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Sample records for calyptogena magnifica chemoautotrophic

  1. The Calyptogena magnifica chemoautotrophic symbiont genome

    Energy Technology Data Exchange (ETDEWEB)

    Newton, I.L.; Woyke, T.; Auchtung, T.A.; Dilly, G.F.; Dutton,R.J.; Fisher, M.C.; Fontanez, K.M.; Lau, E.; Stewart, F.J.; Richardson,P.M.; Barry, K.W.; Saunders, E.; Detter, J.C.; Wu, D.; Eisen, J.A.; Cavanaugh, C.M.

    2007-03-01

    Chemoautotrophic endosymbionts are the metabolic cornerstone of hydrothermal vent communities, providing invertebrate hosts with nearly all of their nutrition. The Calyptogena magnifica (Bivalvia: Vesicomyidae) symbiont, Candidatus Ruthia magnifica, is the first intracellular sulfur-oxidizing endosymbiont to have its genome sequenced, revealing a suite of metabolic capabilities. The genome encodes major chemoautotrophic pathways as well as pathways for biosynthesis of vitamins, cofactors, and all 20 amino acids required by the clam.

  2. Long-term Cultivation of the Deep-Sea Clam Calyptogena okutanii: Changes in the Abundance of Chemoautotrophic Symbiont, Elemental Sulfur, and Mucus.

    Science.gov (United States)

    Ohishi, Kazue; Yamamoto, Masahiro; Tame, Akihiro; Kusaka, Chiho; Nagai, Yukiko; Sugimura, Makoto; Inoue, Koji; Uematsu, Katsuyuki; Yoshida, Takao; Ikuta, Tetsuro; Toyofuku, Takashi; Maruyama, Tadashi

    2016-06-01

    Survival of deep-sea Calyptogena clams depends on organic carbon produced by symbiotic, sulfur-oxidizing, autotrophic bacteria present in the epithelial cells of the gill. To understand the mechanism underlying this symbiosis, the development of a long-term cultivation system is essential. We cultivated specimens of Calyptogena okutanii in an artificial chemosynthetic aquarium with a hydrogen sulfide (H2S) supply system provided by the sulfate reduction of dog food buried in the sediment. We studied morphological and histochemical changes in the clams' gills by immunohistochemical and energy-dispersive X-ray analyses. The freshly collected clams contained a high amount of elemental sulfur in the gill epithelial cells, as well as densely packed symbiotic bacteria. Neither elemental sulfur nor symbiotic bacteria was detected in any other organs except the ovaries, where symbiotic bacteria, but not sulfur, was detected. The longest survival of an individual clam in this aquarium was 151 days. In the 3 clams dissected on Days 57 and 91 of the experiment, no elemental sulfur was detected in the gills. The symbiotic bacteria content had significantly decreased by Day 57, and was absent by Day 91. For comparison, we also studied the deep-sea mussel Bathymodiolus septemdierum, which harbors a phylogenetically close, sulfur-oxidizing, symbiotic bacterium with similar sulfur oxidation pathways. Sulfur particles were not detected, even in the gills of the freshly collected mussels. We discuss the importance of the proportion of available H2S and oxygen to the bivalves for elemental sulfur accumulation. Storage of nontoxic elemental sulfur, an energy source, seems to be an adaptive strategy of C. okutanii. PMID:27365420

  3. Aural Myiasis by Wohlfahrtia magnifica: Case Report

    OpenAIRE

    Yazgi, Halil; Uyanik, M. Hamidullah; Yoruk, Ozgur; Aslan, Irfan

    2009-01-01

    A 5-year-old child living in Erzurum, Turkey, complaining of otalgia, otorrhea and pruritus in the right ear for three days, was examined. Otoscopic examination at the Department of Otorhinolaryngology revealed live maggots in the external auditory canal. Ten maggots were recovered and were identified as third stage larvae of Wohlfahrtia magnifica (Diptera: Sarcophagidae). Local and systemic antibiotic therapies were applied. No pathological findings were present at the follow-up examination ...

  4. Identification of microbiota associated with Pectinatella magnifica in South Bohemia

    Czech Academy of Sciences Publication Activity Database

    Vlková, E.; Killer, Jiří; Kmeť, V.; Rada, V.; Musilová, Š.; Bunešová, V.; Hovorková, P.; Božik, M.; Salmonová, H.; Rajchard, J.

    2015-01-01

    Roč. 70, č. 3 (2015), s. 365-371. ISSN 0006-3088 Institutional support: RVO:67985904 Keywords : Pectinatella magnifica * bacteria * South Bohemia Subject RIV: EE - Microbiology, Virology Impact factor: 0.827, year: 2014

  5. World-wide distribution of the Bryozoan Pectinatella magnifica (Leidy 1851

    Directory of Open Access Journals (Sweden)

    Zuzana Balounová

    2013-12-01

    Full Text Available Pectinatella magnifica (Leidy 1851 is an invasive freshwater colonial animal belonging to the phylum Bryozoa. It is native to the area east of the Mississippi River, from Ontario to Florida. Currently it occurs throughout North America and the first record for it outside that continent was for Bille near Hamburg in 1883. Later, it was found in the Elbe (Havel by Spandau, in Tegeler See, a pond in Wroclaw and in Silesia and Brandenburg. In addition, floatoblasts of P. magnifica were found in the upper Elbe in Germany in the 1950s. Then, P. magnifica spread to the area of Spandau in Berlin and the Oder, and Wroclaw. It is also recorded in Romania and Turkey. In France, it was recorded occurring in the area called Franche-Comte in 1994. Its occurrence in the Netherlands was first reported in 2003 and then each following year. The newest discoveries are for the Rhine basin in the area between Luxembourg and Germany. Recently, it was also recorded in the Czech Republic and Austria. Besides Europe and North America, it is also recorded in Japan and Korea. The statoblasts of P. magnifica are spread by flowing water, zoochory and probably also by anthropochory.

  6. Orbital Myiasis: Due to Invasion of Larvae of Flesh Fly (Wohlfahrtia magnifica) in a Child; Rare Presentation

    OpenAIRE

    R P Maurya; Deepak Mishra,; Prashant Bhushan; Singh, V. P.; M K Singh

    2012-01-01

    Wohlfahrtia magnifica larvae cause myiasis in mammals, mainly in sheep and rarely in human. In human it may infest the ear, eye, mouth or nose, damaging living tissues. We report a case of ocular myiasis in 1.5 years old child belonging to urban slum after history of minor injury on left upper lid due to fall from bed. The purpose of reporting this case is to highlight the ocular association of W. magnifica.

  7. Orbital Myiasis: Due to Invasion of Larvae of Flesh Fly (Wohlfahrtia magnifica) in a Child; Rare Presentation.

    Science.gov (United States)

    Maurya, R P; Mishra, Deepak; Bhushan, Prashant; Singh, V P; Singh, M K

    2012-01-01

    Wohlfahrtia magnifica larvae cause myiasis in mammals, mainly in sheep and rarely in human. In human it may infest the ear, eye, mouth or nose, damaging living tissues. We report a case of ocular myiasis in 1.5 years old child belonging to urban slum after history of minor injury on left upper lid due to fall from bed. The purpose of reporting this case is to highlight the ocular association of W. magnifica. PMID:22606492

  8. Broad-scale Population Genetics of the Host Sea Anemone, Heteractis magnifica

    KAUST Repository

    Emms, Madeleine

    2015-12-01

    Broad-scale population genetics can reveal population structure across an organism’s entire range, which can enable us to determine the most efficient population-wide management strategy depending on levels of connectivity. Genetic variation and differences in genetic diversity on small-scales have been reported in anemones, but nothing is known about their broad-scale population structure, including that of “host” anemone species, which are increasingly being targeted in the aquarium trade. In this study, microsatellite markers were used as a tool to determine the population structure of a sessile, host anemone species, Heteractis magnifica, across the Indo-Pacific region. In addition, two rDNA markers were used to identify Symbiodinium from the samples, and phylogenetic analyses were used to measure diversity and geographic distribution of Symbiodinium across the region. Significant population structure was identified in H. magnifica across the Indo-Pacific, with at least three genetic breaks, possibly the result of factors such as geographic distance, geographic isolation and environmental variation. Symbiodinium associations were also affected by environmental variation and supported the geographic isolation of some regions. These results suggests that management of H. magnifica must be implemented on a local scale, due to the lack of connectivity between clusters. This study also provides further evidence for the combined effects of geographic distance and environmental distance in explaining genetic variance.

  9. Immune Response Evaluation in Sheep Infected with Larvae of Wohlfahrtia Magnifica

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    Daniela Marina Mot

    2013-05-01

    Full Text Available The sheep myiasis is a seriously debilitating disease that has the potential to generate a substantial stress to affected animals. All lesions severity and animals state of health can be retrieved in immunological parameters detection, because always results an immune response to challenge factors which intercede in their productive life. Today is important to find non-chemical methods of ectoparasites control, from natural resistance or vaccine induced resistance. The study was carried out to infected and uninfected sheep with larvae of Wohlfahrtia magnifica. From two groups of healthy and parasited sheep were been taken blood samples. From the group from sheep with myiasis were been detected the cutaneous lesions with W. magnifica maggots and these maggots were been collected. The mechanisms of unspecific immune defending were been studied through cellular effectors by leucogram. In leucogram appear quantitative differences between different categories of cells which take part in immune response, such as polymorphonuclears (neutrophiles, eozinophiles and mononuclears (limphocytes.  The immune specific answer were been detected through radial simple immunodiffusion test made with antigen prepared from W. magnifica maggots from the third stage of development, in the view of estimating the presence of an immune reaction through antibodies synthesis in infested sheep. In both studies were been detected immune responses of parasite hosts. All immunological studies may allow a sustainable ectoparasites control utilizing host resistance which seems to be attainable in the near future.

  10. Exclusive localization of carbonic anhydrase in bacteriocytes of the deep-sea clam Calyptogena okutanii with thioautotrophic symbiotic bacteria.

    Science.gov (United States)

    Hongo, Yuki; Nakamura, Yoshimitsu; Shimamura, Shigeru; Takaki, Yoshihiro; Uematsu, Katsuyuki; Toyofuku, Takashi; Hirayama, Hisako; Takai, Ken; Nakazawa, Masatoshi; Maruyama, Tadashi; Yoshida, Takao

    2013-12-01

    Deep-sea Calyptogena clams harbor thioautotrophic intracellular symbiotic bacteria in their gill epithelial cells. The symbiont fixes CO2 to synthesize organic compounds. Carbonic anhydrase (CA) from the host catalyzes the reaction CO2 + H2O ↔ HCO3(-) + H(+), and is assumed to facilitate inorganic carbon (Ci) uptake and transport to the symbiont. However, the localization of CA in gill tissue remains unknown. We therefore analyzed mRNA sequences, proteins and CA activity in Calyptogena okutanii using expression sequence tag, SDS-PAGE and LC-MS/MS. We found that acetazolamide-sensitive soluble CA was abundantly expressed in the gill tissue of C. okutanii, and the enzyme was purified by affinity chromatography. Mouse monoclonal antibodies against the CA of C. okutanii were used in western blot analysis and immunofluorescence staining of the gill tissues of C. okutanii, which showed that CA was exclusively localized in the symbiont-harboring cells (bacteriocytes) in gill epithelial cells. Western blot analysis and measurement of activity showed that CA was abundantly (26-72% of total soluble protein) detected in the gill tissues of not only Calyptogena clams but also deep-sea Bathymodiolus mussels that harbor thioautotrophic or methanotrophic symbiotic bacteria, but was not detected in a non-symbiotic mussel, Mytilus sp. The present study showed that CA is abundant in the gill tissues of deep-sea symbiotic bivalves and specifically localizes in the cytoplasm of bacteriocytes of C. okutanii. This indicates that the Ci supply process to symbionts in the vacuole (symbiosome) in bacteriocytes is essential for symbiosis. PMID:24031050

  11. Traumatic myiasis agents in Iran with introducing of new dominant species, Wohlfahrtia magnifica (Diptera:Sarcophagidae)

    Institute of Scientific and Technical Information of China (English)

    Javad Rafinejad; Kamran Akbarzadeh; Yavar Rassi; Jamasp Nozari; Mohammad Mehdi Sedaghat; Mostafa Hosseini; Hamzeh Alipour; Abdolmajid Ranjbar; Danial Zeinali

    2014-01-01

    Objective: To study agents of animal wound myiasis in various geographical districts of Fars province.Methods:of 10358 domestic animals have been visited from April 2011 to March 2012. The infected wounds in any parts of animal body were sampled by means of forceps.Results:This study has been done in Fars province, located in the southern part of Iran. Sums The most wound myiasis cases due to this species occurred in central part of Fars province. There wasn’t any significant difference between sheep and goat in infestation with myiasis (P>0.05). The infestation rate of myiasis in cattle community was 0.86%. About 61% of all animal wound myiasis were caused by larvae of Wohlfahrtia magnifica. Conclusions: The infestation rate of livestock was lower than other works in Iran and some other countries like Saudi Arabia. Chrysomya bezziana has been mentioned as main myiasis agent in Iran. But in this study it cleared that similarly to some European countries, the common animal myiasis agent in Iran is Wohlfahrtia magnifica. Introducing new species as principal agent for myiasis can help public health and animal husbandry policy makers to prepare sufficient and effective control and/or preventive measures for this disease.

