan, and tyrosine are aromatic amino acids which are synthesized by the shikimate pathway in plants and bacteria. Herbicide glyphosate can inhibit the biosynthesis of these amino acids. So, identification of the gene tolerant to glyphosate is very important. It has been shown that the common reed or Phragmites australis Cav. (Poaceae) is relatively tolerant to glyphosate. The aim of the current research is identification, cloning, sequencing, and registering of partial aro A gene of the common reed P. australis. The partial aro A gene of common reed (P. australis) was cloned in Escherichia coli and the amino acid sequence was identified/determined for the first time. This is the first report for isolation, cloning, and sequencing of a part of aro A gene from the common reed. A 670 bp fragment including two introns (86 bp and 289 bp) was obtained. The open reading frame (ORF) region in part of gene was encoded for 98 amino acids. Alignment showed high similarity among this region with Zea mays (L.) (Poaceae) (94.6%), Eleusine indica L. Gaertn (Poaceae) (94.2%), and Zoysia japonica Steud. (Poaceae) (94.2%). The alignment of amino acid sequence of the investigated part of the gene showed a homology with aro A from several other plants. This conserved region forms the enzyme active site. The alignment results of nucleotide and amino acid residues with related sequences showed that there are some differences among them. The relative glyphosate tolerance in the common reed may be related to these differences.

  3. Phytoextraction of chloride from a cement kiln dust (CKD) contaminated landfill with Phragmites australis.

    PubMed

    McSorley, Kaitlin; Rutter, Allison; Cumming, Robert; Zeeb, Barbara A

    2016-05-01

    Cement kiln dust (CKD) is a globally produced by-product from cement manufacturing that is stockpiled or landfilled. Elevated concentrations of chloride pose toxic threats to plants and aquatic communities, as the anion is highly mobile in water and can leach into surrounding water sources. Re-vegetation and in situ phytoextraction of chloride from a CKD landfill in Bath, ON, Canada, was investigated with the resident invasive species Phragmites australis (haplotype M). Existing stands of P. australis were transplanted from the perimeter of the site into the highest areas of contamination (5.9×10(3)μg/g). Accumulation in the shoots of P. australis was quantified over one growing season by collecting samples from the site on a bi-weekly basis and analyzing for chloride. Concentrations decreased significantly from early May (24±2.2×10(3)μg/g) until mid-June (15±2.5×10(3)μg/g), and then remained stable from June to August. Shoot chloride accumulation was not significantly affected by water level fluctuations at the site, however elevated potassium concentrations in the soil may have contributed to uptake. Based on shoot chloride accumulation and total biomass, it was determined that phytoextraction from the CKD landfill can remove 65±4kg/km(2) of chloride per season. Based on this extraction rate, removal of chloride present in the highly contaminated top 10cm of soil can be achieved in 3-9years. This is the first study to apply phytotechnologies at a CKD landfill, and to successfully demonstrate in situ phytoextraction of chloride. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Vegetation persistence and carbon storage: Implications for environmental water management for Phragmites australis

    NASA Astrophysics Data System (ADS)

    Whitaker, Kai; Rogers, Kerrylee; Saintilan, Neil; Mazumder, Debashish; Wen, Li; Morrison, R. J.

    2015-07-01

    Environmental water allocations are used to improve the ecological health of wetlands. There is now increasing demand for allocations to improve ecosystem productivity and respiration, and enhance carbon sequestration. Despite global recognition of wetlands as carbon sinks, information regarding carbon dynamics is lacking. This is the first study estimating carbon sequestration for semiarid Phragmites australis reedbeds. The study combined aboveground biomass assessments with stable isotope analyses of soils and modeling of biomass using Normalized Digital Vegetation Index (NDVI) to investigate the capacity of environmental water allocations to improve carbon storage. The study considered relationships between soil organic carbon (SOC), carbon sources, and reedbed persistence in the Macquarie Marshes, a regulated semiarid floodplain of the Murray-Darling Basin, Australia. SOC storage levels to 1 m soil depth were higher in persistent reedbeds (167 Mg ha-1) than ephemeral reedbeds (116-138 Mg ha-1). In situ P. australis was the predominant source of surface SOC at persistent reedbeds; mixed sources of surface SOC were proposed for ephemeral reedbeds. 13C enrichment with increasing soil depth occurred in persistent and ephemeral reedbeds and may not relate to flow characteristics. Despite high SOC at persistent reedbeds, differences in the rate of accretion contributed to significantly higher rates of carbon sequestration at ephemeral reedbeds (approximately 554 and 465 g m-2 yr-1) compared to persistent reedbeds (5.17 g m-2 yr-1). However, under current water regimes, rapid accretion at ephemeral reedbeds cannot be maintained. Effective management of persistent P. australis reedbeds may enhance carbon sequestration in the Macquarie Marshes and floodplain wetlands more generally.

  5. Evapotranspiration from pilot-scale constructed wetlands planted with Phragmites australis in a Mediterranean environment.

    PubMed

    Milani, Mirco; Toscano, Attilio

    2013-01-01

    This article reports the results of evapotranspiration (ET) experiments carried out in Southern Italy (Sicily) in a pilot-scale constructed wetland (CW) made of a combination of vegetated (Phragmites australis) and unvegetated sub-surface flow beds. Domestic wastewater from a conventional wastewater treatment plant was used to fill the beds. Microclimate data was gathered from an automatic weather station close to the experimental plant. From June to November 2009 and from April to November 2010, ET values were measured as the amount of water needed to restore the initial volume in the beds after a certain period. Cumulative reference evapotranspiration (ET(0)) was similar to the cumulative ET measured in the beds without vegetation (ET(con)), while the Phragmites ET (ET (phr) ) was significantly higher underlining the effect of the vegetation. The plant coefficient of P. australis (K(p)) was very high (up to 8.5 in August 2009) compared to the typical K(c) for agricultural crops suggesting that the wetland environment was subjected to strong "clothesline" and "oasis" effects. According to the FAO 56 approach, K(p) shows different patterns and values in relation to growth stages correlating significantly to stem density, plant height and total leaves. The mean Water Use Efficiency (WUE) value of P. australis was quite low, about 2.27 g L(-1), probably due to the unlimited water availability and the lack of the plant's physiological adaptations to water conservation. The results provide useful and valid information for estimating ET rates in small-scale constructed wetlands since ET is a relevant issue in arid and semiarid regions. In these areas CW feasibility for wastewater treatment and reuse should also be carefully evaluated for macrophytes in relation to their WUE values.

  6. [Bud population dynamics of Phragmites australis in heterogeneous habitats of Northeast grassland, China].

    PubMed

    2015-02-01

    To adapt ecological environment, typical clonal plants can occur continuously by means of buds. The changes in the bud bank and bud flow in the heterogeneous habitats become the foundation for deep understanding the characteristics of vegetative propagation. By sampling soil from the unit area, a comparative analysis was performed for rhizome bud population dynamics of Phragmites australis community in both meadow soil and saline-alkali soil habitats in meadow grassland of Northeast China. The one-age class rhizome buds formed in the current year were used as input, with the other age classes rhizome buds as output, counting the dormancy buds and death buds. The results showed that the storage, input, output, dormancy, death and the input rates of P. australis rhizome bud populations in meadow soil habitat were significantly higher than that in saline-alkali habitat. There was no significant difference in output rate between the two habitats. The dormant rate in saline-alkali habitat was significantly greater than that in meadow soil habitat. The death rates remained at relatively low levels in both, less than 2%. With the going of growing season, the input buds and input rate of bud bank increased in the two habitats, while the output buds remained relatively stable. The output rate increased first and decreased later, the dormancy buds and dormant rate decreased. Bud bank and bud flow were positively related to soil moisture, soil organic matter and soil available nitrogen content. However, they were negatively related to soil pH value and soil available phosphorus content. Bud bank and bud flow had a similar seasonal variation. Constantly for both habitats, P. australis populations generated new rhizome buds supplied to the bud bank and kept a stable output to maintain their vegetative propagation.

  7. Determinants of acid secretion.

    PubMed

    Khanna, M U; Abraham, P

    1990-09-01

    Acid secretion is regulated by hormonal factors acting peripherally and centrally, as well as neural factors. Gastrin and histamine are the two most important peripheral hormonal stimulants, while the vagus is the predominant nerve affecting acid secretion. Meal related acid secretion occurs in three phases: cephalic, gastric and intestinal. Acid secretion is stimulated in the first two phases while it is inhibited in the intestinal phase. Proteins are potent acid stimulants but carbohydrates and fats are inhibitors. Tea, coffee, milk and alcohol are acid stimulants; on the other hand the damaging influence of spices on the stomach may not be related to increased acid secretion. Psychological stress has a variable effect. The effect of Helicobacter pylori infection on acid secretion is being elucidated. Many drugs modifying acid secretion are available and are useful in the treatment of acid peptic disease.

  8. Long-term (two annual cycles) phytoremediation of heavy metal-contaminated estuarine sediments by Phragmites australis.

    PubMed

    Cicero-Fernández, Diego; Peña-Fernández, Manuel; Expósito-Camargo, Jose A; Antizar-Ladislao, Blanca

    2017-09-25

    The long-term (i.e., two consecutive annual cycles) ability of Phragmites australis to remediate estuarine sediments contaminated with heavy metals (Co, Ni, Mo, Cd, Pb, Cr, Cu, Fe, Mn, Zn and Hg) and trace elements of concern (As, Se, Ba) was investigated using an experimental approach on a pilot plant scale. The accumulation of these elements on belowground and aboveground tissues was monitored during vegetative and senescence periods for two populations of P. australis, originally from contaminated (MIC) and non-contaminated (GAL) estuaries, respectively. The initial concentration of the elements in the contaminated estuarine sediment decreased in the following order: Fe>Mn>Zn>Pb>Ba>Cr>As>Cu>Ni>Co>Mo>Cd>Se>Hg. A similar trend was recorded in the belowground biomass following remediation, suggesting the potential role of P. australis as an effective biomonitoring tool. Hg was not detected in any plant tissue. An overall annual increase of concentration levels in belowground tissue was observed. Overall, this study suggested that P. australis populations from GAL were substantially more efficient in taking up Ni, Mo and Cr during the second annual cycle in both belowground and aboveground tissue than P. australis populations from MIC. Calculated bio-concentration factors (BCF) suggested a clear metal excluder strategy for Co, Cd, Pb, Cu and Fe, with accumulation and stabilisation belowground, with limited translocation into aerial tissues observed during the length of this study. An excluder behaviour for Zn, Ba and Mn was detected during the second annual cycle, coinciding with a substantial increase of concentration levels belowground. This study demonstrated for the first time the long term efficacy of P. australis for phytoremediation of heavy metal contaminated estuarine sediments. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Long-distance dispersal and high genetic diversity are implicated in the invasive spread of the common reed, Phragmites australis (Poaceae), in northeastern North America.

    PubMed

    Kirk, Heather; Paul, Jennifer; Straka, Jason; Freeland, Joanna R

    2011-07-01

    The Eurasian subspecies of the common reed (Phragmites australis subsp. australis, hereafter abbreviated as P. a. australis) was introduced to North America in the late 18(th) century and rapidly expanded its range, posing an ecological threat to wetlands. In this study, we aimed to determine whether admixture among multiple lineages, dispersal mechanisms, and high genetic diversity have contributed to the invasion of P. a. australis in the northeastern part of its range. Understanding mechanisms of the P. a. australis invasion will 1) contribute to a broader understanding of the factors that facilitate plant invasion, and 2) help us to develop effective management strategies for wetlands threatened by P. a. australis invasion. We used a population genetics approach incorporating nine microsatellite loci to study genetic diversity and population structure in relation to biogeography of introduced North American Phragmites a. australis stands in the northeastern continental region. Phragmites a. australis is genetically diverse in the region studied here. Significant population structure exists, and population structure is likely influenced by both long-distance dispersal via major waterways, and short-distance dispersal overland. Different lineages sometimes colonize geographically proximate locations leading to opportunities for admixture. Clonal reproduction likely exaggerates geographical structure among some stands, although high genetic and clonal diversity within some stands implies that sexual reproduction occurs frequently in P. a. australis. A variety of factors, including admixture among multiple lineages, multiple modes of dispersal, and plasticity in reproductive strategy promote the invasion success of Phragmites a. australis. Wetland managers in the St. Lawrence River/Great Lakes region should focus monitoring efforts on the shores of conservation lands to prevent the establishment of propagules from novel lineages.

  10. [Identification of seeds of Cuscuta australis and C. chinensis by TLC and HPLC].

    PubMed

    Ye, M; Zhou, P; Yan, Y; Li, Y; Liu, H

    2001-02-01

    Identification of seeds of Cuscuta australis R. Br. and C. chinensis Lam. was carried out by TLC and HPLC. Polyamide membrane was used as stationary phase, MeOH-HOAc-H2O and CHCl3-MeOH-HOAc were used as mobile phase for TLC. For HPLC, Hypersil-ODS column was used; the mobile phase was MeOH-0.025 M H3PO4; the flow rate was 1.0 ml.min-1; detection wavelength was 360 nm; and column temperature was 40 degrees C. Both methods represented significant identification characteristics, and were simple, accurate and reproducible.

  11. Geographic variation in apparent competition between native and invasive Phragmites australis.

    PubMed

    Bhattarai, Ganesh P; Meyerson, Laura A; Cronin, James T

    2017-02-01

    Apparent competition, the negative interaction between species mediated by shared natural enemies, is thought to play an important role in shaping the structure and dynamics of natural communities. However, its importance in driving species invasions, and whether the strength of this indirect interaction varies across the latitudinal range of the invasion, has not been fully explored. We performed replicated field experiments at four sites spanning 900 km along the Atlantic Coast of the United States to assess the presence and strength of apparent competition between sympatric native and invasive lineages of Phragmites australis. Four herbivore guilds were considered: stem-feeders, leaf-miners, leaf-chewers and aphids. We also tested the hypothesis that the strength of this interaction declines with increasing latitude. Within each site, native and invasive plants of P. australis were cross-transplanted between co-occurring native and invasive patches in the same marsh habitat and herbivore damage was evaluated at the end of the growing season. Apparent competition was evident for both lineages and involved all but the leaf-chewer guild. For native plants, total aphids per plant was 296% higher and the incidence of stem-feeding and leaf-mining herbivores was 34% and 221% higher, respectively, when transplanted into invasive than native patches. These data suggest that invasive P. australis has a negative effect on native P. australis via apparent competition. Averaged among herbivore types, the indirect effects of the invasive lineage on the native lineage was 57% higher than the reverse situation, suggesting that apparent competition was asymmetric. We also found that the strength of apparent competition acting against the native lineage was comparable to the benefits to the invasive lineage from enemy release (i.e., proportionately lower mean herbivory of the invasive relative to the native taxa). Finally, we found the first evidence that the strength of

  12. Aurora Australis or Southern Lights as seen from STS-60 Shuttle Discovery

    NASA Technical Reports Server (NTRS)

    1994-01-01

    The Astronauts and Cosmonaut aboard Space Shuttle Discovery observed the display of the Aurora Australis or Southern Lights. The multi-hued shafts of light, extending upward to 200 miles above the Earth's surface, are caused by beams of energetic electrons colliding with the oxygen and nitrogen in the Earth's upper atmosphere. The strong red glow occurs at the highest altitude where the air is least dense and composed mostly of oxygen. At lower altitudes, the greater density favors the green color, also produced by atomic oxygen. Sometimes at the bottom (the lowest altitude of the aurora) a pink border is produced by nitrogen.

  13. Aurora Australis or Southern Lights as seen from STS-60 Shuttle Discovery

    NASA Technical Reports Server (NTRS)

    1994-01-01

    The Astronauts and Cosmonaut aboard Space Shuttle Discovery observed the display of the Aurora Australis or Southern Lights. The multi-hued shafts of light, extending upward to 200 miles above the Earth's surface, are caused by beams of energetic electrons colliding with the oxygen and nitrogen in the Earth's upper atmosphere. The strong red glow occurs at the highest altitude where the air is least dense and composed mostly of oxygen. At lower altitudes, the greater density favors the green color, also produced by atomic oxygen. Sometimes at the bottom (the lowest altitude of the aurora) a pink border is produced by nitrogen.

  14. Alpha Trianguli Australis (K2 II-III) - Hybrid or composite?

    NASA Technical Reports Server (NTRS)

    Ayres, T. R.

    1985-01-01

    The prototype hybrid-spectrum giant Alpha Trianguli Australis exhibits a far-ultraviolet continuum which is considerably bluer than would be expected of a star of its optical colors, suggesting the presence of a previously unrecognized companion. If the K-type primary is as luminous as indicated by the widths of its Ca II and H-alpha lines, the companion could be an early F-type dwarf that only recently has arrived on the main sequence. Indeed, the flux of C IV from Alpha TrA - an important measure of hybridness - would not be inconsistent with that expected from a very young chromospherically active F star.

  15. Collaborations, research, and adaptive management to address nonnative Phragmites australis in the Great Lakes Basin

    USGS Publications Warehouse

    Kowalski, Kurt P.

    2016-06-30

    Phragmites australis, also known as common reed, is a native North American wetland grass that has grown in North America for thousands of years. More recently, a nonnative, invasive variety of Phragmites from Eurasia is rapidly invading wetlands across the continental United States and other parts of North America, where it negatively impacts humans and the environment. U.S. Geological Survey scientists, funded by the Great Lakes Restoration Initiative, are leading innovative efforts to improve management of nonnative Phragmites in the Great Lakes Basin.

  16. Alpha Trianguli Australis (K2 II-III) - Hybrid or composite?

    NASA Technical Reports Server (NTRS)

    Ayres, T. R.

    1985-01-01

    The prototype hybrid-spectrum giant Alpha Trianguli Australis exhibits a far-ultraviolet continuum which is considerably bluer than would be expected of a star of its optical colors, suggesting the presence of a previously unrecognized companion. If the K-type primary is as luminous as indicated by the widths of its Ca II and H-alpha lines, the companion could be an early F-type dwarf that only recently has arrived on the main sequence. Indeed, the flux of C IV from Alpha TrA - an important measure of hybridness - would not be inconsistent with that expected from a very young chromospherically active F star.

  17. New species causing decay on living Polylepis australis in Cordoba, central Argentina.

    PubMed

    Robledo, Gerardo; Urcelay, Carlos; Rajchenberg, Mario

    2003-01-01

    Two new species of poroid Hymenochaetaceae (Aphyllophorales, Basidiomycota) are described and illustrated. They were causing decay on living and standing dead Polylepis australis ("tabaquillo" or "queñoa") in the Córdoba Mountains in central Argentina. Inonotus serranus is characterized by a biannual basidiocarp, with a dark line separating tomentum from context; ellipsoid to ovoid, thick walled, colored spores; and the absence of setae. Phellinus uncisetus is characterized by uncinate setae with ventricose uniradicate base and well-differentiated apical portion; a basidiocarp attached by a narrow area to the substrate; ventricose, hyaline cistidioles; and by subglobose, hyaline spores, with very thick walls. The identity of Phellinus setulosus is discussed.

  18. Leaves of Phragmites australis as potential atmospheric biomonitors of Platinum Group Elements.

    PubMed

    Bonanno, Giuseppe; Pavone, Pietro

    2015-04-01

    The increasing emissions of Platinum Group Elements (PGEs), namely Pt, Pd and Rh, may pose a significant risk to ecosystem processes and human health. A periodic assessment of PGEs distribution in the environment is thus of the utmost importance for the implementation of timely measures of mitigation. Although several studies have quantified PGEs in different life forms such as mammals, birds, fish, crustaceans, algae, mosses and even human beings, data about vascular plants need further surveys. This study aimed to test the suitability of the grass Phragmites australis (common reed) as a biomonitor of PGEs atmospheric pollution. The results showed that Pd and Pt concentrations in leaves are significantly higher in urban areas. In particular, Pd showed the highest range of values in line with current studies that consider palladium as the main element of traffic-related pollution. Overall, the leaves of Phragmites australis reflected the different gradient of PGEs emissions, and may thus be considered as potential biomonitors of atmospheric pollution. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. Phosphate and ammonium adsorption of the modified biochar based on Phragmites australis after phytoremediation.

    PubMed

    Gong, Yu-Peng; Ni, Zhi-Yi; Xiong, Zhao-Zhao; Cheng, Li-Hua; Xu, Xin-Hua

    2017-03-01

    To effectively remove N and P from eutrophic water, the Phragmites australis after phytoremediation was harvested for preparation of modified biochar. The MgCl2-modified biochar (MPB) was successfully synthesized at 600 °C under N2 circumstance. The physiochemical characteristics, the adsorption capacity for N and P in the simulated solution, and their adsorption mechanism of MPB were then determined, followed by the treatment of eutrophic water of Tai lake and its inflow river from agricultural source. The results demonstrated that the MPB presented high adsorption capacity to both simulated NH4-N and PO4-P with the maximum adsorption capacity exceeding 30 and 100 mg g(-1), respectively. The entire ammonium adsorption process could be described by a pseudo-second-order kinetic model whereas the phosphate adsorption process could be divided into three phases, as described by both intra-particle diffusion model and the pseudo-first-order kinetic. It was further found that the dominant mechanism for ammonium adsorption was Mg(2+) exchange instead of functional groups and surface areas and the Mg-P precipitation was the main mechanism for phosphate adsorption. The MPB also showed high removal ratio of practical TP which reached nearly 90% for both the water in Tai lake and its agricultural source. It suggested that MPB based on harvested P. australis was a promising composite for eutrophic water treatment and it could deliver multiple benefits. Graphic abstract.

  20. Pseudechis australis venomics: adaptation for a defense against microbial pathogens and recruitment of body transferrin.

    PubMed

    Georgieva, Dessislava; Seifert, Jana; Öhler, Michaela; von Bergen, Martin; Spencer, Patrick; Arni, Raghuvir K; Genov, Nicolay; Betzel, Christian

    2011-05-06

    The venom composition of Pseudechis australis, a widely distributed in Australia reptile, was analyzed by 2-DE and mass spectrometric analysis. In total, 102 protein spots were identified as venom toxins. The gel is dominated by horizontal trains of spots with identical or very similar molecular masses but differing in the pI values. This suggests possible post-translational modifications of toxins, changing their electrostatic charge. The results demonstrate a highly specialized biosynthesis of toxins destroying the hemostasis (P-III metalloproteases, SVMPs), antimicrobial proteins (L-amino acid oxidases, LAAOs, and transferrin-like proteins, TFLPs), and myotoxins (phospholipase A(2)s, PLA(2)s). The three transferrin isoforms of the Australian P. australis (Elapidae snake) venom are highly homologous to the body transferrin of the African Lamprophis fuliginosus (Colubridae), an indication for the recruitment of body transferrin. The venomic composition suggests an adaptation for a defense against microbial pathogens from the prey. Transferrins have not previously been reported as components of elapid or other snake venoms. Ecto-5'-nucleotidases (5'-NTDs), nerve growth factors (VNGFs), and a serine proteinase inhibitor (SPI) were also identified. The venom composition and enzymatic activities explain the clinical manifestation of the king brown snakebite. The results can be used for medical, scientific, and biotechnological purposes.

  1. The effect of sampling methods on the apparent constituents of ink from the squid Sepioteuthis australis.

    PubMed

    Madaras, F; Gerber, J P; Peddie, F; Kokkinn, M J

    2010-11-01

    Results of experiments conducted on ink recovered from the squid Sepioteuthis australis indicate that there is no epinephrine or protein naturally present in the ink as it would be ejected in vivo. Protein content was effectively zero when ink was syringed from the duct end of the ink sac of freshly killed animals. By contrast, there were proteins in samples collected from dead specimens where ink was collected by a stripping method. From these samples, a single large molecular weight protein was identified as having tyrosinase activity. Digestion of syringed ink did not yield signs of melanin-bound proteins. Analysis of supernatants after centrifugation of squid ink consistently revealed the presence of DOPA, dopamine, and taurine, whereas epinephrine and nor-epinephrine were recorded from what was believed to be contaminated ink. Histological investigations of the ink sac revealed a compartmentalised glandular structure distal to the duct end. Closer observation of the glandular tissue showed that compartments increased in size as they matured and moved further into the lumen. It was concluded that the presence of epinephrine and tyrosinase (or a related protein) in the ink of S. australis could be attributed to rupturing of basal glandular compartments or contamination from other sources during the extraction process.

  2. Burial Duration and Frequency Influences Resilience of Differing Propagule Types in a Subtidal Seagrass, Posidonia australis

    PubMed Central

    2016-01-01

    Sedimentation that leads to periodic, and often prolonged, burial events is becoming more common on the world’s coastlines as human populations expand and create urbanised marine environments. Different seagrass species react differently to sediment burial but many species in the southern hemisphere are yet to be examined. How seagrasses react to burial has restoration implications. There is a need to critically assess seagrass transplant propagule responses to periodic (pulse) and prolonged (press) burial events before selecting the most appropriate species, transplant propagule, and transplant site. In my study, mesocosm experiments, coupled with field measurements were used to assess how sexual (seedlings) and vegetative (sprigs) propagules of Posidonia australis responded to pulse and press burial events. Seedlings were highly susceptible to burial (both pulse and press), with no survival at the end of the experimental period. In contrast, rhizome growth in vegetative propagules was stimulated by pulse burial, although press burial events resulted in mortality. The implication for Posidonia australis restoration efforts in areas where burial is periodic, was that vegetative propagules are optimal transplant units, in comparison to seedlings. Press burial however, renders a transplant site sub-optimal for both seedling and sprig transplants. PMID:27526020

  3. Morphology of the eye of the southern right whales (Eubalaena australis).

    PubMed

    Buono, Mónica R; Fernández, Marta S; Herrera, Yanina

    2012-02-01

    Recently, there has been a growing interest in the anatomy and optics of the visual system of cetaceans. However, much of the new information has been focused on odontocetes, and relatively little is known about the visual anatomy of baleen whales. The aim of this study was describe the eye anatomy of the southern right whale (Eubalaena australis). Eye samples were collected from 26 calves, four adults with known body length, as well as two specimens of unknown body length that had stranded near their nursery ground at Península Valdés, Argentina, over 6 years. We provide anatomical descriptions of the eyeball and extraocular structures, as well as quantitative data in the form of eyeball, corneal, scleral, and lens measurements. To explore the sensitivity of the eye to light, the f-number was estimated in one specimen. We found that the eyes of the calves differed from those of the adults in having less periorbital fat surrounding the eyeball. We also observed variations in the abundance of periorbital fat among the adult specimens. The regression analysis revealed a correlation between body length and eyeball size. By contrast, the dimensions of the cornea were only weakly correlated with body length. The estimated f-number suggests that the optical sensitivity of the Eubalaena australis eye is relatively low. However, caution had to be taken in interpreting f-number as a proxy of eye sensitivity because it depends on the lens size, which can be affected by the fixation methods used.

  4. Burial Duration and Frequency Influences Resilience of Differing Propagule Types in a Subtidal Seagrass, Posidonia australis.

    PubMed

    Campbell, Marnie L

    2016-01-01

    Sedimentation that leads to periodic, and often prolonged, burial events is becoming more common on the world's coastlines as human populations expand and create urbanised marine environments. Different seagrass species react differently to sediment burial but many species in the southern hemisphere are yet to be examined. How seagrasses react to burial has restoration implications. There is a need to critically assess seagrass transplant propagule responses to periodic (pulse) and prolonged (press) burial events before selecting the most appropriate species, transplant propagule, and transplant site. In my study, mesocosm experiments, coupled with field measurements were used to assess how sexual (seedlings) and vegetative (sprigs) propagules of Posidonia australis responded to pulse and press burial events. Seedlings were highly susceptible to burial (both pulse and press), with no survival at the end of the experimental period. In contrast, rhizome growth in vegetative propagules was stimulated by pulse burial, although press burial events resulted in mortality. The implication for Posidonia australis restoration efforts in areas where burial is periodic, was that vegetative propagules are optimal transplant units, in comparison to seedlings. Press burial however, renders a transplant site sub-optimal for both seedling and sprig transplants.

  5. Placement of the unclassified Cyranomonas australis Lee 2002 within a novel clade of Cercozoa.

    PubMed

    Lee, Won Je; Park, Jong Soo

    2016-10-01

    Two heterotrophic flagellate strains were isolated from marine sediment samples off eastern Canada and Korea. These new isolates are indistinguishable by light microscopy from the unclassified protist Cyranomonas australis. The organisms are ovoid-shaped cells, 3.5-6μm long, laterally compressed, and somewhat flexible. They have two unequal flagella, about 1.1-2.5 times body length. Typically, the cells show a gliding motility and do not exhibit any amoeboid form or pseudopodia. 18S rDNA phylogenies clearly indicate that the isolates can be assigned to the taxon Filosa, within Cercozoa. The isolates are closest to an environmental sequence (CYSGM-16; 99% identity). Cyranomonas, CYSGM-16, and uncultured eukaryote RM1-SGM46 form a clade with strong statistical supports, here called novel clade CU (Cyranomonas plus Uncultured eukaryotes). This clade may be sister to the order Marimonadida. The novel clade CU and the Marimonadida have been detected only in marine habitats. Our findings suggest that C. australis may not belong to any previously described family within Filosa and Cercozoa.

  6. Influence of salinity on the life table demography of a rare Cladocera Latonopsis australis.

    PubMed

    Haridevan, G; Jyothibabu, R; Arunpandi, N; Jagadeesan, L; Biju, A

    2015-10-01

    Latonopsis australis is a rare Cladocera inhabiting the entire stretch of the Cochin backwaters, the largest monsoonal estuary along the West Coast of India, during the summer monsoon, but restricted to the upper reaches during the non-monsoon periods. Here, we present the results of an experimental study, which assessed the influence of salinity on the life table demography of the species at different salinity levels. The life table demographic parameters such as net reproduction rate, generation time, intrinsic growth rate, gross reproductive rate, and survivorship of the species were measured in different salinities ranging from freshwater to mesohaline levels (salinity 14). The study showed that higher salinity had a significant negative effect on all life table demography parameters of the species, whereas freshwater to low saline conditions (salinity up to 8) favored the survivorship, life expectancy, net production, and growth rate. It was also noticed that salinity above 8 caused a significant decrease in the survivorship, life expectancy, and reproduction rate of the species, which clearly explained the seasonal distribution pattern of the species in the Cochin backwaters. The present study suggests salinity 2 to 6 as the optimum range for the large-scale production of L. australis for purposes like live feed in aquaculture.

  7. The potential for constructed wetlands to treat alkaline bauxite-residue leachate: Phragmites australis growth.

    PubMed

    Higgins, D; Curtin, T; Pawlett, M; Courtney, R

    2016-12-01

    High alkalinity (pH > 12) of bauxite-residue leachates presents challenges for the long-term storage and managements of the residue. Recent evidence has highlighted the potential for constructed wetlands to effectively buffer the alkalinity, but there is limited evidence on the potential for wetland plants to establish and grow in soils inundated with residue leachate. A pot-based trial was conducted to investigate the potential for Phragmites australis to establish and grow in substrate treated with residue leachate over a pH range of 8.6-11.1. The trial ran for 3 months, after which plant growth and biomass were determined. Concentrations of soluble and exchangeable trace elements in the soil substrate and also in the aboveground and belowground biomass were determined. Residue leachate pH did not affect plant biomass or microbial biomass. With the exception of Na, there was no effect on exchangeable trace elements in the substrate; however, increases in soluble metals (As, Cd and Na) were observed with increasing leachate concentration. Furthermore, increases in Al, As and V were observed in belowground biomass and for Cd and Cr in aboveground biomass. Concentrations within the vegetation biomass were less than critical phytotoxic levels. Results demonstrate the ability for P. australis to grow in bauxite-residue leachate-inundated growth media without adverse effects.