  12. Origins of Wohlfahrtia magnifica in Italy based on the identification of mitochondrial cytochrome b gene haplotypes.

    Science.gov (United States)

    Marangi, Marianna; Hall, Martin J R; Aitken, Alex; Ready, Paul D; Giangaspero, Annunziata

    2016-02-01

    To identify the geographical origins of larvae of Wohlfahrtia magnifica (Diptera: Sarcophagidae) causing myiasis of sheep in Italy, comparative DNA sequence analysis of the mitochondrial cytochrome b gene was performed, based on gene fragments amplified by PCR from genomic DNA isolated from individual specimens. DNA extractions of 19 larvae from Lazio, Molise, Puglia, and Sicilia generated 17 readable sequences homologous to 2 haplotypes, either CB_magn01 or CB_magn02; DNA extracts from 4 adult flies from Calabria (reared from larvae) produced 4 readable sequences belonging to the haplotype CB_magn01. The two haplotypes found represent both the East and West phylogenetic lineages of W. magnifica, which is consistent with the species' arrival from central/southeast Europe (East lineage) and/or from southwest Europe/northwest Africa (West lineage). This is the first report of the sympatric occurrence of the two lineages, which could have resulted from natural or human-assisted dispersal. Polymorphic nuclear loci will have to be characterized in order to explain the origins and lack of mitochondrial haplotype diversity of this pest in Italy, where it poses increasing veterinary problems. PMID:26453092

  13. Antifouling activity by sea anemone (Heteractis magnifica and H. aurora extracts against marine biofilm bacteria Actividades antiincrustantes de las extractos de las anémonas marinas Heteractis magnifica y H. aurora frente a biofilm de bacterias marinas

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    Subramanian Bragadeeswaran

    2011-07-01

    Full Text Available Sea anemones (Actiniaria are solitary, ocean-dwelling members of the phylum Cnidaria and the class Anthozoa. In this study, we screened antibacterial activity of two benthic sea anemones (Heteractis magnifica and H. aurora collected from the Mandapam coast of southeast India. Crude extracts of the sea anemone were assayed against seven bacterial biofilms isolated from three different test panels. The crude extract of H. magnifica showed a maximum inhibition zone of 18 mm against Pseudomonas sp. and Escherichia coli and a minimum inhibition zone of 3 mm against Pseudomonas aeruginosa, Micrococcus sp., and Bacillus cerens for methanol, acetone, and DCM extracts, respectively. The butanol extract of H. aurora showed a maximum inhibition zone of 23 mm against Vibrio parahaemolyticus, whereas the methanol extract revealed a minimum inhibition zone of 1 mm against V. parahaemolyticus. The present study revealed that the H. aurora extracts were more effective than those of H. magnifica and that the active compounds from the sea anemone can be used as antifouling compounds.Las anémonas de mar (Actiniaria son solitarias, habitantes oceánicos del phylum Cnidaria y de la clase Anthozoa. En este estudio se determina la actividad antibacteriana de dos anémonas bentónicas Heteractis magnifica y H. aurora recolectadas en la costa de Mandapam, sudeste de India. Los extractos crudos de estas anémonas fueron ensayados frente a siete biofilms bacterianos aislados de tres paneles de control distintos. El extracto crudo de la anémona H. magnifica mostró una zona inhibición máxima de 18 mm contra Psudomonas sp. y Escherichia coli y la zona de inhibición mínima de 3 mm fue encontrada frente a Pseudomonas aeruginosa, Micrococus sp. y Bacillus cerens de extractos de metanol, acetona y DCM respectivamente. El extracto de butanol de la anémona H. magnifica mostró una zona de inhibición máxima de 23 mm frente a Vibrio parahemolyticus, mientras que con el

  14. The metabolic demands of endosymbiotic chemoautotrophic metabolism on host physiological capacities

    OpenAIRE

    J. J. Childress; Peter R. Girguis

    2011-01-01

    While chemoautotrophic endosymbioses of hydrothermal vents and other reducing environments have been well studied, little attention has been paid to the magnitude of the metabolic demands placed upon the host by symbiont metabolism and the adaptations necessary to meet such demands. Here we make the first attempt at such an evaluation, and show that moderate to high rates of chemoautotrophic or methanotrophic metabolism impose oxygen uptake and proton equivalent elimination demands upon the h...

  15. Metabolic evolution of a deep-branching hyperthermophilic chemoautotrophic bacterium.

    Science.gov (United States)

    Braakman, Rogier; Smith, Eric

    2014-01-01

    Aquifex aeolicus is a deep-branching hyperthermophilic chemoautotrophic bacterium restricted to hydrothermal vents and hot springs. These characteristics make it an excellent model system for studying the early evolution of metabolism. Here we present the whole-genome metabolic network of this organism and examine in detail the driving forces that have shaped it. We make extensive use of phylometabolic analysis, a method we recently introduced that generates trees of metabolic phenotypes by integrating phylogenetic and metabolic constraints. We reconstruct the evolution of a range of metabolic sub-systems, including the reductive citric acid (rTCA) cycle, as well as the biosynthesis and functional roles of several amino acids and cofactors. We show that A. aeolicus uses the reconstructed ancestral pathways within many of these sub-systems, and highlight how the evolutionary interconnections between sub-systems facilitated several key innovations. Our analyses further highlight three general classes of driving forces in metabolic evolution. One is the duplication and divergence of genes for enzymes as these progress from lower to higher substrate specificity, improving the kinetics of certain sub-systems. A second is the kinetic optimization of established pathways through fusion of enzymes, or their organization into larger complexes. The third is the minimization of the ATP unit cost to synthesize biomass, improving thermodynamic efficiency. Quantifying the distribution of these classes of innovations across metabolic sub-systems and across the tree of life will allow us to assess how a tradeoff between maximizing growth rate and growth efficiency has shaped the long-term metabolic evolution of the biosphere. PMID:24516572

  16. Metabolic evolution of a deep-branching hyperthermophilic chemoautotrophic bacterium.

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    Rogier Braakman

    Full Text Available Aquifex aeolicus is a deep-branching hyperthermophilic chemoautotrophic bacterium restricted to hydrothermal vents and hot springs. These characteristics make it an excellent model system for studying the early evolution of metabolism. Here we present the whole-genome metabolic network of this organism and examine in detail the driving forces that have shaped it. We make extensive use of phylometabolic analysis, a method we recently introduced that generates trees of metabolic phenotypes by integrating phylogenetic and metabolic constraints. We reconstruct the evolution of a range of metabolic sub-systems, including the reductive citric acid (rTCA cycle, as well as the biosynthesis and functional roles of several amino acids and cofactors. We show that A. aeolicus uses the reconstructed ancestral pathways within many of these sub-systems, and highlight how the evolutionary interconnections between sub-systems facilitated several key innovations. Our analyses further highlight three general classes of driving forces in metabolic evolution. One is the duplication and divergence of genes for enzymes as these progress from lower to higher substrate specificity, improving the kinetics of certain sub-systems. A second is the kinetic optimization of established pathways through fusion of enzymes, or their organization into larger complexes. The third is the minimization of the ATP unit cost to synthesize biomass, improving thermodynamic efficiency. Quantifying the distribution of these classes of innovations across metabolic sub-systems and across the tree of life will allow us to assess how a tradeoff between maximizing growth rate and growth efficiency has shaped the long-term metabolic evolution of the biosphere.

  17. Independent phylogenetic origins of methanotrophic and chemoautotrophic bacterial endosymbioses in marine bivalves

    OpenAIRE

    Distel, D L; Cavanaugh, Colleen Marie

    1994-01-01

    The discovery of bacterium-bivalve symbioses capable of utilizing methane as a carbon and energy source indicates that the endosymbionts of hydrothermal vent and cold seep bivalves are not restricted to sulfur-oxidizing chemoautotrophic bacteria but also include methanotrophic bacteria. The phylogenetic origin of methanotrophic endosymbionts and their relationship to known symbiotic and free-living bacteria, however, have remained unexplored. In situ localization and phylogenetic analysis of ...

  18. Assimilation of Inorganic Nitrogen by Marine Invertebrates and Their Chemoautotrophic and Methanotrophic Symbionts

    OpenAIRE

    Lee, Raymond W; Childress, James J.

    1994-01-01

    Symbioses between marine invertebrates and their chemoautotrophic and methanotrophic symbionts are now known to exist in a variety of habitats where reduced chemical species are present. The utilization of chemical energy and reliance on C1 compounds by these symbioses are well documented. Much less is known about their metabolism of nitrogen. Earlier work has shown that the tissues of organisms in these associations are depleted of 15N compared with those of other marine organisms, indicatin...

  19. Fine-scale population structure of two anemones (Stichodactyla gigantea and Heteractis magnifica) in Kimbe Bay, Papua New Guinea

    KAUST Repository

    Gatins, Remy

    2014-12-01

    Anemonefish are one of the main groups that have been used over the last decade to empirically measure larval dispersal and connectivity in coral reef populations. A few species of anemones are integral to the life history of these fish, as well as other obligate symbionts, yet the biology and population structure of these anemones remains poorly understood. The aim of this study was to measure the genetic structure of these anemones within and between two reefs in order to assess their reproductive mode and dispersal potential. To do this, we sampled almost exhaustively two anemones species (Stichodactyla gigantea and Heteractis magnifica) at two small islands in Kimbe Bay (Papua New Guinea) separated by approximately 25 km. Both the host anemones and the anemonefish are heavily targeted for the aquarium trade, in addition to the populations being affected by bleaching pressures (Hill and Scott 2012; Hobbs et al. 2013; Saenz- Agudelo et al. 2011; Thomas et al. 2014), therefore understanding their biology is crucial for better management strategies. Panels of microsatellite markers were developed for each species using next generation sequencing tools. Clonality analyses confirm six pairs of identical genotypes for S. gigantea (n=350) and zero for H. magnifica (n=128), indicating presence/absence of asexual reproduction in this region. S. gigantea showed low structure between islands (FST= 0.003, p-value= 0.000), however, even if the majority of the individuals were unrelated (r~0), 81 families that shared 50% of their genetic material formed from two to four members were found. Out of these families, 45% were found with individuals only within Tuare Island, 11% only in Kimbe Island, and 44% were sharing individuals among islands. In comparison, H. magnifica showed no structure (FST= 0.002, p-value= 0.278), mean relatedness indicated the majority of individuals were unrelated, and 31 families were identified. Families again consisted from two to four members and

  20. Analysis of past recurrent methane seep activity using radiocarbon dating of Calyptogena spp. shells in the eastern Nankai subduction zone, Japan

    Science.gov (United States)

    Yagasaki, Kazuhiro; Ashi, Juichiro; Yokoyama, Yusuke; Miyairi, Yosuke; Kuramoto, Shin'ichi

    2016-04-01

    Fault activity around subduction zones have been widely studied and monitored through drilling of oceanic plates, studying piston cores, use of monitoring equipment or through visual analysis using submersible vehicles. Yet the understanding of how small scale faults near shallow regions of the seabed behave in relation to cold seep vent activity is still vague, especially determining when they were active in the past. In tectonically active margins such as the Nankai and Tokai regions off Japan, dense methane hydrate reservoirs have been identified. Cold seeps releasing methane rich hydrocarbon fluids are common here, supporting a wide variety of biological species that hold a symbiotic relationship with the chemosynthetic bacteria. In 1998 a large dead Calyptogena spp. bivalve colony (over 400m2 in size) was discovered off Tokai, Japan. It is unusual for a bivalve colony this size to mostly be dead, raising questions as to what caused their death. In this study we document the radiocarbon 14C age of these bivalve shells to attempt analysing the possible methane seep bahaviour in the past. The measured 14C age ranged in three age groups of 1396±36-1448±34, 1912±31-1938±35 and 5975±34. The 14C age of shells that were alive upon collection and the dissolved inorganic carbon (DIC) in seawater show little difference (˜100 14C age) indicating that shells are not heavily affected by the dead carbon effect from cold seeps that is of biogenic or thermogenic origin, which can make the age to become considerably older than the actual age. Thus the novel calibration model used was based on the seawater DIC collected above the Calyptogena spp. colony site (1133±31), which resulted in the dead shells to be clustered around 1900 Cal AD. This proves to be interesting as the predicted epicenter of the Ansei-Tokai earthquake (M 8.4) in 1854 is extremely close to the bibalve colony site. Using geological data obtained using visual analysis and sub-seafloor structural

  1. Variability of the cleistothecia and distribution of Erysiphe magnifica (U. Braun U. Braun & S. Takam. on Magnolia L. plants in O.V. Fomin Botanical garden

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    Petro Chumak

    2012-03-01

    Full Text Available The variability of morphometrie characteristics of the cleistothecia of fungus Erysiphe magnifica on different species from the genus Magnolia L. has been considered. It has been shown that on the different nutrient plants are forming the micropopulations of fungus which are notable for the cleistothecia parameters frequency of distribution and variability of their indices. The invasion activity of fungus increases in сonditions of the Botanical garden, it dеmages 8 species of plants of the genus Magnolia.

  2. Characterization, purification and phylogenetic analysis of a cytolysin from the sea anemone Heteractis magnifica of the Indian Ocean

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    S Karthikayalu

    2010-01-01

    Full Text Available It is well established that sea anemones comprise a rich source of cytolytic toxins. The present study reports the isolation and characterization of a cytolysin obtained from the sea anemone Heteractis magnifica collected in the Andaman Islands of the Indian Ocean. The crude extract was screened for hemolytic activity by a blood agar plate method and a 6-mm zone of clearance was observed after incubation. The hemolytic property of the crude extract, tested by the microtiter plate method, revealed positive results at concentrations as low as 120 ng/mL. Furthermore, it was favored by alkaline pH and was stable up to 60°C. On the other hand, the hemolytic effect was abolished by the addition of human serum. Purification steps involved ammonium sulfate precipitation and subsequent desalting by dialysis, followed by anion- and cation-exchange chromatographies. The purified fractions displayed the presence of a 19-kDa cytolysin when analyzed by SDS-PAGE. The conserved region of the cytolysin (with 303 bp was amplified by RT-PCR and was sequenced. The sequence showed maximum homology (97% with the already reported cytolysins from other sea anemone species.

  3. Chemoautotrophic Bacterial Production in the Redoxycline of an Ice-Covered Antarctic Lake (Invited)

    Science.gov (United States)

    Mikucki, J.; Kong, W.; Priscu, J. C.; Morgan-Kiss, R.

    2010-12-01

    Chemolithoautotrophic organisms obtain energy for growth from inorganic substrates and use simple inorganic carbon molecules to construct biomass. As such, chemosynthetic processes are tightly linked to biogeochemical cycles. In polar regions, winter darkness shuts down photosynthetic inputs and the contribution of chemosynthesis to total ecosystem energetics and carbon fixation may be significant. Few reports exist on chemosynthesis in polar environments and the rates of these processes remain largely unexplored. Here we present data on chemoautotrophic activity in the redoxycline (~15m depth) of the permanently ice-covered Lake Bonney in the McMurdo Dry Valleys, Antarctica (MCM). Rates of radio-labeled bicarbonate incorporation were measured under light and dark conditions using whole community and bacterial sized-fraction (< 3 μm) samples. Rates of uptake in the bacterial sized-fraction (0.18 μg C L-1 d-1) were comparable to that of heterotrophic bacterial activity (0.16 μg C L-1 d-1) as measured by radio-labeled thymidine incorporation. Molecular analyses of the (cbbM) Rubisco gene, a key enzyme in the Calvin cycle, revealed relatives to the Thiobacillus genera confirming the genomic potential for in situ bacterial carbon fixation. Further, quantification of cbbM gene copy number by real time PCR from samples collected throughout the trophogenic zones of the west and east lobes of Lake Bonney confirmed that chemotrophic bacteria harboring form II RubisCO are restricted to depths at or below the redoxycline of the west lobe. These data provide insight into the structure-function relationship between the microbial consortia and carbon budget and imply that chemoautotrophic production in the MCM may provide a significant source of previously un-quantified fixed carbon to the lake system. Studies on other icy systems, including dark, isolated subglacial environments report evidence for chemolithoautotrophy suggesting that chemoautotrophic production can sustain

  4. Environmental controls on chemoautotrophic primary producers at deep-sea vents

    Science.gov (United States)

    Le Bris, Nadine; Mullineaux, Lauren; Sievert, Stefan

    2014-05-01

    High biomasses and fast growth rates of dominant chemosynthetic species characterize hydrothermal ecosystems, raising the issue of their contribution to energy transfer and carbon cycling in the deep-sea. Addressing this issue, however, needs to account for the temporal instability of hydrothermal systems, both, in terms of biological colonization and habitat conditions. Volcanic eruptions on mid-ocean ridges offer the opportunity to investigate the environmental conditions favoring the successive modes of chemoautotrophic primary production (i.e. free living microbes and symbiotic invertebrates). In that perspective, habitat-scale approaches distinguish from vent field-scale approaches based on fluid composition and provide relevant information on environmental constraints exerted at different stages of colonization focusing on parameters linked with physiological limits and available energy. Investigation of habitat physicochemical properties along a typical successional sequence of recolonization at 9°50'N EPR diffuse-flow vents, between 2006 and 2014, was performed in order to examine potential changes in environmental features associated with chemoautotrophic primary producers, from early microbial colonizers to symbiotic invertebrates. Combined in situ measurements of temperature, pH and hydrogen sulfide were used and their variability documented over a series of assemblages characterizing recolonization stages. The distributions of mature assemblages of dominant invertebrate species associate with substantial differences in habitat conditions, pointing to a strong influence of habitat properties on potential productivity. Among the differences observed, however, the amplitude and rate of environmental fluctuation appear more important than average conditions in the succession, highlighting the role of spatial heterogeneity and temporal dynamics as a control on primary producers. Invertebrate species acting as engineer species are expected to play a primary

  5. Spatial distribution of mud flows, chemoautotrophic communities, and biogeochemical habitats at Håkon Mosby Mud Volcano

    OpenAIRE

    Jerosch, Kerstin; Schlüter, Michael; Foucher, J. P.; Allais, A. G.; Klages, Michael; Edy, C.

    2007-01-01

    Marine mud volcanoes are significant source locations contributing to the marine methane cycle. Enhanced heat flow, unique chemoautotrophic communities, occurrence of massive gas hydrates and large gas plumes are direct evidences of elevated methane concentrations and the dynamic environment of mud volcanoes. Related to the high concentrations and large inventories of CH4 in surface sediments only a fraction of the methane is exported to the bottom water. This is mainly due to chemoautotrophi...

  6. A remarkable finding that suggests the existence of a new groundwater biome based on chemoautotrophic resources, named

    OpenAIRE

    Ştefan Negrea

    2009-01-01

    An important work of subterranean biology, signed by Francis Dov Por, Ophel: a groundwater biome based on chemoautotrophic resources. The global significance of the Ayyalon cave finds, Israel is presented and discussed in the present paper. The subject is a remarkable discovery suggesting the existence of a new aquatic subterranean biome autonomous energy based the author calls Ophel, the Hebrew word for “darkness” and “netherworld”). For F.D. Por, this biome links different marine chemosynth...

  7. Unsuspected diversity of Niphargus amphipods in the chemoautotrophic cave ecosystem of Frasassi, central Italy

    Directory of Open Access Journals (Sweden)

    Dattagupta Sharmishtha

    2010-06-01

    Full Text Available Abstract Background The sulfide-rich Frasassi caves in central Italy contain a rare example of a freshwater ecosystem supported entirely by chemoautotrophy. Niphargus ictus, the sole amphipod species previously reported from this locality, was recently shown to host the first known case of a freshwater chemoautotrophic symbiosis. Since the habitat of N. ictus is highly fragmented and is comprised of streams and lakes with various sulfide concentrations, we conducted a detailed study to examine the potential genetic diversity of this species within Frasassi. Results By sequencing one nuclear (ITS and two mitochondrial (COI and 12S regions, we show that four partially sympatric Niphargus clades are present in Frasassi. Morphological and behavioral data obtained for three of these clades are perfectly congruent with this molecular delineation and make it possible to distinguish them in the field. Phylogenetic analyses of 28S ribosomal DNA sequences reveal that, among the four clades, only two are closely related to each other. Moreover, these four clades occupy distinct niches that seem to be related to the chemical properties and flow regimes of the various water bodies within Frasassi. Conclusions Our results suggest that four distinct Niphargus species are present in Frasassi and that they originated from three or four independent invasions of the cave system. At least two among the four species harbor Thiothrix epibionts, which paves the way for further studies of the specificity and evolutionary history of this symbiosis.

  8. Modeling arsenite oxidation by chemoautotrophic Thiomonas arsenivorans strain b6 in a packed-bed bioreactor

    International Nuclear Information System (INIS)

    Arsenic is a major toxic pollutant of concern for the human health. Biological treatment of arsenic contaminated water is an alternative strategy to the prevalent conventional treatments. The biological treatment involves a pre-oxidation step transforming the most toxic form of arsenic, As (III), to the least toxic form, As (V), respectively. This intermediate process improves the overall efficiency of total arsenic removal from the contaminated water. As (III) oxidation by the chemoautotrophic bacterium Thiomonas arsenivorans strain b6 was investigated in a fixed-film reactor under variable influent As (III) concentrations (500–4000 mg/L) and hydraulic residence times (HRTs) (0.2–1 day) for a duration of 137 days. During the entire operation, seven steady-state conditions were obtained with As (III) oxidation efficiency ranging from 48.2% to 99.3%. The strong resilience of the culture was exhibited by the recovery of the bioreactor from an As (III) overloading of 5300 ± 400 mg As (III)/L day operated at a HRT of 0.2 day. An arsenic mass balance revealed that As (III) was mainly oxidized to As (V) with unaccounted arsenic (≤ 4%) well within the analytical error of measurement. A modified Monod flux expression was used to determine the biokinetic parameters by fitting the model against the observed steady-state flux data obtained from operating the bioreactor under a range of HRTs (0.2–1 day) and a constant influent As (III) concentration of 500 mg/L. Model parameters, k = 0.71 ± 0.1 mg As (III)/mg cells h, and Ks = 13.2 ± 2.8 mg As (III)/L were obtained using a non-linear estimation routine and employing the Marquardt–Levenberg algorithm. Sensitivity analysis revealed k to be more sensitive to model simulations of As (III) oxidation under steady-state conditions than parameter Ks. -- Highlights: ► As (III) oxidation. ► Biokinetic parameters. ► Model validation and sensitivity analysis.

  9. Isotopic evidences and constraints in the chemoautotrophic system of the Movile cave, Romania

    International Nuclear Information System (INIS)

    The stable isotope (2H, 13C, 34S) content for samples from the chemoautotrophic ecosystem of the Movile cave have been used to provide information about the life in this closed system.. The groundwater is rich in H2S (8-12 mg/l) and the cave atmosphere is poor in oxygen (7-10%), rich in CO2 (2-3.5%) and contains a significant amount of CH4 (1-2%). The 13C content of cave organic matter exhibits low values of δ13C (between -47.5 and -37.5 0/00) and does not reflect the isotopic composition of the local organic materials from surface and subsurface. The concentration of 13C in the area near to cave is typical for aquatic and terrestrial ecosystems that use photoautotrophic carbon fixation (between -30 and -23 0/00). This discrepancy suggests other way of carbon fixation in the trophic web and it is possible that the organic matter is derived from lipid-rich organisms biosynthesized by chemosynthetic microorganisms which use H2S as energy source for carbon fixation. Gases collected from the groundwater (H2S) and the cave atmosphere (CH4 and CO2) have isotope ratios that point out the following: the groundwater from cave is not originated from Black Sea. The δ34S values range between +3.5 to +4.2 0/00 for cave being rich in 34S versus isotopic composition of deep water from Black Sea (-40 0/00); the sulphur isotope content from H2S (+5.9 to +8.3 0/00) and SO42-(+1.1 0/00) presents a contrast trend versus the general trend of the isotopic fractionation of the microbially mediated sulphur transformations. In the cave, H2S with δ34S values lower than that of the SO42- reactant were not recorded; the carbon isotope data for CO2-CH4 pairs (-23 0/00 for CO2 and -56.5 0/00 for CH4) of the cave gases cannot clearly delineate the biogenic methane origin as marine or non-marine provenance; the equilibrium carbon isotope fractionation between CH4 and CO2 is αc = 1. 35 indicating that the CO2 reduction pathway for methanogenesis is very improbable and the natural conditions of

  10. Characterizing the plasticity of nitrogen metabolism by the host and symbionts of the hydrothermal vent chemoautotrophic symbioses Ridgeia piscesae.

    Science.gov (United States)

    Liao, Li; Wankel, Scott D; Wu, Min; Cavanaugh, Colleen M; Girguis, Peter R

    2014-03-01

    Chemoautotrophic symbionts of deep sea hydrothermal vent tubeworms are known to provide their hosts with all their primary nutrition. While studies have examined how chemoautotrophic symbionts provide the association with nitrogen, fewer have examined if symbiont nitrogen metabolism varies as a function of environmental conditions. Ridgeia piscesae tubeworms flourish at Northeastern Pacific vents, occupy a range of microhabitats, and exhibit a high degree of morphological plasticity [e.g. long-skinny (LS) and short-fat (SF) phenotypes] that may relate to environmental conditions. This plasticity affords an opportunity to examine whether symbiont nitrogen metabolism varies among host phenotypes. LS and SF R. piscesae were recovered from the Axial and Main Endeavour Field hydrothermal vents. Nitrate and ammonium were quantified in Ridgeia blood, and the expression of key nitrogen metabolism genes, as well as stable nitrogen isotope ratios, was quantified in host branchial plume and symbiont-containing tissues. Nitrate and ammonium were abundant in the blood of both phenotypes though environmental ammonium concentrations were, paradoxically, lowest among individuals with the highest blood ammonium. Assimilatory nitrate reductase transcripts were always below detection, though in both LS and SF R. piscesae symbionts, we observed elevated expression of dissimilatory nitrate reductase genes, as well as symbiont and host ammonium assimilation genes. Site-specific differences in expression, along with tissue stable isotope analyses, suggest that LS and SF Ridgeia symbionts are engaged in both dissimilatory nitrate reduction and ammonia assimilation to varying degrees. As such, it appears that environmental conditions -not host phenotype-primarily dictates symbiont nitrogen metabolism. PMID:24237389

  11. A remarkable finding that suggests the existence of a new groundwater biome based on chemoautotrophic resources, named

    Directory of Open Access Journals (Sweden)

    Ştefan Negrea

    2009-01-01

    Full Text Available An important work of subterranean biology, signed by Francis Dov Por, Ophel: a groundwater biome based on chemoautotrophic resources. The global significance of the Ayyalon cave finds, Israel is presented and discussed in the present paper. The subject is a remarkable discovery suggesting the existence of a new aquatic subterranean biome autonomous energy based the author calls Ophel, the Hebrew word for “darkness” and “netherworld”. For F.D. Por, this biome links different marine chemosynthetic ecosystems in a global biospheric entity. Finally, F.D. POR hypothesizes on the existence of three overlapped biospheres: the bacteriosphere in the depths of the planet’s crust, which does not require light or oxygen; the aphotic, subterranean deuterobiosphere, formed of bacterial chemosynthesis based eukaryotes and limited-supplied dissolved oxygen from above-ground; the above-ground eubiosphere, based on aerobic photosynthesis. I would like to emphasize that, at my suggestion, Prof. Dr. F.D. Por participated at the 18th International Symposium of Biospeleology from Cluj-Napoca (Romania at 10th to 15th July 2006 where he mentioned for the first time orally some data on the Ayyalon Cave and the Ophel biome.