  8. The effect of the heterologous expression of Phragmites australis gamma-glutamylcysteine synthetase on the Cd2+ accumulation of Agrostis palustris.

    PubMed

    Zhao, Cuizhu; Qiao, Meng; Yu, Yanchong; Xia, Guangmin; Xiang, Fengning

    2010-06-01

    Heavy metal pollution has become one of the most serious environmental problems today. To develop a more efficient plant to clean up heavy metal contaminated soils, a gamma-glutamylcysteine synthetase (GCS) cDNA, named PaGCS, was isolated by PCR from Phragmites australis. The PaGCS sequence was transformed via agroinfection into the heavy metal intolerant grass Agrostis palustris. Five confirmed transgenic A. palustris plants expressing PaGCS were compared with the wild-type line for growth and Cd(2+) accumulation, as well as for the expression of a number of phytochelatin synthesis and stress-responsive enzymes when challenged with Cd(2+) stress. GCS and phytochelatin synthase (PCS) were up-regulated in the transgenic lines. All the transgenic lines accumulated more Cd(2+) and phytochelatins (PCs) than the wild-type line, and three of the five lines grew more effectively than the wild-type after either five or 21 d of Cd(2+) stress. Variation among the transgenics was observed for the distribution of Cd(2+) in the root, shoot and leaf. The malondialdehyde content of all the transgenic lines was lower than that of the wild type under Cd(2+) treatment, while the activity of both superoxide dismutase and peroxidase present in the transgenic lines increased markedly 24 h after Cd(2+) stress, and then rapidly declined.

  9. Response of Arbuscular Mycorrhizal Fungi to Hydrologic Gradients in the Rhizosphere of Phragmites australis (Cav.) Trin ex. Steudel Growing in the Sun Island Wetland.

    PubMed

    Wang, Li; Wu, Jieting; Ma, Fang; Yang, Jixian; Li, Shiyang; Li, Zhe; Zhang, Xue

    2015-01-01

    Within the rhizosphere, AM fungi are a sensitive variable to changes of botanic and environmental conditions, and they may interact with the biomass of plant and other microbes. During the vegetative period of the Phragmites australis growing in the Sun Island Wetland (SIW), the variations of AM fungi colonization were studied. Root samples of three hydrologic gradients generally showed AM fungi colonization, suggesting that AM fungi have the ability for adaptation to flooded habitats. There were direct and indirect hydrological related effects with respect to AM fungi biomass, which interacted simultaneously in the rhizosphere. Though water content in soil and reed growth parameters were both positively associated with AM fungi colonization, only the positive correlations between reed biomass parameters and the colonization could be expected, or both the host plant biomass and the AM fungi could be beneficial. The variations in response of host plant to the edaphic and hydrologic conditions may influence the effectiveness of the plant-mycorrhizal association. This study included a hydrologic component to better assess the role and distribution of AM fungi in wetland ecosystems. And because of that, the range of AM fungi was extended, since they actually showed a notable adaptability to hydrologic gradients.

  10. Response of Arbuscular Mycorrhizal Fungi to Hydrologic Gradients in the Rhizosphere of Phragmites australis (Cav.) Trin ex. Steudel Growing in the Sun Island Wetland

    PubMed Central

    Wang, Li; Wu, Jieting; Ma, Fang; Yang, Jixian; Li, Shiyang; Li, Zhe; Zhang, Xue

    2015-01-01

    Within the rhizosphere, AM fungi are a sensitive variable to changes of botanic and environmental conditions, and they may interact with the biomass of plant and other microbes. During the vegetative period of the Phragmites australis growing in the Sun Island Wetland (SIW), the variations of AM fungi colonization were studied. Root samples of three hydrologic gradients generally showed AM fungi colonization, suggesting that AM fungi have the ability for adaptation to flooded habitats. There were direct and indirect hydrological related effects with respect to AM fungi biomass, which interacted simultaneously in the rhizosphere. Though water content in soil and reed growth parameters were both positively associated with AM fungi colonization, only the positive correlations between reed biomass parameters and the colonization could be expected, or both the host plant biomass and the AM fungi could be beneficial. The variations in response of host plant to the edaphic and hydrologic conditions may influence the effectiveness of the plant-mycorrhizal association. This study included a hydrologic component to better assess the role and distribution of AM fungi in wetland ecosystems. And because of that, the range of AM fungi was extended, since they actually showed a notable adaptability to hydrologic gradients. PMID:26146633

  11. Inducing gravitropic curvature of primary roots of Zea mays cv Ageotropic

    NASA Technical Reports Server (NTRS)

    Moore, R.; Evans, M. L.; Fondren, W. M.

    1990-01-01

    Primary roots of the mutant 'Ageotropic' cultivar of Zea mays are nonresponsive to gravity. Their root caps secrete little or no mucilage and touch the root only at the extreme apex. A gap separates the cap and root at the periphery of the cap. Applying mucilage from normal roots or substances with a consistency similar to that of mucilage to tips of mutant roots causes these roots to become strongly graviresponsive. Gravicurvature stops when these substances are removed. Caps of some mutants secrete small amounts of mucilage and are graviresponsive. These results indicate that (a) the lack of graviresponsiveness in the mutant results from disrupting the transport pathway between the cap and root, (b) movement of the growth-modifying signal from the cap to the root occurs via an apoplastic pathway, and (c) mucilage is necessary for normal communication between the root cap and root in Zea mays cv Ageotropic.

  12. Inducing gravitropic curvature of primary roots of Zea mays cv Ageotropic

    NASA Technical Reports Server (NTRS)

    Moore, R.; Evans, M. L.; Fondren, W. M.

    1990-01-01

    Primary roots of the mutant 'Ageotropic' cultivar of Zea mays are nonresponsive to gravity. Their root caps secrete little or no mucilage and touch the root only at the extreme apex. A gap separates the cap and root at the periphery of the cap. Applying mucilage from normal roots or substances with a consistency similar to that of mucilage to tips of mutant roots causes these roots to become strongly graviresponsive. Gravicurvature stops when these substances are removed. Caps of some mutants secrete small amounts of mucilage and are graviresponsive. These results indicate that (a) the lack of graviresponsiveness in the mutant results from disrupting the transport pathway between the cap and root, (b) movement of the growth-modifying signal from the cap to the root occurs via an apoplastic pathway, and (c) mucilage is necessary for normal communication between the root cap and root in Zea mays cv Ageotropic.

  13. Authentication Without Secrets

    SciTech Connect

    Pierson, Lyndon G.; Robertson, Perry J.

    2015-11-01

    This work examines a new approach to authentication, which is the most fundamental security primitive that underpins all cyber security protections. Current Internet authentication techniques require the protection of one or more secret keys along with the integrity protection of the algorithms/computations designed to prove possession of the secret without actually revealing it. Protecting a secret requires physical barriers or encryption with yet another secret key. The reason to strive for "Authentication without Secret Keys" is that protecting secrets (even small ones only kept in a small corner of a component or device) is much harder than protecting the integrity of information that is not secret. Promising methods are examined for authentication of components, data, programs, network transactions, and/or individuals. The successful development of authentication without secret keys will enable far more tractable system security engineering for high exposure, high consequence systems by eliminating the need for brittle protection mechanisms to protect secret keys (such as are now protected in smart cards, etc.). This paper is a re-release of SAND2009-7032 with new figures numerous edits.

  14. Salt tolerance and osmotic adjustment of Spartina alterniflora (Poaceae) and the invasive M haplotype of Phragmites australis (Poaceae) along a salinity gradient

    USGS Publications Warehouse

    Vasquez, Edward A.; Glenn, Edward P.; Guntenspergen, Glenn R.; Brown, J. Jed; Nelson, Stephen G.

    2006-01-01

    An invasive variety of Phragmites australis (Poaceae, common reed), the M haplotype, has been implicated in the spread of this species into North American salt marshes that are normally dominated by the salt marsh grass Spartina alterniflora (Poaceae, smooth cordgrass). In some European marshes, on the other hand, Spartina spp. derived from S. alterniflora have spread into brackish P. australis marshes. In both cases, the non-native grass is thought to degrade the habitat value of the marsh for wildlife, and it is important to understand the physiological processes that lead to these species replacements. We compared the growth, salt tolerance, and osmotic adjustment of M haplotype P. australis and S. alterniflora along a salinity gradient in greenhouse experiments. Spartina alterniflora produced new biomass up to 0.6 M NaCl, whereas P. australis did not grow well above 0.2 M NaCl. The greater salt tolerance of S. alterniflora compared with P. australis was due to its ability to use Na+ for osmotic adjustment in the shoots. On the other hand, at low salinities P. australis produced more shoots per gram of rhizome tissue than did S. alterniflora. This study illustrates how ecophysiological differences can shift the competitive advantage from one species to another along a stress gradient. Phragmites australis is spreading into North American coastal marshes that are experiencing reduced salinities, while Spartina spp. are spreading into northern European brackish marshes that are experiencing increased salinities as land use patterns change on the two continents.

  15. Salt tolerance and osmotic adjustment of Spartina alterniflora (Poaceae) and the invasive M haplotype of Phragmites australis (Poaceae) along a salinity gradient.

    PubMed

    Vasquez, Edward A; Glenn, Edward P; Guntenspergen, Glenn R; Brown, J Jed; Nelson, Stephen G

    2006-12-01

    An invasive variety of Phragmites australis (Poaceae, common reed), the M haplotype, has been implicated in the spread of this species into North American salt marshes that are normally dominated by the salt marsh grass Spartina alterniflora (Poaceae, smooth cordgrass). In some European marshes, on the other hand, Spartina spp. derived from S. alterniflora have spread into brackish P. australis marshes. In both cases, the non-native grass is thought to degrade the habitat value of the marsh for wildlife, and it is important to understand the physiological processes that lead to these species replacements. We compared the growth, salt tolerance, and osmotic adjustment of M haplotype P. australis and S. alterniflora along a salinity gradient in greenhouse experiments. Spartina alterniflora produced new biomass up to 0.6 M NaCl, whereas P. australis did not grow well above 0.2 M NaCl. The greater salt tolerance of S. alterniflora compared with P. australis was due to its ability to use Na(+) for osmotic adjustment in the shoots. On the other hand, at low salinities P. australis produced more shoots per gram of rhizome tissue than did S. alterniflora. This study illustrates how ecophysiological differences can shift the competitive advantage from one species to another along a stress gradient. Phragmites australis is spreading into North American coastal marshes that are experiencing reduced salinities, while Spartina spp. are spreading into northern European brackish marshes that are experiencing increased salinities as land use patterns change on the two continents.

  16. Effects of genotypic diversity of Phragmites australis on primary productivity and water quality in an experimental wetland.

    PubMed

    Tomimatsu, Hiroshi; Nakano, Kazunori; Yamamoto, Nozomi; Suyama, Yoshihisa

    2014-05-01

    An increasing number of studies have shown that genetic diversity within plant species can influence important ecological processes. Here, we report a two-year wetland mesocosm experiment in which genotypic richness of Phragmites australis was manipulated to examine its effects on primary productivity and nitrogen removal from water. We used six genotypes of P. australis, and compared primary productivity and nitrogen concentration in the outflow water of the mesocosms between monocultures and polycultures of all six genotypes. We also quantified the abundance of denitrifying bacteria, as denitrification is a primary mechanism of nitrogen removal in addition to the biotic uptake by P. australis. Plant productivity was significantly greater in genotypic polycultures compared to what was expected based on monocultures. This richness effect on productivity was driven by both complementary and competitive interactions among genotypes. In addition, nitrogen removal rates of mesocosms were generally greater in genotypic polycultures compared to those expected based on monocultures. This effect, particularly pronounced in autumn, may largely be attributable to the enhanced uptake of nitrogen by P. australis, as the abundance of nitrite reducers did not increase with plant genotypic diversity. Although our effect sizes were relatively small compared to previous experiments, our study emphasizes the effect of genotypic interactions in regulating multiple ecological processes.

  17. The Effect of Artificial Mowing on the Competition of Phragmites australis and Spartina alterniflora in the Yangtze Estuary

    PubMed Central

    Zhang, Chao

    2017-01-01

    Spartina alterniflora Loisel. is one of the most invasive species in the world. However, little is known about the role of artificial mowing in its invasiveness and competiveness. In this work, we studied the effect of mowing on its interspecific interactions with native species Phragmites australis (Cav.) Trin ex Steud of the Yangtze Estuary, China. We calculated their relative neighbor effect (RNE) index, effect of relative crowding (Dr) index, and interaction strength (I) index. The results showed that the RNE of Phragmites australis and Spartina alterniflora was 0.354 and 0.619, respectively, and they have competitive interactions. The mowing treatments can significantly influence the RNE of Phragmites australis and Spartina alterniflora on each other. Concretely, the RNE of Spartina alterniflora in the removal treatments was significantly higher than the value in the controls. But the RNE of Phragmites australis in the removal treatments was significantly lower than the value in the controls. Meanwhile, Dr of the two species on the targets was higher in the removal treatments than that in the controls, and the opposite was for I. We concluded that artificial mowing could promote the invasion of Spartina alterniflora by increasing its competitive performance compared with native species. PMID:28348921

  18. The Effect of Artificial Mowing on the Competition of Phragmites australis and Spartina alterniflora in the Yangtze Estuary.

    PubMed

    Yuan, Yue; Zhang, Chao; Li, Dezhi

    2017-01-01

    Spartina alterniflora Loisel. is one of the most invasive species in the world. However, little is known about the role of artificial mowing in its invasiveness and competiveness. In this work, we studied the effect of mowing on its interspecific interactions with native species Phragmites australis (Cav.) Trin ex Steud of the Yangtze Estuary, China. We calculated their relative neighbor effect (RNE) index, effect of relative crowding (Dr ) index, and interaction strength (I) index. The results showed that the RNE of Phragmites australis and Spartina alterniflora was 0.354 and 0.619, respectively, and they have competitive interactions. The mowing treatments can significantly influence the RNE of Phragmites australis and Spartina alterniflora on each other. Concretely, the RNE of Spartina alterniflora in the removal treatments was significantly higher than the value in the controls. But the RNE of Phragmites australis in the removal treatments was significantly lower than the value in the controls. Meanwhile, Dr of the two species on the targets was higher in the removal treatments than that in the controls, and the opposite was for I. We concluded that artificial mowing could promote the invasion of Spartina alterniflora by increasing its competitive performance compared with native species.

  19. Phragmites australis + Typha latifolia Community Enhanced the Enrichment of Nitrogen and Phosphorus in the Soil of Qin Lake Wetland.

    PubMed

    Ge, Zhiwei; An, Ran; Fang, Shuiyuan; Lin, Pengpeng; Li, Chuan; Xue, Jianhui; Yu, Shuiqiang

    2017-01-01

    Aquatic plants play an essential role and are effective in mitigating lake eutrophication by forming complex plant-soil system and retaining total nitrogen (TN) and phosphorus (TP) in soils to ultimately reduce their quantities in aquatic systems. Two main vegetation types (Phragmites australis community and P. australis + Typha latifolia community) of Qin Lake wetland were sampled in this study for the analysis of TN and TP contents and reserves in the wetland soils. The results showed that (1) the consumption effect of Qin Lake wetland on soluble N was much more significant than on soluble P. (2) The efficiency of TN enrichment in wetland soil was enhanced by vegetation covering of P. australis and T. latifolia. (3) Wetland soil P was consumed by P. australis community and this pattern was relieved with the introduction of T. latifolia. (4) According to the grey relativity analysis, the most intensive interaction between plants and soil occurred in summer. In addition, the exchange of N in soil-vegetation system primarily occurred in the 0-15 cm soil layer. Our results indicated that vegetation covering was essential to the enrichment of TN and TP, referring to the biology-related fixation in the wetland soil.

  20. Protosclerogibba australis gen. et sp. nov., new genus and species of sclerogibbid wasps (Hymenoptera: Sclerogibbidae) from South Africa.

    PubMed

    Olmi, Massimo; Marletta, Alessandro; Guglielmino, Adalgisa; Speranza, Stefano

    2016-03-01

    Protosclerogibba australis Olmi, Marletta, Guglielmino & Speranza, gen. et sp. nov. is described and illustrated from specimens collected in Kimberley (Northern Cape Province, South Africa). The female of the new taxon is the first micropterous sclerogibbid. Females of other extant Sclerogibbidae are always apterous, whereas fossil females can be apterous or macropterous.

  1. Antioxidative system and oxidative stress markers in wild populations of Erica australis L. differentially exposed to pyrite mining activities.

    PubMed

    Márquez-García, Belén; Córdoba, Francisco

    2009-11-01

    Erica australis L. is a widely distributed shrub able to grow in a variety of environments. In the Iberian Pyritic Belt (SW Spain and Portugal), E. australis can be observed growing successfully in very acidic and highly metal-enriched soils. However, no data about the metal tolerance of this plant in wild populations have been reported so far. In this study, we have analysed metal contents in the leaves of E. australis from three wild populations growing in soils affected by metals in different ways (mine wastes, the terrace of a river affected by acid mine drainage and soils not affected by mining activities but enriched in metals due the geology of the area) and, taking into account that metals may generate reactive oxygen species, we also assayed the oxidative damages and the antioxidative defences. All plants contained high levels of Fe and Mn in the leaves, but plants exposed to mining activities also accumulate different levels of As, Ni, Mo, Pb, and Zn depending on the population considered. Our data show that E. australis responds to metal-catalysed production of reactive radicals by oxidising ascorbic acid, which is present at concentrations much higher than described in other plant species, but it is highly oxidised, close to 40%. Ascorbic acid may counteract reactive oxygen species, and no cell damage was produced, as shown by the low levels of H(2)O(2) and lipid peroxidation found compared with other plant species and no damage reflected in pigment levels.

  2. Phragmites australis + Typha latifolia Community Enhanced the Enrichment of Nitrogen and Phosphorus in the Soil of Qin Lake Wetland

    PubMed Central

    An, Ran; Fang, Shuiyuan; Lin, Pengpeng; Xue, Jianhui; Yu, Shuiqiang

    2017-01-01

    Aquatic plants play an essential role and are effective in mitigating lake eutrophication by forming complex plant-soil system and retaining total nitrogen (TN) and phosphorus (TP) in soils to ultimately reduce their quantities in aquatic systems. Two main vegetation types (Phragmites australis community and P. australis + Typha latifolia community) of Qin Lake wetland were sampled in this study for the analysis of TN and TP contents and reserves in the wetland soils. The results showed that (1) the consumption effect of Qin Lake wetland on soluble N was much more significant than on soluble P. (2) The efficiency of TN enrichment in wetland soil was enhanced by vegetation covering of P. australis and T. latifolia. (3) Wetland soil P was consumed by P. australis community and this pattern was relieved with the introduction of T. latifolia. (4) According to the grey relativity analysis, the most intensive interaction between plants and soil occurred in summer. In addition, the exchange of N in soil-vegetation system primarily occurred in the 0–15 cm soil layer. Our results indicated that vegetation covering was essential to the enrichment of TN and TP, referring to the biology-related fixation in the wetland soil. PMID:28299233

  3. Expansion of Phragmites australis alters methane dynamics and methanogen, methanotroph, and sulfate reducing bacteria communities in tidal marsh in Korea

    NASA Astrophysics Data System (ADS)

    Kim, J.; Lee, J.; Kim, H.; Gauhar, M.; Kang, H.

    2016-12-01

    Plant invasion is known to change substantially methane dynamics in tidal marshes. However, the exact mechanisms related to methane dynamics change due to plant invasion have not been fully understood. In Suncheon Bay, South Korea, Phragmites australis has invaded the habitat of native species, Suaeda japonica, and becomes dominant vegetation in this area. We measured methane fluxes, soil biogeochemistry, and microbial communities from both vegetation sites throughout a growing season and conducted a chronosequence analysis in order to illustrate the effect of plant invasion on methane dynamics and microbial communities. For analyzing microbial communities, we collected 1m intact soil cores and conducted functional gene-targeted real-time qPCR, T-RFLP, and PLFA. P. australis invasion significantly increased methane emission in a summer season, accompanied by greater dissolved organic carbon and soil water content. Methanogen, methanotroph, and sulfate reducing bacterial communities were gradually changed along with the invasion periods. In particular, abundances ratio of mcrA/pmoA and mcrA/dsrA had a positive correlation with methane emission, which indicates that P. australis invasion reduces methane oxidation by methanotroph, and competitive inhibition between methanogen and sulfate reducing bacteria. In conclusion, P. australis invasion on S. japonica significantly increased methane emission in tidal marsh by altering the microbial communities in a way that C decomposition would be dominated by methanogenesis.

  4. Comparing the efficiency of Cyperus alternifolius and Phragmites australis in municipal wastewater treatment by subsurface constructed wetland.

    PubMed

    Shahi, Davod Hossein; Eslami, Hadi; Ehrampoosh, Mohamad Hasan; Ebrahimi, Asghar; Ghaneian, Mohamad Taghy; Ayatollah, Shirin; Mozayan, Mohamad Reza

    2013-04-15

    Nowadays, application of natural wastewater treatment systems such as wetland not only reduces economic costs and energy consumption, but also decreases environmental pollution. This study aimed to compare efficiency of Cyperus alternifolius and Phragmites australis in Municipal wastewater treatment by Subsurface Constructed Wetland Method. This is an applied-interventionnal study in which three reactors (control pilot, Cyperus alternifolius (umbrella palm) plant pilot and Phragmites australis (reed) plant pilot were designed by subsurface constructed wetland method. Then 90 samples were taken from input and output of reactors with four-day retention time. These samples were tested and finally the data were analyzed by Paired Sample Test statistical analysis. The results showed that removal efficiency of the parameters such as COD, BOD5, TSS, NO3-N, NH3-N, PO4-P, total coliform and fecal coliform was 74, 73, 84, 40, 36, 70, 33 and 38% in Cyperus alternifolius plant wetland, 44, 34, 77, 15, 0.3, 1, 17 and 26% in control wetland and 59, 54, 73, 6, 3, 10, 93 and 50 in Phragmites australis plant wetland, respectively. This reduction rate in all parameters- except fecal coliform- was statistically significant (p = 0.05). The results of this study showed that Cyperus alternifolius plant had higher efficiency in the removal of chemical parameters, whereas Phragmites australis plant had appropriate efficiency in the removal of microbiological parameters. Therefore, it can be concluded that application of these two plants can be effective in wastewater treatment.

  5. Effects of planting Phragmites australis on nitrogen removal, microbial nitrogen cycling, and abundance of ammonia-oxidizing and denitrifying microorganisms in sediments.

    PubMed

    Toyama, Tadashi; Nishimura, Yoshiko; Ogata, Yuka; Sei, Kazunari; Mori, Kazuhiro; Ike, Michihiko

    2015-10-21

    We examined the effect of planting an emergent aquatic plant (Phragmites australis) on nitrogen removal from sediments using a 42-d pot experiment. The experimental pot systems comprised two types of sediments planted with and without young P. australis. Total nitrogen (total N), total dissolved N, and NH4-N in the sediments decreased markedly after planting. In contrast, those levels decreased only slightly in the unplanted sediments. The decrease in total N in the P. australis-planted sediments was 7-20 times those in the unplanted sediments. Abundances of bacterial 16S rRNA, archaeal 16S rRNA, ammonia-oxidizing bacterial ammonia monooxygenase (amoA), ammonia-oxidizing archaeal amoA, and denitrifying bacterial nitrite reductase (nirK) genes increased significantly in sediments after planting. Phragmites australis appears to have released oxygen and created a repeating cycle of oxidizing and reducing conditions in the sediments. These conditions should promote mineralization of organic N, nitrification, and denitrification in the sediments. Phragmites australis absorbed bioavailable nitrogen generated by microbial nitrogen metabolism. During the 42-d period after planting, 31-44% of total N was removed by microbial nitrogen cycling, and 56-69% was removed via absorption by P. australis. These results suggest that planting P. australis can increase microbial populations and their activities, and that nitrogen removal can be accelerated by the combined functions of P. australis and microorganisms in the sediment. Thus, planting P. australis has considerable potential as an effective remediation technology for eutrophic sediments.

  6. The Australian mulga snake (Pseudechis australis: Elapidae): report of a large case series of bites and review of current knowledge.

    PubMed

    Razavi, Shahab; Weinstein, Scott A; Bates, David J; Alfred, Sam; White, Julian

    2014-07-01

    The mulga snake (Pseudechis australis) is the largest terrestrial venomous snake in Australia. It is capable of inflicting severe and occasionally fatal envenoming, but there have been few studies of P. australis bites. To highlight and reinforce the main features of P. australis envenoming and to provide a clearer picture of the epidemiology of bites from this species. Selected case records kept by the Toxinology Dept. (Women's and Children's Hospital, Adelaide, Australia) were reviewed retrospectively to determine definite P. australis bites. definite cases where the snake was identified by a competent person and/or lab specimens (bite site/urine) tested positive for "black snake" using CSL snake venom detection kit in a locality within the known range of P. australis, but without sympatry with other Pseudechis spp. where the snake could not be clearly identified under criteria above. Epidemiological and clinical information was recorded and analysed for the definite cases. A total of 27 cases were identified as definite P. australis bites; there were no fatalities. The median age was 35.5 years (IQR 51-23) and 80% of bites occurred in males. More bites occurred in the warmer months (Dec-March) and in those handling/interfering with snakes. Seven people were bitten whilst asleep at night. 21/27 patients developed systemic envenoming (based on signs, symptoms and laboratory results) and 17 cases received antivenom. Local bite site pain (18) and swelling (17) were common as were non-specific generalised symptoms such as nausea, vomiting and headache. Myotoxicity (11) and anticoagulant coagulopathy (10) occurred frequently; haemolysis was seen in fewer cases (3). Two patients developed local tissue injury around the bite site requiring further treatment. This study confirms previous reports about P. australis bites with respect to high rates of envenoming, commonly associated with pain and swelling and systemic effects of rhabdomyolysis and anticoagulant

  7. Automated Root Tracking with "Root System Analyzer"

    NASA Astrophysics Data System (ADS)

    Schnepf, Andrea; Jin, Meina; Ockert, Charlotte; Bol, Roland; Leitner, Daniel

    2015-04-01

    Crucial factors for plant development are water and nutrient availability in soils. Thus, root architecture is a main aspect of plant productivity and needs to be accurately considered when describing root processes. Images of root architecture contain a huge amount of information, and image analysis helps to recover parameters describing certain root architectural and morphological traits. The majority of imaging systems for root systems are designed for two-dimensional images, such as RootReader2, GiA Roots, SmartRoot, EZ-Rhizo, and Growscreen, but most of them are semi-automated and involve mouse-clicks in each root by the user. "Root System Analyzer" is a new, fully automated approach for recovering root architectural parameters from two-dimensional images of root systems. Individual roots can still be corrected manually in a user interface if required. The algorithm starts with a sequence of segmented two-dimensional images showing the dynamic development of a root system. For each image, morphological operators are used for skeletonization. Based on this, a graph representation of the root system is created. A dynamic root architecture model helps to determine which edges of the graph belong to an individual root. The algorithm elongates each root at the root tip and simulates growth confined within the already existing graph representation. The increment of root elongation is calculated assuming constant growth. For each root, the algorithm finds all possible paths and elongates the root in the direction of the optimal path. In this way, each edge of the graph is assigned to one or more coherent roots. Image sequences of root systems are handled in such a way that the previous image is used as a starting point for the current image. The algorithm is implemented in a set of Matlab m-files. Output of Root System Analyzer is a data structure that includes for each root an identification number, the branching order, the time of emergence, the parent

  8. Root gravitropism

    NASA Technical Reports Server (NTRS)

    Masson, P. H.

    1995-01-01

    When a plant root is reoriented within the gravity field, it responds by initiating a curvature which eventually results in vertical growth. Gravity sensing occurs primarily in the root tip. It may involve amyloplast sedimentation in the columella cells of the root cap, or the detection of forces exerted by the mass of the protoplast on opposite sides of its cell wall. Gravisensing activates a signal transduction cascade which results in the asymmetric redistribution of auxin and apoplastic Ca2+ across the root tip, with accumulation at the bottom side. The resulting lateral asymmetry in Ca2+ and auxin concentration is probably transmitted to the elongation zone where differential cellular elongation occurs until the tip resumes vertical growth. The Cholodny-Went theory proposes that gravity-induced auxin redistribution across a gravistimulated plant organ is responsible for the gravitropic response. However, recent data indicate that the gravity-induced reorientation is more complex, involving both auxin gradient-dependent and auxin gradient-independent events.

  9. Root (Botany)

    Treesearch

    Robert R. Ziemer

    1981-01-01

    Plant roots can contribute significantly to the stability of steep slopes. They can anchor through the soil mass into fractures in bedrock, can cross zones of weakness to more stable soil, and can provide interlocking long fibrous binders within a weak soil mass. In deep soil, anchoring to bedrock becomes negligible, and lateral reinforcement predominates

  10. Secrets to success.

    PubMed

    Sorrel, Amy Lynn

    2014-02-01

    A new national study reveals what it takes for physician practices to stay financially viable. Several Texas practices, among those rated as "better performers," share their secrets to success. One of those secrets, a physician says, is "hiring good people and getting out of their way."

  11. First molecular identification of Ascocotyle (Phagicola) longa in its first intermediate host the mud snail Heleobia australis.

    PubMed

    Alda, Pilar; Bonel, Nicolás; Panei, Carlos J; Cazzaniga, Néstor J; Martorelli, Sergio R

    2015-12-01

    This is the first study that used species-specific DNA primers to confirm the presence of the heterophyid Ascocotyle (Phagicola) longa Ransom, 1920 in its first intermediate host. The larval stages (rediae and cercariae) of this parasite were morphologically and genetically identified in the gonad of the intertidal mud snail Heleobia australis (d'Orbigny, 1835) (Cochliopidae) in the Bahía Blanca estuary, Argentina. In addition, we asked whether the prevalence in H. australis varied between seasons. Mullets - the second intermediate host of this heterophyid - migrate in estuaries during the warmer seasons and it is expected that piscivorous birds and mammals - the definitive hosts - prey more intensively on this species at those times. Thus, the number of parasite eggs released into the tidal flat within their feces should be higher, thereby increasing the ingestion of the parasite by H. australis.We therefore expected a higher prevalence of A. (P.) longa in H. australis in the Bahía Blanca estuary during spring and summer than autumn and winter. We found that 16 out of 2,744 specimens of H. australis had been infected with A. (P.) longa (total prevalence of 0.58%). Nonetheless, the prevalence showed no significant variation between seasons. Hence, we discuss an alternative scenario where the lack of seasonal changes might be mostly related to the permanent residence of definitive hosts in the estuary and not to the seasonal recruitment of mullets. Finally, we highlight the need for more experimental and comparative approaches in order to understand the diagnosis and geographical distribution of this worldwide heterophyid.

  12. Natural humic substances effects on the life history traits of Latonopsis australis SARS (1888) (Cladocera--Crustacea).

    PubMed

    de Carvalho-Pereira, Ticiana Soares de Andrade; Santos, Thirza de Santana; Pestana, Edilene M S; Souza, Fábio Neves; Lage, Vivian Marina Gomes Barbosa; Nunesmaia, Bárbara Janaína Bezerra; Sena, Palloma Thaís Souza; Mariano-Neto, Eduardo; da Silva, Eduardo Mendes

    2015-02-01

    Cultivation medium is one of the first aspects to be considered in zooplankton laboratory cultivation. The use of artificial media does not concern to reproduce natural conditions to the cultivations, which may be achieved by using natural organic compounds like humic substances (HS). This study aimed to evaluate the effects of a concentrate of dissolved organic carbon (DOC) from the Negro River (NR(1)) and an extraction of humic acids (HA) from humus produced by Eisenia andrei on the life history traits of laboratory-based Latonopsis australis SARS (1888). A cohort life table approach was used to provide information about the effectiveness of NR and HA as supplements for the artificial cultivation of L. australis. Additionally, we seek to observe a maximization of L. australis artificial cultivation fitness by expanding the range of HS concentrations. The first experiment demonstrated that the females of L. australis reared under NR10 (mgDOCL(-1)) may have experienced an acceleration of the population life cycle, as the females have proportionally reproduced more and lived shorter than controls. By contrast, the use of the HA did not improve life history traits considered. The expansion of the concentration range (5, 10, 20 and 50 mgDOCL(-1)) corroborated the patterns observed on the first assay. Results for the fitness estimates combined with shorter lifespans than controls demonstrated trade-offs between reproductive output and female longevity reared under NR conditions, with NR20 been suggested as the best L. australis cultivation medium. This response might be associated with hormone-like effects.