  12. Colonoscopia com magnificação de imagem no diagnóstico de carcinoma colorretal invasivo da submucosa na polipose adenomatosa familiar Magnifying colonoscopy diagnosis of submucosal invasive colorectal carcinoma in familial adenomatous polyposis

    Directory of Open Access Journals (Sweden)

    Cláudio TARTA

    2000-04-01

    Full Text Available O desenvolvimento da colonoscopia com magnificação de imagem possibilitou o estudo detalhado da mucosa colônica e o diagnóstico diferencial entre lesões neoplásicas e não-neoplásicas, a partir da observação dos pit patterns. Os resultados são comparáveis à estereomicroscopia, sendo possível, assim, presumir o diagnóstico histológico. Foi realizada colonoscopia com magnificação de imagem em paciente portadora de polipose adenomatosa familiar, demonstrando-se com este método, a diversidade de lesões polipóides benignas e as apresentações morfológicas do câncer colorretal precoce. Nesta paciente, a avaliação por magnificação (videocolonoscópio FUJINON 410 - CM -- 40X, combinada à cromoscopia com indigo carmine 0,4%, demonstrou ampla variedade de lesões distribuídas por todo o cólon: lesão de espalhamento lateral no ceco com padrão IIIL + IV, pólipos subpediculados e sésseis distribuídos pelo cólon com padrão tipo IIIL, pólipo subpediculado no cólon transverso com diâmetro aproximado de 2,0 cm e padrão IV + V, lesões plano-elevadas tipo IIIL e no cólon sigmóide lesão IIa + IIc, com padrão V de Kudo. A avaliação dos pit patterns de lesões no cólon transverso e sigmóide permitiu o diagnóstico endoscópico de lesão com invasão de submucosa.The development of colonoscopy with image magnification has enable to study the colonic mucosa in detail and to do differential diagnosis between neoplastic and non-neoplastic lesions from the observation of pit patterns. The results are comparable to stereomicroscopy being possible to predict the histologic diagnosis. In a patient with familial adenomatous polyposis magnifying colonoscopy was performed and this method demonstrated a wide variaton of benign polypoid lesions and the morphological features of early colorectal cancer. In this patient, the evaluation by image magnification, together with indigo carmin 0,4% chromoscopy, showed a wide variety of

  13. AcEST: DK954929 [AcEST

    Lifescience Database Archive (English)

    Full Text Available J4|C3H63_ORYSJ Zinc finger CCCH domain-containing protein... 32 3.0 sp|A1AV60|SECA_RUTMC Protein translocase...7 IASPRWPG 224 >sp|A1AV60|SECA_RUTMC Protein translocase subunit secA OS=Ruthia magnifica subsp. Calyptogena

  14. AcEST: DK959487 [AcEST

    Lifescience Database Archive (English)

    Full Text Available n osa OS=Drosophila me... 31 4.0 sp|A1AVR9|NUOH_RUTMC NADH-quinone oxidoreductase subunit H OS=Ru... 31 4.0 ...GGS 1347 >sp|A1AVR9|NUOH_RUTMC NADH-quinone oxidoreductase subunit H OS=Ruthia magnifica subsp. Calyptogena

  15. Alkalilimnicola ehrlichii sp. nov., a novel, arsenite-oxidizing haloalkaliphilic gammaproteobacterium capable of chemoautotrophic or heterotrophic growth with nitrate or oxygen as the electron acceptor

    Science.gov (United States)

    Hoeft, S.E.; Blum, J.S.; Stolz, J.F.; Tabita, F.R.; Witte, B.; King, G.M.; Santini, J.M.; Oremland, R.S.

    2007-01-01

    A facultative chemoautotrophic bacterium, strain MLHE-1T, was isolated from Mono Lake, an alkaline hypersaline soda lake in California, USA. Cells of strain MLHE-1T were Gram-negative, short motile rods that grew with inorganic electron donors (arsenite, hydrogen, sulfide or thiosulfate) coupled with the reduction of nitrate to nitrite. No aerobic growth was attained with arsenite or sulfide, but hydrogen sustained both aerobic and anaerobic growth. No growth occurred when nitrite or nitrous oxide was substituted for nitrate. Heterotrophic growth was observed under aerobic and anaerobic (nitrate) conditions. Cells of strain MLHE-1T could oxidize but not grow on CO, while CH4 neither supported growth nor was it oxidized. When grown chemoautotrophically, strain MLHE-1T assimilated inorganic carbon via the Calvin-Benson-Bassham reductive pentose phosphate pathway, with the activity of ribulose 1,5-bisphosphate carboxylase (RuBisCO) functioning optimally at 0.1 M NaCl and at pH 7.3. Strain MLHE-1T grew over broad ranges of pH (7.3-10.0; optimum, 9.3), salinity (115-190 g l-1; optimum 30 g l-1) and temperature (113-40 ??C; optimum, 30 ??C). Phylogenetic analysis of 16S rRNA gene sequences placed strain MLHE-1T in the class Gammaproteobacteria (family Ectothiorhodospiraceae) and most closely related to Alkalispirillum mobile (98.5%) and Alkalilimnicola halodurans (98.6%), although none of these three haloalkaliphilic micro-organisms were capable of photoautotrophic growth and only strain MLHE-1T was able to oxidize As(III). On the basis of physiological characteristics and DNA-DNA hybridization data, it is suggested that strain MLHE-1T represents a novel species within the genus Alkalilimnicola for which the name Alkalilimnicola ehrlichii is proposed. The type strain is MLHE-1T (=DSM 17681T =ATCC BAA-1101T). Aspects of the annotated full genome of Alkalilimnicola ehrlichii are discussed in the light of its physiology. ?? 2007 IUMS.

  16. Culture-Independent Identification of Manganese-Oxidizing Genes from Deep-Sea Hydrothermal Vent Chemoautotrophic Ferromanganese Microbial Communities Using a Metagenomic Approach

    Science.gov (United States)

    Davis, R.; Tebo, B. M.

    2013-12-01

    Microbial activity has long been recognized as being important to the fate of manganese (Mn) in hydrothermal systems, yet we know very little about the organisms that catalyze Mn oxidation, the mechanisms by which Mn is oxidized or the physiological function that Mn oxidation serves in these hydrothermal systems. Hydrothermal vents with thick ferromanganese microbial mats and Mn oxide-coated rocks observed throughout the Pacific Ring of Fire are ideal models to study the mechanisms of microbial Mn oxidation, as well as primary productivity in these metal-cycling ecosystems. We sampled ferromanganese microbial mats from Vai Lili Vent Field (Tmax=43°C) located on the Eastern Lau Spreading Center and Mn oxide-encrusted rhyolytic pumice (4°C) from Niua South Seamount on the Tonga Volcanic Arc. Metagenomic libraries were constructed and assembled from these samples and key genes known to be involved in Mn oxidation and carbon fixation pathways were identified in the reconstructed genomes. The Vai Lili metagenome assembled to form 121,157 contiguous sequences (contigs) greater than 1000bp in length, with an N50 of 8,261bp and a total metagenome size of 593 Mbp. Contigs were binned using an emergent self-organizing map of tetranucleotide frequencies. Putative homologs of the multicopper Mn-oxidase MnxG were found in the metagenome that were related to both the Pseudomonas-like and Bacillus-like forms of the enzyme. The bins containing the Pseudomonas-like mnxG genes are most closely related to uncultured Deltaproteobacteria and Chloroflexi. The Deltaproteobacteria bin appears to be an obligate anaerobe with possible chemoautotrophic metabolisms, while the Chloroflexi appears to be a heterotrophic organism. The metagenome from the Mn-stained pumice was assembled into 122,092 contigs greater than 1000bp in length with an N50 of 7635 and a metagenome size of 385 Mbp. Both forms of mnxG genes are present in this metagenome as well as the genes encoding the putative Mn

  17. Formation of Zn- and Fe-sulfides near hydrothermal vents at the Eastern Lau Spreading Center: implications for sulfide bioavailability to chemoautotrophs

    Directory of Open Access Journals (Sweden)

    Yucel Mustafa

    2008-05-01

    Full Text Available Abstract Background The speciation of dissolved sulfide in the water immediately surrounding deep-ocean hydrothermal vents is critical to chemoautotrophic organisms that are the primary producers of these ecosystems. The objective of this research was to identify the role of Zn and Fe for controlling the speciation of sulfide in the hydrothermal vent fields at the Eastern Lau Spreading Center (ELSC in the southern Pacific Ocean. Compared to other well-studied hydrothermal systems in the Pacific, the ELSC is notable for unique ridge characteristics and gradients over short distances along the north-south ridge axis. Results In June 2005, diffuse-flow ( 250°C vent fluids were collected from four field sites along the ELSC ridge axis. Total and filtered Zn and Fe concentrations were quantified in the vent fluid samples using voltammetric and spectrometric analyses. The results indicated north-to-south variability in vent fluid composition. In the high temperature vent fluids, the ratio of total Fe to total Zn varied from 39 at Kilo Moana, the most northern site, to less than 7 at the other three sites. The concentrations of total Zn, Fe, and acid-volatile sulfide indicated that oversaturation and precipitation of sphalerite (ZnS(s and pyrite (FeS2(s were possible during cooling of the vent fluids as they mixed with the surrounding seawater. In contrast, most samples were undersaturated with respect to mackinawite (FeS(s. The reactivity of Zn(II in the filtered samples was tested by adding Cu(II to the samples to induce metal-exchange reactions. In a portion of the samples, the concentration of labile Zn2+ increased after the addition of Cu(II, indicating the presence of strongly-bound Zn(II species such as ZnS clusters and nanoparticles. Conclusion Results of this study suggest that Zn is important to sulfide speciation at ELSC vent habitats, particularly at the southern sites where Zn concentrations increase relative to Fe. As the hydrothermal

  18. Characterization of Microbial Communities Associated With Deep-Sea Hydrothermal Vent Animals of the East Pacific Rise and the Galápagos Rift

    Science.gov (United States)

    Ward, N.; Page, S.; Heidelberg, J.; Eisen, J. A.; Fraser, C. M.

    2002-12-01

    The composition of microbial communities associated with deep-sea hydrothermal vent animals is of interest because of the key role of bacterial symbionts in driving the chemosynthetic food chain of the vent system, and also because bacterial biofilms attached to animal exterior surfaces may play a part in settlement of larval forms. Sequence analysis of 16S ribosomal RNA (rRNA) genes from such communities provides a snapshot of community structure, as this gene is present in all Bacteria and Archaea, and a useful phylogenetic marker for both cultivated microbial species, and uncultivated species such as many of those found in the deep-sea environment. Specimens of giant tube worms (Riftia pachyptila), mussels (Bathymodiolus thermophilus), and clams (Calyptogena magnifica) were collected during the 2002 R/V Atlantis research cruises to the East Pacific Rise (9N) and Galápagos Rift. Microbial biofilms attached to the exterior surfaces of individual animals were sampled, as were tissues known to harbor chemosynthetic bacterial endosymbionts. Genomic DNA was extracted from the samples using a commercially available kit, and 16S rRNA genes amplified from the mixed bacterial communities using the polymerase chain reaction (PCR) and oligonucleotide primers targeting conserved terminal regions of the 16S rRNA gene. The PCR products obtained were cloned into a plasmid vector and the recombinant plasmids transformed into cells of Escherichia coli. Individual cloned 16S rRNA genes were sequenced at the 5' end of the gene (the most phylogenetically informative region in most taxa) and the sequence data compared to publicly available gene sequence databases, to allow a preliminary assignment of clones to taxonomic groups within the Bacteria and Archaea, and to determine the overall composition and phylogenetic diversity of the animal-associated microbial communities. Analysis of Riftia pachyptila exterior biofilm samples revealed the presence of members of the delta and

  19. Molecular Characterization of Methanotrophic and Chemoautotrophic Communities at Cold Seeps

    OpenAIRE

    Lösekann, Tina

    2006-01-01

    Cold seeps are complex ecosystems based on chemosynthesis. Sulfide and methane are available in high concentrations and support a variety of highly adapted microorganisms and symbiont-bearing invertebrates. The anaerobic oxidation of methane (AOM) is a key biogeochemical process at cold seeps and is assumed to be mediated by a consortium of anaerobic methanotrophic archaea (ANME) and sulfate-reducing bacteria. In this thesis I used 16S rRNA-based molecular methods to identify and quantify met...

  20. Dicty_cDB: Contig-U05804-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available ner... 48 0.69 1 ( CP000488 ) Candidatus Ruthia magnifica str. Cm (Calyptogena ... 48 0...320_33( FN392320 |pid:none) Pichia pastoris GS115 chromosome ... 77 8e-13 AL162651_19( AL162651 |pid:none) Arabidopsis thaliana...la mojavensis strain MJBC1... 71 6e-11 (Q9Y7Q2) RecName: Full=Glutathi... EU079426_1( EU079426 |pid:none) Drosophila mojavensis strain MJBC1... 71 7e-11 EU079444_1( EU079444 |pid:none) Drosophila nav.... 69 3e-10 EU079421_1( EU079421 |pid:none) Drosophila mojavensis strain MJ68 ... 69 3e-10 AF061253_1( AF0612

  1. Immune Response Evaluation in Sheep Infected with Larvae of Wohlfahrtia Magnifica

    OpenAIRE

    Daniela Marina Mot; Emil Tirziu; Teodor Mot; Ileana Nichita

    2013-01-01

    The sheep myiasis is a seriously debilitating disease that has the potential to generate a substantial stress to affected animals. All lesions severity and animals state of health can be retrieved in immunological parameters detection, because always results an immune response to challenge factors which intercede in their productive life. Today is important to find non-chemical methods of ectoparasites control, from natural resistance or vaccine induced resistance. The study was carried out t...