  13. Noise and gastric secretion.

    PubMed

    Tomei, F; Papaleo, B; Baccolo, T P; Persechino, B; Spanò, G; Rosati, M V

    1994-09-01

    In view of the increasing incidence of diseases such as gastritis and ulcers in workers exposed to noise, we assessed whether noise does in fact affect gastric secretion. Then, considering the conflicting findings published on the effects of noise on gastric secretion, we also investigated whether the response was related to differences in baseline secretion, and whether it was further modified by a hydroalcoholic meal. We studied 50 dyspeptic subjects engaged in various types of work but not occupationally exposed to noise. They were exposed to a "pink noise" stimulus of 95 dB administered through earphones, lasting 15 minutes. Gastric secretion sometimes remained unchanged, sometimes increased, or sometimes even decreased in relation to the baseline hydrochloric acid secretion. The hydroalcoholic meal did not generally modify the effects of noise. These findings might help explain the differences in previous reports on this question.

  14. Physiological ecology and functional traits of North American native and Eurasian introduced Phragmites australis lineages

    PubMed Central

    Mozdzer, Thomas J.; Brisson, Jacques; Hazelton, Eric L. G.

    2013-01-01

    Physiological ecology and plant functional traits are often used to explain plant invasion. To gain a better understanding of how traits influence invasion, studies usually compare the invasive plant to a native congener, but there are few conspecific examples in the literature. In North America, the presence of native and introduced genetic lineages of the common reed, Phragmites australis, presents a unique example to evaluate how traits influence plant invasion. We reviewed the literature on functional traits of P. australis lineages in North America, specifically contrasting lineages present on the Atlantic Coast. We focused on differences in physiology between the lineage introduced from Eurasia and the lineage native to North America, specifically seeking to identify the causes underlying the recent expansion of the introduced lineage. Our goals were to better understand which traits may confer invasiveness, provide predictions of how these lineages may respond to interspecific competition or imminent global change, and provide guidance for future research. We reviewed published studies and articles in press, and conducted personal communications with appropriate researchers and managers to develop a comparative dataset. We compared the native and introduced lineages and focused on plant physiological ecology and functional traits. Under both stressful and favourable conditions, our review showed that introduced P. australis consistently exhibited greater ramet density, height and biomass, higher and more plastic relative growth rate, nitrogen productivity and specific leaf area, higher mass specific nitrogen uptake rates, as well as greater phenotypic plasticity compared with the native lineage. We suggest that ecophysiological and other plant functional traits elucidate potential mechanisms for the introduced lineage's invasiveness under current and predicted global change conditions. However, our review identified a disconnect between field surveys

  15. Anti-Mayaro virus activity of Cassia australis extracts (Fabaceae, Leguminosae).

    PubMed

    Spindola, Kassia C W; Simas, Naomi K; Salles, Tiago S; de Meneses, Marcelo D F; Sato, Alice; Ferreira, Davis; Romão, Wanderson; Kuster, Ricardo M

    2014-11-27

    The arthropod-borne Mayaro virus (MAYV) causes 'Mayaro fever', a disease of medical significance, primarily affecting individuals in permanent contact with forested areas in tropical South America. Studies showed that the virus could also be transmitted by the mosquito Aedes aegypti. Recently, MAYV has attracted attention due to its likely urbanization. To date, there are no drugs that can treat this illness. Fractions and compounds were obtained by chromatography from leaf extracts of C. australis and chemically identified as flavonoids and condensed tannins using spectroscopic and spectrometric techniques (UV, NMR, and ESI-FT-ICR MS). Cytotoxicity of EtOAc, n-BuOH and EtOAc-Pp fractions were measured by the dye-uptake assay while their antiviral activity was evaluated by a virus yield inhibition assay. Larvicidal activity was measured by the procedures recommended by the WHO expert committee for determining acute toxicity. The following group of substances was identified from EtOAc, n-BuOH and EtOAc-Pp fractions: flavones, flavonols, and their glycosides and condensed tannins. EtOAc and n-BuOH fractions inhibited MAYV production, respectively, by more than 70% and 85% at 25 μg/mL. EtOAc-Pp fraction inhibited MAYV production by more than 90% at 10 μg/mL, displaying a stronger antiviral effect than the licensed antiviral ribavirin. This fraction had an excellent antiviral effect (IC90 = 4.7 ± 0.3 μg/mL), while EtOAc and n-BuOH fractions were less active (IC90 = 89.1 ± 4.4 μg/mL and IC90 = 40.9 ± 5.7 μg/mL, respectively). C. australis can be used as a source of compounds with anti-Mayaro virus activity. This is the first report on the biological activity of C. australis.

  16. Pathology in skeletons of Peale's dolphin Lagenorhynchus australis from southern South America.

    PubMed

    San Martín, Analía A; Macnie, Silvina V; Goodall, R Natalie P; Boy, Claudia C

    2016-06-15

    Peale's dolphin Lagenorhynchus australis is frequently seen off the coast of southern South America, where it feeds among coastal kelp beds and occasionally strands. We searched for macroscopic evidence of skeletal lesions in 78 specimens of Peale's dolphin from 2 museum collections, which contain almost all of the species' skeletons known in collections worldwide. Thirty-two specimens (41%) had some type of osteological abnormalities. In 21 cases (66%), congenital deformations were the most predominant abnormality found. Acquired lesions included (1) induced trauma: abnormal curvature (n=5 specimens) and fractures (n=2); (2) infectious diseases: spondylo-osteomyelitis (n=3); and (3) degenerative diseases: exostoses (n=8) and spondylosis deformans (n=4). It is noteworthy that all of these animals died incidentally in gillnet entanglement and were presumably healthy at the time of death. The effect that different osseous lesions may have on an animal's quality of life may depend on the area of the spine affected and the number of vertebrae involved.

  17. Palatability and chemical defense of Phragmites australis to the marsh periwinkle snail Littoraria irrorata.

    PubMed

    Hendricks, Lindsey G; Mossop, Hannah E; Kicklighter, Cynthia E

    2011-08-01

    Coastal marsh habitats are impacted by many disturbances, including habitat destruction, pollution, and the introduction of invasive species. The common reed, Phragmites australis, has been particularly invasive in the mesohaline regions of the Chesapeake Bay, but few studies have investigated its role in trophic interactions with North American marsh consumers. The marsh periwinkle snail Littoraria irrorata is a common grazer in marshes and grazes on the native grass Spartina alterniflora. Whether this snail grazes on Phragmites has not been addressed. We found Spartina leaves to be tougher than those of Phragmites, but despite this, snails consumed significantly more Spartina than Phragmites. Subsequent experiments demonstrated that Phragmites is chemically deterrent to snails by an unknown, moderately polar, compound. Further studies are required to more fully understand the interactions between Phragmites, herbivores, and Spartina, and how they may impact marsh ecosystems.

  18. Severe soft tissue ossification in a southern right whale Eubalaena australis.

    PubMed

    La Sala, Luciano F; Pozzi, Luciana M; McAloose, Denise; Kaplan, Frederick S; Shore, Eileen M; Kompanje, Erwin J O; Sidor, Inga F; Musmeci, Luciana; Uhart, Marcela M

    2012-12-27

    The carcass of a stranded southern right whale Eubalaena australis, discovered on the coast of Golfo Nuevo in Península Valdés, Argentina, exhibited extensive orthotopic and heterotopic ossification, osteochondroma-like lesions, and early degenerative joint disease. Extensive soft tissue ossification led to ankylosis of the axial skeleton in a pattern that, in many respects, appeared more similar to a disabling human genetic disorder, fibrodysplasia ossificans progressiva (FOP), than to more common skeletal system diseases in cetaceans and other species. This is the first reported case of a FOP-like condition in a marine mammal and raises important questions about conserved mechanisms of orthotopic and heterotopic ossification in this clade.

  19. Severe soft tissue ossification in a southern right whale Eubalaena australis

    PubMed Central

    Sala, Luciano F. La; Pozzi, Luciana M.; McAloose, Denise; Kaplan, Frederick S.; Shore, Eileen M.; Kompanje, Erwin J. O.; Sidor, Inga F.; Musmeci, Luciana; Uhart, Marcela M.

    2013-01-01

    The carcass of a stranded southern right whale Eubalaena australis, discovered on the coast of Golfo Nuevo in Península Valdés, Argentina, exhibited extensive orthotopic and heterotopic ossification, osteochondroma-like lesions, and early degenerative joint disease. Extensive soft tissue ossification led to ankylosis of the axial skeleton in a pattern that, in many respects, appeared more similar to a disabling human genetic disorder, fibrodysplasia ossificans progressiva (FOP), than to more common skeletal system diseases in cetaceans and other species. This is the first reported case of a FOP-like condition in a marine mammal and raises important questions about conserved mechanisms of orthotopic and heterotopic ossification in this clade. PMID:23269389

  20. Mapping the change of Phragmites australis live biomass in the lower Mississippi River Delta marshes

    USGS Publications Warehouse

    Ramsey, Elijah W.; Rangoonwala, Amina

    2017-07-28

    Multiyear remote sensing mapping of the normalized difference vegetation index (NDVI) was carried out as an indicator of live biomass composition of the Phragmites australis (hereafter Phragmites) marsh in the lower Mississippi River Delta (hereafter delta) from 2014 to 2017. Maps of NDVI change showed that the Phragmites condition was fairly stable between May 2014 and July 2015. From July 2015 to April 2016 NDVI change indicated Phragmites suffered a widespread decline in the live biomass proportion.  Between April and September 2016, most marsh remained unchanged from the earlier period or showed improvement; although there were pockets of continued decline scattered throughout the lower delta. From September 2016 to May 2017 a pronounced and widely exhibited decline in the condition of Phragmites marsh again occurred throughout the lower delta. This final NDVI change mapping supported field observations of Phragmites decline during the same period.

  1. IRAS observations of young stellar objects in the Corona Australis dark cloud

    NASA Technical Reports Server (NTRS)

    Wilking, Bruce A.; Greene, Thomas P.; Lada, Charles J.; Meyer, Michael R.; Young, Erick T.

    1992-01-01

    The young stellar object (YSO) population associated with the dark cloud complex in Corona Australis is studied by synthesizing IRAS data with newly obtained near-IR and mid-IR photometry and previously published optical/IR data. Twenty-four YSOs in the Cr A complex are identified. The observed range of spectral energy distribution shapes and bolometric luminosities are consistent with those observed in other dark clouds. The duration and efficiency of star formation are found to be similar to the Rho Ophiuchi IR cluster. The low number of YSOs compared to other dark clouds is understood by a reevaluation of the molecular mass of the R Cr A cloud which shows it to be much less massive than previously assumed.

  2. New cladiellane diterpenes from the soft coral Cladiella australis of the Andaman and Nicobar Islands.

    PubMed

    Rao, C B; Rao, D S; Satyanarayana, C; Rao, D V; Kassühlke, K E; Faulkner, D J

    1994-05-01

    Five new cladiellane diterpenes, (1R*,2R*,3R*,6S*,7S*,9R*,10R*,14R*)-3- acetoxy-6-(3-methylbutanoyloxy)cladiell-11(17)-en-7-ol [2], (1R*,2R*,3R*,6S*,7S*,9R*, 10R*,14R*)-3-butanoyloxycladiell-11(17)-en-6,7-diol [3], (1R*,2R*,3R*,6S*,9R*,10R*,14R*)-3-acetoxycladiell-7(16),11(1 7)-dien-6-ol [4], 3-acetoxycladiell-11(17)-en-6-one [5], and its stereoisomer [6], have been isolated from the soft coral Cladiella australis collected on the coasts of the Andaman and Nicobar Islands of the Indian Ocean. In addition, sclerophytins C [7] and E [8], reported earlier from Sclerophytum capitalis, were also isolated. The structures of these metabolites were elucidated by interpretation of spectral data.

  3. Metazoan parasites of Brama australis from southern Chile: a tool for stock discrimination?

    PubMed

    Oliva, M E; Espinola, J F; Ñacari, L A

    2016-03-01

    The metazoan parasites of 403 specimens of the southern ray's bream Brama australis from three localities in southern Chile (Lebu 36° 70' S; 73° 40' W, Calbuco 41° 50' S; 73° 08' W and Punta Arenas 53° 10' S; 70° 50' W) were recorded. More than 23 400 parasite specimens belonging to 12 taxa were registered. Metazoan parasites were dominated by the copepod Hatschekia conifera, constituting 97% of the total number of parasites; the larval cestode Hepatoxylon trichiuri was the second most important parasite (2·1% of the total number of parasites). The remaining 10 species constituted <1% of the metazoan parasites. Parasitological evidence, based on univariate and multivariate analysis, does not support the existence of discrete stocks in the studied zone. © 2016 The Fisheries Society of the British Isles.

  4. TSH secreting pituitary adenoma.

    PubMed

    Jha, S; Kumar, S

    2009-07-01

    Thyrotropin (TSH) secreting pituitary adenomas are a very rare cause of hyperthyroidism. They typically present with signs and symptoms of hyperthyroidism and rarely can be asymptomatic. TSH secreting tumors account for 1 percent of all pituitary adenoma. They are a rare cause of thyrotoxicosis in which adenomas completely or partially lose feedback regulation of thyroid hormones and lead to sustained stimulation of thyroid gland. The most definitive treatment of thyrotropin (TSH)-secreting pituitary adenomas is transsphenoidal removal of tumor after restoring euthyroidism. We report a case of pituitary adenoma associated with elevated serum free thyroid hormones and non-suppressed TSH levels.

  5. Macroinvertebrates communities associated with the decomposition of Phragmites australis and Fucus vesiculosus in transitional systems

    NASA Astrophysics Data System (ADS)

    Lopes, Marta Lobão; Martins, Patrícia; Rodrigues, Ana Maria; Quintino, Victor

    2013-10-01

    The decomposition rates of a macrophyte (Phragmites australis) and an alga (Fucus vesiculosus) and the associated macrofauna communities were studied along a full salinity gradient, using the leaf-bag technique and four sampling times (days 3, 7, 15 and 30). A control was set up using an artificial substrate. A subsequent study conducted in the mesohaline part of the salinity gradient also included empty bags as procedure control. The decay rates of the alga and the macrophyte were significantly different, the alga decaying faster, and presented an opposite trend along the salinity gradient, with the faster decay rate for reed in the less saline areas and for the alga in the euhaline part of the gradient. The fauna associated with the decaying and the artificial substrate showed equally well the benthic succession from the marine to the freshwater areas, in all sampling times. Arthropods were dominant in all substrates along the estuarine gradient and replaced by annelids in freshwater. No significant differences were found between the benthic communities associated with P. australis and F. vesiculosus, despite the strong differences in the decay rates, suggesting that these do not seem to be primarily related to the benthic colonizers. Although the organic substrates sustained a more abundant fauna, the benthic communities did not show significant differences between the organic and the artificial substrates, especially at the level of the species composition, suggesting that the macroinvertebrates may colonize both substrates to feed on the biofilm and/or to seek shelter. The strongly impoverished benthic community sampled by the empty bags reinforced this idea.

  6. Uptake of carbamazepine by rhizomes and endophytic bacteria of Phragmites australis.

    PubMed

    Sauvêtre, Andrés; Schröder, Peter

    2015-01-01

    Carbamazepine is an antiepileptic and mood-stabilizing drug which is used widely in Europe and North America. In the environment, it is found as a persistent and recalcitrant contaminant, being one of the most prominent hazardous pharmaceuticals and personal care products in effluents of wastewater treatment plants. Phragmites australis is one of the species with both, the highest potential of detoxification and phytoremediation. It has been used successfully in the treatment of industrial and municipal wastewater. Recently, the identification of endophytic microorganisms from different plant species growing in contaminated sites has provided a list of candidates which could be used as bio-inoculants for bioremediation of difficult compounds. In this study, Phragmites australis plants were exposed to 5 mg/L of carbamazepine. After 9 days the plants had removed 90% of the initial concentration. Endophytic bacteria were isolated from these plants and further characterized. Phylogenetic analysis based on 16S rDNA sequencing revealed that the majority of these isolates belong to three groups: Proteobacteria, Actinobacteria, and Bacteroidetes. Carbamazepine uptake and plant growth promoting (PGP) traits were analyzed among the isolates. Ninety percent of the isolates produce indole acetic acid (IAA) and all of them possess at least one of the PGP traits tested. One isolate identified as Chryseobacterium taeanense combines good carbamazepine uptake and all of the PGP traits. Rhizobium daejeonense can remove carbamazepine and produces 23 μg/mL of IAA. Diaphorobacter nitroreducens and Achromobacter mucicolens are suitable for carbamazepine removal while both, Pseudomonas veronii and Pseudomonas lini show high siderophore production and phosphate solubilization. Alone or in combination, these isolates might be applied as inoculates in constructed wetlands in order to enhance the phytoremediation of carbamazepine during wastewater treatment.

  7. Decomposition of Phragmites australis rhizomes in artificial land-water transitional zones (ALWTZs) and management implications

    NASA Astrophysics Data System (ADS)

    Han, Zhen; Cui, Baoshan; Zhang, Yongtao

    2015-09-01

    Rhizomes are essential organs for growth and expansion of Phragmites australis. They function as an important source of organic matter and as a nutrient source, especially in the artificial land-water transitional zones (ALWTZs) of shallow lakes. In this study, decomposition experiments on 1- to 6-year-old P. australis rhizomes were conducted in the ALWTZ of Lake Baiyangdian to evaluate the contribution of the rhizomes to organic matter accumulation and nutrient release. Mass loss and changes in nutrient content were measured after 3, 7, 15, 30, 60, 90, 120, and 180 days. The decomposition process was modeled with a composite exponential model. The Pearson correlation analysis was used to analyze the relationships between mass loss and litter quality factors. A multiple stepwise regression model was utilized to determine the dominant factors that affect mass loss. Results showed that the decomposition rates in water were significantly higher than those in soil for 1- to 6-year-old rhizomes. However, the sequence of decomposition rates was identical in both water and soil. Significant relationships between mass loss and litter quality factors were observed at a later stage, and P-related factors proved to have a more significant impact than N-related factors on mass loss. According to multiple stepwise models, the C/P ratio was found to be the dominant factor affecting the mass loss in water, and the C/N and C/P ratios were the main factors affecting the mass loss in soil. The combined effects of harvesting, ditch broadening, and control of water depth should be considered for lake administrators.

  8. Soil pathogen communities associated with native and non-native Phragmites australis populations in freshwater wetlands

    PubMed Central

    Nelson, Eric B; Karp, Mary Ann

    2013-01-01

    Soil pathogens are believed to be major contributors to negative plant–soil feedbacks that regulate plant community dynamics and plant invasions. While the theoretical basis for pathogen regulation of plant communities is well established within the plant–soil feedback framework, direct experimental evidence for pathogen community responses to plants has been limited, often relying largely on indirect evidence based on above-ground plant responses. As a result, specific soil pathogen responses accompanying above-ground plant community dynamics are largely unknown. Here, we examine the oomycete pathogens in soils conditioned by established populations of native noninvasive and non-native invasive haplotypes of Phragmites australis (European common reed). Our aim was to assess whether populations of invasive plants harbor unique communities of pathogens that differ from those associated with noninvasive populations and whether the distribution of taxa within these communities may help to explain invasive success. We compared the composition and abundance of pathogenic and saprobic oomycete species over a 2-year period. Despite a diversity of oomycete taxa detected in soils from both native and non-native populations, pathogen communities from both invaded and noninvaded soils were dominated by species of Pythium. Pathogen species that contributed the most to the differences observed between invaded and noninvaded soils were distributed between invaded and noninvaded soils. However, the specific taxa in invaded soils responsible for community differences were distinct from those in noninvaded soils that contributed to community differences. Our results indicate that, despite the phylogenetic relatedness of native and non-native P. australis haplotypes, pathogen communities associated with the dominant non-native haplotype are distinct from those of the rare native haplotype. Pathogen taxa that dominate either noninvaded or invaded soils suggest different potential

  9. Pharmacokinetics and pharmacodynamics of the myotoxic venom of Pseudechis australis (mulga snake) in the anesthetised rat.

    PubMed

    Hart, A J; Hodgson, W C; O'Leary, M; Isbister, G K

    2014-07-01

    Myotoxicity is a common clinical effect of snake envenoming and results from either local or systemic myotoxins in snake venoms. Although numerous myotoxins have been isolated from snake venoms, there has been limited study on the relationship between the time course of venom concentrations (pharmacokinetics) and the time course of muscle injury measured as a rise in creatine kinase (CK) (pharmacodynamics). The aim of this study was to develop an in vivo model of myotoxicity to investigate the time course of myotoxicity and the effect of antivenom. Anesthetised rats were administered Pseudechis australis (mulga snake) venom either through i.v., i.m. or s.d. route, including a range of doses (5-100 μg/kg). Serial blood samples were collected for measurement of venom using enzyme immunoassay and measurement of CK and creatinine. Antivenom was administered before, 1 and 6 h after venom administration to investigate its effect on muscle injury. Plots of venom and CK versus time were made and the area under the curve (AUC) was calculated. There was a significant dose-dependent increase in CK concentration after administration of P. australis venom, which was greatest for i.v. administration. Timed measurement of venom concentrations showed a rapid absorption through s.d. and i.m. routes and a delayed rise in CK concentrations following any route. Antivenom prevented myotoxicity shown by a decrease in the CK AUC, which was most effective if given earliest. There was a rise in creatinine following i.v. venom administration. The study shows the delayed relationship between venom absorption and the rise in CK, consistent with the delayed onset of myotoxicity in human envenoming. Antivenom prevented myotoxicity more effectively if given earlier.

  10. Retinal Amino Acid Neurochemistry of the Southern Hemisphere Lamprey, Geotria australis

    PubMed Central

    Nivison-Smith, Lisa; Collin, Shaun P.; Zhu, Yuan; Ready, Sarah; Acosta, Monica L.; Hunt, David M.; Potter, Ian C.; Kalloniatis, Michael

    2013-01-01

    Lampreys are one of the two surviving groups of the agnathan (jawless) stages in vertebrate evolution and are thus ideal candidates for elucidating the evolution of visual systems. This study investigated the retinal amino acid neurochemistry of the southern hemisphere lamprey Geotria australis during the downstream migration of the young, recently-metamorphosed juveniles to the sea and during the upstream migration of the fully-grown and sexually-maturing adults to their spawning areas. Glutamate and taurine were distributed throughout the retina, whilst GABA and glycine were confined to neurons of the inner retina matching patterns seen in most other vertebrates. Glutamine and aspartate immunoreactivity was closely matched to Müller cell morphology. Between the migratory phases, few differences were observed in the distribution of major neurotransmitters i.e. glutamate, GABA and glycine, but changes in amino acids associated with retinal metabolism i.e. glutamine and aspartate, were evident. Taurine immunoreactivity was mostly conserved between migrant stages, consistent with its role in primary cell functions such as osmoregulation. Further investigation of glutamate signalling using the probe agmatine (AGB) to map cation channel permeability revealed entry of AGB into photoreceptors and horizontal cells followed by accumulation in inner retinal neurons. Similarities in AGB profiles between upstream and downstream migrant of G. australis confirmed the conservation of glutamate neurotransmission. Finally, calcium binding proteins, calbindin and calretinin were localized to the inner retina whilst recoverin was localized to photoreceptors. Overall, conservation of major amino acid neurotransmitters and calcium-associated proteins in the lamprey retina confirms these elements as essential features of the vertebrate visual system. On the other hand, metabolic elements of the retina such as neurotransmitter precursor amino acids and Müller cells are more sensitive

  11. Edge Effects along a Seagrass Margin Result in an Increased Grazing Risk on Posidonia australis Transplants

    PubMed Central

    Statton, John; Gustin-Craig, Samuel; Dixon, Kingsley W.; Kendrick, Gary A.

    2015-01-01

    A key issue in habitat restoration are the changes in ecological processes that occur when fragments of habitat are lost, resulting in the persistence of habitat-degraded margins. Margins often create or enhance opportunities for negative plant-herbivore interactions, preventing natural or assisted re-establishment of native vegetation into the degraded area. However, at some distance from the habitat margin these negative interactions may relax. Here, we posit that the intensity of species interactions in a fragmented Posidonia australis seagrass meadow may be spatially dependent on proximity to the seagrass habitat edge, whereby the risk of grazing is high and the probability of survival of seagrass transplants is low. To test this, transplants were planted 2 m within the meadow, on the meadow edge at 0m, and at 2m, 10m, 30m, 50m and 100m distance from the edge of the seagrass meadow into the unvegetated sand sheet. There was an enhanced grazing risk 0-10m from the edge, but decreased sharply with increasing distances (>30m). Yet, the risk of grazing was minimal inside the seagrass meadow, indicating that grazers may use the seagrass meadow for refuge but are not actively grazing within it. The relationship between short-term herbivory risk and long-term survival was not straightforward, suggesting that other environmental filters are also affecting survival of P. australis transplants within the study area. We found that daily probability of herbivory was predictable and operating over a small spatial scale at the edge of a large, intact seagrass meadow. These findings highlight the risk from herbivory can be high, and a potential contributing factor to seagrass establishment in restoration programs. PMID:26465926

  12. Uptake of carbamazepine by rhizomes and endophytic bacteria of Phragmites australis

    PubMed Central

    Sauvêtre, Andrés; Schröder, Peter

    2015-01-01

    Carbamazepine is an antiepileptic and mood-stabilizing drug which is used widely in Europe and North America. In the environment, it is found as a persistent and recalcitrant contaminant, being one of the most prominent hazardous pharmaceuticals and personal care products in effluents of wastewater treatment plants. Phragmites australis is one of the species with both, the highest potential of detoxification and phytoremediation. It has been used successfully in the treatment of industrial and municipal wastewater. Recently, the identification of endophytic microorganisms from different plant species growing in contaminated sites has provided a list of candidates which could be used as bio-inoculants for bioremediation of difficult compounds. In this study, Phragmites australis plants were exposed to 5 mg/L of carbamazepine. After 9 days the plants had removed 90% of the initial concentration. Endophytic bacteria were isolated from these plants and further characterized. Phylogenetic analysis based on 16S rDNA sequencing revealed that the majority of these isolates belong to three groups: Proteobacteria, Actinobacteria, and Bacteroidetes. Carbamazepine uptake and plant growth promoting (PGP) traits were analyzed among the isolates. Ninety percent of the isolates produce indole acetic acid (IAA) and all of them possess at least one of the PGP traits tested. One isolate identified as Chryseobacterium taeanense combines good carbamazepine uptake and all of the PGP traits. Rhizobium daejeonense can remove carbamazepine and produces 23 μg/mL of IAA. Diaphorobacter nitroreducens and Achromobacter mucicolens are suitable for carbamazepine removal while both, Pseudomonas veronii and Pseudomonas lini show high siderophore production and phosphate solubilization. Alone or in combination, these isolates might be applied as inoculates in constructed wetlands in order to enhance the phytoremediation of carbamazepine during wastewater treatment. PMID:25750647

  13. Non-linear growth in tree ferns, Dicksonia antarctica and Cyathea australis

    PubMed Central

    Blair, David P.; Blanchard, Wade; Banks, Sam C.; Lindenmayer, David B.

    2017-01-01

    Tree ferns are an important structural component of forests in many countries. However, because their regeneration is often unrelated to major disturbances, their age is often difficult to determine. In addition, rates of growth may not be uniform, which further complicates attempts to determine their age. In this study, we measured 5 years of growth of Cyathea australis and Dicksonia antarctica after a large wildfire in 2009 in south-eastern Australia. We found growth rates of these two species were unaffected by aspect and elevation but slope had a minor effect with D. antarctica growing 0.3mm faster for each additional degree of slope. Geographic location influenced growth in both species by up to 12 – 14mm/yr. The most consistent factor influencing growth rate, however, was initial height at the time of the 2009 fire; a finding consistent in both species and all geographic locations. For both tree fern species, individuals that were taller at the commencement of the study had greater overall growth for the duration of the study. This effect did not decrease even among the tallest tree ferns in our study (up to 6 metres tall). Overall, Cyathea australis averaged 73 (± 22)mm/year of growth (± 1SD), with the rate increasing 5mm/yr per metre of additional height. Dicksonia antarctica averaged 33 (± 13)mm/year, increasing by 6mm/yr/m. Growth rates dependent on initial height were unexpected and we discuss possible reasons for this finding. Variable growth rates also suggest that common age estimation methods of dividing height by average growth rate are likely to underestimate the age of short tree ferns, while overestimating the age of tall tree ferns, particularly if they have been subject to a fire. PMID:28493884

  14. Non-linear growth in tree ferns, Dicksonia antarctica and Cyathea australis.

    PubMed

    Blair, David P; Blanchard, Wade; Banks, Sam C; Lindenmayer, David B

    2017-01-01

    Tree ferns are an important structural component of forests in many countries. However, because their regeneration is often unrelated to major disturbances, their age is often difficult to determine. In addition, rates of growth may not be uniform, which further complicates attempts to determine their age. In this study, we measured 5 years of growth of Cyathea australis and Dicksonia antarctica after a large wildfire in 2009 in south-eastern Australia. We found growth rates of these two species were unaffected by aspect and elevation but slope had a minor effect with D. antarctica growing 0.3mm faster for each additional degree of slope. Geographic location influenced growth in both species by up to 12 - 14mm/yr. The most consistent factor influencing growth rate, however, was initial height at the time of the 2009 fire; a finding consistent in both species and all geographic locations. For both tree fern species, individuals that were taller at the commencement of the study had greater overall growth for the duration of the study. This effect did not decrease even among the tallest tree ferns in our study (up to 6 metres tall). Overall, Cyathea australis averaged 73 (± 22)mm/year of growth (± 1SD), with the rate increasing 5mm/yr per metre of additional height. Dicksonia antarctica averaged 33 (± 13)mm/year, increasing by 6mm/yr/m. Growth rates dependent on initial height were unexpected and we discuss possible reasons for this finding. Variable growth rates also suggest that common age estimation methods of dividing height by average growth rate are likely to underestimate the age of short tree ferns, while overestimating the age of tall tree ferns, particularly if they have been subject to a fire.

  15. Water and Energy Balance in Response to the Removal of Invasive Phragmites Australis in a Riparian Wetland

    NASA Astrophysics Data System (ADS)

    Mykleby, P.; Lenters, J. D.; Cutrell, G. J.; Herrman, K.; Istanbulluoglu, E.; Scott, D.