  2. A RARE CASE OF PALATINAL ORAL MYIASIS CAUSED BY WOHLFAHRTIA MAGNIFICA

    OpenAIRE

    Gümüşsoy, İsmail; ÇAĞLAYAN, Fatma; GÜVEN , Esra; MİLOĞLU, Özkan

    2015-01-01

    Myiasis (from the Greek word for fly, myia) is an uncommon disease in human caused by fly larvae. Especially, oral myiasis is very rare condition in healthy persons; it is usually associated with poor public and personal hygiene. Most of the patients with oral myiasis were reported from the tropical countries with low socioeconomic status; however, sporadic cases were occurred in developed countries. We present here a case of oral myiasis in a healthy 4 year-old boy. Three maggots found in an...

  3. New symbiotic associations involving Syllidae (Annelida: Polychaetae), with taxonomic and biological remarks on Pionosyllis magnifica and Syllis cf armillaris

    OpenAIRE

    E. López; Britayev, Temir A.; Martin, Daniel; San Martín, Guillermo

    2001-01-01

    Several new symbiotic associations involving Syllidae (Annelida: Polychaeta) are reported. The number of known host sponge species infested by Haplosyllis spongicola is updated to 36, with seven hosts being reported for the first time (i.e. Aplysina corrugata, Aplysina sp., Cliona sp., Cliona viridis, Phorbas tenacior, one sponge from Iran, one sponge from Cambodia). Two infestation patterns (a few worms per host cm3 in temperate waters and 10s or 100s in tropical waters) are identified. The ...

  4. Chromodoris magnifica (Quoy & Gaimard, 1832), a new nudibranch host for the shrimp Periclimenes imperator Bruce, 1967 (Pontoniinae)

    NARCIS (Netherlands)

    Fransen, C.H.J.M.; Goud, J.

    1999-01-01

    During the NNM/Maluku Expedition 1996, in the framework of the NNM Fauna Malesiana Marine Program, a shrimp belonging to the species Periclimenes imperator Bruce, 1967, was found on a nudibranch while diving at 20 m depth in Seri Bay, on the south coast of Ambon. Periclimens imperator has been recor

  5. Characterization of the symbiosis between chemoautotrophic bacteria and the bivalve Lucinoma aequizonata: morphology, biochemistry, and phylogeny

    International Nuclear Information System (INIS)

    Low magnification electron microscopy and light microscopy were performed on plastic embedded and fresh samples of bacteriocyte tissues from L. annulata, L. aequizonata and L. floridana. Serial sectioning was used to determine the three dimensional relationship between host tissues, symbiont cells, and the external environment. Possible effects of structure on the exchange of metabolites and inorganic molecules are discussed. Density gradient centrifugation was used to purify symbiotic bacteria from homogenates of host bacteriocyte tissue. The results demonstrate that bacteria can be recovered intact, biologically active and nearly free of contaminants from host tissue. Incorporation of H14CO3- into acid soluble metabolic intermediates by either whole gills, isolated bacteria or bacteria isolated from gills previously exposed to label was examined in L. aequizonata. HPLC, paper chromatography and enzymatic techniques were used to identify and quantify labeled products. The initial fixation product in whole gills is malate. In the symbionts aspartate and 3-phosphoglycerate are the major labeled compounds. Possible pathways of carbon exchange between hosts and symbionts are discussed

  6. Chemoautotrophic Carbon Fixation Rates and Active Bacterial Communities in Intertidal Marine Sediments

    NARCIS (Netherlands)

    Boschker, H.T.S.; Vasquez-Cardenas, D.; Bolhuis, H.; Moerdijk-Poortvliet, T.C.W.; Moodley, L.

    2014-01-01

    Chemoautotrophy has been little studied in typical coastal marine sediments, but may be an important component ofcarbon recycling as intense anaerobic mineralization processes in these sediments lead to accumulation of high amounts ofreduced compounds, such as sulfides and ammonium. We studied chemo

  7. Assessing the role of soil chemoautotrophs in carbon cycling: An investigation into isotopically labelled soil microorganisms

    OpenAIRE

    Hart, Kris M.

    2011-01-01

    Recently observed increases in atmospheric CO2 have created great interest in carbon capture technologies and natural sinks of this major component of the carbon cycle. Humic substances are a large, operationally defined fraction of soil organic matter. It was thought that humic substances consist of cross-linked macromolecular structures forming a distinct class of compounds. However, it was recently concluded by members of my research group that the vast majority of humic material in soils,...

  8. A process economic assessment of hydrocarbon biofuels production using chemoautotrophic organisms

    Energy Technology Data Exchange (ETDEWEB)

    Khan, NE; Myers, JA; Tuerk, AL; Curtis, WR

    2014-11-01

    Economic analysis of an ARPA-e Electrofuels (http://arpa-e.energy.gov/?q=arpa-e-programs/electrofuels) process is presented, utilizing metabolically engineered Rhodobacter capsulatus or Ralstonia eutropha to produce the C30+ hydrocarbon fuel, botryococcene, from hydrogen, carbon dioxide, and oxygen. The analysis is based on an Aspen plus (R) bioreactor model taking into account experimentally determined Rba. capsulatus and Rls. eutropha growth and maintenance requirements, reactor residence time, correlations for gas-liquid mass-transfer coefficient, gas composition, and specific cellular fuel productivity. Based on reactor simulation results encompassing technically relevant parameter ranges, the capital and operating costs of the process were estimated for 5000 bbl-fuel/day plant and used to predict fuel cost. Under the assumptions used in this analysis and crude oil prices, the Levelized Cost of Electricity (LCOE) required for economic feasibility must be less than 2(sic)/kWh. While not feasible under current market prices and costs, this work identifies key variables impacting process cost and discusses potential alternative paths toward economic feasibility. (C) 2014 Elsevier Ltd. All rights reserved.

  9. Molecular Ecology of Free-Living Chemoautotrophic Microbial Communities at a Shallow-sea Hydrothermal Vent

    OpenAIRE

    Huang, Chia-I

    2012-01-01

    Deep-sea hydrothermal systems are unique habitats for microbial life with primary production based on chemosynthesis. They are considered to be windows to the subsurface biosphere. Their far more accessible shallow-sea counterparts are valuable targets to study the effects of hydrothermal activity on geology, seawater chemistry and microorganisms. Such an area of shallow-sea hydrothermal venting is observed approximately 2.5 km east off Panarea Island (Sicily, Italy). This system is character...

  10. Co-evolution of marine worms and their chemoautotrophic bacterial symbionts: unexpected host switches explained by ecological fitting?

    Science.gov (United States)

    Brune, A

    2016-07-01

    Mutualistic associations of bacteria and invertebrates are widespread and encompass an enormous diversity on the side of both partners. The advantages gained from the symbiosis favour reciprocal adaptations that increase the stability of the association and can lead to codiversification of symbiont and host. While numerous examples of a strictly vertical transfer of the symbionts from parent to offspring among intracellular associations abound, little is known about the fidelity of the partners in extracellular associations, where symbionts colonize the surface or body cavity of their host. In this issue of Molecular Ecology, Zimmermann et al. () investigated the evolutionary history of the symbiotic association between a monophyletic clade of sulphur-oxidizing Gammaproteobacteria and two distantly related lineages of marine worms (nematodes and annelids). The study supports the surprising conclusion that partner fidelity does not necessarily increase with the intimacy of the association. Ectosymbionts on the cuticle of the nematodes seem to be cospeciating with their hosts, whereas endosymbionts housed in the body cavity of the annelids must have originated multiple times, probably by host switching, from ectosymbionts of sympatric nematodes. This excellent case study on the evolutionary history of invertebrate-microbe interactions supports the emerging concept that the co-evolutionary processes shaping such mutualistic symbioses include both codiversification and ecological fitting. PMID:27373707

  11. Chemoautotrophic growth of ammonia-oxidizing Thaumarchaeota enriched from a pelagic redox gradient in the Baltic Sea

    Directory of Open Access Journals (Sweden)

    Carlo eBerg

    2015-01-01

    Full Text Available Ammonia-oxidizing archaea (AOA are an important component of the planktonic community in aquatic habitats, linking nitrogen and carbon cycles through nitrification and carbon fixation. Therefore, measurements of these processes in culture-based experiments can provide insights into their contributions to energy conservation and biomass production by specific AOA. In this study, by enriching AOA from a brackish, oxygen-depleted water-column in the Landsort Deep, central Baltic Sea, we were able to investigate ammonium oxidation, chemoautotrophy, and growth in seawater batch experiments. The highly enriched culture consisted of up to 97% archaea, with maximal archaeal numbers of 2.9 × 107 cells mL-1. Phylogenetic analysis of the 16S rRNA and ammonia monooxygenase subunit A (amoA gene sequences revealed an affiliation with assemblages from low-salinity and freshwater habitats, with Candidatus Nitrosoarchaeum limnia as the closest relative. Growth correlated significantly with nitrite production, ammonium consumption, and CO2 fixation, which occurred at a ratio of 10 atoms N oxidized per 1 atom C fixed. According to the carbon balance, AOA biomass production can be entirely explained by chemoautotrophy. The cellular carbon content was estimated to be 9 fg C per cell. Single-cell-based 13C and 15N labeling experiments and analysis by nano-scale secondary ion mass spectrometry provided further evidence that cellular carbon was derived from bicarbonate and that ammonium was taken up by the cells. Our study therefore revealed that growth by an AOA belonging to the genus Nitrosoarchaeum can be sustained largely by chemoautotrophy.

  12. Massive barite deposits and carbonate mineralization in the Derugin Basin, Sea of Okhotsk: precipitation processes at cold seep sites

    Science.gov (United States)

    Greinert, Jens; Bollwerk, Sandra M.; Derkachev, Alexander; Bohrmann, Gerhard; Suess, Erwin

    2002-10-01

    An area of massive barite precipitations was studied at a tectonic horst in 1500 m water depth in the Derugin Basin, Sea of Okhotsk. Seafloor observations and dredge samples showed irregular, block- to column-shaped barite build-ups up to 10 m high which were scattered over the seafloor along an observation track 3.5 km long. High methane concentrations in the water column show that methane expulsion and probably carbonate precipitation is a recently active process. Small fields of chemoautotrophic clams ( Calyptogena sp., Acharax sp.) at the seafloor provide additional evidence for active fluid venting. The white to yellow barites show a very porous and often layered internal fabric, and are typically covered by dark-brown Mn-rich sediment; electron microprobe spectroscopy measurements of barite sub-samples show a Ba substitution of up to 10.5 mol% of Sr. Rare idiomorphic pyrite crystals (˜1%) in the barite fabric imply the presence of H 2S. This was confirmed by clusters of living chemoautotrophic tube worms (1 mm in diameter) found in pores and channels within the barite. Microscopic examination showed that micritic aragonite and Mg-calcite aggregates or crusts are common authigenic precipitations within the barite fabric. Equivalent micritic carbonates and barite carbonate cemented worm tubes were recovered from sediment cores taken in the vicinity of the barite build-up area. Negative δ 13C values of these carbonates (>-43.5‰ PDB) indicate methane as major carbon source; δ 18O values between 4.04 and 5.88‰ PDB correspond to formation temperatures, which are certainly below 5°C. One core also contained shells of Calyptogena sp. at different core depths with 14C-ages ranging from 20 680 to >49 080 yr. Pore water analyses revealed that fluids also contain high amounts of Ba; they also show decreasing SO 42- concentrations and a parallel increase of H 2S with depth. Additionally, S and O isotope data of barite sulfate (δ 34S: 21.0-38.6‰ CDT; δ 18O

  13. Bioaugmentation of nitrate-dependent anaerobic ferrous oxidation by heterotrophic denitrifying sludge addition: A promising way for promotion of chemoautotrophic denitrification.

    Science.gov (United States)

    Wang, Ru; Zheng, Ping; Zhang, Meng; Zhao, He-Ping; Ji, Jun-Yuan; Zhou, Xiao-Xin; Li, Wei

    2015-12-01

    Nitrate-dependent anaerobic ferrous oxidation (NAFO) is a new and valuable bio-process for the treatment of wastewaters with low C/N ratio, and the NAFO process is in state of the art. The heterotrophic denitrifying sludge (HDS), possessing NAFO activity, was used as bioaugmentation to enhance NAFO efficiency. At a dosage of 6% (V/V), the removal of nitrate and ferrous was 2.4 times and 2.3 times of as primary, and the volumetric removal rate (VRR) of nitrate and ferrous was 2.4 times and 2.2 times of as primary. Tracing experiments of HDS indicated that the bioaugmentation on NAFO reactor was resulted from the NAFO activity by HDS itself. The predominant bacteria in HDS were identified as Thauera (52.5%) and Hyphomicrobium (20.0%) which were typical denitrifying bacteria and had potential ability to oxidize ferrous. In conclusion, HDS could serve as bioaugmentation or a new seeding sludge for operating high-efficiency NAFO reactors. PMID:26348287

  14. Abundance and distribution of archaeal acetyl-CoA/propionyl-CoA carboxylase genes indicative for putatively chemoautotrophic Archaea in the tropical Atlantic's interior

    OpenAIRE

    Bergauer, Kristin; Sintes, Eva; van Bleijswijk, Judith; Witte, Harry; Herndl, Gerhard J.; Lueders, Tillmann

    2013-01-01

    Recently, evidence suggests that dark CO2 fixation in the pelagic realm of the ocean does not only occur in the suboxic and anoxic water bodies but also in the oxygenated meso- and bathypelagic waters of the North Atlantic. To elucidate the significance and phylogeny of the key organisms mediating dark CO2 fixation in the tropical Atlantic, we quantified functional genes indicative for CO2 fixation. We used a Q-PCR-based assay targeting the bifunctional acetyl-CoA/propionyl-CoA carboxylase (a...

  15. Abundance and distribution of archaeal acetyl-CoA/propionyl-CoA carboxylase genes indicative for putatively chemoautotrophic Archaea in the tropical Atlantic's interior

    NARCIS (Netherlands)

    Bergauer, K.; Sintes, E.; van Bleijswijk, J.; Witte, H.; Herndl, G.J.