    2011-12-01

    Vegetation plays an important role in the surface energy and water balance of wetlands. Transpiration from phreatophytes, in particular, withdraws water directly from groundwater, often impacting streamflow rates in adjacent tributaries. In the Republican River basin of the Central Plains (USA), streamflow has declined significantly in the past 30-40 years. Invasive vegetation species (such as Phragmites australis) have been removed from portions of the riparian corridor in an effort to halt or reverse the downward trend in streamflow. In this study, we investigated the energy and water balance of a P. australis-dominated riparian wetland in south-central Nebraska to assess the potential effectiveness of such an approach. Evapotranspiration (ET) rates were measured during two growing seasons - one being 2009, when the P. australis was at full growth, and the other during 2010, after the vegetation had been sprayed with herbicide (and remained only as dead, standing biomass). Energy balance measurements at the field site included net radiation, heat storage rates in the canopy, soil, and standing water, and sensible heat flux, which was measured using a large-aperture scintillometer (LAS). Latent heat flux (i.e., ET) was calculated as a residual of the energy balance, and comparisons were made between the two growing seasons. As a result of the spraying of the P. australis vegetation, season-mean ET rates dropped from 4.4 mm day-1 in 2009 to 3.0 mm day-1 in 2010. This decrease in ET was associated with a large increase in sensible heat flux, which more than doubled between the two years (from 33 W m-2 in 2009 to 76 W m-2 in 2010). Meteorological conditions at the site were slightly different from one year to the next, but the differences were not large enough to account for the dramatic changes in latent and sensible heat flux that were observed. We conclude, therefore, that the majority of the ~30% decrease in ET (and ~130% increase in sensible heat flux) was the

  16. Six secrets of champagne

    NASA Astrophysics Data System (ADS)

    Liger-Belair, Gérard

    2015-12-01

    Popping open a bottle of champagne is one of life's great delights, but how much do you really know about the science behind this greatest of wines? Gérard Liger-Belair reveals his six favourite champagne secrets.

  17. Type VI secretion system.

    PubMed

    Salomon, Dor; Orth, Kim

    2015-03-30

    Bacteria employ a variety of tools to survive in a competitive environment. Salomon and Orth describe one such tool-the Type 6 Secretion Systems used by bacteria to deliver a variety of toxins into competing cells.

  18. Secret quality of love.

    PubMed

    Strachan-Hall, Elaine

    2016-09-01

    Many of us can recite three Donabedian dimensions of the quality of care of structure, process and outcome. Recently, I was introduced to another of Avedis Donabedian's quotes about the 'secret quality of love'.

  19. Haemophilus paragallinarum secretes metalloproteases.

    PubMed

    Rivero-García, P C; Cruz, C Vázquez; Alonso, P Sánchez; Vaca, S; Negrete-Abascal, E

    2005-10-01

    Haemophilus paragallinarum secretes metalloproteases into different culture media lacking serum. Secreted proteins, concentrated by precipitation with 70% ammonium sulphate ((NH(4))(2)SO(4)) or methanol, displayed proteolytic activity at >100 kDa molecular mass in 10% polyacrylamide gels co-polymerized with porcine gelatin (0.1%). They were active in a broad pH range (4-9); pH 7.5 being the optimum. Protease activity was inhibited by 20 mmol EDTA/L and reactivated by calcium. The proteolytic activity was heat-stable at 40, 50, and 60 degrees C, but its activity diminished at 70 degrees C or higher. Secreted proteins partially degraded chicken immunoglobulin G (IgG) and cross-reacted with a polyclonal serum against a high molecular mass protease secreted by Actinobacillus pleuropneumoniae. Extracellular proteases could play a role in infectious coryza caused by H. paragallinarum.

  20. Positive Root Bounds and Root Separation Bounds

    NASA Astrophysics Data System (ADS)

    Herman, Aaron Paul

    In this thesis, we study two classes of bounds on the roots of a polynomial (or polynomial system). A positive root bound of a polynomial is an upper bound on the largest positive root. A root separation bound of a polynomial is a lower bound on the distance between the roots. Both classes of bounds are fundamental tools in computer algebra and computational real algebraic geometry, with numerous applications. In the first part of the thesis, we study the quality of positive root bounds. Higher quality means that the relative over-estimation (the ratio of the bound and the largest positive root) is smaller. We find that all known positive root bounds can be arbitrarily bad. We then show that a particular positive root bound is tight for certain important classes of polynomials. In the remainder of the thesis, we turn to root separation bounds. We observe that known root separation bounds are usually very pessimistic. To our surprise, we also find that known root separation bounds are not compatible with the geometry of the roots (unlike positive root bounds). This motivates us to derive new root separation bounds. In the second part of this thesis, we derive a new root separation for univariate polynomials by transforming a known bound into a new improved bound. In the third part of this thesis, we use a similar strategy to derive a new improved root separation bound for polynomial systems.

  1. Efficient quantum secret sharing

    NASA Astrophysics Data System (ADS)

    Qin, Huawang; Dai, Yuewei

    2016-05-01

    An efficient quantum secret sharing scheme is proposed, in which the dealer generates some single particles and then uses the operations of quantum-controlled-not and Hadamard gate to encode a determinate secret into these particles. The participants get their shadows by performing the single-particle measurements on their particles, and even the dealer cannot know their shadows. Compared to the existing schemes, our scheme is more practical within the present technologies.

  2. Environmental effects of dredging. Role of contaminant uptake in the potential use of phragmites australis (cav.) trin. On confined disposal facilities. Technical notes

    SciTech Connect

    Folsom, B.L.; VanDerWerff, M.

    1988-12-01

    PURPOSE: Phragmites australis (Cav.) Trin., common reed, is a plant species that is common to fresh- and brackish-water marshes of the world. P. australis has been recommended as one plant species that could survive and grow after being completely buried during dredged material disposal (Lee et al. 1976). P. australis can also serve as a physical barrier, because of its strong stems, to dredged material flow during hydraulic disposal. Decreasing dredged material flow helps to increase consolidation of hydraulically dredged material (Lee et al. 1976). P. australis is a plant species recommended for habitat development on dredged material disposal sites (Hunt et al. 1978). Plant establishment on marsh creation projects using uncontaminated dredged material poses little threat of increasing environmental cycling of contaminants. However, plant establishment or natural invasion of plants on contaminated dredged material has the potential for increased environmental cycling (mobility) of contaminants. Therefore, a literature review was conducted to determine contaminant uptake by P. australis since many dredged material disposal sites support lush stands of P. australis and contaminant uptake by this species was unknown.

  3. Multilayer quantum secret sharing based on GHZ state and generalized Bell basis measurement in multiparty agents

    NASA Astrophysics Data System (ADS)

    Wang, Xiao-Jun; An, Long-Xi; Yu, Xu-Tao; Zhang, Zai-Chen

    2017-10-01

    A multilayer quantum secret sharing protocol based on GHZ state is proposed. Alice has the secret carried by quantum state and wants to distribute this secret to multiple agent nodes in the network. In this protocol, the secret is transmitted and shared layer by layer from root Alice to layered agents. The number of agents in each layer is a geometric sequence with a specific common ratio. By sharing GHZ maximally entangled states and making generalized Bell basis measurement, one qubit state can be distributed to multiparty agents and the secret is shared. Only when all agents at the last layer cooperate together, the secret can be recovered. Compared with other protocols based on the entangled state, this protocol adopts layered construction so that secret can be distributed to more agents with fewer particles GHZ state. This quantum secret sharing protocol can be used in wireless network to ensure the security of information delivery.

  4. Metabolic priming by a secreted fungal effector.

    PubMed

    Djamei, Armin; Schipper, Kerstin; Rabe, Franziska; Ghosh, Anupama; Vincon, Volker; Kahnt, Jörg; Osorio, Sonia; Tohge, Takayuki; Fernie, Alisdair R; Feussner, Ivo; Feussner, Kirstin; Meinicke, Peter; Stierhof, York-Dieter; Schwarz, Heinz; Macek, Boris; Mann, Matthias; Kahmann, Regine

    2011-10-05

    Maize smut caused by the fungus Ustilago maydis is a widespread disease characterized by the development of large plant tumours. U. maydis is a biotrophic pathogen that requires living plant tissue for its development and establishes an intimate interaction zone between fungal hyphae and the plant plasma membrane. U. maydis actively suppresses plant defence responses by secreted protein effectors. Its effector repertoire comprises at least 386 genes mostly encoding proteins of unknown function and expressed exclusively during the biotrophic stage. The U. maydis secretome also contains about 150 proteins with probable roles in fungal nutrition, fungal cell wall modification and host penetration as well as proteins unlikely to act in the fungal-host interface like a chorismate mutase. Chorismate mutases are key enzymes of the shikimate pathway and catalyse the conversion of chorismate to prephenate, the precursor for tyrosine and phenylalanine synthesis. Root-knot nematodes inject a secreted chorismate mutase into plant cells likely to affect development. Here we show that the chorismate mutase Cmu1 secreted by U. maydis is a virulence factor. The enzyme is taken up by plant cells, can spread to neighbouring cells and changes the metabolic status of these cells through metabolic priming. Secreted chorismate mutases are found in many plant-associated microbes and might serve as general tools for host manipulation.

  5. The mitogenomes of the pouched lamprey (Geotria australis) and least brook lamprey (Lampetra aepyptera) with phylogenetic considerations.

    PubMed

    Ren, Jianfeng; Pu, Jiafei; Buchinger, Tyler; Zhu, Xinyun; Baker, Cindy; Li, Weiming

    2016-09-01

    We report the mitogenomes of the pouched lamprey (Geotria australis) and least brook lamprey (Lampetra aepyptera) in the families Geotriidae and Petromyzontidae, respectively. Both of the mitogenomes contain the 37 typical vertebrate genes. Their gene order and contents are identical to those of previously described lamprey mitogenomes. The mitogenome of G. australis (17 080 bp) is the largest among the 10 reported lamprey mitogenomes, owed to two long noncoding regions. The mitogenome of L. aepyptera is 77 bp longer (16 236 bp) than that of the congeneric European river lamprey L. fluviatilis, a size difference mostly due to different copy numbers of tandem repeats in the noncoding regions. The phylogenetic analysis supports that the pouched lamprey (Geotriidae) diverged earlier from the common ancestor of lampreys than the Petromyzonids, and the placement of the least brook lamprey in the genus Lampetra.

  6. Acid protease production in fungal root endophytes.

    PubMed

    Mayerhofer, Michael S; Fraser, Erica; Kernaghan, Gavin

    2015-01-01

    Fungal endophytes are ubiquitous in healthy root tissue, but little is known about their ecosystem functions, including their ability to utilize organic nutrient sources such as proteins. Root-associated fungi may secrete proteases to access the carbon and mineral nutrients within proteins in the soil or in the cells of their plant host. We compared the protein utilization patterns of multiple isolates of the root endophytes Phialocephala fortinii s.l., Meliniomyces variabilis and Umbelopsis isabellina with those of two ectomycorrhizal (ECM) fungi, Hebeloma incarnatulum and Laccaria bicolor, and the wood-decay fungus Irpex lacteus at pH values of 2-9 on liquid BSA media. We also assessed protease activity using a fluorescently labeled casein assay and gelatin zymography and characterized proteases using specific protease inhibitors. I. lacteus and U. isabellina utilized protein efficiently, while the ECM fungi exhibited poor protein utilization. ECM fungi secreted metallo-proteases and had pH optima above 4, while other fungi produced aspartic proteases with lower pH optima. The ascomycetous root endophytes M. variabilis and P. fortinii exhibited intermediate levels of protein utilization and M. variabilis exhibited a very low pH optimum. Comparing proteolytic profiles between fungal root endophytes and fungi with well defined ecological roles provides insight into the ecology of these cryptic root associates.

  7. Jack-and-master trait responses to elevated CO2 and N: a comparison of native and introduced Phragmites australis.

    PubMed

    Mozdzer, Thomas J; Megonigal, J Patrick

    2012-01-01

    Global change is predicted to promote plant invasions world-wide, reducing biodiversity and ecosystem function. Phenotypic plasticity may influence the ability of introduced plant species to invade and dominate extant communities. However, interpreting differences in plasticity can be confounded by phylogenetic differences in morphology and physiology. Here we present a novel case investigating the role of fitness trait values and phenotypic plasticity to global change factors between conspecific lineages of Phragmites australis. We hypothesized that due to observed differences in the competitive success of North American-native and Eurasian-introduced P. australis genotypes, Eurasian-introduced P. australis would exhibit greater fitness in response to global change factors. Plasticity and plant performance to ambient and predicted levels of carbon dioxide and nitrogen pollution were investigated to understand how invasion pressure may change in North America under a realistic global change scenario. We found that the introduced Eurasian genotype expressed greater mean trait values in nearly every ecophysiological trait measured--aboveground and belowground--to elevated CO(2) and nitrogen, outperforming the native North American conspecific by a factor of two to three under every global change scenario. This response is consistent with "jack and master" phenotypic plasticity. We suggest that differences in plant nitrogen productivity, specific leaf area, belowground biomass allocation, and inherently higher relative growth rate are the plant traits that may enhance invasion of Eurasian Phragmites in North America. Given the high degree of genotypic variability within this species, and our limited number of genotypes, our results must be interpreted cautiously. Our study is the first to demonstrate the potential importance of jack-and-master phenotypic plasticity in plant invasions when facing imminent global change conditions. We suggest that jack

  8. Testing two potential fates for coastal marshes: Greenhouse gas emissions from native, Phragmites australis-invaded, and permanently inundated zones

    NASA Astrophysics Data System (ADS)

    Moseman-Valtierra, S.; Martin, R.; Tang, J.; Morkeski, K.; China, I.; Brannon, E.; Watson, E. B.

    2014-12-01

    Global changes such as biological invasions and sea level rise can significantly affect GHG emissions from coastal wetlands by changing plant community composition and/or environmental conditions. To first characterize GHG fluxes across major plant-defined marsh zones, CO2, N2O, and CH4 fluxes were compared between S. patens- dominated high marsh and S. alterniflora low marsh during 2012 and 2013 growing seasons in 3 New England marshes. To test how these fluxes may change in response to biological invasions and sea level rise, GHG fluxes were then compared between native, P.australis- invaded, and permanently inundated marsh zones at these sites in 2013 and 2014. GHG emissions were analyzed simultaneously from marsh ecosystems using infrared-based spectrometers connected to static flux chambers. Daytime CO2 uptake rates (ranging on average between -2 and -21 μmol CO2 m-2s-1) were generally greater in S. alterniflora low marsh zones than in S. patens high marsh among all 3 sites. Methane fluxes were generally low in both native marsh zones (< 50 μmol CH4 m-2 h-1) and N2O emissions were rare. However, CO2 uptake and CH4 emissions from P. australis zones were typically more than an order of magnitude greater than those of either native marsh zone. In contrast, permanently inundated marsh soils had similar GHG emissions to native marsh zones. . Though large, the P. australis CH4 emissions are estimated to offset less than 5% of observed CO2 uptake rates based on a global warming potential of 25 (100 years). These results suggest that two alternative fates for coastal marshes in the future- conversion to P. australis marshes or to standing water with sea level rise- will substantially affect CO2 and CH4 emissions. Net impacts on climatic forcing of these ecosystems will depend on how long term C sequestration is affected as these emissions shift.

  9. Jack-and-Master Trait Responses to Elevated CO2 and N: A Comparison of Native and Introduced Phragmites australis

    PubMed Central

    Mozdzer, Thomas J.; Megonigal, J. Patrick

    2012-01-01

    Global change is predicted to promote plant invasions world-wide, reducing biodiversity and ecosystem function. Phenotypic plasticity may influence the ability of introduced plant species to invade and dominate extant communities. However, interpreting differences in plasticity can be confounded by phylogenetic differences in morphology and physiology. Here we present a novel case investigating the role of fitness trait values and phenotypic plasticity to global change factors between conspecific lineages of Phragmites australis. We hypothesized that due to observed differences in the competitive success of North American-native and Eurasian-introduced P. australis genotypes, Eurasian-introduced P. australis would exhibit greater fitness in response to global change factors. Plasticity and plant performance to ambient and predicted levels of carbon dioxide and nitrogen pollution were investigated to understand how invasion pressure may change in North America under a realistic global change scenario. We found that the introduced Eurasian genotype expressed greater mean trait values in nearly every ecophysiological trait measured – aboveground and belowground – to elevated CO2 and nitrogen, outperforming the native North American conspecific by a factor of two to three under every global change scenario. This response is consistent with “jack and master” phenotypic plasticity. We suggest that differences in plant nitrogen productivity, specific leaf area, belowground biomass allocation, and inherently higher relative growth rate are the plant traits that may enhance invasion of Eurasian Phragmites in North America. Given the high degree of genotypic variability within this species, and our limited number of genotypes, our results must be interpreted cautiously. Our study is the first to demonstrate the potential importance of jack-and-master phenotypic plasticity in plant invasions when facing imminent global change conditions. We suggest that jack

  10. Control of renin secretion.

    PubMed

    Abe, Y; Iwao, H; Okahara, T; Yamamoto, K

    1977-03-01

    The present study was designed to examine the interrelationship between the intrarenal vascular receptor and the sympathetic nerve, beta-adrenergic system, for renin secretion in the anesthetized dog. 1) A reduction in renal arterial pressure from a control pressure to 100 mmHg changed neither ther flow rates of all cortex zones nor renin secretion. Further reduction of renal arterial pressure to 75 mmHg resulted in a significant increase of renin secretion and a decrease of blood flow in the outer cortex. Intrarenal arterial infusion of norepinephrine at a control pressure increased a renin secretion. However, norepinephrine infusion at a reduced pressure suppressed the renin release with a recovery of the vascular resistance to the control level. These results suggest that the changes in the degree of blood flow and pressure in the renal afferent arterioles are not essential for the renin secretion,but renin secretion by the pressure reduction might be related to the autoregulatory capacity of afferent arterioles in the outer cortex. 2) At 5 min of hemorrhagic period (75 mmHg) arterial PRA elevated in control, and phenoxybenzamine and propranolol treated groups and any significant difference in responses was not observed among groups. However, at 60 min of hemorrhagic hypotensive period PRA in control and phenoxybenzamine treated groups further increased, but PRA in propranolol treated group was not alter from its 15 min value. These results indicated that the roles of vascular receptor and renal sympathetic nervous sytem in receptor and renal sympathetic nervous system in renin secretion might be separated, and that the renal sympathetic nervous system did not relate to the early response of renin release, but related to the late response. 3) Intrarenal arterial infusion of cAMP and DbcAMP resulted in a significant increase of renin release. In addition, CaC12 solution was infuesed into the renal artery and a significant rise in renal venous PRA was observed

  11. Effects of parasitism and environment on shell size of the South American intertidal mud snail Heleobia australis (Gastropoda)

    NASA Astrophysics Data System (ADS)

    Alda, Pilar; Bonel, Nicolás; Cazzaniga, Néstor J.; Martorelli, Sergio R.

    2010-04-01

    The aim of this work was to evaluate the effects of parasitism and certain environmental factors on the shell size of Heleobia australis (Hydrobiidae, Cochliopinae). We report sporocysts and metacercariae of Microphallus simillimus (Microphallidae, Trematoda) parasitizing the gonad and digestive gland of H. australis specimens from two sites of Bahía Blanca estuary, Argentina. The prevalence of infection was significantly higher (34.17% in winter and 68.14% in late spring) in snails from the outer estuary at Site 2 than in those from the inner estuary at Site 1 (5.88% and 4.71% respectively). The only known definitive host for this digenean is the white-backed stilt Himantopus melanurus (Recurvirostridae, Aves), most abundant in the estuary during winter. Parasitism by M. simillimus causes variations in the shell dimensions of H. australis, the shells of infected snails being narrower than those of uninfected snails. Snails from Site 2 were found in general to be significantly smaller than those at Site 1, possibly as a result of differences in environmental factors such as the degree of exposure to wave energy, the allocation of energy to reproduction rather than growth (induced by predation and/or parasitic castrators) and anthropogenic stressors.

  12. Do the changes in temperature and light affect the functional response of the benthic mud snail Heleobia australis (Mollusca: Gastropoda)?

    PubMed

    Magalhães, Thaisa R F; Neves, Raquel A F; Valentin, Jean L; Figueiredo, Gisela M

    2014-09-01

    The aim of this study was to determine the influence of temperature increase combined to conditions of light incidence on functional response of Heleobia australis. Experiments were conducted using nine to ten food concentrations for each treatment: 20°C without light; 30°C without light and, 30°C under low light intensity. For each experiment, the functional response type III (sigmoidal) was fitted and equation parameters were determined. Results suggest that, if the sediment temperature increases, H. australis will not have its ingestion rates affected negatively, whilst its feeding behavior seems to be negatively affected by light. Ingestion rates estimated for organic content in the Guanabara Bay were: 0.34 µgC ind-1h-1 at 20°C without light, 1.44 µgC ind-1h-1 at 30°C without light and 0.64 µgC ind-1h-1 at 30°C under light incidence. Higher ingestion rates were estimated at the high temperature, even under light incidence, and temperature seems to have outweighed the light effect. In contrast, if higher carbon content is considered, despite high temperature, the experiment conducted with light incidence showed lower ingestion rates than those from the experiment at 20°C without light. This study provides the first quantification of H. australis ingestion rates and the effects that changes in temperature and light have on its feeding behavior.

  13. Ontogenetic shifts in brain scaling reflect behavioral changes in the life cycle of the pouched lamprey Geotria australis

    PubMed Central

    Salas, Carlos A.; Yopak, Kara E.; Warrington, Rachael E.; Hart, Nathan S.; Potter, Ian C.; Collin, Shaun P.

    2015-01-01

    Very few studies have described brain scaling in vertebrates throughout ontogeny and none in lampreys, one of the two surviving groups of the early agnathan (jawless) stage in vertebrate evolution. The life cycle of anadromous parasitic lampreys comprises two divergent trophic phases, firstly filter-feeding as larvae in freshwater and secondly parasitism as adults in the sea, with the transition marked by a radical metamorphosis. We characterized the growth of the brain during the life cycle of the pouched lamprey Geotria australis, an anadromous parasitic lamprey, focusing on the scaling between brain and body during ontogeny and testing the hypothesis that the vast transitions in behavior and environment are reflected in differences in the scaling and relative size of the major brain subdivisions throughout life. The body and brain mass and the volume of six brain structures of G. australis, representing six points of the life cycle, were recorded, ranging from the early larval stage to the final stage of spawning and death. Brain mass does not increase linearly with body mass during the ontogeny of G. australis. During metamorphosis, brain mass increases markedly, even though the body mass does not increase, reflecting an overall growth of the brain, with particularly large increases in the volume of the optic tectum and other visual areas of the brain and, to a lesser extent, the olfactory bulbs. These results are consistent with the conclusions that ammocoetes rely predominantly on non-visual and chemosensory signals, while adults rely on both visual and olfactory cues. PMID:26283894

  14. Triton's trident: cryptic Neogene divergences in a marine clam (Lasaea australis) correspond to Australia's three temperate biogeographic provinces.

    PubMed

    Li, Jingchun; Foighil, Diarmaid O; Park, Joong-Ki

    2013-04-01

    The southern coast of Australia is composed of three distinct biogeographic provinces distinguished primarily by intertidal community composition. Several ecological mechanisms have been proposed to explain their formation and persistence, but no consensus has been reached. The marine clam Lasaea australis is arguably the most common bivalve on southern Australian rocky shores and occurs in all three provinces. Here, we tested if this species exhibits cryptic genetic structuring corresponding to the provinces and if so, what mechanisms potentially drove its divergence. Variation in two mitochondrial genes (16S and COIII) and one nuclear gene (ITS2) was assayed to test for genetic structuring and to reconstruct the clam's phylogenetic history. Our results showed that L. australis is comprised of three cryptic mitochondrial clades, each corresponding almost perfectly to one of the three biogeographic provinces. Divergence time estimates place their cladogenesis in the Neogene. The trident-like topology and Neogene time frame of L. australis cladogenesis are incongruent with Quaternary vicariance predictions: a two-clade topology produced by Pleistocene Bass Strait land bridge formation. We hypothesize that the interaction of the Middle Miocene Climate Transition with the specific geography of the southern coastline of Australia was the primary cladogenic driver in this clam lineage. Additional in-depth studies of the endemic southern Australian marine biota across all three provinces are needed to establish the generality of this proposed older framework for regional cladogenesis.

  15. CO2 and CH4 exchange by Phragmites australis under different climates

    NASA Astrophysics Data System (ADS)

    Serrano Ortiz, Penélope; Chojnickic, Bogdan H.; Sánchez-Cañete, Enrique P.; Kowalska, Natalia; López-Ballesteros, Ana; Fernández, Néstor; Urbaniak, Marek; Olejnik, Janusz; Kowalski, Andrew S.

    2015-04-01

    The key role of wetlands regarding global warming is the resulting balance between net CO2 assimilation, via photosynthesis, and CO2 and CH4 emissions, given the potential to release stored carbon, because of the high temperature sensitivity of heterotrophic soil respiration and anoxic conditions. However, it is still unknown whether wetlands will convert from long-term carbon sinks to sources as a result of climate change and other anthropogenic effects such as land use changes. Phragmites australis is one of the most common species found in wetlands and is considered the most globally widespread and productive plant species in this type of ecosystem. In this context, the main objective of this study is to analyse the GHG exchange (CO2 and CH4) of two wetlands with Phragmites australis as the dominant species under different climates using the eddy covariance (EC) technique. The first site, Padul, is located in southern Spain, with a sub-humid warm climate, characterised by a mean annual temperature of 16°C and annual precipitation of ca. 470 mm, with a very dry summer. The second site, Rzecin is located in Poland with a mean annual temperature of 8°C, and annual precipitation around 600mm with no dry season. The Padul EC station is equipped with two infrared gas analysers to measure CO2 and CH4 fluxes (LI-7200 and LI-7700 respectively) while the Rzecin EC station has the same CH4 sensor as Padul, but also a sensor measuring both GHG fluxes (DLT-100 Fast Methane Analyser, Los Gatos). In this study, we present: i) the results of a CH4 analyser inter-comparison campaign (LI-7700 vs. Los Gatos), ii) a comparative analysis of the functional behaviour of respiration and photosynthesis in both sites testing relationships between CO2 fluxes measured with the EC technique and meteorological variables such as temperature and direct or diffuse radiation and iii) the CH4 dynamicsat both sites by identifying, when possible, annual, seasonal and diurnal patterns.

  16. Evapotranspiration from subsurface horizontal flow wetlands planted with Phragmites australis in sub-tropical Australia.

    PubMed

    Headley, T R; Davison, L; Huett, D O; Müller, R

    2012-02-01

    The balance between evapotranspiration (ET) loss and rainfall ingress in treatment wetlands (TWs) can affect their suitability for certain applications. The aim of this paper was to investigate the water balance and seasonal dynamics in ET of subsurface horizontal flow (HF) TWs in a sub-tropical climate. Monthly water balances were compiled for four pilot-scale HF TWs receiving horticultural runoff over a two year period (Sep. 1999-Aug. 2001) on the sub-tropical east-coast of Australia. The mean annual wetland ET rate increased from 7.0 mm/day in the first year to 10.6 mm/day in the second, in response to the development of the reed (Phragmites australis) population. Consequently, the annual crop coefficients (ratio of wetland ET to pan evaporation) increased from 1.9 in the first year to 2.6 in the second. The mean monthly ET rates were generally greater and more variable than the Class-A pan evaporation rates, indicating that transpiration is an important contributor to ET in HF TWs. Evapotranspiration rates were generally highest in the summer and autumn months, and corresponded with the times of peak standing biomass of P. australis. It is likely that ET from the relatively small 1 m wide by 4 m long HF TWs was enhanced by advection through so-called "clothesline" and "oasis" effects, which contributed to the high crop coefficients. For the second year, when the reed population was well established, the annual net loss to the atmosphere (taking into account rainfall inputs) accounted for 6.1-9.6 % of the influent hydraulic load, which is considered negligible. However, the net loss is likely to be higher in arid regions with lower rainfall. The Water Use Efficiency (WUE) of the wetlands in the second year of operation was 1.3 g of above-ground biomass produced per kilogram of water consumed, which is low compared to agricultural crops. It is proposed that system level WUE provides a useful metric for selecting wetland plant species and TW design alternatives to

  17. Dispersal and population structure at different spatial scales in the subterranean rodent Ctenomys australis

    PubMed Central

    2010-01-01

    Background The population genetic structure of subterranean rodent species is strongly affected by demographic (e.g. rates of dispersal and social structure) and stochastic factors (e.g. random genetic drift among subpopulations and habitat fragmentation). In particular, gene flow estimates at different spatial scales are essential to understand genetic differentiation among populations of a species living in a highly fragmented landscape. Ctenomys australis (the sand dune tuco-tuco) is a territorial subterranean rodent that inhabits a relatively secure, permanently sealed burrow system, occurring in sand dune habitats on the coastal landscape in the south-east of Buenos Aires province, Argentina. Currently, this habitat is threatened by urban development and forestry and, therefore, the survival of this endemic species is at risk. Here, we assess population genetic structure and patterns of dispersal among individuals of this species at different spatial scales using 8 polymorphic microsatellite loci. Furthermore, we evaluate the relative importance of sex and habitat configuration in modulating the dispersal patterns at these geographical scales. Results Our results show that dispersal in C. australis is not restricted at regional spatial scales (~ 4 km). Assignment tests revealed significant population substructure within the study area, providing support for the presence of two subpopulations from three original sampling sites. Finally, male-biased dispersal was found in the Western side of our study area, but in the Eastern side no apparent philopatric pattern was found, suggesting that in a more continuous habitat males might move longer distances than females. Conclusions Overall, the assignment-based approaches were able to detect population substructure at fine geographical scales. Additionally, the maintenance of a significant genetic structure at regional (~ 4 km) and small (less than 1 km) spatial scales despite apparently moderate to high levels of

  18. Detecting and Mapping Invasive Phragmites australis in the coastal Great Lakes with ALOS PALSAR imagery

    NASA Astrophysics Data System (ADS)

    Bourgeau-chavez, L. L.; Scarbrough, K.; Jenkins, L. K.; Riordan, K.; Powell, R. B.; Brooks, C.; Kowalski, K.; Carlson Mazur, M.; Huberty, B.

    2011-12-01

    Phragmites australis is a non-native invasive plant that can form dense monocultures, causing negative impacts on coastal Great Lakes wetlands by reducing ecosystem services including habitat and therefore, biological diversity. Through Great Lakes Restoration Initiative funding, ALOS PALSAR imagery is being used to map the invasive plant as it occurs in monoculture stands of the U.S. coastal Great Lakes wetlands. These invasive Phragmites maps are being used as part of a USGS Great Lakes Science Center (GLSC) and US Fish and Wildlife Service (USFWS) National Wetlands Inventory (NWI) program to identify major environmental drivers of invasive Phragmites distribution, to assess areas vulnerable to new invasion, and to provide this information to regional stakeholders through a decision support tool. The invasive Phragmites map is the first U.S. basin-wide map to be produced on the distribution of this species. Methods include maximum likelihood classification of multi-season ALOS PALSAR HH and HV polarization data. PALSAR is an L-band (23 cm wavelength) imaging radar sensor which is sensitive to differences in plant biomass and inundation patterns, allowing for the extraction of these tall (up to 15 m), high-density, high-biomass Phragmites wetland stands. To improve discrimination of Phragmites australis, the three date (spring, summer, fall) dataset is being used, which takes advantage of phenological changes in vegetation and inundation patterns over the seasons. Field collections of training and randomly selected validation data were conducted in spring summer and fall of 2010-11 to aid in the mapping and for accuracy assessment. The minimum mapping unit is 1/2 acre and thus all field sites were sampled at 1/2 acre units. All map products and field validation data will be complete by December 2011. Maps are being completed on a Lake basin basis. The first final map product was delivered for Lake Erie coastal wetlands to 10 km inland, with an overall map accuracy

  19. Multiparty quantum secret sharing

    SciTech Connect

    Zhang Zhanjun; Li Yong; Man Zhongxiao

    2005-04-01

    Based on a quantum secure direct communication (QSDC) protocol [Phys. Rev. A 69 052319 (2004)], we propose a (n,n)-threshold scheme of multiparty quantum secret sharing of classical messages (QSSCM) using only single photons. We take advantage of this multiparty QSSCM scheme to establish a scheme of multiparty secret sharing of quantum information (SSQI), in which only all quantum information receivers collaborate can the original qubit be reconstructed. A general idea is also proposed for constructing multiparty SSQI schemes from any QSSCM scheme.

  20. Zinc, cadmium, and copper mobility and accumulation in reeds (Phragmites australis) in urban sediments from two stormwater infiltration basins

    NASA Astrophysics Data System (ADS)

    Bedell, J.-P.; Saulais, S.; Delolme, C.

    2012-04-01

    Infiltration basins are stormwater management techniques that are widely used to reduce stormwater volume. The settling of stormwater particles leads to a contaminated sediment layer at the basin surface. Phragmites australis used in constructed wetlands are widely present in infiltration basins. Such plant can play a role on the fate of heavy metals either directly by their uptake or indirectly by modification of physico-chemical characteristics of the sediment. The aim of this study is to assess Zn, Cd and Cu potential mobility and their bioaccumulation by reeds during plant's growth in urban sediments offering two different geochemical contexts. Methodology is based on the monitoring (in june, august and december) of physico-chemical characteristics of sediment deposit in two basins. These basins, "Minerve" and "Grézieu", located on both sides of Lyon city are characteristic of two different geochemical context. "Minerve" is in the east and "Grézieu" in the west part. The geology of the eastern part of Lyon is characterized by carbonated fluvio-glacial deposits. In the western part, the subsoil is mainly composed of gneiss and granit. Moreover, 20 cm of gravel and a sand layer were initially added at the surface of the "Grézieu" basin. In "Minerve", a clay material was initially added and a filter trench was built along the basin to allow water infiltration. We characterized the sediment deposit by the identification of their geochemical characteristics (Zn, Cu, Cd, total content, pH, CEC, C/N, carbonates and major elements contents …). Then we studied the potential mobility of the three metals by single chemical extraction (CaCl2 for the exchangeable phase, acetate buffer for the acido-soluble phase and diethylenetriamine-pentaacetic acid (DTPA) for the fraction associated to the organic matter). The accumulation of Zn, Cd and Cu in aerial parts and roots of the reeds was also measured. The results show clearly that "Grézieu" sediment is more enriched in

  1. Seedling root targets

    Treesearch

    Diane L. Haase

    2011-01-01

    Roots are critical to seedling performance after outplanting. Although root quality is not as quick and simple to measure as shoot quality, target root characteristics should be included in any seedling quality assessment program. This paper provides a brief review of root characteristics most commonly targeted for operational seedling production. These are: root mass...

  2. Salivary Gland Secretion.

    ERIC Educational Resources Information Center

    Dorman, H. L.; And Others

    1981-01-01

    Describes materials and procedures for an experiment utilizing a live dog to demonstrate: (1) physiology of the salivary gland; (2) parasympathetic control of the salivary gland; (3) influence of varying salivary flow rates on sodium and potassium ions, osmolarity and pH; and (4) salivary secretion as an active process. (DS)

  3. Analysis of secreted proteins.

    PubMed

    Severino, Valeria; Farina, Annarita; Chambery, Angela

    2013-01-01

    Most biological processes including growth, proliferation, differentiation, and apoptosis are coordinated by tightly regulated signaling pathways, which also involve secreted proteins acting in an autocrine and/or paracrine manner. In addition, extracellular signaling molecules affect local niche biology and influence the cross-talking with the surrounding tissues. The understanding of this molecular language may provide an integrated and broader view of cellular regulatory networks under physiological and pathological conditions. In this context, the profiling at a global level of cell secretomes (i.e., the subpopulations of a proteome secreted from the cell) has become an active area of research. The current interest in secretome research also deals with its high potential for the biomarker discovery and the identification of new targets for therapeutic strategies. Several proteomic and mass spectrometry platforms and methodologies have been applied to secretome profiling of conditioned media of cultured cell lines and primary cells. Nevertheless, the analysis of secreted proteins is still a very challenging task, because of the technical difficulties that may hamper the subsequent mass spectrometry analysis. This chapter describes a typical workflow for the analysis of proteins secreted by cultured cells. Crucial issues related to cell culture conditions for the collection of conditioned media, secretome preparation, and mass spectrometry analysis are discussed. Furthermore, an overview of quantitative LC-MS-based approaches, computational tools for data analysis, and strategies for validation of potential secretome biomarkers is also presented.

  4. Secrets of Successful Homeschooling

    ERIC Educational Resources Information Center

    Rivero, Lisa

    2011-01-01

    Parents who homeschool gifted children often find the daily practice of home education very different from what they had imagined. Gifted children are complex in both personality and learning styles. Parents who say that homeschooling works well for their gifted children have learned from others or discovered on their own several secrets that make…

  5. Trade-Secret Dispute.

    ERIC Educational Resources Information Center

    Blumenstyk, Goldie

    1994-01-01

    A Michigan court has ruled that a Wayne State University (Michigan) chemistry professor appropriated a trade secret from a Massachusetts chemist for whom he was consulting and incorporated it into his own patent application, violating a written agreement. The university contends its pursuit of the patent was not improper. (MSE)

  6. Salivary Gland Secretion.

    ERIC Educational Resources Information Center

    Dorman, H. L.; And Others

    1981-01-01

    Describes materials and procedures for an experiment utilizing a live dog to demonstrate: (1) physiology of the salivary gland; (2) parasympathetic control of the salivary gland; (3) influence of varying salivary flow rates on sodium and potassium ions, osmolarity and pH; and (4) salivary secretion as an active process. (DS)

  7. US weapons secrets revealed

    SciTech Connect

    Norris, R.S.; Arkin, W.M.

    1993-03-01

    Extraordinary details have only recently been revealed about the struggle over the control of early U.S. nuclear weapons and their initial deployments abroad. The information comes from a newly declassified top secret report, part of a larger study, The History of the Strategic Arms Competition, 1945-1972, commissioned by Defense Secretary James R. Schlisinger in summer 1974.

  8. Secrets of Successful Homeschooling

    ERIC Educational Resources Information Center

    Rivero, Lisa

    2011-01-01

    Parents who homeschool gifted children often find the daily practice of home education very different from what they had imagined. Gifted children are complex in both personality and learning styles. Parents who say that homeschooling works well for their gifted children have learned from others or discovered on their own several secrets that make…

  9. Physiology of bile secretion

    PubMed Central

    Esteller, Alejandro

    2008-01-01

    The formation of bile depends on the structural and functional integrity of the bile-secretory apparatus and its impairment, in different situations, results in the syndrome of cholestasis. The structural bases that permit bile secretion as well as various aspects related with its composition and flow rate in physiological conditions will first be reviewed. Canalicular bile is produced by polarized hepatocytes that hold transporters in their basolateral (sinusoidal) and apical (canalicular) plasma membrane. This review summarizes recent data on the molecular determinants of this primary bile formation. The major function of the biliary tree is modification of canalicular bile by secretory and reabsorptive processes in bile-duct epithelial cells (cholangiocytes) as bile passes through bile ducts. The mechanisms of fluid and solute transport in cholangiocytes will also be discussed. In contrast to hepatocytes where secretion is constant and poorly controlled, cholangiocyte secretion is regulated by hormones and nerves. A short section dedicated to these regulatory mechanisms of bile secretion has been included. The aim of this revision was to set the bases for other reviews in this series that will be devoted to specific issues related with biliary physiology and pathology. PMID:18837079

  10. Invading Phragmites australis stimulates methane emissions from North American tidal marshes

    NASA Astrophysics Data System (ADS)

    Mueller, Peter; Meschter, Justin E.; Hager, Rachel N.; Mozdzer, Thomas J.; Jensen, Kai; Langley, J. Adam; Baldwin, Andrew; Megonigal, J. Patrick

    2015-04-01

    Most studies concerned with invasive plant species focus on effects on biodiversity, while only few have investigated how the greenhouse gas balance of an ecosystem or, in particular, how methane emissions are affected by invasion driven shifts in plant species composition. In this study, conducted in brackish marsh sites of the Chesapeake Bay, United States, we investigated the effect of the none-native grass Phragmites australis invading native shortgrass communities on methane emissions. In situ gas flux measurements using static chambers were used to quantify methane emissions along transects of progressive invasion by Phragmites. Methane emissions were several fold higher in Phragmites stands than in adjacent native communities and increased with progressive invasion of Phragmites. Results of a mesocosm experiment support our field observations and show consistently higher methane emissions from mesocoms planted with Phragmites even at different hydrological conditions. Because tidal marshes, as blue carbon ecosystems, sequester soil carbon rapidly and emit methane slowly compared to other wetland ecosystems, they are increasingly recognized as having a high carbon value. Our results indicate that the replacement of native marsh communities by Phragmites may considerably change the green house gas balance of these ecosystems and thus lower their carbon sequestration value.

  11. Native and European haplotypes of Phragmites Australis (common reed) in the central Platte River, Nebraska

    USGS Publications Warehouse

    Larson, D.L.; Galatowitsch, S.M.; Larson, J.L.

    2011-01-01

    Phragmites australis (common reed) is known to have occurred along the Platte River historically, but recent rapid increases in both distribution and density have begun to impact habitat for migrating sandhill cranes and nesting piping plovers and least terns. Invasiveness in Phragmites has been associated with the incursion of a European genotype (haplotype M) in other areas; determining the genotype of Phragmites along the central Platte River has implications for proper management of the river system. In 2008 we sampled Phragmites patches along the central Platte River from Lexington to Chapman, NE, stratified by bridge segments, to determine the current distribution of haplotype E (native) and haplotype M genotypes. In addition, we did a retrospective analysis of historical Phragmites collections from the central Platte watershed (1902-2006) at the Bessey Herbarium. Fresh tissue from the 2008 survey and dried tissue from the herbarium specimens were classified as haplotype M or E using the restriction fragment length polymorphism procedure. The European haplotype was predominant in the 2008 samples: only 14 Phragmites shoots were identified as native haplotype E; 224 were non-native haplotype M. The retrospective analysis revealed primarily native haplotype individuals. Only collections made in Lancaster County, near Lincoln, NE, were haplotype M, and the earliest of these was collected in 1973. ?? 2011 Copyright by the Center for Great Plains Studies, University of Nebraska-Lincoln.

  12. Phragmites australis expansion in a restored brackish marsh: documentation at different time scales

    USGS Publications Warehouse

    Howard, Rebecca J.; Turluck, Theodore D.

    2013-01-01

    Invasive plants in restored habitats can alter the system such that restoration goals are not met. Non-native lineages of Phragmites australis (hereafter Phragmites) are invasive in North American wetlands, and their presence can be problematic because of decreased species diversity and altered physicochemical processes. Phragmites is a challenging species for restoration because both native and non-native lineages can co-occur. We documented Phragmites expansion in a brackish marsh in Louisiana, USA that was restored with dredged sediments. Invasive Phragmites clones were inadvertently planted at the site. Phragmites expansion was documented through field measurements and aerial imagery. No growth differences were apparent between lineages during the first growing season. Horizontal expansion of 2.27 ± 0.15 m (mean ± 1SE) 5 months after planting occurred through rhizome growth. Seven years after planting, three patches with a combined aerial cover of about 0.7 ha were delineated. The study verified that Phragmites can grow relatively rapidly and persist on dredged sediments. Long-term rapid growth of invasive Phragmites may be a positive attribute in areas subject to high erosion and subsidence rates, despite reductions in species diversity. Acceptability of the presence of invasive Phragmites will depend on restoration goals.

  13. Southern Right Whale (Eubalaena australis) Reproductive Success is Influenced by Krill (Euphausia superba) Density and Climate.

    PubMed

    Seyboth, Elisa; Groch, Karina R; Dalla Rosa, Luciano; Reid, Keith; Flores, Paulo A C; Secchi, Eduardo R

    2016-06-16

    The reproductive success of southern right whale (Eubalaena australis) depends on body condition and, therefore, on foraging success. This, in turn, might be affected by climatically driven change in the abundance of the species main prey, krill (Euphausia superba), on the feeding grounds. Annual data on southern right whale number of calves were obtained from aerial surveys carried out between 1997 and 2013 in southern Brazil, where the species concentrate during their breeding season. The number of calves recorded each year varied from 7 to 43 ( = 21.11 ± 11.88). Using cross-correlation analysis we examined the response of the species to climate anomalies and krill densities. Significant correlations were found with krill densities (r = 0.69, p = 0.002, lag 0 years), Oceanic Niño Index (r = -0.65, p = 0.03, lag 6 years), Antarctic Oscillation (r = 0.76, p = 0.01, lag 7 years) and Antarctic sea ice area (r = -0.68, p = 0.002, lag 0 years). Our results suggest that global climate indices influence southern right whale breeding success in southern Brazil by determining variation in food (krill) availability for the species. Therefore, increased frequency of years with reduced krill abundance, due to global warming, is likely to reduce the current rate of recovery of southern right whales from historical overexploitation.

  14. Southern Right Whale (Eubalaena australis) Reproductive Success is Influenced by Krill (Euphausia superba) Density and Climate

    PubMed Central

    Seyboth, Elisa; Groch, Karina R.; Dalla Rosa, Luciano; Reid, Keith; Flores, Paulo A. C.; Secchi, Eduardo R.

    2016-01-01

    The reproductive success of southern right whale (Eubalaena australis) depends on body condition and, therefore, on foraging success. This, in turn, might be affected by climatically driven change in the abundance of the species main prey, krill (Euphausia superba), on the feeding grounds. Annual data on southern right whale number of calves were obtained from aerial surveys carried out between 1997 and 2013 in southern Brazil, where the species concentrate during their breeding season. The number of calves recorded each year varied from 7 to 43 ( = 21.11 ± 11.88). Using cross-correlation analysis we examined the response of the species to climate anomalies and krill densities. Significant correlations were found with krill densities (r = 0.69, p = 0.002, lag 0 years), Oceanic Niño Index (r = −0.65, p = 0.03, lag 6 years), Antarctic Oscillation (r = 0.76, p = 0.01, lag 7 years) and Antarctic sea ice area (r = −0.68, p = 0.002, lag 0 years). Our results suggest that global climate indices influence southern right whale breeding success in southern Brazil by determining variation in food (krill) availability for the species. Therefore, increased frequency of years with reduced krill abundance, due to global warming, is likely to reduce the current rate of recovery of southern right whales from historical overexploitation. PMID:27306583

  15. Crassulacean acid metabolism enhances underwater photosynthesis and diminishes photorespiration in the aquatic plant Isoetes australis.

    PubMed

    Pedersen, Ole; Rich, Sarah Meghan; Pulido, Cristina; Cawthray, Gregory Robert; Colmer, Timothy David

    2011-04-01

    • Underwater photosynthesis by aquatic plants is often limited by low availability of CO(2), and photorespiration can be high. Some aquatic plants utilize crassulacean acid metabolism (CAM) photosynthesis. The benefits of CAM for increased underwater photosynthesis and suppression of photorespiration were evaluated for Isoetes australis, a submerged plant that inhabits shallow temporary rock pools. • Leaves high or low in malate were evaluated for underwater net photosynthesis and apparent photorespiration at a range of CO(2) and O(2) concentrations. • CAM activity was indicated by 9.7-fold higher leaf malate at dawn, compared with at dusk, and also by changes in the titratable acidity (μmol H(+) equivalents) of leaves. Leaves high in malate showed not only higher underwater net photosynthesis at low external CO(2) concentrations but also lower apparent photorespiration. Suppression by CAM of apparent photorespiration was evident at a range of O(2) concentrations, including values below air equilibrium. At a high O(2) concentration of 2.2-fold the atmospheric equilibrium concentration, net photosynthesis was reduced substantially and, although it remained positive in leaves containing high malate concentrations, it became negative in those low in malate. • CAM in aquatic plants enables higher rates of underwater net photosynthesis over large O(2) and CO(2) concentration ranges in floodwaters, via increased CO(2) fixation and suppression of photorespiration.

  16. Histological patterns of the intestinal attachment of Corynosoma australe (Acanthocephala: Polymorphidae) in Arctocephalus australis (Mammalia: Pinnipedia).

    PubMed

    Silva, Renato Z; Pereira, Joaber; Cousin, João Carlos B

    2014-12-01

    The mucosal attachment pattern of Corynosoma australe in the intestines of Arctocephalus australis is described. Normal and abnormal tissue were sampled from 32 hosts to be submitted to histological routine protocol to embedding in paraffin and permanent mounting in balsam. Corynosoma australe shows three different degrees of body depth intestinal attachment (BDINA-1-3). BDINA-1: it is exclusive of the small intestine and the parasite attaches on the villi; BDINA-2: parasite affects the Lieberkühn crypts in several depth levels and, BDINA-3: the parasite reaches the submucosa. These attachment patterns alter the mucosa by degeneration and dysfunction due to necrosis of mucosal structure, great quantities of cellular debris and significant reduction of the mucosal thickness. Other aspects are crater-like concave holes (CLCHs) as sites where C. australe could be attached-detached several times according to adult migratory processes within luminal intestine space. The submucosa shows edema probably due to the local mucosal alterations resulting in homeostatic break. There is no severe inflammatory response by host but BDINA-1 to BDINA-3 and CLCH could represent foci to secondary opportunistic infections and significant areas of malabsorption in severally infected hosts contributing to increase clinical signs of preexistent pathologies.

  17. Assessment of suitable habitat for Phragmites australis (common reed) in the Great Lakes coastal zone

    USGS Publications Warehouse

    Carlson Mazur, Martha L.; Kowalski, Kurt P.; Galbraith, David

    2014-01-01

    In the Laurentian Great Lakes, the invasive form of Phragmites australis (common reed) poses a threat to highly productive coastal wetlands and shorelines by forming impenetrable stands that outcompete native plants. Large, dominant stands can derail efforts to restore wetland ecosystems degraded by other stressors. To be proactive, landscape-level management of Phragmites requires information on the current spatial distribution of the species and a characterization of areas suitable for future colonization. Using a recent basin-scale map of this invasive plant’s distribution in the U.S. coastal zone of the Great Lakes, environmental data (e.g., soils, nutrients, disturbance, climate, topography), and climate predictions, we performed analyses of current and predicted suitable coastal habitat using boosted regression trees, a type of species distribution modeling. We also investigated differential influences of environmental variables in the upper lakes (Lakes Superior, Michigan, and Huron) and lower lakes (Lakes St. Clair, Erie, and Ontario). Basin-wide results showed that the coastal areas most vulnerable to Phragmites expansion were in close proximity to developed lands and had minimal topographic relief, poorly drained soils, and dense road networks. Elevated nutrients and proximity to agriculture also influenced the distribution of Phragmites. Climate predictions indicated an increase in suitable habitat in coastal Lakes Huron and Michigan in particular. The results of this study, combined with a publicly available online decision support tool, will enable resource managers and restoration practitioners to target and prioritize Phragmites control efforts in the Great Lakes coastal zone.

  18. Far-infrared observations of a star-forming region in the Corona Australis dark cloud

    NASA Technical Reports Server (NTRS)

    Cruz-Gonzalez, I.; Mcbreen, B.; Fazio, G. G.

    1984-01-01

    A high-resolution far-IR (40-250-micron) survey of a 0.9-sq-deg section of the core region of the Corona Australis dark cloud (containing very young stellar objects such as T Tauri stars, Herbig Ae and Be stars, Herbig-Haro objects, and compact H II regions) is presented. Two extended far-IR sources were found, one associated with the Herbig emission-line star R CrA and the other with the irregular emission-line variable star TY CrA. The two sources have substantially more far-IR radiation than could be expected from a blackbody extrapolation of their near-IR fluxes. The total luminosities of these sources are 145 and 58 solar luminosity, respectively, implying that the embedded objects are of intermediate or low mass. The infrared observations of the sources associated with R CrA and TY CrA are consistent with models of the evolution of protostellar envelopes of intermediate mass. However, the TY CrA source appears to have passed the evolutionary stage of expelling most of the hot dust near the central source, yielding an age of about 1 Myr.

  19. Cellular and ultrastructural characterization of the grey-morph phenotype in southern right whales (Eubalaena australis)

    PubMed Central

    Eroh, Guy D.; Clayton, Fred C.; Florell, Scott R.; Cassidy, Pamela B.; Chirife, Andrea; Marón, Carina F.; Valenzuela, Luciano O.; Campbell, Michael S.; Seger, Jon; Rowntree, Victoria J.; Leachman, Sancy A.

    2017-01-01

    Southern right whales (SRWs, Eubalena australis) are polymorphic for an X-linked pigmentation pattern known as grey morphism. Most SRWs have completely black skin with white patches on their bellies and occasionally on their backs; these patches remain white as the whale ages. Grey morphs (previously referred to as partial albinos) appear mostly white at birth, with a splattering of rounded black marks; but as the whales age, the white skin gradually changes to a brownish grey color. The cellular and developmental bases of grey morphism are not understood. Here we describe cellular and ultrastructural features of grey-morph skin in relation to that of normal, wild-type skin. Melanocytes were identified histologically and counted, and melanosomes were measured using transmission electron microscopy. Grey-morph skin had fewer melanocytes when compared to wild-type skin, suggesting reduced melanocyte survival, migration, or proliferation in these whales. Grey-morph melanocytes had smaller melanosomes relative to wild-type skin, normal transport of melanosomes to surrounding keratinocytes, and normal localization of melanin granules above the keratinocyte nuclei. These findings indicate that SRW grey-morph pigmentation patterns are caused by reduced numbers of melanocytes in the skin, as well as by reduced amounts of melanin production and/or reduced sizes of mature melanosomes. Grey morphism is distinct from piebaldism and albinism found in other species, which are genetic pigmentation conditions resulting from the local absence of melanocytes, or the inability to synthesize melanin, respectively. PMID:28170433

  20. Comparative sensitivity of commercially available aPTT reagents to mulga snake (Pseudechis australis) venom.

    PubMed

    Lincz, Lisa F; Scorgie, Fiona E; Johnston, Christopher I; O'Leary, Margaret; Prasad, Ritam; Seldon, Michael; Favaloro, Emmanuel; Isbister, Geoffrey K

    2014-08-01

    This study aimed to determine the relative sensitivity of activated partial thromboplastin time (aPTT) reagents to the anticoagulant effects of phospholipases in mulga snake (Pseudechis australis) venom.Twenty-one haematology laboratories participating in the Royal College of Pathologists of Australasia Quality Assurance Programs were sent human plasma samples spiked with mulga venom (n=25 total results). Results for 17 patients with mulga snake envenoming were available through the Australian Snakebite Project.Only 12 of 25 venom spiked samples returned an abnormally prolonged aPTT. Tests performed with Dade Actin FS (n=7) did not identify any of the spiked samples as abnormal. Although clotting times were significantly prolonged using the lupus anticoagulant sensitive Actin FSL (n=5, p=0.043), only one was reported as abnormal. Only laboratories using TriniCLOT aPTT S (n=6), HemosIL APTT SP (n=2) and Stago PTT-A (n=1) consistently recorded the spiked sample as being above the upper normal reference interval. Abnormally prolonged aPTTs were recorded for four of eight patients whose tests were performed with Actin FSL, five of eight patients with TriniCLOT aPTT HS, and three of three patients using TriniCLOT aPTT S.We conclude that some reagents used for routine aPTT testing are relatively insensitive to the anticoagulant effects of mulga snake venom. Tests performed with these reagents should be interpreted with caution.

  1. From flowering to dispersal: reproductive ecology of an endemic plant, Astragalus australis var. olympicus (Fabaceae).

    PubMed

    Kaye, T N

    1999-09-01

    Astragalus australis var. olympicus is an endemic plant of the Olympic Mountains, Washington. It is considered a Species of Concern by the U.S. Fish and Wildlife Service. This study focused on the reproductive biology of the plant from flower production through seed germination to identify possible weak points that might contribute to its rarity and impede its conservation. Most plants produced a large mean number of flowers and ovules (314.8 and 4106, respectively), but relatively few of these formed fruits and seeds (25.8 and 3.8%, respectively). In decreasing importance, ovules in fruits were lost to predation, seed abortion, and lack of fertilization. The percentages of these fates differed among sites and years. Excluding pollinators by bagging flowers reduced fruit set by ∼50%, but seed set per fruit and seed mass were unaffected. Germination was affected by scarification, temperature, and moisture availability. About 11% of seeds damaged by predispersal seed predators (weevil larvae) remained viable and were released from dormancy. I hypothesize that predispersal seed predation (over 80% at one site) has a negative effect on population growth. Conservation of this species could benefit from improved fruit set and decreased seed predation.

  2. Mitochondrial DNA diversity and population structure among southern right whales (Eubalaena australis).

    PubMed

    Patenaude, Nathalie J; Portway, Vicky A; Schaeff, Cathy M; Bannister, John L; Best, Peter B; Payne, Roger S; Rowntree, Vicky J; Rivarola, Mariana; Baker, C Scott

    2007-01-01

    The population structure and mitochondrial (mt) DNA diversity of southern right whales (Eubalaena australis) are described from 146 individuals sampled on 4 winter calving grounds (Argentina, South Africa, Western Australia, and the New Zealand sub-Antarctic) and 2 summer feeding grounds (South Georgia and south of Western Australia). Based on a consensus region of 275 base pairs of the mtDNA control region, 37 variable sites defined 37 unique haplotypes, of which only one was shared between regional samples of the Indo-Pacific and South Atlantic Oceans. Phylogenetic reconstruction of the southern right whale haplotypes revealed 2 distinct clades that differed significantly in frequencies between oceans. An analysis of molecular variance confirmed significant overall differentiation among the 4 calving grounds at both the haplotype and the nucleotype levels (F(ST) = 0.159; Phi(ST) = 0.238; P < 0.001). Haplotype diversity was significantly lower in the Indo-Pacific (h = 0.701 +/- 0.037) compared with the South Atlantic (h = 0.948 +/- 0.013), despite a longer history of exploitation and larger catches in the South Atlantic. In fact, the haplotype diversity in the Indo-Pacific basin was similar to that of the North Atlantic right whale that currently numbers about 300 animals. Multidimensional scaling of genetic differentiation suggests that gene flow occurred primarily between adjacent calving grounds within an ocean basin, with mixing of lineages from different calving grounds occurring on feeding grounds.

  3. Resting metabolic rate and heat increment of feeding in juvenile South American fur seals (Arctocephalus australis).

    PubMed

    Dassis, M; Rodríguez, D H; Ieno, E N; Denuncio, P E; Loureiro, J; Davis, R W

    2014-02-01

    Bio-energetic models used to characterize an animal's energy budget require the accurate estimate of different variables such as the resting metabolic rate (RMR) and the heat increment of feeding (HIF). In this study, we estimated the in air RMR of wild juvenile South American fur seals (SAFS; Arctocephalus australis) temporarily held in captivity by measuring oxygen consumption while at rest in a postabsorptive condition. HIF, which is an increase in metabolic rate associated with digestion, assimilation and nutrient interconversion, was estimated as the difference in resting metabolic rate between the postabsorptive condition and the first 3.5h postprandial. As data were hierarchically structured, linear mixed effect models were used to compare RMR measures under both physiological conditions. Results indicated a significant increase (61%) for the postprandial RMR compared to the postabsorptive condition, estimated at 17.93±1.84 and 11.15±1.91mL O2 min(-1)kg(-1), respectively. These values constitute the first estimation of RMR and HIF in this species, and should be considered in the energy budgets for juvenile SAFS foraging at-sea. Copyright © 2013 Elsevier Inc. All rights reserved.

  4. The removal of heavy metals by iron mine drainage sludge and Phragmites australis

    NASA Astrophysics Data System (ADS)

    Hoang Ha, Nguyen Thi; Anh, Bui Thi Kim

    2017-06-01

    This study was conducted to assess the removal of heavy metals from solutions by the combination of modified iron mine drainage sludge (sorbent column) and surface and subsurface flow constructed wetlands using the common reed (Phragmites australis) during 30 days of experiment. The results of this study demonstrated that the average removal rates of Zn, Pb, Mn, and As by sorbent column were 59.0, 55.1, 38.7, and 42.4%, respectively. The decreasing trend of removal rates of metals by sorbent column was obtained during the experiment. The average removal rates of Zn, Pb, Mn, and As by sorbent column-surface constructed wetland were 78.9, 73.5, 91.2, and 80.5%, respectively; those by sorbent column-subsurface flow constructed wetland were 81.7, 81.1, 94.1, and 83.1% which reflected that subsurface flow constructed wetland showed higher removal rate than the surface system. Concentrations of heavy metals in the outlet water were lower than the Vietnamese standard limits regulated for industrial wastewater. The results indicate the feasibility of integration of iron mine drainage sludge and constructed wetlands for wastewater treatment.

  5. Reproductive behavior in the squid Sepioteuthis australis from South Australia: ethogram of reproductive body patterns.

    PubMed

    Jantzen, Troy M; Havenhand, Jon N

    2003-06-01

    Squids use a diverse range of body patterns for communication. Each pattern consists of a series of chromatic, postural, and locomotor components that are under neural control and can change within fractions of a second. Here we describe an ethogram of 48 body pattern components from in situ observations of reproductively active Sepioteuthis australis. In addition, we identify the total time and average duration that each component is shown, to a resolution of 1 s. Our results suggest that only a few components (e.g., "Golden epaulettes," "Stitchwork fins," and "Rigid arms") are temporally common, that is, shown for more than 80% of the time. In contrast to the component classification reported for other species of squid, for this species we suggest a classification system consisting of "short acute" (lasting for < 10 s); some of these same components were also classified as "medium acute" (11-60 s) or "chronic" (> 60 s). Several body patterning components were previously unreported, as were some of the combinations observed. The significance of these patterning components is discussed within the context of the associated behaviors of the squid on the spawning grounds.

  6. Cellular and ultrastructural characterization of the grey-morph phenotype in southern right whales (Eubalaena australis).

    PubMed

    Eroh, Guy D; Clayton, Fred C; Florell, Scott R; Cassidy, Pamela B; Chirife, Andrea; Marón, Carina F; Valenzuela, Luciano O; Campbell, Michael S; Seger, Jon; Rowntree, Victoria J; Leachman, Sancy A

    2017-01-01

    Southern right whales (SRWs, Eubalena australis) are polymorphic for an X-linked pigmentation pattern known as grey morphism. Most SRWs have completely black skin with white patches on their bellies and occasionally on their backs; these patches remain white as the whale ages. Grey morphs (previously referred to as partial albinos) appear mostly white at birth, with a splattering of rounded black marks; but as the whales age, the white skin gradually changes to a brownish grey color. The cellular and developmental bases of grey morphism are not understood. Here we describe cellular and ultrastructural features of grey-morph skin in relation to that of normal, wild-type skin. Melanocytes were identified histologically and counted, and melanosomes were measured using transmission electron microscopy. Grey-morph skin had fewer melanocytes when compared to wild-type skin, suggesting reduced melanocyte survival, migration, or proliferation in these whales. Grey-morph melanocytes had smaller melanosomes relative to wild-type skin, normal transport of melanosomes to surrounding keratinocytes, and normal localization of melanin granules above the keratinocyte nuclei. These findings indicate that SRW grey-morph pigmentation patterns are caused by reduced numbers of melanocytes in the skin, as well as by reduced amounts of melanin production and/or reduced sizes of mature melanosomes. Grey morphism is distinct from piebaldism and albinism found in other species, which are genetic pigmentation conditions resulting from the local absence of melanocytes, or the inability to synthesize melanin, respectively.