    2013-01-01

    Recently, evidence suggests that dark CO2 fixation in the pelagic realm of the ocean does not only occur in the suboxic and anoxic water bodies but also in the oxygenated meso- and bathypelagic waters of the North Atlantic. To elucidate the significance and phylogeny of the key organisms mediating d

  16. Community Genomic and Proteomic Analyses of Chemoautotrophic Iron-Oxidizing "Leptospirillum rubarum" (Group II) and "Leptospirillum ferrodiazotrophum" (Group III) Bacteria in Acid Mine Drainage Biofilms

    Energy Technology Data Exchange (ETDEWEB)

    Goltsman, Daniela [University of California, Berkeley; Denef, Vincent [University of California, Berkeley; Singer, Steven [Lawrence Livermore National Laboratory (LLNL); Verberkmoes, Nathan C [ORNL; Lefsrud, Mark G [ORNL; Mueller, Ryan [University of California, Berkeley; Dick, Gregory J. [University of California, Berkeley; Sun, Christine [University of California, Berkeley; Wheeler, Korin [Lawrence Livermore National Laboratory (LLNL); Zelma, Adam [Lawrence Livermore National Laboratory (LLNL); Baker, Brett J. [University of California, Berkeley; Hauser, Loren John [ORNL; Land, Miriam L [ORNL; Shah, Manesh B [ORNL; Thelen, Michael P. [University of California, Berkeley; Hettich, Robert {Bob} L [ORNL; Banfield, Jillian F. [University of California, Berkeley

    2009-01-01

    We analyzed near-complete population (composite) genomic sequences for coexisting acidophilic iron-oxidizing Leptospirillum group II and III bacteria (phylum Nitrospirae) and an extrachromosomal plasmid from a Richmond Mine, Iron Mountain, CA, acid mine drainage biofilm. Community proteomic analysis of the genomically characterized sample and two other biofilms identified 64.6% and 44.9% of the predicted proteins of Leptospirillum groups II and III, respectively, and 20% of the predicted plasmid proteins. The bacteria share 92% 16S rRNA gene sequence identity and >60% of their genes, including integrated plasmid-like regions. The extrachromosomal plasmid carries conjugation genes with detectable sequence similarity to genes in the integrated conjugative plasmid, but only those on the extrachromosomal element were identified by proteomics. Both bacterial groups have genes for community-essential functions, including carbon fixation and biosynthesis of vitamins, fatty acids, and biopolymers (including cellulose); proteomic analyses reveal these activities. Both Leptospirillum types have multiple pathways for osmotic protection. Although both are motile, signal transduction and methyl-accepting chemotaxis proteins are more abundant in Leptospirillum group III, consistent with its distribution in gradients within biofilms. Interestingly, Leptospirillum group II uses a methyl-dependent and Leptospirillum group III a methyl-independent response pathway. Although only Leptospirillum group III can fix nitrogen, these proteins were not identified by proteomics. The abundances of core proteins are similar in all communities, but the abundance levels of unique and shared proteins of unknown function vary. Some proteins unique to one organism were highly expressed and may be key to the functional and ecological differentiation of Leptospirillum groups II and III.

  17. Community genomic and proteomic analysis of chemoautotrophic, iron-oxidizing "Leptospirillum rubarum" (Group II) and Leptospirillum ferrodiazotrophum (Group III) in acid mine drainage biofilms

    Energy Technology Data Exchange (ETDEWEB)

    Goltsman, Daniela [University of California, Berkeley; Denef, Vincent [University of California, Berkeley; Singer, Steven [Lawrence Livermore National Laboratory (LLNL); Verberkmoes, Nathan C [ORNL; Lefsrud, Mark G [McGill University, Montreal, Quebec; Mueller, Ryan [University of California, Berkeley; Dick, Gregory J. [University of California, Berkeley; Sun, Christine [University of California, Berkeley; Wheeler, Korin [Lawrence Livermore National Laboratory (LLNL); Zelma, Adam [Lawrence Livermore National Laboratory (LLNL); Baker, Brett J. [University of California, Berkeley; Hauser, Loren John [ORNL; Land, Miriam L [ORNL; Shah, Manesh B [ORNL; Thelen, Michael P. [University of California, Berkeley; Hettich, Robert {Bob} L [ORNL; Banfield, Jillian F. [University of California, Berkeley

    2009-01-01

    We analyzed near-complete population (composite) genomic sequences for coexisting acidophilic iron-oxidizing Leptospirillum Groups II and III bacteria (phylum Nitrospirae) and an extrachromosomal plasmid from a Richmond Mine, CA acid mine drainage (AMD) biofilm. Community proteomic analysis of the genomically characterized sample and two other biofilms identified 64.6% and 44.9% of the predicted proteins of Leptospirillum Groups II and III, respectively and 20% of the predicted plasmid proteins. The bacteria share 92% 16S rRNA gene sequence identity and > 60% of their genes, including integrated plasmid-like regions. The extrachromosomal plasmid encodes conjugation genes with detectable sequence similarity to genes in the integrated conjugative plasmid, but only those on the extrachromosomal element were identified by proteomics. Both bacteria have genes for community-essential functions, including carbon fixation, biosynthesis of vitamins, fatty acids and biopolymers (including cellulose); proteomic analyses reveal these activities. Both Leptospirillum types have multiple pathways for osmotic protection. Although both are motile, signal transduction and methyl-accepting chemotaxis proteins are more abundant in Leptospirillum Group III, consistent with its distribution in gradients within biofilms. Interestingly, Leptospirillum Group II uses a methyl-dependent and Leptospirillum Group III a methyl-independent response pathway. Although only Leptospirillum Group III can fix nitrogen, these proteins were not identified by proteomics. Abundances of core proteins are similar in all communities, but abundance levels of unique and shared proteins of unknown function vary. Some proteins unique to one organism were highly expressed and may be key to the functional and ecological differentiation of Leptospirillum Groups II and III.

  18. Evidence of paleo-cold seep activity from the Bay of Bengal, offshore India

    Digital Repository Service at National Institute of Oceanography (India)

    Mazumdar, A.; Dewangan, P.; Joao, H.M.; Peketi, A.; Khosla, V.R.; Kocherla, M.; Badesab, F.K.; Joshi, R.K.; Roxanne, P.; Ramamurty, P.B.; Karisiddaiah, S.M.; Patil, D.J.; Dayal, A.M.; Ramprasad, T.; Hawkesworth, C.J.; Avanzinelli, R.

    Evidence of paleo–cold seep associated activities, preserved in methane-derived carbonates in association with chemosynthetic clams (Calyptogena sp.) from a sediment core in the Krishna-Godavari basin, Bay of Bengal is reported. Visual observations...

  19. La wolhphartiosis en ganado ovino de la provincia de Albacete : aspectos epidemiológicos y sanitarios

    OpenAIRE

    Otero Primo, José Luis

    2016-01-01

    Con el presente trabajo hemos pretendido buscar los siguientes objetivos: La presencia de Wohlfahria magnifica in la provincia de Albacete, en relación con el padecimiento de las ovejas con W. magnifica en función de su aptitud productiva, tamaño del rebaño, nivel estructural e higiénico-sanitario y el manejo de los operarios. • Pare ello hemos utilizado la siguiente metodología. Se realizaron visitas-encuestas a 122 explotaciones. Se recogieron datos e información y ejemplares de larvas y mo...

  20. La wohlfahrtiosis en ganado ovino de la provincia de Albacete : aspectos epidemiológicos y sanitarios

    OpenAIRE

    Otero Primo, José Luis

    2016-01-01

    • Con el presente trabajo hemos pretendido buscar los siguientes objetivos: La presencia de Wohlfahria magnifica in la provincia de Albacete, en relación con el padecimiento de las ovejas con W. magnifica en función de su aptitud productiva, tamaño del rebaño, nivel estructural e higiénico-sanitario y el manejo de los operarios. • Pare ello hemos utilizado la siguiente metodología. Se realizaron visitas-encuestas a 122 explotaciones. Se recogieron datos e información y ejemplares ...

  1. Immobilized reactor for rapid destruction of recalcitrant organics and inorganics in tannery wastewater

    Institute of Scientific and Technical Information of China (English)

    A. Ganesh Kumar; G. Sekaran; S. Swarnalatha; B. Prasad Rao

    2005-01-01

    The wastewater discharged from tanneries lack biodegradability due to the presence of recalcitrant compounds at significant concentration. The focal theme of the present investigation was to use chemo-autotrophic activated carbon oxidation(CAACO) reactor, an immobilized cell reactor using chemoautotrophs for the treatment of tannery wastewater. The treatment scheme comprised of anaerobic treatment, sand filtration, and CAACO reactor, which remove COD, BOD, TOC, VFA and sulphides respectively by 86%, 95%, 81%,71% and 100%. Rice bran mesoporous activated carbon prepared indigenously and was used for immobilization of chemoautotrophs. The degradation of xenobiotic compounds by CAACO was confirmed through HPLC and FT-IR techniques.

  2. Leaching of Copper Ore by Thiobacillus Ferrooxidans.

    Science.gov (United States)

    Lennox, John; Biaha, Thomas

    1991-01-01

    A quantitative laboratory exercise based upon the procedures copper manufacturers employ to increase copper production is described. The role of chemoautotrophic microorganisms in biogeologic process is emphasized. Safety considerations when working with bacteria are included. (KR)

  3. AcEST: BP912128 [AcEST

    Lifescience Database Archive (English)

    Full Text Available 1|LELP1_HUMAN Late cornified envelope-like proline-rich ... 30 5.0 sp|A1AVC7|SAT_RUTM...KCLPCPSQSPSSCPPQPCTKPCPPKCPSS 85 >sp|A1AVC7|SAT_RUTMC Sulfate adenylyltransferase OS=Ruthia magnifica subsp.

  4. AcEST: BP917139 [AcEST

    Lifescience Database Archive (English)

    Full Text Available tein S2 OS=Pseudomonas syri... 30 3.7 sp|A1AXW9|RS2_RUTMC 30S ribosomal protein S2 OS=Ruthia magnifica... 30...G +I +++H+ Sbjct: 10 LKAGCHFGHQTR------YWNPKMGKYIFGARNKIHI 40 >sp|A1AXW9|RS2_RUTMC 30S ribosomal protein S2

  5. AcEST: DK947825 [AcEST

    Lifescience Database Archive (English)

    Full Text Available A_DROME Trithorax group protein osa OS=Drosophila me... 31 4.7 sp|A1AVR9|NUOH_RUTMC NADH-quinone oxidoreduct...PAAGAPYPPGGS 1347 >sp|A1AVR9|NUOH_RUTMC NADH-quinone oxidoreductase subunit H OS=Ruthia magnifica subsp. Cal

  6. Les pigments respiratoires de la faune inféodée à l'hydrothermalisme océanique profond

    OpenAIRE

    Toulmond, A.; Frescheville, J; Frisch, M-h; Jouin, C.

    1988-01-01

    Examples of the two main classes of circulating respiratory pigments (heme pigments and hemocyanins) have been found in four typical members of the deep-sea hydrothermal vent communities. The studies now in progress concern the hemoglobin of Calyptogena ; the erythrocruorins of Alvinella and Riftia ; and the hemocyanin of Bythograea . This paper summarizes the available data of the molecular structure of these pigments and the functional properties allowing some of them to fix and transport o...

  7. First report of three redlisted tree species from swampy relics of Goa State, India

    OpenAIRE

    A. Prabhugaonkar; D.K. Mesta; M. K. Janarthanam

    2014-01-01

    Myristica swamps, one of the relic ecosystems of Western Ghats, are considered home for many rare and endemic angiosperms. During an inventory of Myristica swamps in Goa State, two critically endangered species and one endangered species, viz. Semecarpus kathalekanensis Dasappa and M.H.Swaminath, Syzygium travancoricum Gamble and Myristica fatua Houtt. var. magnifica (Bedd.) J. Sinclair respectively were recorded. Present report forms first record of these three tree species from the Goa Stat...

  8. Notes on the genus Amphiprion Bloch & Schneider, 1801 (Teleostei: Pomacentridae) and its host sea anemones in the Seychelles

    OpenAIRE

    Hartog, den, J.M.P.

    1997-01-01

    The genus Amphiprion Bloch & Schneider, 1801, is represented in the Seychelles by two species, A. akallopisos Bleeker, 1853, and the endemic A. fuscocaudatus Allen, 1972. Throughout its distributional range Amphiprion akallopisos has exclusively been recorded to associate with the clownfish anemones Heteractis magnifica (Quoy & Gaimard, 1833) and Stichodactyla mertensii Brandt, 1835. During the Netherlands Indian Ocean Programme (NIOP) Seychelles Expedition 19921993 this was confirmed for the...

  9. Cloning and characterization analysis of the genes encoding precursor of mast cell degranulating peptide from 2 honeybee and 3 wasp species.

    Science.gov (United States)

    Zhang, Su-Fang; Shi, Wan-Jun; Cheng, Jia-An; Zhang, Chuan-Xi

    2003-09-01

    The precursors of mast cell degranulating peptide (MCDP) genes were amplified by RT-PCR from the total RNA of venom gland of two honeybee species, Apis mellifera ligustica, Apis cerana cerana, and three wasp species, Vespa magnifica, Vespa velutina nigrothorax and Polistes hebraeus, respectively. Their PCR products were ligated into pGEM T-easy vector and the nucleotide sequences were analyzed. The length of five fragments was the same, it was 341 bp containing an ORF of 153 bp coding the precursor of MCDP and 188 bp 3' noncoding region. They have more than 90% homologues with each other in nucleotide sequences. The precursors of MCDP of A. cerana cerana, V. magnifica, V. velutina nigrothorax and P. hebraeus shared 96%, 100%, 94% and 98% homology with A. mellifera ligustica, respectively. The two species of wasps, V. magnifica and V. velutina nigrothorax, contained the same MCDP as A. mellifera ligustica, though they belong to different families with quite different biological properties, while A. cerana cerana contained the different MCDP in their venom as A. mellifera ligustica though they belong to the same genus. The fifth amino acid residue of MCDP in A. cerana cerana and P. hebraeus is arginine, replacing the cysteine, an important disulfide bridges element, in the position as in A. mellifera ligustica. PMID:14577379

  10. Future Mars geophysical observatories for understanding its internal structure, rotation, and evolution

    DEFF Research Database (Denmark)

    Dehant, Veronique; Banerdt, Bruce; Lognonné, Philippe;

    2012-01-01

    of Mars, these measurements will provide important constraints for the astrobiology of Mars by helping to understand why Mars failed to sustain a magnetic field, by helping to understand the planet’s climate evolution, and by providing a limit for the energy available to the chemoautotrophic biosphere...