  7. Identification and quantification of phenolics in Australian native mint (Mentha australis R. Br.).

    PubMed

    Tang, Kitty S C; Konczak, Izabela; Zhao, Jian

    2016-02-01

    Australian native mints have traditionally been used by the aboriginal people for natural remedies; however, their bioactive components have not been studied. Antioxidant capacity and composition of phenolic compounds of Mentha australis R. Br., Lamiaceae were investigated for the first time. Phenolic compounds were analyzed by HPLC photodiode array detector, liquid chromatography high resolution mass spectrometry, tandem mass spectrometry and nuclear magnetic resonance spectroscopy. Aqueous methanolic extract of the mint exhibited comparable antioxidant capacity to the common spearmint. Major compounds identified in the extract were rosmarinic acid (160.4 ± 0.85 μg mg(-1)purified extract), neoponcirin (145.0 ± 0.42 μg gallic acid equivalent(GAE) mg(-1)), narirutin (30.3 ± 0.02 μg GAE mg(-1)), chlorogenic acid (15.4 ± 0.05 μg mg(-1)) and biochanin A (9.6 ± 0.06 μg GAE mg(-1)), while minor compounds were caffeic acid, apigenin, hesperetin and naringenin. Neoponcirin and biochanin A were identified for the first time in the Mentha genus.

  8. A comparison of the impact of 'seagrass-friendly' boat mooring systems on Posidonia australis.

    PubMed

    Demers, Marie-Claire A; Davis, Andrew R; Knott, Nathan A

    2013-02-01

    Permanent boat moorings have contributed to the decline of seagrasses worldwide, prompting the development of 'seagrass-friendly' moorings. We contrasted seagrass cover and density (predominantly Posidonia australis) in the vicinity of three mooring types and nearby reference areas lacking moorings in Jervis Bay, Australia. We examined two types of 'seagrass-friendly' mooring and a conventional 'swing' mooring. 'Swing' moorings produced significant seagrass scour, denuding patches of ~9 m radius. Seagrass-friendly 'cyclone' moorings produced extensive denuded patches (average radius of ~18 m). Seagrass-friendly 'screw' moorings, conversely, had similar seagrass cover to nearby reference areas. Our findings reinforce previous work highlighting the negative effects of 'swing' and 'cyclone' moorings. In contrast, the previously unstudied 'screw' moorings were highly effective. We conclude that regular maintenance of moorings and the monitoring of surrounding seagrass are required to ensure that 'seagrass-friendly' moorings are operating effectively. This is important, as following damage Posidonia will take many decades to recover. Copyright © 2012 Elsevier Ltd. All rights reserved.

  9. Silicon supply modifies C:N:P stoichiometry and growth of Phragmites australis.

    PubMed

    Schaller, J; Brackhage, C; Gessner, M O; Bäuker, E; Gert Dudel, E

    2012-03-01

    Silicon is a non-essential element for plant growth. Nevertheless, it affects plant stress resistance and in some plants, such as grasses, it may substitute carbon (C) compounds in cell walls, thereby influencing C allocation patterns and biomass production. How variation in silicon supply over a narrow range affects nitrogen (N) and phosphorus (P) uptake by plants has also been investigated in some detail. However, little is known about effects on the stoichiometric relationships between C, N and P when silicon supply varies over a broader range. Here, we assessed the effect of silicon on aboveground biomass production and C:N:P stoichiometry of common reed, Phragmites australis, in a pot experiment in which three widely differing levels of silicon were supplied. Scanning electron microscopy (SEM) showed that elevated silicon supply promoted silica deposition in the epidermis of Phragmites leaves. This resulted in altered N:P ratios, whereas C:N ratios changed only slightly. Plant growth was slightly (but not significantly) enhanced at intermediate silicon supply levels but significantly decreased at high levels. These findings point to the potential of silicon to impact plant growth and elemental stoichiometry and, by extension, to affect biogeochemical cycles in ecosystems dominated by Phragmites and other grasses and sedges.

  10. Myoglobins of cartilaginous fishes III. Amino acid sequence of myoglobin of the shark Galeorhinus australis.

    PubMed

    Fisher, W K; Koureas, D D; Thompson, E O

    1981-01-01

    Myoglobin isolated from the red muscle of the school shark Galeorhinus australis was purified by gel filtration and ion-exchange chromatography. The amino acid sequence was determined following digestion with trypsin and purification of the peptides by paper ionophoresis and chromatography. Sequences of purified peptides were determined by the dansyl-Edman procedure and the peptides aligned by homology with the sequence of the myoglobin of the gummy shark Mustelus antarcticus. The two myoglobin sequences showed a marked similarity (16 differences), but both sequences showed approximately the same number of differences (68) from myoglobin of the Port Jackson shark Heterodontus portusjacksoni. There are 19 residues unique to three shark myoglobin sequences. As found with other fish myoglobins there are 148 residues with deletions of four residues at the amino terminal end as well as one residue in the CD region. The amino terminal residue is acetylated. The distal E7 histidine residue was found to be replaced by glutamine, as only previously reported for the myoglobin sequence of gummy shark.

  11. Androctonus australis hector venom contributes to the interaction between neuropeptides and mast cells in pulmonary hyperresponsiveness.

    PubMed

    Chaïr-Yousfi, Imène; Laraba-Djebari, Fatima; Hammoudi-Triki, Djelila

    2015-03-01

    Lung injury and respiratory distress syndrome are frequent symptoms observed in the most severe cases of scorpion envenomation. The uncontrolled transmigration of leukocyte cells into the lung interstitium and alveolar space and pulmonary edema may be the cause of death. Mast cells can release various inflammatory mediators known to be involved in the development of lung edema following scorpion venom injection. The present study was designed to determine the evidence of neurokinin 1 (NK1) receptor and the involvement of mast cell activation to induce pulmonary edema and to increase vascular permeability after Androctonus australis hector (Aah) venom administration. To this end, mast cells were depleted using compound 48/80 (C48/80). Furthermore, the involvement of tachykinin NK1 receptors expressed on mast cell membranes was elucidated by their blocking with an antagonist. On the other hand, the ability of Aah venom to increase vascular permeability and to induce edema was also assessed by measuring the amount of Evans blue dye (EBD) extravasation in bronchoalveolar lavage (BAL) fluid and in the lungs of mice. Pulmonary edema, as assessed by the levels of EBD extravasation, was completely inhibited in compound 48/80-treated animals. Depletion by stimuli non-immunological C48/80 component markedly reduced induced inflammatory response following the venom administration. The mast cells seem to play an important role in the development of lung injury and the increase of vascular permeability in mice following the subcutaneous administration of Aah scorpion venom through the NK1 receptor.

  12. Far-infrared observations of a star-forming region in the Corona Australis dark cloud

    NASA Technical Reports Server (NTRS)

    Cruz-Gonzalez, I.; Mcbreen, B.; Fazio, G. G.

    1984-01-01

    A high-resolution far-IR (40-250-micron) survey of a 0.9-sq-deg section of the core region of the Corona Australis dark cloud (containing very young stellar objects such as T Tauri stars, Herbig Ae and Be stars, Herbig-Haro objects, and compact H II regions) is presented. Two extended far-IR sources were found, one associated with the Herbig emission-line star R CrA and the other with the irregular emission-line variable star TY CrA. The two sources have substantially more far-IR radiation than could be expected from a blackbody extrapolation of their near-IR fluxes. The total luminosities of these sources are 145 and 58 solar luminosity, respectively, implying that the embedded objects are of intermediate or low mass. The infrared observations of the sources associated with R CrA and TY CrA are consistent with models of the evolution of protostellar envelopes of intermediate mass. However, the TY CrA source appears to have passed the evolutionary stage of expelling most of the hot dust near the central source, yielding an age of about 1 Myr.

  13. Seasonal transpiration pattern of Phragmites australis in a wetland of semi-arid Spain

    NASA Astrophysics Data System (ADS)

    Moro, María José; Domingo, Francisco; López, Germán

    2004-02-01

    Transpiration rates were measured in a flooded population of Phragmites australis ssp. altissima in a wetland located in El Hondo Natural Park (southeastern Spain) during the growing season of 2000. The heat balance method for measuring sap flow was used to calculate the rate of water transpiration on a whole-stem basis. Four series of measurements were carried out in selected weeks in May, June, August and October. Structure, biomass and leaf area index of the reed population were simultaneously quantified in order to scale transpiration on a plot-area basis.Overall, transpiration flux was high during the sampling period and showed a typical diurnal pattern with a maximum at about midday. Mean transpiration was highest at the end of June coinciding with the peak of reed growth and with the maximum leaf area both at individual and plot scales. Rates decreased abruptly in October, in parallel with the advanced foliar senescence. The variation of both midday and integrated daily transpiration is significantly related to that of the air temperature on clear days. Cloudy and rainy days exert a pronounced effect on water loss by decreasing transpiration. Our results highlight the potential use of the sap-flow method to measure transpiration in reed ecosystems and the relevance of this flux for the water balance in wetlands in semi-arid environments. Thus, it is suggested that water management in these areas could be favoured by acquiring high-quality experimental data.

  14. No allocation trade-offs between flowering and sproutingin the lignotuberous, Mediterranean shrub Erica australis

    NASA Astrophysics Data System (ADS)

    Cruz, Alberto; Moreno, José M.

    2001-04-01

    Trade-offs between allocation to sexual or vegetative regeneration capacity are well established as a driving force in the life history patterns of plants in fire-prone environments. However, it is not known whether such trade-offs exist in plants which after aboveground removing disturbances, such as fire, may regenerate by sexual (seeding) or asexual (sprouting) mechanisms. We evaluated whether in the fire-recruiting resprouter Erica australis, which after fire can regenerate by seedling establishment or resprouting, a larger investment in flowers and seeds prior to being disturbed by clipping its aboveground parts would decrease subsequent sprouting, that is, its vegetative regeneration capacity. We analysed the relationships between flower and seed production and the ensuing production and growth of sprouts of six plants from thirteen different sites in central-western Spain. We found no significant relationships between measures of sexual reproductive effort and resprout production and growth 6 months after clipping the aboveground parts of the plants. No evidence of trade-offs between sexual and asexual efforts was found. Furthermore, no significant relationship was found between lignotuber total non-structural carbohydrates and sexual reproductive effort. In addition, 2 years after the disturbance, resprout biomass was positively and significantly correlated with sexual reproductive effort prior to the disturbance. This indicates that growth of resprouts was higher at the sites where plants made a greater reproductive effort. The sites that were more favourable to producing flowers and seeds could also be more favourable to resprouting.

  15. Effects of sediment burial disturbance on macro and microelement dynamics in decomposing litter of Phragmites australis in the coastal marsh of the Yellow River estuary, China.

    PubMed

    Sun, Zhigao; Mou, Xiaojie

    2016-03-01

    From April 2008 to November 2009, a field decomposition experiment was conducted to investigate the effects of sediment burial on macro (C, N) and microelement (Pb, Cr, Cu, Zn, Ni, and Mn) variations in decomposing litter of Phragmites australis in the coastal marsh of the Yellow River estuary. Three one-off sediment burial treatments [no sediment burial (0 mm year(-1), S0), current sediment burial (100 mm year(-1), S10), and strong sediment burial (200 mm year(-1), S20)] were laid in different decomposition sites. Results showed that sediment burials showed significant influence on the decomposition rate of P. australis, in the order of S10 (0.001990 day(-1)) ≈ S20 (0.001710 day(-1)) > S0 (0.000768 day(-1)) (p < 0.05). The macro and microelement in decomposing litters of the three burial depths exhibited different temporal variations except for Cu, Zn, and Ni. No significant differences in C, N, Pb, Cr, Zn, and Mn concentrations were observed among the three burial treatments except for Cu and Ni (p > 0.05). With increasing burial depth, N, Cr, Cu, Ni, and Mn concentrations generally increased, while C, Pb, and Zn concentrations varied insignificantly. Sediment burial was favorable for C and N release from P. australis, and, with increasing burial depth, the C release from litter significantly increased, and the N in litter shifted from accumulation to release. With a few exceptions, Pb, Cr, Zn, and Mn stocks in P. australis in the three treatments evidenced the export of metals from litter to environment, and, with increasing burial depth, the export amounts increased greatly. Stocks of Cu and Ni in P. australis in the S10 and S20 treatments were generally positive, evidencing incorporation of the two metals in most sampling times. Except for Ni, the variations of C, N, Pb, Cr, Cu, Zn, and Mn stocks in P. australis in the S10 and S20 treatments were approximated, indicating that the strong burial episodes (S20) occurred in P. australis marsh in

  16. Are Secrets Immoral? The Construction of Secrets in Everyday Conversation.

    ERIC Educational Resources Information Center

    Gunthner, Susanne; Luckmann, Thomas

    1998-01-01

    Investigates the communicative treatment of secrets, presenting examples from recorded communicative interactions in a wide range of social milieus and settings in which the participants revealed knowledge of secrets, tried to dig out old secrets without appearing to be doing so, and occasionally, appeared to be hiding some items of knowledge from…

  17. Wrapped up in Covers: Preschoolers' Secrets and Secret Hiding Places

    ERIC Educational Resources Information Center

    Corson, Kimberly; Colwell, Malinda J.; Bell, Nancy J.; Trejos-Castillo, Elizabeth

    2014-01-01

    In this qualitative study, interviews about children's secret hiding places were conducted with 3-5-year-olds (n?=?17) in a university sponsored preschool programme using art narratives. Since prior studies indicate that children understand the concept of a secret as early as five and that they associate secrets with hiding places, the purpose of…

  18. Wrapped up in Covers: Preschoolers' Secrets and Secret Hiding Places

    ERIC Educational Resources Information Center

    Corson, Kimberly; Colwell, Malinda J.; Bell, Nancy J.; Trejos-Castillo, Elizabeth

    2014-01-01

    In this qualitative study, interviews about children's secret hiding places were conducted with 3-5-year-olds (n?=?17) in a university sponsored preschool programme using art narratives. Since prior studies indicate that children understand the concept of a secret as early as five and that they associate secrets with hiding places, the purpose of…

  19. Extracellular secretion of recombinant proteins

    SciTech Connect

    Linger, Jeffrey G.; Darzins, Aldis

    2014-07-22

    Nucleic acids encoding secretion signals, expression vectors containing the nucleic acids, and host cells containing the expression vectors are disclosed. Also disclosed are polypeptides that contain the secretion signals and methods of producing polypeptides, including methods of directing the extracellular secretion of the polypeptides. Exemplary embodiments include cellulase proteins fused to secretion signals, methods to produce and isolate these polypeptides, and methods to degrade lignocellulosic biomass.

  20. Telling stories: keeping secrets.

    PubMed

    Jensen, Joan M

    2009-01-01

    This article addresses the reticence of some farm women to share their experiences with historians and how that desire to keep secrets collides with the desire by scholars to tell the stories of these women. It argues that scholars must continue to struggle with the issue of which stories to tell publicly and which to keep private. The author discusses her own experience telling stories about rural women in the 1970s and the need to give voice to the heritage of rural women, especially of groups that have feared revealing their experiences. She offers examples of historians of rural women who have successfully worked with formerly silenced populations and urges historians to continue to tell stories about these lives, to reevaluate what has been already learned, to ask new questions, and to discuss which secrets need to be shared.

  1. Generalized quantum secret sharing

    SciTech Connect

    Singh, Sudhir Kumar; Srikanth, R.

    2005-01-01

    We explore a generalization of quantum secret sharing (QSS) in which classical shares play a complementary role to quantum shares, exploring further consequences of an idea first studied by Nascimento, Mueller-Quade, and Imai [Phys. Rev. A 64, 042311 (2001)]. We examine three ways, termed inflation, compression, and twin thresholding, by which the proportion of classical shares can be augmented. This has the important application that it reduces quantum (information processing) players by replacing them with their classical counterparts, thereby making quantum secret sharing considerably easier and less expensive to implement in a practical setting. In compression, a QSS scheme is turned into an equivalent scheme with fewer quantum players, compensated for by suitable classical shares. In inflation, a QSS scheme is enlarged by adding only classical shares and players. In a twin-threshold scheme, we invoke two separate thresholds for classical and quantum shares based on the idea of information dilution.

  2. Proactive quantum secret sharing

    NASA Astrophysics Data System (ADS)

    Qin, Huawang; Dai, Yuewei

    2015-11-01

    A proactive quantum secret sharing scheme is proposed, in which the participants can update their key shares periodically. In an updating period, one participant randomly generates the EPR pairs, and the other participants update their key shares and perform the corresponding unitary operations on the particles of the EPR pairs. Then, the participant who generated the EPR pairs performs the Bell-state measurement and updates his key share according to the result of the Bell-state measurement. After an updating period, each participant can change his key share, but the secret is changeless, and the old key shares will be useless even if they have been stolen by the attacker. The proactive property of our scheme is very useful to resist the mobile attacker.

  3. Cell secretion: an update

    PubMed Central

    Jeremic, A

    2008-01-01

    This past decade has witnessed the publication of a flurry of scientific papers and reports on the subject of cell secretion, following discovery of a permanent plasma membrane structure termed ‘porosome’ and its determination as the universal secretory machinery in cells. This discovery has led to a paradigm shift in our understanding of the secretory process, demonstrating that membrane-bound secretory vesicles transiently dock and fuse at the porosome base to release their contents to the cell exterior. The regulated release of intravesicular contents during cell secretion is governed by dilation of the porosome opening to the outside, and the extent of vesicle swelling. In agreement, a great number of articles have been written and studies performed, which are briefly discussed in this article. PMID:18363838

  4. Secret Key Crypto Implementations

    NASA Astrophysics Data System (ADS)

    Bertoni, Guido Marco; Melzani, Filippo

    This chapter presents the algorithm selected in 2001 as the Advanced Encryption Standard. This algorithm is the base for implementing security and privacy based on symmetric key solutions in almost all new applications. Secret key algorithms are used in combination with modes of operation to provide different security properties. The most used modes of operation are presented in this chapter. Finally an overview of the different techniques of software and hardware implementations is given.

  5. Bile Formation and Secretion

    PubMed Central

    Boyer, James L.

    2014-01-01

    Bile is a unique and vital aqueous secretion of the liver that is formed by the hepatocyte and modified down stream by absorptive and secretory properties of the bile duct epithelium. Approximately 5% of bile consists of organic and inorganic solutes of considerable complexity. The bile-secretory unit consists of a canalicular network which is formed by the apical membrane of adjacent hepatocytes and sealed by tight junctions. The bile canaliculi (~1 μm in diameter) conduct the flow of bile countercurrent to the direction of portal blood flow and connect with the canal of Hering and bile ducts which progressively increase in diameter and complexity prior to the entry of bile into the gallbladder, common bile duct, and intestine. Canalicular bile secretion is determined by both bile salt-dependent and independent transport systems which are localized at the apical membrane of the hepatocyte and largely consist of a series of adenosine triphosphate-binding cassette transport proteins that function as export pumps for bile salts and other organic solutes. These transporters create osmotic gradients within the bile canalicular lumen that provide the driving force for movement of fluid into the lumen via aquaporins. Species vary with respect to the relative amounts of bile salt-dependent and independent canalicular flow and cholangiocyte secretion which is highly regulated by hormones, second messengers, and signal transduction pathways. Most determinants of bile secretion are now characterized at the molecular level in animal models and in man. Genetic mutations serve to illuminate many of their functions. PMID:23897680

  6. Restriction endonuclease analysis as a taxonomic tool in the study of pig isolates belonging to the Australis serogroup of Leptospira interrogans.

    PubMed Central

    Ellis, W A; Montgomery, J M; Thiermann, A B

    1991-01-01

    Restriction endonuclease analysis was performed on DNAs from the type strains of the Australis serogroup of Leptospira interrogans by using 20 restriction enzymes, and the electrophoretic patterns obtained were compared with patterns obtained from 162 Australis serogroup isolates from pigs. It proved to be a quick and reliable method for typing such strains. All of the pig isolates were identified as either serovar bratislava or muenchen. It also showed differences at the subserovar level which may be important in (i) understanding the epidemiology of the Australis serogroup, (ii) the development of suitable vaccines, and (iii) pathogenesis and pathogenicity studies. Two genotypes (B2b and M2) accounted for 92% of isolates from aborted or stillborn piglets, while a third genotype (B2a) was the only one recovered from the brains of piglets with meningitis. Images PMID:1647408

  7. Restriction endonuclease analysis as a taxonomic tool in the study of pig isolates belonging to the Australis serogroup of Leptospira interrogans.

    PubMed

    Ellis, W A; Montgomery, J M; Thiermann, A B

    1991-05-01

    Restriction endonuclease analysis was performed on DNAs from the type strains of the Australis serogroup of Leptospira interrogans by using 20 restriction enzymes, and the electrophoretic patterns obtained were compared with patterns obtained from 162 Australis serogroup isolates from pigs. It proved to be a quick and reliable method for typing such strains. All of the pig isolates were identified as either serovar bratislava or muenchen. It also showed differences at the subserovar level which may be important in (i) understanding the epidemiology of the Australis serogroup, (ii) the development of suitable vaccines, and (iii) pathogenesis and pathogenicity studies. Two genotypes (B2b and M2) accounted for 92% of isolates from aborted or stillborn piglets, while a third genotype (B2a) was the only one recovered from the brains of piglets with meningitis.

  8. Potentially toxic Pseudo-nitzschia species in plankton and fecal samples of Eubalaena australis from Península Valdés calving ground, Argentina

    NASA Astrophysics Data System (ADS)

    D'Agostino, Valeria C.; Hoffmeyer, Mónica S.; Almandoz, Gastón O.; Sastre, Viviana; Degrati, Mariana

    2015-12-01

    Península Valdés (PV) in Argentina is an important calving ground for the southern right whale Eubalaena australis. However, a high mortality of calves has been observed in the last years, which could be associated with phycotoxin exposure. During a sampling program conducted late in the calving seasons of 2004, 2005 and 2010, potentially toxic species of the genus Pseudo-nitzschia were observed to be an important component of the phytoplankton community and they were also found in fecal samples of two live whales and three stranded whales. In line with this, in the present study Pseudo-nitzschia australis, Pseudo-nitzschia fraudulenta, Pseudo-nitzschia pungens and the complex Pseudo-nitzschia pseudodelicatissima were identified in fecal samples and phytoplankton samples by light and electron microscopy. Although no toxin analysis was carried out in the present study, our findings suggest that E. australis could be exposed to domoic acid in their calving ground.

  9. An integrated modeling approach for monitoring and predicting common reed (Phragmites australis) colonization in a managed South Carolina estuary

    NASA Astrophysics Data System (ADS)

    Walker, Samuel Peter

    Recently, research efforts have focused on the development and testing of geographic information processing (GIP) techniques to more effectively identify and monitor invasive plant species in coastal ecosystems. While these efforts are progressing, particularly with refinements in hyperspectral image processing, there remains a lack of practical, science-based tools for decision-making with respect to the monitoring and mitigation of invasive plant species. Therefore, a geographic information systems (GIS) model is proposed to quantify the probability of a future exotic plant invasion in a user-defined area of interest. The primary objective of this investigation is to present conceptual and technical descriptions of a proposed modeling approach for prediction of common reed (Phragmites australis) colonization in a managed coastal wetland environment. Successful validation and adoption of the model will promote continued discourse regarding the impact of invasive species in coastal ecosystems, while providing the management community with a valuable decision support tool. Three main chapters comprise this manuscript; Chapter 1 focuses on the evaluation of remote sensing data and techniques for directly identifying Phragmites australis in a coastal ecosystem; Chapter 2 describes proposed, GIS-based models for predicting Phragmites colonization and future growth projections; and Chapter 3 discusses the results of the compiled relative suitability index (RSI) compilation and growth models, and considers the key management implications of the investigation. In the absence of a universal eradication solution for the invasive species Phragmites australis, an integrated management approach that utilizes a suite of dynamic, geo-spatial techniques in concert with more traditional practices is ultimately recommended. Keywords. Invasive species, estuary, NERRS, Phragmites, GIS-based models, remote sensing, coastal resource management, geographic information processing.

  10. Interactive effects of elevated temperature and CO2 on two phylogeographically distinct clones of common reed (Phragmites australis)

    PubMed Central

    Eller, Franziska; Lambertini, Carla; Nguyen, Loc Xuan; Achenbach, Luciana; Brix, Hans

    2012-01-01

    The aboveground growth, physiological and biochemical parameters of two clones of the cosmopolitan wetland grass Phragmites australis, grown at four treatment combinations of temperature and CO2, were investigated to elucidate whether their climate response differed due to inherent differences in their ecological adaptation. The two phylogeographically distinct P. australis clones (DK clone, European genetic background; ALG clone, Mediterranean genetic background) were grown for 151 days in phytotrons at 19/12 °C (day/night temperature) and 390 ppm CO2, and at elevated temperature (+5 °C) and CO2 (700 ppm) with treatment factors alone or in combination. The ALG clone had 2–4 times higher aboveground biomass, higher light-saturated rates of photosynthesis (Pmax), maximum electron transport rates (ETRmax) and Rubisco activity, and higher photosynthetic nitrogen-use efficiency than the DK clone. The DK clone, however, produced more shoots, leaves and side-shoots, and had 9–51 % higher specific leaf area and 15–39 % higher leaf nitrogen concentration than the ALG clone. Although elevated atmospheric CO2 alone barely affected the aboveground growth of the two P. australis clones, simultaneously elevated temperature and CO2 stimulated growth and aboveground biomass. Overall, elevated CO2 stimulated photosynthesis, but the clones responded differently to a concomitant increase in CO2 and temperature, depending on the phylogeographic background of the plant. The DK clone showed overall stronger responses, and can be considered the more plastic of the two clones with respect to CO2 and temperature. Thus, the DK clone may be better adapted to climate change than the ALG clone, at least in the short term.

  11. Rapid growth of a Eurasian haplotype of Phragmites australis in a restored brackish marsh in Louisiana, USA

    USGS Publications Warehouse

    Howard, R.J.; Travis, S.E.; Sikes, B.A.

    2008-01-01

    While numerous studies have documented patterns of invasion by non-indigenous plant species, few have considered the invasive properties of non-native genotypes of native species. Characteristics associated with specific genotypes, such as tolerance to disturbance, may mistakenly be applied to an entire species in the absence of genetic information, which consequently may affect management decisions. We report here on the incidence and growth of an introduced lineage of Phragmites australis in the Gulf of Mexico coastal zone of Louisiana. P. australis was collected from nine separate locations for inclusion in a series of growth experiments. Chloroplast DNA analysis indicated that specimens collected from four locations in the Mississippi River Delta represented the introduced Eurasian haplotype; the remainder represented the gulf coast haplotype. Three distinct genotypes, or clones, were identified within each haplotype via analysis using amplified fragment length polymorphisms, which also revealed reduced genetic diversity of the gulf coast clones compared to the Eurasian clones. Clones of each haplotype were planted along with three other native macrophytes at similar densities in a restored brackish marsh and monitored for growth. After 14 months, the Eurasian haplotype had spread vegetatively to cover about 82% of the experimental plots, more than four times the coverage (18%) of the gulf coast haplotype. Thus, the use of P. australis plantings for wetland restoration should consider the genetic lineage of plants used since our results indicate the potential of the Eurasian haplotype to grow rapidly at newly restored sites. This rapid growth may limit the establishment of more slowly growing native species. ?? 2007 Springer Science+Business Media B.V.

  12. Phylogeography of Australia's king brown snake (Pseudechis australis) reveals Pliocene divergence and Pleistocene dispersal of a top predator.

    PubMed

    Kuch, Ulrich; Keogh, J Scott; Weigel, John; Smith, Laurie A; Mebs, Dietrich

    2005-03-01

    King brown snakes or mulga snakes (Pseudechis australis) are the largest and among the most dangerous and wide-ranging venomous snakes in Australia and New Guinea. They occur in diverse habitats, are important predators, and exhibit considerable morphological variation. We infer the relationships and historical biogeography of P. australis based on phylogenetic analysis of 1,249 base pairs from the mitochondrial cytochrome b, NADH dehydrogenase subunit 4 and three adjacent tRNA genes using Bayesian, maximum-likelihood, and maximum-parsimony methods. All methods reveal deep phylogenetic structure with four strongly supported clades comprising snakes from New Guinea (I), localities all over Australia (II), the Kimberleys of Western Australia (III), and north-central Australia (IV), suggesting a much more ancient radiation than previously believed. This conclusion is robust to different molecular clock estimations indicating divergence in Pliocene or Late Miocene, after landbridge dispersal to New Guinea had occurred. While members of clades I, III and IV are medium-sized, slender snakes, those of clade II attain large sizes and a robust build, rendering them top predators in their ecosystems. Genetic differentiation within clade II is low and haplotype distribution largely incongruent with geography or colour morphs, suggesting Pleistocene dispersal and recent ecomorph evolution. Significant haplotype diversity exists in clades III and IV, implying that clade IV comprises two species. Members of clade II are broadly sympatric with members of both northern Australian clades. Thus, our data support the recognition of at least five species from within P. australis (auct.) under various criteria. We discuss biogeographical, ecological and medical implications of our findings.

  13. Modelling temperature, photoperiod and vernalization responses of Brunonia australis (Goodeniaceae) and Calandrinia sp. (Portulacaceae) to predict flowering time

    PubMed Central

    Cave, Robyn L.; Hammer, Graeme L.; McLean, Greg; Birch, Colin J.; Erwin, John E.; Johnston, Margaret E.

    2013-01-01

    Background and Aims Crop models for herbaceous ornamental species typically include functions for temperature and photoperiod responses, but very few incorporate vernalization, which is a requirement of many traditional crops. This study investigated the development of floriculture crop models, which describe temperature responses, plus photoperiod or vernalization requirements, using Australian native ephemerals Brunonia australis and Calandrinia sp. Methods A novel approach involved the use of a field crop modelling tool, DEVEL2. This optimization program estimates the parameters of selected functions within the development rate models using an iterative process that minimizes sum of squares residual between estimated and observed days for the phenological event. Parameter profiling and jack-knifing are included in DEVEL2 to remove bias from parameter estimates and introduce rigour into the parameter selection process. Key Results Development rate of B. australis from planting to first visible floral bud (VFB) was predicted using a multiplicative approach with a curvilinear function to describe temperature responses and a broken linear function to explain photoperiod responses. A similar model was used to describe the development rate of Calandrinia sp., except the photoperiod function was replaced with an exponential vernalization function, which explained a facultative cold requirement and included a coefficient for determining the vernalization ceiling temperature. Temperature was the main environmental factor influencing development rate for VFB to anthesis of both species and was predicted using a linear model. Conclusions The phenology models for B. australis and Calandrinia sp. described development rate from planting to VFB and from VFB to anthesis in response to temperature and photoperiod or vernalization and may assist modelling efforts of other herbaceous ornamental plants. In addition to crop management, the vernalization function could be used to

  14. Transcriptome/Degradome-Wide Discovery of MicroRNAs and Transcript Targets in Two Paulownia australis Genotypes

    PubMed Central

    Niu, Suyan; Fan, Guoqiang; Xu, Enkai; Deng, Minjie; Zhao, Zhenli; Dong, Yanpeng

    2014-01-01

    MicroRNAs (miRNAs) are involved in plant growth, development, and response to biotic and abiotic stresses. Most of the miRNAs that have been identified in model plants are well characterized, but till now, no reports have previously been published concerning miRNAs in Paulownia australis. In order to investigate miRNA-guided transcript target regulation in P. australis, small RNA libraries from two P. australis (diploids, PA2; and autotetraploids, PA4) genotypes were subjected to Solexa sequencing. As a result, 10,691,271 (PA2) and 10,712,733 (PA4) clean reads were obtained, and 45 conserved miRNAs belonging to 15 families, and 31 potential novel miRNAs candidates were identified. Compared with their expression levels in the PA2 plants, 26 miRNAs were up-regulated and 15 miRNAs were down-regulated in the PA4 plants. The relative expressions of 12 miRNAs were validated by quantitative real-time polymerase chain reaction. Using the degradome approach, 53 transcript targets were identified and annotated based on Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analysis. These targets were associated with development, stimulus response, metabolism, signaling transduction and biological regulation. Among them, 11 targets, including TCP transcription factors, auxin response factors, squamosa promoter-binding-like proteins, scarecrow-like proteins, L-type lectin-domain containing receptor kinases and zinc finger CCCH domain-containing protein, cleaved by four known miRNA family and two potentially novel miRNAs were found to be involved in regulating plant development, biotic and abiotic stresses. The findings will be helpful to facilitate studies on the functions of miRNAs and their transcript targets in Paulownia. PMID:25198709

  15. Use of plant roots for phytoremediation and molecular farming.

    PubMed

    Gleba, D; Borisjuk, N V; Borisjuk, L G; Kneer, R; Poulev, A; Skarzhinskaya, M; Dushenkov, S; Logendra, S; Gleba, Y Y; Raskin, I

    1999-05-25

    Alternative agriculture, which expands the uses of plants well beyond food and fiber, is beginning to change plant biology. Two plant-based biotechnologies were recently developed that take advantage of the ability of plant roots to absorb or secrete various substances. They are (i) phytoextraction, the use of plants to remove pollutants from the environment and (ii) rhizosecretion, a subset of molecular farming, designed to produce and secrete valuable natural products and recombinant proteins from roots. Here we discuss recent advances in these technologies and assess their potential in soil remediation, drug discovery, and molecular farming.

  16. Use of plant roots for phytoremediation and molecular farming

    PubMed Central

    Gleba, Doloressa; Borisjuk, Nikolai V.; Borisjuk, Ludmyla G.; Kneer, Ralf; Poulev, Alexander; Skarzhinskaya, Marina; Dushenkov, Slavik; Logendra, Sithes; Gleba, Yuri Y.; Raskin, Ilya

    1999-01-01

    Alternative agriculture, which expands the uses of plants well beyond food and fiber, is beginning to change plant biology. Two plant-based biotechnologies were recently developed that take advantage of the ability of plant roots to absorb or secrete various substances. They are (i) phytoextraction, the use of plants to remove pollutants from the environment and (ii) rhizosecretion, a subset of molecular farming, designed to produce and secrete valuable natural products and recombinant proteins from roots. Here we discuss recent advances in these technologies and assess their potential in soil remediation, drug discovery, and molecular farming. PMID:10339526

  17. Dissolved inorganic nitrogen pools and surface flux under different brackish marsh vegetation types, common reed (Phragmites australis) and salt hay (Spartina patens)

    USGS Publications Warehouse

    Windham-Myers, L.

    2005-01-01

    The current expansion of Phragmites australis into the high marsh shortgrass (Spartina patens, Distichlis spicata) communities of eastern U.S. salt marshes provided an opportunity to identify the influence of vegetation types on pools and fluxes of dissolved inorganic nitrogen (DIN). Two brackish tidal marshes of the National Estuarine Research Reserve system were examined, Piermont Marsh of the Hudson River NERR in New York and Hog Island in the Jacques Coustaeu NERR of New Jersey. Pools of DIN in porewater and rates of DIN surface flux were compared in replicated pairs of recently-expanded P. australis and neighboring S. patens-dominated patches on the high marsh surface. Both marshes generally imported nitrate (NO3-) and exported ammonium (NH4+), such that overall DIN was exported. No differences in surface exchange of NO3- or NH4+ were observed between vegetation types. Depth-averaged porewater NH4+ concentrations over the entire growing season were 56% lower under P. australis than under S. patens (average 1.4 vs. 3.2 mg NH4+ L-1) with the most profound differences in November. Porewater profiles showed an accumulation of NH4+ at depth in S. patens and constant low concentrations in P. australis from the soil surface to 50 cm depth, with no significant differences in porewater salinity. Despite these profound differences in porewater, NH 4+ diffusion from soils of P. australis and S. patens were not measurably different, were similar to other published rates, and were well below estimated rates based on passive diffusion alone. Rapid adsorption and uptake by litter and microbes in surface soils of both communities may buffer NH4+ loss to flooding tides in both communities, thereby reducing the impact of P. australis invasion on NH4+ flux to flooding waters. ?? Springer 2005.

  18. Toxicokinetic and toxicodynamic analyses of Androctonus australis hector venom in rats: Optimization of antivenom therapy

    SciTech Connect

    Hammoudi-Triki, D.; Lefort, J.; Rougeot, C.; Robbe-Vincent, A.; Bon, C.; Laraba-Djebari, F.; Choumet, V. . E-mail: vchoumet@pasteur.fr

    2007-02-01

    This paper reports the simultaneous determination of toxicokinetic and toxicodynamic properties of Androctonus australis hector venom, in the absence and presence of antivenom (F(ab'){sub 2} and Fab), in envenomed rats. After subcutaneous injection of the venom, toxins showed a complete absorption phase from the site of injection associated with a distribution into a large extravascular compartment. The injection of Fab and F(ab'){sub 2} induced the neutralization of venom antigens in the blood compartment, as well as the redistribution of venom components from the extravascular compartment to the blood compartment. Interestingly, F(ab'){sub 2} and Fab showed distinct efficiencies depending on their route of injection. F(ab'){sub 2} induced a faster venom neutralization and redistribution than Fab when injected intravenously. Fab was more effective than F(ab'){sub 2} by the intramuscular route. The hemodynamic effects of Aah venom were further investigated. Changes in mean arterial pressure and heart rate were observed in parallel with an upper airway obstruction. Fab was more effective than F(ab'){sub 2} for preventing early symptoms of envenomation, whatever their route of administration. Intraperitoneal injection of F(ab'){sub 2} and Fab was similar for the prevention of the delayed symptoms, even after a late administration. Fab was more effective than F(ab'){sub 2} in the inhibition of airway resistance, independent of the route and time of administration. These results show that the treatment for scorpion stings might be improved by the intravascular injection of a mixture of Fab and F(ab'){sub 2}. If antivenom cannot be administered intravenously, Fab might be an alternative as they are more effective than F(ab'){sub 2} when injected intramuscularly.

  19. Comparison of mercury contamination in live and dead dolphins from a newly described species, Tursiops australis.

    PubMed

    Monk, Alissa; Charlton-Robb, Kate; Buddhadasa, Saman; Thompson, Ross M

    2014-01-01

    Globally it is estimated that up to 37% of all marine mammals are at a risk of extinction, due in particular to human impacts, including coastal pollution. Dolphins are known to be at risk from anthropogenic contaminants due to their longevity and high trophic position. While it is known that beach-cast animals are often high in contaminants, it has not been possible to determine whether levels may also be high in live animals from the same populations. In this paper we quantitatively assess mercury contamination in the two main populations of a newly described dolphin species from south eastern Australia, Tursiops australis. This species appear to be limited to coastal waters in close proximity to a major urban centre, and as such is likely to be vulnerable to anthropogenic pollution. For the first time, we were able to compare blubber mercury concentrations from biopsy samples of live individuals and necropsies of beach-cast animals and show that beach-cast animals were highly contaminated with mercury, at almost three times the levels found in live animals. Levels in live animals were also high, and are attributable to chronic low dose exposure to mercury from the dolphin's diet. Measurable levels of mercury were found in a number of important prey fish species. This illustrates the potential for low dose toxins in the environment to pass through marine food webs and potentially contribute to marine mammal deaths. This study demonstrates the potential use of blubber from biopsy samples to make inferences about the health of dolphins exposed to mercury.

  20. Freshwater wetlands: fertile grounds for the invasive Phragmites australis in a climate change context.

    PubMed

    Tougas-Tellier, Marie-Andrée; Morin, Jean; Hatin, Daniel; Lavoie, Claude

    2015-08-01

    Climate change will likely affect flooding regimes, which have a large influence on the functioning of freshwater riparian wetlands. Low water levels predicted for several fluvial systems make wetlands especially vulnerable to the spread of invaders, such as the common reed (Phragmites australis), one of the most invasive species in North America. We developed a model to map the distribution of potential germination grounds of the common reed in freshwater wetlands of the St. Lawrence River (Québec, Canada) under current climate conditions and used this model to predict their future distribution under two climate change scenarios simulated for 2050. We gathered historical and recent (remote sensing) data on the distribution of common reed stands for model calibration and validation purposes, then determined the parameters controlling the species establishment by seed. A two-dimensional model and the identified parameters were used to simulate the current (2010) and future (2050) distribution of germination grounds. Common reed stands are not widespread along the St. Lawrence River (212 ha), but our model suggests that current climate conditions are already conducive to considerable further expansion (>16,000 ha). Climate change may also exacerbate the expansion, particularly if river water levels drop, which will expose large bare areas propitious to seed germination. This phenomenon may be particularly important in one sector of the river, where existing common reed stands could increase their areas by a factor of 100, potentially creating the most extensive reedbed complex in North America. After colonizing salt and brackishwater marshes, the common reed could considerably expand into the freshwater marshes of North America which cover several million hectares. The effects of common reed expansion on biodiversity are difficult to predict, but likely to be highly deleterious given the competitiveness of the invader and the biological richness of freshwater

  1. Reproductive Tract Histology in South American Fur Seal Pups (Arctophoca australis).

    PubMed

    Katz, Helena; Johansson, Olle

    2017-03-01

    In the present study, a detailed histological description of the female reproductive tract of South American fur seal (Arctophoca australis) pups has been conducted. The uterine tube was covered by cuboidal to columnar epithelium; nerve fibers were present in the mesosalpinx and beneath the muscular layer. The uterus was bipartitus; the endometrial surface of the horns was lined by a simple cuboidal or columnar epithelium with deep tubular glands; caudally ("the transition area"), the epithelium changed to pseudostratified columnar, few tubular glands were present and the myometrium increased in width. A bistratified epithelium internally coated the uterine body, whereas it changed to cylindrical stratified epithelium with a highly vascularized lamina propria and a strong muscular layer in the cervix; no endometrial glands were observed in this region. From the transition area of the uterus to the vagina there were several nerve fibers and ganglia belonging to the uterovaginalis plexus. In the vestibule, hymenal folds were poorly developed; adnexa structures included the major vestibular glands and a neurovascular structure similar to the vestibular bulb. Minor vestibular glands were associated with the clitoris. The skin of the perineum was lined by a keratinized stratified epithelium, pigmented, with sebaceous glands, sweat glands and hair follicles. This is the first detailed histological description of the reproductive tract of South American fur seal pups, including the glandular adnexa and nerve structures. These results contribute to the reproductive biology in Pinniped species, and give a better understanding of the utero-placental perfusion mechanism during diving. Anat Rec, 2017. © 2017 Wiley Periodicals, Inc. Anat Rec, 300:600-613, 2017. © 2016 Wiley Periodicals, Inc.

  2. Reproduction at the extremes: pseudovivipary, hybridization and genetic mosaicism in Posidonia australis (Posidoniaceae)

    PubMed Central

    Sinclair, Elizabeth A.; Statton, John; Hovey, Renae; Anthony, Janet M.; Dixon, Kingsley W.; Kendrick, Gary A.

    2016-01-01

    Background and Aims Organisms occupying the edges of natural geographical ranges usually survive at the extreme limits of their innate physiological tolerances. Extreme and prolonged fluctuations in environmental conditions, often associated with climate change and exacerbated at species’ geographical range edges, are known to trigger alternative responses in reproduction. This study reports the first observations of adventitious inflorescence-derived plantlet formation in the marine angiosperm Posidonia australis, growing at the northern range edge (upper thermal and salinity tolerance) in Shark Bay, Western Australia. These novel plantlets are described and a combination of microsatellite DNA markers and flow cytometry is used to determine their origin. Methods Polymorphic microsatellite DNA markers were used to generate multilocus genotypes to determine the origin of the adventitious inflorescence-derived plantlets. Ploidy and genome size were estimated using flow cytometry. Key Results All adventitious plantlets were genetically identical to the maternal plant and were therefore the product of a novel pseudoviviparous reproductive event. It was found that 87 % of the multilocus genotypes contained three alleles in at least one locus. Ploidy was identical in all sampled plants. The genome size (2 C value) for samples from Shark Bay and from a separate site much further south was not significantly different, implying they are the same ploidy level and ruling out a complete genome duplication (polyploidy). Conclusions Survival at range edges often sees the development of novel responses in the struggle for survival and reproduction. This study documents a physiological response at the trailing edge, whereby reproductive strategy can adapt to fluctuating conditions and suggests that the lower-than-usual water temperature triggered unfertilized inflorescences to ‘switch’ to growing plantlets that were adventitious clones of their maternal parent. This may

  3. Against the odds: complete outcrossing in a monoecious clonal seagrass Posidonia australis (Posidoniaceae)

    PubMed Central

    Sinclair, Elizabeth A.; Gecan, Ilena; Krauss, Siegfried L.; Kendrick, Gary A.

    2014-01-01

    Background and Aims Seagrasses are marine, flowering plants with a hydrophilous pollination strategy. In these plants, successful mating requires dispersal of filamentous pollen grains through the water column to receptive stigmas. Approximately 40 % of seagrass species are monoecious, and therefore little pollen movement is required if inbreeding is tolerated. Outcrossing in these species is further impacted by clonality, which is variable, but can be extensive in large, dense meadows. Despite this, little is known about the interaction between clonal structure, genetic diversity and mating systems in hydrophilous taxa. Methods Polymorphic microsatellite DNA markers were used to characterize genetic diversity, clonal structure, mating system and realized pollen dispersal in two meadows of the temperate, monoecious seagrass, Posidonia australis, in Cockburn Sound, Western Australia. Key Results Within the two sampled meadows, genetic diversity was moderate among the maternal shoots (R = 0·45 and 0·64) and extremely high in the embryos (R = 0·93–0·97). Both meadows exhibited a highly clumping (or phalanx) structure among clones, with spatial autocorrelation analysis showing significant genetic structure among shoots and embryos up to 10–15 m. Outcrossing rates were not significantly different from one. Pollen dispersal distances inferred from paternity assignment averaged 30·8 and 26·8 m, which was larger than the mean clone size (12·8 and 13·8 m). Conclusions These results suggest highly effective movement of pollen in the water column. Despite strong clonal structure and moderate genetic diversity within meadows, hydrophilous pollination is an effective vector for completely outcrossed offspring. The different localized water conditions at each site (highly exposed conditions vs. weak directional flow) appear to have little influence on the success and pattern of successful pollination in the two meadows. PMID:24812250

  4. Dorsal skin color patterns among southern right whales (Eubalaena australis): genetic basis and evolutionary significance.

    PubMed

    Schaeff, C M; Best, P B; Rowntree, V J; Payne, R; Jarvis, C; Portway, V A

    1999-01-01

    Distribution and inheritance of dorsal skin color markings among two populations of southern right whales (Eubalaena australis) suggest that two genes influence dorsal skin color. The grey-morph and partial-grey-morph phenotypes (previously known as partial albino and grey-blaze, respectively) appear to be controlled by an X-linked gene, whereas the white blaze appears controlled by an autosomal gene (recessive phenotype). Calving intervals, calf size, and length of sighting history data suggest that partial-grey-morph, white-blaze, and black cows experience similar levels of reproductive success. Grey-morph cows (XgXg) are rare or absent in the two populations, but this was not unexpected given observed population frequencies of grey-morph males (XgY) and partial-grey-morph females (XGXg). The proportion of partial-grey-morph calves produced by black cows (XGXG) suggests that the reproductive success of grey-morph males was equal to that of black males, however, larger sample sizes are required to determine whether grey-morph males tend to have shorter sighting histories. The reproductive success of white-blaze males appeared similar to that of black males among whales off Argentina. There were significantly fewer white-blaze calves than expected off South Africa, which could be due to white-blaze males experiencing reduced reproductive success or to sighting blases that result in white-marked calves being misidentified as black calves. The relative frequencies of both types of dorsal color markings varied between the South African and Argentinian right whale populations, suggesting limited nuclear gene flow between these populations; analyses using other nuclear markers are under way to confirm the extent of gene flow.

  5. Vegetation recovery in an oil-impacted and burned Phragmites australis tidal freshwater marsh.

    PubMed

    Zengel, Scott; Weaver, Jennifer; Wilder, Susan L; Dauzat, Jeff; Sanfilippo, Chris; Miles, Martin S; Jellison, Kyle; Doelling, Paige; Davis, Adam; Fortier, Barret K; Harris, James; Panaccione, James; Wall, Steven; Nixon, Zachary

    2017-08-26

    In-situ burning of oiled marshes is a cleanup method that can be more effective and less damaging than intrusive manual and mechanical methods. In-situ burning of oil spills has been examined for several coastal marsh types; however, few published data are available for Phragmites australis marshes. Following an estimated 4200gallon crude oil spill and in-situ burn in a Phragmites tidal freshwater marsh at Delta National Wildlife Refuge (Mississippi River Delta, Louisiana), we examined vegetation impacts and recovery across 3years. Oil concentrations in marsh soils were initially elevated in the oiled-and-burned sites, but were below background levels within three months. Oiling and burning drastically affected the marsh vegetation; the formerly dominant Phragmites, a non-native variety in our study sites, had not fully recovered by the end of our study. However, overall vegetation recovery was rapid and local habitat quality in terms of native plants, particularly Sagittaria species, and wildlife value was enhanced by burning. In-situ burning appears to be a viable response option to consider for future spills in marshes with similar plant species composition, hydrogeomorphic settings, and oiling conditions. In addition, likely Phragmites stress from high water levels and/or non-native scale insect damage was also observed during our study and has recently been reported as causing widespread declines or loss of Phragmites stands in the Delta region. It remains an open question if these stressors could lead to a shift to more native vegetation, similar to what we observed following the oil spill and burn. Increased dominance by native plants may be desirable as local patches, but widespread loss of Phragmites, even if replaced by native species, could further acerbate coastal erosion and wetland loss, a major concern in the region. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Assessment of rhizospheric culturable bacteria of Phragmites australis and Juncus effusus from polluted sites.

    PubMed

    Pereira, Sofia I A; Pires, Carlos; Henriques, Isabel; Correia, António; Magan, Naresh; Castro, Paula M L

    2015-10-01

    This study aimed at the isolation and characterization of metal(loid)-tolerant bacteria from the rhizosphere of Phragmites australis and Juncus effusus plants growing in two long-term contaminated sites in Northern Portugal. Site 1 had higher contamination than Site 3. Bacteria were isolated using metal(loid)-supplemented (Cd, Zn, and As) media. Isolates were grouped by random amplified polymorphic DNA and identified by 16S rRNA gene sequencing. Strains were also examined for their metal(loid) tolerance. The counts of metal(loid)-tolerant bacteria were higher in Site 1 and ranged between log 7.17 CFU g(-1) soil in As-containing medium and log 7.57 CFU g(-1) soil in Zn-containing medium, while counts at Site 3 varied between log 5.33 CFU g(-1) soil in Cd-containing medium and log 6.97 CFU g(-1) soil in As-containing medium. The composition of bacterial populations varied between locations. In Site 1, the classes Actinobacteria (36%) and Bacilli (24%) were well represented, while in Site 3 strains were mainly affiliated to classes Actinobacteria (35%), γ-Proteobacteria (35%), and β-Proteobacteria (12%). The order of metal(loid) toxicity for the isolated strains was Cd > As > Zn. Overall, 10 strains grew at 500 mg Cd L(-1) , 1000 mg Zn L(-1) , and 500 mg As L(-1) , being considered the most metal(loid)-tolerant bacteria. These strains belonged to genera Cupriavidus, Burkholderia, Novosphingobium, Sphingobacterium, Castellaniella, Mesorhizobium, Chryseobacterium, and Rhodococcus and were mainly retrieved from Site 1. The multiple metal(loid)-tolerant strains isolated in this study have potential to be used in bioremediation/phytoremediation. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. AaTX1, from Androctonus australis scorpion venom: purification, synthesis and characterization in dopaminergic neurons.

    PubMed

    Mlayah-Bellalouna, Saoussen; Dufour, Martial; Mabrouk, Kamel; Mejdoub, Hafedh; Carlier, Edmond; Othman, Houcemeddine; Belghazi, Maya; Tarbe, Marion; Goaillard, Jean Marc; Gigmes, Didier; Seagar, Michael; El Ayeb, Mohamed; Debanne, Dominique; Srairi-Abid, Najet

    2014-12-15

    We have purified the AaTX1 peptide from the Androctonus australis (Aa) scorpion venom, previously cloned and sequenced by Legros and collaborators in a venom gland cDNA library from Aa scorpion. AaTX1 belongs to the α-Ktx15 scorpion toxins family (αKTx15-4). Characterized members of this family share high sequence similarity and were found to block preferentially IA-type voltage-dependent K(+) currents in rat cerebellum granular cells in an irreversible way. In the current work, we studied the effects of native AaTX1 (nAaTX1) using whole-cell patch-clamp recordings of IA current in substantia nigra pars compacta dopaminergic neurons. At 250 nM, AaTX1 induces 90% decrease in IA current amplitude. Its activity was found to be comparable to that of rAmmTX3 (αKTx15-3), which differs by only one conserved (R/K) amino acid in the 19th position suggesting that the difference between R19 and K19 in AaTX1 and AmmTX3, respectively, may not be critical for the toxins' effects. Molecular docking of both toxins with Kv4.3 channel is in agreement with experimental data and suggests the implication of the functional dyade K27-Y36 in toxin-channel interactions. Since AaTX1 is not highly abundant in Aa venom, it was synthesized as well as AmmTX3. Synthetic peptides, native AaTX1 and rAmmTX3 peptides showed qualitatively the same pharmacological activity. Overall, these data identify a new biologically active toxin that belongs to a family of peptides active on Kv4.3 channel. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Freshwater wetlands: fertile grounds for the invasive Phragmites australis in a climate change context

    PubMed Central

    Tougas-Tellier, Marie-Andrée; Morin, Jean; Hatin, Daniel; Lavoie, Claude

    2015-01-01

    Climate change will likely affect flooding regimes, which have a large influence on the functioning of freshwater riparian wetlands. Low water levels predicted for several fluvial systems make wetlands especially vulnerable to the spread of invaders, such as the common reed (Phragmites australis), one of the most invasive species in North America. We developed a model to map the distribution of potential germination grounds of the common reed in freshwater wetlands of the St. Lawrence River (Québec, Canada) under current climate conditions and used this model to predict their future distribution under two climate change scenarios simulated for 2050. We gathered historical and recent (remote sensing) data on the distribution of common reed stands for model calibration and validation purposes, then determined the parameters controlling the species establishment by seed. A two-dimensional model and the identified parameters were used to simulate the current (2010) and future (2050) distribution of germination grounds. Common reed stands are not widespread along the St. Lawrence River (212 ha), but our model suggests that current climate conditions are already conducive to considerable further expansion (>16,000 ha). Climate change may also exacerbate the expansion, particularly if river water levels drop, which will expose large bare areas propitious to seed germination. This phenomenon may be particularly important in one sector of the river, where existing common reed stands could increase their areas by a factor of 100, potentially creating the most extensive reedbed complex in North America. After colonizing salt and brackishwater marshes, the common reed could considerably expand into the freshwater marshes of North America which cover several million hectares. The effects of common reed expansion on biodiversity are difficult to predict, but likely to be highly deleterious given the competitiveness of the invader and the biological richness of freshwater

  9. Stable Isotopes Indicate Population Structuring in the Southwest Atlantic Population of Right Whales (Eubalaena australis)

    PubMed Central

    Vighi, Morgana; Borrell, Asunción; Crespo, Enrique A.; Oliveira, Larissa R.; Simões-Lopes, Paulo C.; Flores, Paulo A. C.; García, Néstor A.; Aguilar, Alejandro

    2014-01-01

    From the early 17th century to the 1970s southern right whales, Eubalaena australis, were subject to intense exploitation along the Atlantic coast of South America. Catches along this coast recorded by whalers originally formed a continuum from Brazil to Tierra del Fuego. Nevertheless, the recovery of the population has apparently occurred fragmentarily, and with two main areas of concentration, one off southern Brazil (Santa Catarina) and another off central Argentina (Peninsula Valdés). This pattern suggests some level of heterogeneity amongst the population, which is apparently contradicted by records that traced individuals moving throughout the whole geographical extension covered by the species in the Southwest Atlantic. To test the hypothesis of the potential occurrence of discrete subpopulations exploiting specific habitats, we investigated N, C and O isotopic values in 125 bone samples obtained from whaling factories operating in the early 1970s in southern Brazil (n = 72) and from contemporary and more recent strandings occurring in central Argentina (n = 53). Results indicated significant differences between the two sampling areas, being δ13C and δ18O values significantly higher in samples from southern Brazil than in those from central Argentina. This variation was consistent with isotopic baselines from the two areas, indicating the occurrence of some level of structure in the Southwest Atlantic right whale population and equally that whales more likely feed in areas commonly thought to exclusively serve as nursing grounds. Results aim at reconsidering of the units currently used in the management of the southern right whale in the Southwest Atlantic Ocean. In the context of the current die-off affecting the species in Peninsula Valdés, these results also highlight the necessity to better understand movements of individuals and precisely identify their feeding areas. PMID:24598539

  10. Stable isotopes indicate population structuring in the southwest Atlantic population of right whales (Eubalaena australis).

    PubMed

    Vighi, Morgana; Borrell, Asunción; Crespo, Enrique A; Oliveira, Larissa R; Simões-Lopes, Paulo C; Flores, Paulo A C; García, Néstor A; Aguilar, Alex; Aguilar, Alejandro

    2014-01-01

    From the early 17th century to the 1970s southern right whales, Eubalaena australis, were subject to intense exploitation along the Atlantic coast of South America. Catches along this coast recorded by whalers originally formed a continuum from Brazil to Tierra del Fuego. Nevertheless, the recovery of the population has apparently occurred fragmentarily, and with two main areas of concentration, one off southern Brazil (Santa Catarina) and another off central Argentina (Peninsula Valdés). This pattern suggests some level of heterogeneity amongst the population, which is apparently contradicted by records that traced individuals moving throughout the whole geographical extension covered by the species in the Southwest Atlantic. To test the hypothesis of the potential occurrence of discrete subpopulations exploiting specific habitats, we investigated N, C and O isotopic values in 125 bone samples obtained from whaling factories operating in the early 1970s in southern Brazil (n=72) and from contemporary and more recent strandings occurring in central Argentina (n=53). Results indicated significant differences between the two sampling areas, being δ13C and δ18O values significantly higher in samples from southern Brazil than in those from central Argentina. This variation was consistent with isotopic baselines from the two areas, indicating the occurrence of some level of structure in the Southwest Atlantic right whale population and equally that whales more likely feed in areas commonly thought to exclusively serve as nursing grounds. Results aim at reconsidering of the units currently used in the management of the southern right whale in the Southwest Atlantic Ocean. In the context of the current die-off affecting the species in Peninsula Valdés, these results also highlight the necessity to better understand movements of individuals and precisely identify their feeding areas.

  11. Mapping an invasive plant, Phragmites australis, in coastal wetlands using the EO-1 Hyperion hyperspectral sensor

    USGS Publications Warehouse

    Pengra, B.W.; Johnston, C.A.; Loveland, T.R.

    2007-01-01

    Mapping tools are needed to document the location and extent of Phragmites australis, a tall grass that invades coastal marshes throughout North America, displacing native plant species and degrading wetland habitat. Mapping Phragmites is particularly challenging in the freshwater Great Lakes coastal wetlands due to dynamic lake levels and vegetation diversity. We tested the applicability of Hyperion hyperspectral satellite imagery for mapping Phragmites in wetlands of the west coast of Green Bay in Wisconsin, U.S.A. A reference spectrum created using Hyperion data from several pure Phragmites stands within the image was used with a Spectral Correlation Mapper (SCM) algorithm to create a raster map with values ranging from 0 to 1, where 0 represented the greatest similarity between the reference spectrum and the image spectrum and 1 the least similarity. The final two-class thematic classification predicted monodominant Phragmites covering 3.4% of the study area. Most of this was concentrated in long linear features parallel to the Green Bay shoreline, particularly in areas that had been under water only six years earlier when lake levels were 66??cm higher. An error matrix using spring 2005 field validation points (n = 129) showed good overall accuracy-81.4%. The small size and linear arrangement of Phragmites stands was less than optimal relative to the sensor resolution, and Hyperion's 30??m resolution captured few if any pure pixels. Contemporary Phragmites maps prepared with Hyperion imagery would provide wetland managers with a tool that they currently lack, which could aid attempts to stem the spread of this invasive species. ?? 2006 Elsevier Inc. All rights reserved.

  12. Diversity of fungal endophytes in non-native Phragmites australis in the Great Lakes

    USGS Publications Warehouse

    Clay, Keith; Shearin, Zachery; Bourke, Kimberly; Bickford, Wesley A.; Kowalski, Kurt P.

    2016-01-01

    Plant–microbial interactions may play a key role in plant invasions. One common microbial interaction takes place between plants and fungal endophytes when fungi asymptomatically colonize host plant tissues. The objectives of this study were to isolate and sequence fungal endophytes colonizing non-native Phragmites australis in the Great Lakes region to evaluate variation in endophyte community composition among three host tissue types and three geographical regions. We collected entire ramets from multiple clones and populations, surface sterilized plant tissues, and plated replicate tissue samples from leaves, stems, and rhizomes on corn meal agar plates to culture and isolate fungal endophytes. Isolates were then subjected to Sanger sequencing of the ITS region of the nuclear ribosomal DNA. Sequences were compared to fungal databases to define operational taxonomic units (OTUs) that were analyzed statistically for community composition. In total, we obtained 173 endophyte isolates corresponding to 55 OTUs, 39 of which were isolated only a single time. The most common OTU corresponded most closely to Sarocladium strictum and comprised 25 % of all fungal isolates. More OTUs were found in stem tissues, but endophyte diversity was greatest in rhizome tissues. PERMANOVA analyses indicated significant differences in endophyte communities among tissue types, geographical regions, and the interaction between those factors, but no differences among individual ramets were detected. The functional role of the isolated endophytes is not yet known, but one genus isolated here (Stagonospora) has been reported to enhance Phragmites growth. Understanding the diversity and functions of Phragmites endophytes may provide targets for control measures based on disrupting host plant/endophyte interactions.

  13. Comparison of Mercury Contamination in Live and Dead Dolphins from a Newly Described Species, Tursiops australis

    PubMed Central

    Monk, Alissa; Charlton-Robb, Kate; Buddhadasa, Saman; Thompson, Ross M.

    2014-01-01

    Globally it is estimated that up to 37% of all marine mammals are at a risk of extinction, due in particular to human impacts, including coastal pollution. Dolphins are known to be at risk from anthropogenic contaminants due to their longevity and high trophic position. While it is known that beach-cast animals are often high in contaminants, it has not been possible to determine whether levels may also be high in live animals from the same populations. In this paper we quantitatively assess mercury contamination in the two main populations of a newly described dolphin species from south eastern Australia, Tursiops australis. This species appear to be limited to coastal waters in close proximity to a major urban centre, and as such is likely to be vulnerable to anthropogenic pollution. For the first time, we were able to compare blubber mercury concentrations from biopsy samples of live individuals and necropsies of beach-cast animals and show that beach-cast animals were highly contaminated with mercury, at almost three times the levels found in live animals. Levels in live animals were also high, and are attributable to chronic low dose exposure to mercury from the dolphin's diet. Measurable levels of mercury were found in a number of important prey fish species. This illustrates the potential for low dose toxins in the environment to pass through marine food webs and potentially contribute to marine mammal deaths. This study demonstrates the potential use of blubber from biopsy samples to make inferences about the health of dolphins exposed to mercury. PMID:25137255

  14. Vasculitis secondary to presumptive leptospirosis treated with long-term corticosteroids in a captive lesser kudu (Tragelaphus imberbis australis).