  11. The use of stable and radiocarbon isotopes as a method for delineating sources of organic material in anchialine systems

    OpenAIRE

    Neisch, Julie A.; Pohlman, John W.; Iliffe, Thomas M.

    2012-01-01

    A duel isotope (stable and radiocarbon) investigation of anchialine cave systems in the Yucatan Peninsula compares the food web of a coastal and an inland cenote. Isotopic data demonstrates distinct photosynthetic and chemoautotrophic trophic levels, as well as the ability of fauna within the cave to be selective feeders even within these nutrient poor environments.

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

    NARCIS (Netherlands)

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

    1988-01-01

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

  13. Large Vesicomyidae (Mollusca: Bivalvia) from cold seeps in the Gulf of Guinea off the coasts of Gabon, Congo and northern Angola

    Science.gov (United States)

    von Cosel, Rudo; Olu, Karine

    2009-12-01

    Two new genera and three new species of large Vesicomyidae are described from cold-seep sites on pockmarks and other sulfide-rich environments in the Gulf of Guinea (tropical east Atlantic) off Gabon, Congo (Brazzaville) and northern Angola, from 500 to 4000 m depth: " Calyptogena" (s.l.) regab n. sp., Wareniconcha (n.g.) guineensis (Thiele and Jaeckel 1931), Elenaconcha guiness n.g. n. sp., and Isorropodon atalantae n. sp. For two other species already taken by the R/V Valdivia in 1898, Calyptogena valdiviae (Thiele and Jaeckel 1931) and Isorropodon striatum (Thiele and Jaeckel 1931) new localities were discovered, and the species are rediscussed. E. guiness n.g. n.sp. is also recorded from off Banc d'Arguin, Mauritania, collected by commercial fishing vessels. The vesicomyid species here treated were encountered in different depth ranges along the Gabon-Congo-Angola margin, between 500 and 4000 m depth, and it was found that, in comparison with the dredge samples taken by the Valdivia expedition off southern Cameroon and off Rio de Oro (both at 2500 m), the same species occur in other depth ranges, in some cases with a vertical difference of more than 1000 m. .That means that the species are not confined to a given depth thought being typical for them and that the characteristics of the biotope are likely to play a major role in the distribution of the vesicomyids associated to cold seeps or other reduced environments along the West African margin.

  14. Two possible hydrothermal vents in the northern Oki-nawa Trough

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    As the Okinawa Trough is a back-arc basin in early spreading, modern submarine hydrothermal activity and minerallization have many characteristics which have aroused wide attention. Up to now, three well-known hy-drothermal venting areas are all located in the middle part of the trough. During two cruise investigations to map and sample the seafloor, numbers of Calyptogena sp. shells were dredged at two sites in the northern trough with compara-tively thicker crust and numerous submarine volcanoes. Based on the fact that Calyptogena sp. is only observed around the hydrothermal vents and lives on hydrothermal activities, it is predicted that there is the possibility of mod-ern hydrothermal activities in the northern part of the trough. In this note, the shell is carefully characterized and the sample locations with possible hydrothermal activity are given. It is pointed out that the research of biogenic fossils to trace hydrothermal activity changes in venting time, strength fluctuations, evolution in chemical compositions and so on should be stressed in the future in addition to the study of the ecological characteristics of hydrothermal organisms.

  15. Pharmacological and biomedical properties of sea anemones Paracondactylis indicus, Paracondactylis sinensis, Heteractis magnificaand Stichodactyla haddonifrom East coast of India

    Institute of Scientific and Technical Information of China (English)

    Bragadeeswaran Subramanian; Thangaraj Sangappellai; Rajiv Chandra Rajak; Balaji Diraviam

    2011-01-01

    Objective:To explore the biomedical and pharmacological activity ofParacondactylis indicus (P. indicus),Paracondactylis sinensis(P. sinensis),Heteractis magnifica (H. magnifica) and Stichodactyla haddoni (S. haddoni).Methods: The live sea anemones were kept inside the glass bowl along with some amount of distilled water in an ice container for15 min. During stress condition, nematocysts released from the tentacles were collected and centrifuged at5 000 rpm for 15 min. The supernatant were collected in separate cleaned beakers for lyophilisation.Results:The protein content of crude extracts was15.2, 28.7, 18.2 and35.4μg/mL. In hemolytic assay, the P. indicus was sensitive (16.842 HT/mg) on chicken blood butP. sinensis was less sensitive (1.114 HT/mg) on chicken and goat blood. WhereasH. magnificaandS. haddoni showed hemolysis (0.879, 0.903 HT/mg and 56.263, 0.451 HT/mg) in chicken and goat blood. In antimicrobial assay, the methanol extract ofP. indicus showed maximum inhibition zone of9.7mm againstS. typhii andP. sinensisshowed9.8 mm againstK. pneumonia in methanol and ethanol extracts. Whereas theH. magnifica andS. haddoni showed maximum of10 mm againstS. typhii, K. pneumonia in methanol and ethanol extracts.Conclusions: The high toxic sea anemones may also contain some biologically active agents which has haemolytic, analgesic and anti-infilamatory activity.

  16. First report of three redlisted tree species from swampy relics of Goa State, India

    Directory of Open Access Journals (Sweden)

    A. Prabhugaonkar

    2014-02-01

    Full Text Available Myristica swamps, one of the relic ecosystems of Western Ghats, are considered home for many rare and endemic angiosperms. During an inventory of Myristica swamps in Goa State, two critically endangered species and one endangered species, viz. Semecarpus kathalekanensis Dasappa and M.H.Swaminath, Syzygium travancoricum Gamble and Myristica fatua Houtt. var. magnifica (Bedd. J. Sinclair respectively were recorded. Present report forms first record of these three tree species from the Goa State. This report extends their distribution into Northern Western Ghats from central Western Ghats.

  17. Notas metodológicas: De la econometría clásica al análisis no lineal

    OpenAIRE

    Luis Mata Mollejas; Roger Da Costa S.

    2004-01-01

    La complejidad económica, manifestada en los tres conceptos que definen el valor del dinero: capacidad adquisitiva, tasa de interés y tipo de cambio, se magnifica al involucrarse con la com-plejidad política al momento de la previsión. Por ello la Ciencia Económica en su pretensión de proporcionar leyes explicativas para la previsión con un margen aceptable de incertidumbre, vie-ne incorporando métodos de ajustes no lineales y delimitando los aportes de la econometría co-mo herramienta de uso...

  18. Particularités pathologiques des ruminants domestiques en estive dans les montagnes françaises

    OpenAIRE

    Alzieu, J.P.; Brugère-Picoux, J.; Brard, C.

    2014-01-01

    Mis à part certaines pathologies spécifiques telle la myiase à Wohlfartia magnifica, la plupart des maladies infectieuses et parasitaires d’importance sont véhiculées sur l’estive avec leurs hôtes, bovins et ovins. La problématique des cheptels collectifs constitués de troupeaux de statuts sanitaires différents et les fortes variations climatiques et thermiques favorisent l’expression des maladies infectieuses. La montée en estive d’animaux infectés constitue le facteur majeur de risque, indu...

  19. Dicty_cDB: Contig-U11768-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available kveiiqvv*ifaniiinqfiimnlki*lkitispiinlih*iylhfqiiy*ivihqfqqq ihhlyqilehmqlqekkvlsnadslpndeniqemaykeliemgdydtivkrfgkfsi...yv*mylkv*y*rilyhhhhli kveiiqvv*ifaniiinqfiimnlki*lkitispiinlih*iylhfqiiy*ivihqfqqq ihhlyqilehmqlqekkvlsnadslpndeniqemaykeliem...idjiensis Bem, com... 160 2e-37 CP000507_949( CP000507 |pid:none) Shewanella ama... |pid:none) Candidatus Ruthia magnifica str.... 147 2e-33 AJ749949_1310( AJ749949 |pid:none) Francisella tularensi...ase: 6905 Lambda K H 1.37 0.711 1.31 Gapped Lambda K H 1.37 0.711 1.31 Matrix: blastn matrix:1 -3 Gap Penaltie

  20. Evaluación de los errores de medicación notificados antes y después de la implantación de un sistema informatizado de prescripción/validación/preparación/administración en oncohematología. Impacto sobre la calidad del proceso asistencial y seguridad de los pacientes

    OpenAIRE

    Creus Baró, Natàlia

    2014-01-01

    1) INTRODUCCiÓN: Los errores de medicación y sus consecuencias negativas, los acontecimientos adversos por medicamentos, constituyen un problema de salud pública debido a su gran impacto tanto clínico como económico. Dicho impacto se magnifica con los errores de medicación en quimioterapia ya que son fármacos con un margen terapéutico muy estrecho y un error de dosis puede conllevar toxicidad grave (incluso muerte del paciente) o falta de respuesta terapéutica. Existen muchas recomendacio...

  1. Notes on the pollination ecology of the palm genus Johannesteijsmannia (Arecaceae

    Directory of Open Access Journals (Sweden)

    Yoke Mui Chan

    2012-01-01

    Full Text Available The floral biology and flower visitors of the tropical palms Johannesteijsmannia altifrons, J. magnifica and J. perakensis were investigated. We combined the data from this study with published data of J. lanceolata to give an overview of the reproductive biology and pollination system of the genus. Anthesis peaks from 0500–1100 hrs when the inflorescences are visited mainly by flies, beetles and stingless bees (Trigona, the last are potential pollinators. The breeding system is facultative selfing, indicating the ability of the species to reproduce in the absence of pollinators or in isolation.

  2. Indigènes

    Directory of Open Access Journals (Sweden)

    María Eugenia Albornoz Vásquez

    2007-06-01

    Full Text Available El insomnio visito implacable mi noche después de ver esta magnifica y valiente película. El ahogo de los sueños y la manipulación de la esperanza a través del riesgo de la vida y el desangramiento de las mejores cualidades que se poseen es una de las realidades que, sin un ápice de religiosidad fanática, debieran catalogarse de pecado capital y de crimen contra la humanidad. Debiera haber un tribunal que identifique y juzgue la manipulación y la usura que se ha hecho, se hace y seguramente ...

  3. A new species of Litarachna (Acari, Hydrachnidia, Pontarachnidae from a Caribbean mesophotic coral ecosystem

    Directory of Open Access Journals (Sweden)

    Vladimir Pesic

    2014-07-01

    Full Text Available New records of pontarachnid mites (Acari: Hydrachnidia from the Caribbean island of Puerto Rico are presented. Litarachna lopezae sp. n., from substrata collected from Bajo de Sico, a mesophotic coral reef ecosystem in Mona Passage off Puerto Rico, is described as new to science. The new species was collected from nearly 70 m depth, the greatest depth from which pontarachnid mites have been found until now. In addition, a Litarachna sp. was also found in association with the tube of the polychaete Sabellastarte magnifica (Shaw, 1800 at the shallow waters of north Puerto Rico.

  4. Notas, novos registros e novas espécies da coleção de Cerambycidae (Coleoptera do Instituto Nacional de Pesquisas da Amazônia, Manaus

    Directory of Open Access Journals (Sweden)

    Maria Helena M. Galileo

    2011-09-01

    Full Text Available Espécies novas descritas da Amazônia brasileira em Ibidionini: Compsibidion uniforme sp. nov. (Amazonas; Heterachthes rafaeli sp. nov. (Amazonas; em Apomecynini: Amphicnaeia lineolata sp. nov. (Pará; em Desmiphorini: Cotycicuiara magnifica sp. nov. (Amazonas. Novos registros e notas são apresentados para: Gnomidolon insulicola Bates, 1885 e G. lansbergei (Thomson, 1867 (Hexoplonini; Desmiphora (D. uniformis Galileo & Martins, 2003 (Desmiphorini; Omosarotes paradoxum (Tippmann, 1955 (Cyrtinini e Ozotroctes ogeri Tavakilian & Néouze, 2007 (Acanthoderini.

  5. Juvenile Thalassoma amblycephalum Bleeker (Labridae, Teleostei) dwelling among the tentacles of sea anemones

    DEFF Research Database (Denmark)

    Arvedlund, Michael; Iwao, Kenji; Brolund, Thea Marie;

    2006-01-01

    each) of the juvenile wrasse Thalassoma amblycephalum dwelling among the tentacles of the two sea anemones Entacmaea quadricolor (clonal type), and Heteractis magnifica at a coral reef in southern Japan during 16 months in daylight hours. There are only two past records of this facultative association......, one from east Africa and one from Indonesia. The wrasse remained close to and was occasionally in physical contact with the host when foraging amongst the tentacles. When frightened, they took shelter among corals, away from the host anemone. The wrasse co-existed with the anemonefishes Amphiprion...