    PubMed

    Fogelberg, Katherine; Ferrell, Shannon T

    2010-09-01

    A 2-yr-old female lesser kudu (Tragelaphus imberbis australis) was presented for lethargy. Empirical antibiotic treatment appeared to improve its clinical signs, although no etiology for the symptoms was determined. The kudu again presented with lethargy, diffusely swollen limbs, and subcutaneous ecchymoses of 1 day's duration after completion of the initial therapy. Vasculitis secondary to presumptive leptospirosis infection was diagnosed based on a skin biopsy and decreasing paired serologic titers for Leptospira grippotyphosa. The vasculitis was responsive to intramuscular antibiotic therapy and dexamethasone treatment. This case provides evidence that corticosteroids can be used in ruminants at moderate doses for chronic treatment without clinically relevant detrimental effects.

  15. Udonella australis n. sp. (Monogenea), an epibiont on sea-lice from native fish off southern Chile.

    PubMed

    Carvajal, Juan; Sepúlveda, Fabiola

    2002-05-01

    Udonella australis n. sp., an epibiont monogenean living on caligid copepods that infest a native fish, Eleginops maclovinus (Valenciennes), off Chile, South America is described. The species can be separated from other species by its difference in size, especially body size, and the distribution of cephalic glands, vitelline follicles and genital organs. Egg-size is intermediate in comparison with that of other species. The posterior attachment mechanism consists of few muscle fibres and clumped cement-producing glands. All previous descriptions of Udonella caligorum Johnston, 1835 from off Chile correspond to this new species.

  16. Autotransporter protein secretion.

    PubMed

    Tame, Jeremy R H

    2011-12-01

    Autotransporter proteins are a large family of virulence factors secreted from Gram-negative bacteria by a unique mechanism. First described in the 1980s, these proteins have a C-terminal region that folds into a β-barrel in the bacterial outer membrane. The so-called passenger domain attached to this barrel projects away from the cell surface and may be liberated from the cell by self-cleavage or surface proteases. Although the majority of passenger domains have a similar β-helical structure, they carry a variety of sub-domains, allowing them to carry out widely differing functions related to pathogenesis. Considerable biochemical and structural characterisation of the barrel domain has shown that 'autotransporters' in fact require a conserved and essential protein complex in the outer membrane for correct folding. Although the globular domains of this complex projecting into the periplasmic space have also been structurally characterised, the overall secretion pathway of the autotransporters remains highly puzzling. It was presumed for many years that the passenger domain passed through the centre of the barrel domain to reach the cell surface, driven at least in part by folding. This picture is complicated by conflicting data, and there is currently little hard information on the true nature of the secretion intermediates. As well as their medical importance therefore, autotransporters are proving to be an excellent system to study the folding and membrane insertion of outer membrane proteins in general. This review focuses on structural aspects of autotransporters; their many functions in pathogenesis are beyond its scope.

  17. Immunoglobulin in intestinal secretions.

    PubMed

    Cutropia de Guirao, C

    1977-12-01

    The objective of the present investigation is the study and interpretation of the role played by the immunoglobulins, especially IgA, during acute diarrhea in children. IgA, IGG and IgM values in serum and IgA in intestinal secretions were studied in a group of children (between 3 months and 5 years of age) during diarrhea, convalescence and in normals. The method of simple radial immunodiffusion according to Mancini was employed. IgA is the immunoglobulin which suffers the greastest alteration in acute diarrhea. The precipitation halos (the average values), were lower during the diarrhea than in convalescence and in normals.

  18. Estimation of chlorophyll content of Phragmites australis based on PROSPECT and DART models in the saltmarsh of Yangtze Estuary

    NASA Astrophysics Data System (ADS)

    Zeng, Yuyan; Shi, Runhe; Liu, Pudong; Zhang, Chao; Wang, Jiapeng; Liu, Chaoshun; Chen, Maosi

    2016-09-01

    Phragmites australis is a native dominant specie in the Yangtze Estuary, which plays a key role in the structure and function of wetland ecosystem. One key question is how to estimate the Chlorophyll content quickly and effectively at large scales, which could be used to reflect the growth condition and calculate the vegetation productivity. The aim of this work was to estimate Chlorophyll content of P. australis based on the PROSPECT and DART (Discrete Anisotropic Radiative Transfer) model. A total of 6 widely used Vegetation indices (VIs) were chosen (i.e., Normalized Difference Vegetation Index (NDVI), Structure Insensitive Pigment Index (SIPI), Colouration Index (COI), Simple Ratio Index (SR), Cater Index (CAI), and Red-edge Position Linear Interpolation (REP_Li)) and calculated, and then the relationship between VIs and Cab were analyzed. Results showed that COI and SIPI were sensitive to the leaf chlorophyll content as the chlorophyll content changes at the leaf scale. Meanwhile, no obvious saturation phenomenon was observed for these two indices compared to other indices.

  19. Uptake and Bioaccumulation of Pentachlorophenol by Emergent Wetland Plant Phragmites australis (Common Reed) in Cadmium Co-contaminated Soil.

    PubMed

    Hechmi, Nejla; Ben Aissa, Nadhira; Abdenaceur, Hassen; Jedidi, Naceur

    2015-01-01

    Despite many studies on phytoremediation of soils contaminated with either heavy metals or organics, little information is available on the effectiveness of phytoremediation of co-occurring metal and organic pollutants especially by using wetland species. Phragmites australis is a common wetland plant and its potential for phytoremediation of cadmium pentachlorophenol (Cd-PCP) co-contaminated soil was investigated. A greenhouse study was executed to elucidate the effects of Cd (0, 10, and 20 mg kg(-1)) without or with PCP (0, 50, and 250 mg kg(-1)) on the growth of the wetland plant P. australis and its uptake, accumulation and removal of pollutant from soils. After 75 days, plant biomass was significantly influenced by interaction of Cd and PCP and the effect of Cd on plant growth being stronger than that of PCP. Coexistence of PCP at low level lessened Cd toxicity to plants, resulting in improved plant growth and increased Cd accumulation in plant tissues. The dissipation of PCP in soils was significantly influenced by interactions of Cd, PCP and plant presence or absence. As an evaluation of soil biological activities after remediation soil enzyme was measured.

  20. Grillotia australis n. sp. and G. pristiophori n. sp. (Cestoda: Trypanorhyncha) from Australian elasmobranch and teleost fishes.

    PubMed

    Beveridge, I; Campbell, R A

    2001-06-01

    Two new species of Grillotia are described from elasmobranch and teleost fishes from south-eastern Australia. G. australis n. sp., from the Australian angel shark Squatina australis. Regan, most closely resembles G. smarisgora (Wagener, 1854) and G. angeli Dollfus, 1969, differing from both species in the presence of smaller bulbs, two or occasionally three hooks in each intercalary row in the basal region, reduced to one in the metabasal region compared with four or five hooks in the metabasal region of G. smarisgora and a single hook in G. angeli, and in the limited extent of the band of hooklets on the external surface in the basal region of the tentacle, a region which is covered with hooks in G. smarisgora. Plerocerci of this species were found in the mackerel Trachurus declivis (Jenys) (site not known) from Tasmania. G. pristiophori n. sp., from the saw sharks Pristiophorus cirratus (Latham) and P. nudipinnis Günther, most closely resembles G. spinosissima Dollfus, 1969 in possessing a scolex covered with spiniform microtriches, but differs in having six rather than five hooks in each principal row, no intercalary hooks and by possessing a band of hooklets on the external surface of the tentacle which diminishes distally into a single file, rather than persisting as a band eight to nine files wide. G. pristiophori is the first trypanorhynch to be recorded from saw-sharks.

  1. Microcavia australis (Caviidae, Rodentia), a new highly competent host of Trypanosoma cruzi I in rural communities of northwestern Argentina.

    PubMed

    Cecere, M Carla; Cardinal, Marta V; Arrabal, Juan P; Moreno, Claudio; Gürtler, Ricardo E

    2015-02-01

    Rodents are well-known hosts of Trypanosoma cruzi but little is known on the role of some caviomorph rodents. We assessed the occurrence and prevalence of T. cruzi infection in Microcavia australis ("southern mountain, desert or small cavy") and its infectiousness to the vector Triatoma infestans in four rural communities of Tafí del Valle department, northwestern Argentina. Parasite detection was performed by xenodiagnosis and polymerase chain reaction amplification of the hyper-variable region of kinetoplast DNA minicircles of T. cruzi (kDNA-PCR) from blood samples. A total of 51 cavies was captured in traps set up along cavy paths in peridomestic dry-shrub fences located between 25 and 85 m from the nearest domicile. We document the first record of M. australis naturally infected by T. cruzi. Cavies presented a very high prevalence of infection (46.3%; 95% confidence interval, CI=33.0-59.6%). Only one (4%) of 23 cavies negative by xenodiagnosis was found infected by kDNA-PCR. TcI was the only discrete typing unit identified in 12 cavies with a positive xenodiagnosis. The infectiousness to T. infestans of cavies positive by xenodiagnosis or kDNA-PCR was very high (mean, 55.8%; CI=48.4-63.1%) and exceeded 80% in 44% of the hosts. Cavies are highly-competent hosts of T. cruzi in peridomestic habitats near human dwellings in rural communities of Tucumán province in northwestern Argentina.

  2. Bioactivity and chemical composition of the essential oil from the leaves of Guatteria australis A.St.-Hil.

    PubMed

    Siqueira, Carlos Alberto Theodoro; Serain, Alessandra Freitas; Pascoal, Aislan Cristina Rheder Fagundes; Andreazza, Nathalia Luiza; de Lourenço, Caroline Caramano; Ruiz, Ana Lúcia T Góis; de Carvalho, João Ernesto; de Souza, Ana Cláudia Oliveira; Mesquita, Juliana Tonini; Tempone, Andre Gustavo; Salvador, Marcos José

    2015-01-01

    Essential oil from the leaves of Guatteria australis was obtained by hydrodistillation, analyzed by Gas Chromatography coupled to Mass Spectromery (GC-MS) and their antiproliferative, antileishmanial, antibacterial, antifungal and antioxidant activities were also evaluated. Twenty-three compounds were identified among which germacrene B (50.66%), germacrene D (22.22%) and (E)-caryophyllene (8.99%) were the main compounds. The highest antiproliferative activity was observed against NCI-ADR/RES (TGI = 31.08 μg/ml) and HT-29 (TGI = 32.81 μg/ml) cell lines. It also showed good antileishmanial activity against Leishmania infantum (IC50 = 30.71 μg/ml). On the other hand, the oil exhibited a small effect against Staphylococcus aureus ATCC 6538, S. aureus ATCC 14458 and Escherichia coli ATCC 10799 (MIC = 250 μg/ml), as well as small antioxidant activity (457 μmol TE/g) assessed through ORACFL assay. These results represent the first report regarding chemical composition and bioactivity of G. australis essential oil.

  3. Treatment of industrial wastewater with two-stage constructed wetlands planted with Typha latifolia and Phragmites australis.

    PubMed

    Calheiros, Cristina S C; Rangel, António O S S; Castro, Paula M L

    2009-07-01

    Industrial wastewater treatment comprises several processes to fulfill the discharge permits or to enable the reuse of wastewater. For tannery wastewater, constructed wetlands (CWs) may be an interesting treatment option. Two-stage series of horizontal subsurface flow CWs with Phragmites australis (UP series) and Typha latifolia (UT series) provided high removal of organics from tannery wastewater, up to 88% of biochemical oxygen demand (BOD(5)) (from an inlet of 420 to 1000 mg L(-1)) and 92% of chemical oxygen demand (COD) (from an inlet of 808 to 2449 mg L(-1)), and of other contaminants, such as nitrogen, operating at hydraulic retention times of 2, 5 and 7 days. No significant (P<0.05) differences in performance were found between both the series. Overall mass removals of up to 1294 kg COD ha(-1)d(-1) and 529 kg BOD(5)ha(-1)d(-1) were achieved for a loading ranging from 242 to 1925 kg COD ha(-1)d(-1) and from 126 to 900 kg BOD(5)ha(-1)d(-1). Plants were resilient to the conditions imposed, however P. australis exceeded T. latifolia in terms of propagation.

  4. Effects of sorption, sulphate reduction, and Phragmites australis on the removal of heavy metals in subsurface flow constructed wetland microcosms.

    PubMed

    Lesage, E; Rousseau, D P L; Van de Moortel, A; Tack, F M G; De Pauw, N; Verloo, M G

    2007-01-01

    The removal of Co, Ni, Cu and Zn from synthetic industrial wastewater was studied in subsurface flow constructed wetland microcosms filled with gravel or a gravel/straw mixture. Half of the microcosms were planted with Phragmites australis and half were left unplanted. All microcosms received low-strength wastewater (1 mg L(-1) of Co, Ni, and Zn, 0.5 mg L(-1) Cu, 2,000mg L(-1) SO4) during seven 14-day incubation batches. The pore water was regularly monitored at two depths for heavy metals, sulphate, organic carbon and redox potential. Sorption properties of gravel and straw were assessed in a separate experiment. A second series of seven incubation batches with high-strength wastewater (10 mg L(-1) of each metal, 2,000 mg L(-1) SO4) was then applied to saturate the substrate. Glucose was added to the gravel microcosms together with the high-strength wastewater. Sorption processes were responsible for metal removal during start-up, with the highest removal efficiencies in the gravel microcosms. The lower initial efficiencies in the gravel/straw microcosms were presumably caused by the decomposition of straw. However, after establishment of anaerobic conditions (Eh approximately -200 mV), precipitation as metal sulphides provided an additional removal pathway in the gravel/straw microcosms. The addition of glucose to gravel microcosms enhanced sulphate reduction and metal removal, although Phragmites australis negatively affected these processes in the top-layer of all microcosms.

  5. Comparing root architectural models

    NASA Astrophysics Data System (ADS)

    Schnepf, Andrea; Javaux, Mathieu; Vanderborght, Jan

    2017-04-01

    Plant roots play an important role in several soil processes (Gregory 2006). Root architecture development determines the sites in soil where roots provide input of carbon and energy and take up water and solutes. However, root architecture is difficult to determine experimentally when grown in opaque soil. Thus, root architectural models have been widely used and been further developed into functional-structural models that are able to simulate the fate of water and solutes in the soil-root system (Dunbabin et al. 2013). Still, a systematic comparison of the different root architectural models is missing. In this work, we focus on discrete root architecture models where roots are described by connected line segments. These models differ (a) in their model concepts, such as the description of distance between branches based on a prescribed distance (inter-nodal distance) or based on a prescribed time interval. Furthermore, these models differ (b) in the implementation of the same concept, such as the time step size, the spatial discretization along the root axes or the way stochasticity of parameters such as root growth direction, growth rate, branch spacing, branching angles are treated. Based on the example of two such different root models, the root growth module of R-SWMS and RootBox, we show the impact of these differences on simulated root architecture and aggregated information computed from this detailed simulation results, taking into account the stochastic nature of those models. References Dunbabin, V.M., Postma, J.A., Schnepf, A., Pagès, L., Javaux, M., Wu, L., Leitner, D., Chen, Y.L., Rengel, Z., Diggle, A.J. Modelling root-soil interactions using three-dimensional models of root growth, architecture and function (2013) Plant and Soil, 372 (1-2), pp. 93 - 124. Gregory (2006) Roots, rhizosphere and soil: the route to a better understanding of soil science? European Journal of Soil Science 57: 2-12.

  6. Protecting Trade Secrets in Canada

    PubMed Central

    Courage, Noel; Calzavara, Janice

    2015-01-01

    Patents in the life sciences industries are a key form of intellectual property (IP), particularly for products such as brand-name drugs and medical devices. However, trade secrets can also be a useful tool for many types of innovations. In appropriate cases, trade secrets can offer long-term protection of IP for a lower financial cost than patenting. This type of protection must be approached with caution as there is little room for error when protecting a trade secret. Strong agreements and scrupulous security can help to protect the secret. Once a trade secret is disclosed to the public, it cannot be restored as the owner's property; however, if the information is kept from the public domain, the owner can have a property right of unlimited duration in the information. In some situations patents and trade secrets may be used cooperatively to protect innovation, particularly for manufacturing processes. PMID:25986591

  7. Protecting Trade Secrets in Canada.

    PubMed

    Courage, Noel; Calzavara, Janice

    2015-05-18

    Patents in the life sciences industries are a key form of intellectual property (IP), particularly for products such as brand-name drugs and medical devices. However, trade secrets can also be a useful tool for many types of innovations. In appropriate cases, trade secrets can offer long-term protection of IP for a lower financial cost than patenting. This type of protection must be approached with caution as there is little room for error when protecting a trade secret. Strong agreements and scrupulous security can help to protect the secret. Once a trade secret is disclosed to the public, it cannot be restored as the owner's property; however, if the information is kept from the public domain, the owner can have a property right of unlimited duration in the information. In some situations patents and trade secrets may be used cooperatively to protect innovation, particularly for manufacturing processes.

  8. Density-dependent role of an invasive marsh grass, Phragmites australis, on ecosystem service provision.

    PubMed

    Theuerkauf, Seth J; Puckett, Brandon J; Theuerkauf, Kathrynlynn W; Theuerkauf, Ethan J; Eggleston, David B

    2017-01-01

    Invasive species can positively, neutrally, or negatively affect the provision of ecosystem services. The direction and magnitude of this effect can be a function of the invaders' density and the service(s) of interest. We assessed the density-dependent effect of an invasive marsh grass, Phragmites australis, on three ecosystem services (plant diversity and community structure, shoreline stabilization, and carbon storage) in two oligohaline marshes within the North Carolina Coastal Reserve and National Estuarine Research Reserve System (NCNERR), USA. Plant species richness was equivalent among low, medium and high Phragmites density plots, and overall plant community composition did not vary significantly by Phragmites density. Shoreline change was most negative (landward retreat) where Phragmites density was highest (-0.40 ± 0.19 m yr-1 vs. -0.31 ± 0.10 for low density Phragmites) in the high energy marsh of Kitty Hawk Woods Reserve and most positive (soundward advance) where Phragmites density was highest (0.19 ± 0.05 m yr-1 vs. 0.12 ± 0.07 for low density Phragmites) in the lower energy marsh of Currituck Banks Reserve, although there was no significant effect of Phragmites density on shoreline change. In Currituck Banks, mean soil carbon content was approximately equivalent in cores extracted from low and high Phragmites density plots (23.23 ± 2.0 kg C m-3 vs. 22.81 ± 3.8). In Kitty Hawk Woods, mean soil carbon content was greater in low Phragmites density plots (36.63 ± 10.22 kg C m-3) than those with medium (13.99 ± 1.23 kg C m-3) or high density (21.61 ± 4.53 kg C m-3), but differences were not significant. These findings suggest an overall neutral density-dependent effect of Phragmites on three ecosystem services within two oligohaline marshes in different environmental settings within a protected reserve system. Moreover, the conceptual framework of this study can broadly inform an ecosystem services-based approach to invasive species management.

  9. Isolation of a Seawater Tolerant Leptospira spp. from a Southern Right Whale (Eubalaena australis)

    PubMed Central

    Rago, Virginia; Uhart, Marcela

    2015-01-01

    Leptospirosis is the most widespread zoonotic disease in the world. It is caused by pathogenic spirochetes of the genus Leptospira spp. and is maintained in nature through chronic renal infection of carrier animals. Rodents and other small mammals are the main reservoirs. Information on leptospirosis in marine mammals is scarce; however, cases of leptospirosis have been documented in pinniped populations from the Pacific coast of North America from southern California to British Columbia. We report the isolation of a Leptospira spp. strain, here named Manara, from a kidney sample obtained from a Southern Right Whale (Eubalaena australis) calf, which stranded dead in Playa Manara, Península Valdés, Argentina. This strain showed motility and morphology typical of the genus Leptospira spp. under dark-field microscopy; and grew in Ellinghausen-McCullough-Johnson-Harris (EMJH) medium and Fletcher medium after 90 days of incubation at 28°C. Considering the source of this bacterium, we tested its ability to grow in Fletcher medium diluted with seawater at different percentages (1%, 3%, 5%, 7% and 10% v/v). Bacterial growth was detected 48 h after inoculation of Fletcher medium supplemented with 5% sea water, demonstrating the halophilic nature of the strain Manara. Phylogenetic analysis of 16S rRNA gene sequences placed this novel strain within the radiation of the pathogenic species of the genus Leptospira spp., with sequence similarities within the range 97–100%, and closely related to L. interrogans. Two different PCR protocols targeting genus-specific pathogenic genes (G1-G2, B64I-B64II and LigB) gave positive results, which indicates that the strain Manara is likely pathogenic. Further studies are needed to confirm this possibility as well as determine its serogroup. These results could modify our understanding of the epidemiology of this zoonosis. Until now, the resistance and ability to grow in seawater for long periods of time had been proven for the strain

  10. Isolation of a Seawater Tolerant Leptospira spp. from a Southern Right Whale (Eubalaena australis).

    PubMed

    Grune Loffler, Sylvia; Rago, Virginia; Martínez, Mara; Uhart, Marcela; Florin-Christensen, Monica; Romero, Graciela; Brihuega, Bibiana

    2015-01-01

    Leptospirosis is the most widespread zoonotic disease in the world. It is caused by pathogenic spirochetes of the genus Leptospira spp. and is maintained in nature through chronic renal infection of carrier animals. Rodents and other small mammals are the main reservoirs. Information on leptospirosis in marine mammals is scarce; however, cases of leptospirosis have been documented in pinniped populations from the Pacific coast of North America from southern California to British Columbia. We report the isolation of a Leptospira spp. strain, here named Manara, from a kidney sample obtained from a Southern Right Whale (Eubalaena australis) calf, which stranded dead in Playa Manara, Península Valdés, Argentina. This strain showed motility and morphology typical of the genus Leptospira spp. under dark-field microscopy; and grew in Ellinghausen-McCullough-Johnson-Harris (EMJH) medium and Fletcher medium after 90 days of incubation at 28°C. Considering the source of this bacterium, we tested its ability to grow in Fletcher medium diluted with seawater at different percentages (1%, 3%, 5%, 7% and 10% v/v). Bacterial growth was detected 48 h after inoculation of Fletcher medium supplemented with 5% sea water, demonstrating the halophilic nature of the strain Manara. Phylogenetic analysis of 16S rRNA gene sequences placed this novel strain within the radiation of the pathogenic species of the genus Leptospira spp., with sequence similarities within the range 97-100%, and closely related to L. interrogans. Two different PCR protocols targeting genus-specific pathogenic genes (G1-G2, B64I-B64II and LigB) gave positive results, which indicates that the strain Manara is likely pathogenic. Further studies are needed to confirm this possibility as well as determine its serogroup. These results could modify our understanding of the epidemiology of this zoonosis. Until now, the resistance and ability to grow in seawater for long periods of time had been proven for the strain

  11. Reproduction at the extremes: pseudovivipary, hybridization and genetic mosaicism in Posidonia australis (Posidoniaceae).

    PubMed

    Sinclair, Elizabeth A; Statton, John; Hovey, Renae; Anthony, Janet M; Dixon, Kingsley W; Kendrick, Gary A

    2016-02-01

    Organisms occupying the edges of natural geographical ranges usually survive at the extreme limits of their innate physiological tolerances. Extreme and prolonged fluctuations in environmental conditions, often associated with climate change and exacerbated at species' geographical range edges, are known to trigger alternative responses in reproduction. This study reports the first observations of adventitious inflorescence-derived plantlet formation in the marine angiosperm Posidonia australis, growing at the northern range edge (upper thermal and salinity tolerance) in Shark Bay, Western Australia. These novel plantlets are described and a combination of microsatellite DNA markers and flow cytometry is used to determine their origin. Polymorphic microsatellite DNA markers were used to generate multilocus genotypes to determine the origin of the adventitious inflorescence-derived plantlets. Ploidy and genome size were estimated using flow cytometry. All adventitious plantlets were genetically identical to the maternal plant and were therefore the product of a novel pseudoviviparous reproductive event. It was found that 87 % of the multilocus genotypes contained three alleles in at least one locus. Ploidy was identical in all sampled plants. The genome size (2 C value) for samples from Shark Bay and from a separate site much further south was not significantly different, implying they are the same ploidy level and ruling out a complete genome duplication (polyploidy). Survival at range edges often sees the development of novel responses in the struggle for survival and reproduction. This study documents a physiological response at the trailing edge, whereby reproductive strategy can adapt to fluctuating conditions and suggests that the lower-than-usual water temperature triggered unfertilized inflorescences to 'switch' to growing plantlets that were adventitious clones of their maternal parent. This may have important long-term implications as both genetic and

  12. A shallow lake remediation regime with Phragmites australis: Incorporating nutrient removal and water evapotranspiration.

    PubMed

    Zhao, Ying; Yang, Zhifeng; Xia, Xinghui; Wang, Fei

    2012-11-01

    Shallow lake eutrophication has been an important issue of global water environment. Based on the simulation and field sampling experiments in Baiyangdian Lake, the largest shallow lake in North China, this study proposed a shallow lake remediation regime with Phragmites australis (reed) incorporating its opposite effects of nutrient removal and water evapotranspiration on water quality. The results of simulation experiments showed that both total nitrogen (TN) and phosphorus (TP) removal efficiencies increased with the increasing reed coverage. The TN removal efficiencies by reed aboveground uptake and rhizosphere denitrification were 11.2%, 13.8%, 22.6%, 28.4%, and 29.6% for the reed coverage of 20%, 40%, 60%, 80%, and 100%, respectively. Correspondingly, TP removal efficiencies by aboveground reed uptake were 1.4%, 2.5%, 4.4%, 7.4% and 7.9%, respectively. However, the water quality was best when the reed coverage was 60% (72 plants m(-2)). This was due to the fact that the concentration effect of reed evapotranspiration on nutrient increased with reed coverage. When the reed coverage was 100% (120 plants m(-2)), the evapotranspiration was approximately twice that without reeds. The field sampling results showed that the highest aboveground nutrient storages occurred in September. Thus, the proposed remediation regime for Baiyangdian Lake was that the reed coverage should be adjusted to 60%, and the aboveground biomass of reeds should be harvested in each September. With this remediation regime, TN and TP removal in Baiyangdian Lake were 117.8 and 4.0 g m(-2), respectively, and the corresponding removal efficiencies were estimated to be 49% and 8.5% after six years. This study suggests that reed is an effective plant for the remediation of shallow lake eutrophication, and its contrasting effects of nutrient removal and evapotranspiration on water quality should be considered for establishing the remediation regime in the future. Copyright © 2012 Elsevier

  13. Density-dependent role of an invasive marsh grass, Phragmites australis, on ecosystem service provision

    PubMed Central

    Puckett, Brandon J.; Theuerkauf, Kathrynlynn W.; Theuerkauf, Ethan J.; Eggleston, David B.

    2017-01-01

    Invasive species can positively, neutrally, or negatively affect the provision of ecosystem services. The direction and magnitude of this effect can be a function of the invaders’ density and the service(s) of interest. We assessed the density-dependent effect of an invasive marsh grass, Phragmites australis, on three ecosystem services (plant diversity and community structure, shoreline stabilization, and carbon storage) in two oligohaline marshes within the North Carolina Coastal Reserve and National Estuarine Research Reserve System (NCNERR), USA. Plant species richness was equivalent among low, medium and high Phragmites density plots, and overall plant community composition did not vary significantly by Phragmites density. Shoreline change was most negative (landward retreat) where Phragmites density was highest (-0.40 ± 0.19 m yr-1 vs. -0.31 ± 0.10 for low density Phragmites) in the high energy marsh of Kitty Hawk Woods Reserve and most positive (soundward advance) where Phragmites density was highest (0.19 ± 0.05 m yr-1 vs. 0.12 ± 0.07 for low density Phragmites) in the lower energy marsh of Currituck Banks Reserve, although there was no significant effect of Phragmites density on shoreline change. In Currituck Banks, mean soil carbon content was approximately equivalent in cores extracted from low and high Phragmites density plots (23.23 ± 2.0 kg C m-3 vs. 22.81 ± 3.8). In Kitty Hawk Woods, mean soil carbon content was greater in low Phragmites density plots (36.63 ± 10.22 kg C m-3) than those with medium (13.99 ± 1.23 kg C m-3) or high density (21.61 ± 4.53 kg C m-3), but differences were not significant. These findings suggest an overall neutral density-dependent effect of Phragmites on three ecosystem services within two oligohaline marshes in different environmental settings within a protected reserve system. Moreover, the conceptual framework of this study can broadly inform an ecosystem services-based approach to invasive species management

  14. General secretion signal for the mycobacterial type VII secretion pathway

    PubMed Central

    Daleke, Maria H.; Ummels, Roy; Bawono, Punto; Heringa, Jaap; Vandenbroucke-Grauls, Christina M. J. E.; Luirink, Joen; Bitter, Wilbert

    2012-01-01

    Mycobacterial pathogens use specialized type VII secretion (T7S) systems to transport crucial virulence factors across their unusual cell envelope into infected host cells. These virulence factors lack classical secretion signals and the mechanism of substrate recognition is not well understood. Here we demonstrate that the model T7S substrates PE25/PPE41, which form a heterodimer, are targeted to the T7S pathway ESX-5 by a signal located in the C terminus of PE25. Site-directed mutagenesis of residues within this C terminus resulted in the identification of a highly conserved motif, i.e., YxxxD/E, which is required for secretion. This motif was also essential for the secretion of LipY, another ESX-5 substrate. Pathogenic mycobacteria have several different T7S systems and we identified a PE protein that is secreted by the ESX-1 system, which allowed us to compare substrate recognition of these two T7S systems. Surprisingly, this ESX-1 substrate contained a C-terminal signal functionally equivalent to that of PE25. Exchange of these C-terminal secretion signals between the PE proteins restored secretion, but each PE protein remained secreted via its own ESX secretion system, indicating that an additional signal(s) provides system specificity. Remarkably, the YxxxD/E motif was also present in and required for efficient secretion of the ESX-1 substrates CFP-10 and EspB. Therefore, our data show that the YxxxD/E motif is a general secretion signal that is present in all known mycobacterial T7S substrates or substrate complexes. PMID:22733768

  15. Impacts of Macondo oil from Deepwater Horizon spill on the growth response of the common reed Phragmites australis: a mesocosm study.

    PubMed

    Judy, Chad R; Graham, Sean A; Lin, Qianxin; Hou, Aixin; Mendelssohn, Irving A

    2014-02-15

    We investigated impacts of Macondo MC252 oil from the Deepwater Horizon (DWH) spill on the common reed Phragmites australis (Cav.) Trin. ex Steud., a dominant species of the Mississippi River Delta. In greenhouse experiments, we simulated the most common DWH oiling scenarios by applying weathered and emulsified Macondo oil to aboveground shoots at varying degrees of coverage (0-100%) or directly to marsh soil at different dosages (0-16 Lm(-)(2)). P. australis exhibited strong resistance to negative impacts when oil was applied to shoots alone, while reductions in above- and belowground plant growth were apparent when oil was applied to the soil or with repeated shoot-oiling. Although soil-oiling compromised plant function, mortality of P. australis did not occur. Our results demonstrate that P. australis has a high tolerance to weathered and emulsified Macondo oil, and that mode of exposure (aboveground versus belowground) was a primary determinant of impact severity. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. Bioinformatic prediction of G protein-coupled receptor encoding sequences from the transcriptome of the foreleg, including the Haller’s organ, of the cattle tick, Rhipicephalus australis

    USDA-ARS?s Scientific Manuscript database

    The cattle tick of Australia, Rhipicephalus australis, is a vector for microbial parasites that cause serious bovine diseases. The Haller's organ, located in the tick's forelegs, is crucial for host detection and mating. To facilitate the development of new technologies for better control of this ag...

  17. Salmonella-secreted Virulence Factors

    SciTech Connect

    Heffron, Fred; Niemann, George; Yoon, Hyunjin; Kidwai