  6. Dicty_cDB: Contig-U04585-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available E Sequences producing significant alignments: (bits) Value N ( AU037752 ) Dictyostelium discoideum slug cDN...i OSU 85-389, complete genome. 44 5.7 1 ( CP000488 ) Candidatus Ruthia magnifica str. Cm (Cal...IP 10547... 41 0.026 FM178379_2533( FM178379 |pid:none) Aliivibrio salmonicida LFI1238 ... 40 0.044 (Q4KGR0)....Seq.d (567 letters) Database: CSM 6905 sequences; 5,674,871 total letters Score E Sequences producing significant ali...87 ) Caenorhabditis elegans clone Y59H11, *** SEQUENCI... 42 2.0 5 ( EU275726 ) Polysphondylium pallidum str

  7. Notas e novas espécies de Onciderini (Coleoptera, Cerambycidae, Lamiinae

    Directory of Open Access Journals (Sweden)

    Ubirajara R. Martins

    2007-01-01

    Full Text Available Novas espécies descritas do Brasil: Hypsioma carioca sp. nov. (Rio de Janeiro e Hesychotypa maraba sp. nov. (Pará; do Equador: Sternycha ecuatoriana sp. nov. (Pichincha; da Bolívia (Santa Cruz: Hesychotypa magnifica sp. nov., Tibiosioma maculosa sp. nov. e Alexera secunda sp. nov. Transfere-se Hesycha strandi (Breuning, 1943 para o gênero Cacostola Fairmaire & Germain, 1859. Hesychotypa archippa Dillon & Dillon, 1946 é considerada sinônima de H. miniata Thomson, 1868. Novo registro (Trinidad e figura são dados para Trachysomus surdus.Notes and new species of Onciderini (Coleoptera, Cerambycidae, Lamiinae. New species described from Brazil: Hypsioma carioca sp. nov. (Rio de Janeiro and Hesychotypa maraba sp. nov. (Pará; from Ecuador: Sternycha ecuatoriana sp. nov. (Pichincha; from Bolivia (Santa Cruz: Hesychotypa magnifica sp. nov., Tibiosioma maculosa sp. nov. and Alexera secunda sp. nov. Hesycha strandi (Breuning, 1943 is transferred to the genus Cacostola Fairmaire & Germain, 1859. Hesychotypa archippa Dillon & Dillon, 1946 is considered a synonym of H. miniata Thomson, 1868. New record (Trinidad and figure for Trachysomus surdus Dillon & Dillon, 1946 are given.

  8. Extracellular and Mixotrophic Symbiosis in the Whale-Fall Mussel Adipicola pacifica: A Trend in Evolution from Extra- to Intracellular Symbiosis

    OpenAIRE

    Fujiwara, Yoshihiro; Kawato, Masaru; Noda, Chikayo; Kinoshita, Gin; Yamanaka, Toshiro; Fujita, Yuko; Uematsu, Katsuyuki; Miyazaki, Jun-ichi

    2010-01-01

    Background Deep-sea mussels harboring chemoautotrophic symbionts from hydrothermal vents and seeps are assumed to have evolved from shallow-water asymbiotic relatives by way of biogenic reducing environments such as sunken wood and whale falls. Such symbiotic associations have been well characterized in mussels collected from vents, seeps and sunken wood but in only a few from whale falls. Methodology/Principal Finding Here we report symbioses in the gill tissues of two mussels, Adipicola cry...

  9. The presence of putative sulphur-oxidizing bacteria colonizing the periostracal secretion in the endosymbiont-bearing bivalve Loripes lucinalis

    OpenAIRE

    Jonhson, M.A.; Fernandez, C

    2001-01-01

    Loripes lucinalis. a small bivalve belonging to the Lucinacea superfamily living in reducing coastal sediments, possesses chemoautotrophic sulphur-oxidizing bacteria in its gill. Here, a population of putative sulphur-oxidizing bacteria is described colonizing the bivalve's inner periostracal secretion. The bacteria, were particularly abundant in the vicinity of the anterior and posterior inhalant syphons. Most of the bacteria observed were oval to rod-shaped and measured 3.9 +/- 1.2 mum on a...

  10. Energy Transfer Through Food Webs at Hydrothermal Vents: Linking the Lithosphere to the Biosphere

    OpenAIRE

    Breea Govenar

    2012-01-01

    Tectonic and volcanic processes that drive hydrothermal fluid flow and influence its chemistry also regulate the transfer of energy to hydrothermal vent ecosystems. Chemoautotrophic bacteria use the chemical energy generated by mixing the reduced chemicals in hydrothermal fluids with deep-ocean ambient seawater to fix inorganic carbon and produce biomass. These and other microbes, or their products, are then consumed by other organisms, which are subsequently consumed by other organisms. The ...

  11. A Rubisco mutant that confers growth under a normally “inhibitory” oxygen concentration†

    OpenAIRE

    Satagopan, Sriram; Scott, Stephanie S.; Smith, Todd G.; Tabita, F. Robert

    2009-01-01

    Ribulose 1, 5-bisphosphate (RuBP) carboxylase/oxygenase (Rubisco) is a globally significant biocatalyst that facilitates the removal and sequestration of CO2 from the biosphere. Rubisco-catalyzed CO2 reduction thus provides virtually all the organic carbon utilized by living organisms. Despite catalyzing the rate-limiting step of photosynthetic and chemoautotrophic CO2 assimilation, Rubisco is markedly inefficient as the competition between O2 and CO2 for the same substrate limits the ability...

  12. Biogeochemistry of a deep-sea whale fall: sulfate reduction, sulfide efflux and methanogenesis

    OpenAIRE

    Treude, Tina; Smith, C. R.; Wenzhöfer, F.; Carney, E; Bernardino, A. F.; A. K. Hannides; Krüger, M.; A. Boetius

    2009-01-01

    Deep-sea whale falls create sulfidic habits Supporting chemoautotrophic communities, but microbial processes underlying the formation Of Such habitats remain poorly evaluated. Microbial degradation processes (sulfate reduction, methanogenesis) and biogeochemical gradients were studied in a whale-fall habitat created by a 30 t whale carcass deployed at 1675 m depth for 6 to 7 yr on the California margin. A variety of measurements were conducted including photomosaicking, microsensor measuremen...

  13. Seasonal Variation in Rates of Nitrification associated With Patterns of Carbon and Nitrogen Supply in a Southern Appalachian Headwater Stream

    OpenAIRE

    Starry, Olyssa Suzanne

    2004-01-01

    Abstract. Nitrification, the chemoautotrophic process via which ammonium-nitrogen (NH4-N) is converted to nitrate-nitrogen (NO3-N), is an important nitrogen (N) transformation in stream ecosystems. Experimental addition of dissolved organic carbon (DOC) has been shown to inhibit rates of nitrification, and rates have been stimulated by NH4-N addition. Insights regarding the role of particulate organic matter (POM) in this scenario could further enhance our understanding of linkages between...

  14. Tracking the Fate of Microbially Sequestered Carbon Dioxide in Soil Organic Matter

    OpenAIRE

    Hart, Kris; Kulakova, Anna; Allen, Christopher; J. SIMPSON, André; OPPENHEIMER, Seth; Masoom, Hussain; COURTIER-MURIAS, Denis; Soong, Ronald; Kulakov, Leonid; Flanagan, Paul; Murphy, Brian; Kelleher, Brian P.

    2013-01-01

    The microbial contribution to soil organic matter (SOM) has recently been shown to be much larger than previously thought and thus its role in carbon sequestration may also be underestimated. In this study we employ 13C (13CO2) to assess the potential CO2 sequestration capacity of soil chemoautotrophic bacteria and combine nuclear magnetic resonance (NMR) with stable isotope probing (SIP), techniques that independently make use of the isotopic enrichment of soil microbial biomass. In this way...

  15. mejor regulación

    Directory of Open Access Journals (Sweden)

    Julio García Cobos

    2005-01-01

    Full Text Available Las líneas aéreas europeas comienzan a padecer las distorsiones provocadas por la creciente competencia entre aeropuertos. En España estas distorsiones se ven acentuadas por la gestión en red, que magnifica la tradicional débil relación entre quién genera los costes aeroportuarios y quién los paga. En este contexto, proponemos un modelo de gestión más descentralizado para los aeropuertos españoles que (i acerque las tarifas de cada aeropuerto a sus propios costes y (ii facilite el desarrollo de estrategias competitivas diferenciadas entre aeropuertos.

  16. A importância do treinamento da criança com baixa visão, com emprego dos auxílios ópticos, para capacitação educacional: relato de caso The value of optical aids' training for low vision child education: case report

    OpenAIRE

    Eduardo Toshio Sato; Celina Tamaki-Castro; Danilo Dimas Monteiro de Castro

    2010-01-01

    O aprendizado do correto manuseio do auxílio óptico foi treinado: localização, focalização e seguimento com o telescópio de 8x de magnificação. Após essa etapa iniciou-se o aprendizado de cópia da lousa com o auxílio adaptado. Totalizaram-se 17 sessões para a criança receber a prescrição final devido às grandes dificuldades apresentadas pela baixa acentuada das funções visuais.Training of the proper handling of optical devices was performed: location, targeting and tracking with the 8x magnif...

  17. Dicty_cDB: Contig-U14953-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available 7 BA000031_483( BA000031 |pid:none) Vibrio parahaemolyticus RIMD 221... 61 1e-07 AP007255_522( AP007255 |pid:none) Mag...53 |pid:none) Alkaliphilus oremlandii OhILAs, c... 59 6e-07 CP000488_783( CP000488 |pid:none) Candidatus Ruthia mag... 0.711 1.31 Matrix: blastn matrix:1 -3 Gap Penalties: Existence: 5, Extension: 2 Number of Hits to DB: 40,21...019h19, 5'end,... 52 0.065 1 ( BW347955 ) Ciona intestinalis cDNA, clone:ciem838a16, 5'end,... 52 0.06... Dictyostelium discoideum chromosome 2 map 2567470... 32 0.13 15 ( CP000488 ) Candidatus Ruthia magnifica st

  18. Dicty_cDB: Contig-U01152-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available 1477 Culicoides sonorensis female serum-f... 52 2e-12 3 ( CV286104 ) tak65f07.y1 Hydra EST Kiel 7 Hydra magn...ipapillata... 48 3e-12 3 ( CV285878 ) tak65f07.x1 Hydra EST Kiel 7 Hydra magnipapillata... 48 4e-12 3 ( EE25...40 0.13 3 ( DN955586 ) it89h05.g1 Gnetum female cone (NYBG) Gnetum gnemo... 40 0.15 2 ( AC136953 ) Medicago ...-55 AY786549_1( AY786549 |pid:none) Caenorhabditis remanei signal reco... 213 2e-53 CR382139_862( CR382139 |..... 108 4e-22 CP000488_550( CP000488 |pid:none) Candidatus Ruthia magnifica str.... 108 4e-22 CP000436_1435( CP000436 |pid:none) Haem

  19. "pruebas de laboratorio"

    Directory of Open Access Journals (Sweden)

    Manuel Rodríguez

    2007-01-01

    Full Text Available Se exponen los resultados de evaluaciones de laboratorio y del miniaspersor MAMKAD 2255 con boquilla roja, como posible alternativa para el riego de alta frecuencia, baja intensidad y subfoliar en el cultivo del banano. En estas condiciones a 200 kPa de carga, el caudal del miniaspersor fue de 216 L/h, el radio efectivo de 7,8 m y el más alto coeficiente de uniformidad de Christiansen fue de 80,6 % y se obtuvo en el marco de puesta de 9 m entre laterales y 9 m entre miniaspersores, lo que hace de este miniaspersor una alternativa con magnificas características técnicas para el riego del banano plantado en marcos de triángulo equilátero.

  20. Comparative ultrastructure of pretarsi in five calyptrate species.

    Science.gov (United States)

    Wang, Q K; Yang, Y Z; Li, X Y; Li, K; Zhang, D

    2016-06-01

    Pretarsi are the most important structures that allow flies to walk on various smooth surfaces and act as contact sensory organs. The pretarsal ultrastructure, including adhesive pads, claws, unguitractors, and bristles, of five calyptrate species are presented and described in detail, including Calliphora calliphoroides (Rohdendorf, 1931), Lucilia sericata (Meigen, 1826), Sarcophaga portschinskyi (Rohdendorf, 1937), Muscina stabulans (Fallen, 1817) and Portschinskia magnifica Pleske, 1926. Two types of tenent setae (spoon-tipped and spatula-tipped) are present on the ventral side of pulvilli in all species. The density of tenent setae and the pulvilli area in forelegs, midlegs, and hindlegs of both sexes are different. Among the five species, Ca. calliphoroides has unusually large pulvilli to its body size. These results provide morphological details that help to understand the movement and attachment of flies. PMID:26916893

  1. Extracellular and mixotrophic symbiosis in the whale-fall mussel Adipicola pacifica: a trend in evolution from extra- to intracellular symbiosis.

    Directory of Open Access Journals (Sweden)

    Yoshihiro Fujiwara

    Full Text Available BACKGROUND: Deep-sea mussels harboring chemoautotrophic symbionts from hydrothermal vents and seeps are assumed to have evolved from shallow-water asymbiotic relatives by way of biogenic reducing environments such as sunken wood and whale falls. Such symbiotic associations have been well characterized in mussels collected from vents, seeps and sunken wood but in only a few from whale falls. METHODOLOGY/PRINCIPAL FINDING: Here we report symbioses in the gill tissues of two mussels, Adipicola crypta and Adipicola pacifica, collected from whale-falls on the continental shelf in the northwestern Pacific. The molecular, morphological and stable isotopic characteristics of bacterial symbionts were analyzed. A single phylotype of thioautotrophic bacteria was found in A. crypta gill tissue and two distinct phylotypes of bacteria (referred to as Symbiont A and Symbiont C in A. pacifica. Symbiont A and the A. crypta symbiont were affiliated with thioautotrophic symbionts of bathymodiolin mussels from deep-sea reducing environments, while Symbiont C was closely related to free-living heterotrophic bacteria. The symbionts in A. crypta were intracellular within epithelial cells of the apical region of the gills and were extracellular in A. pacifica. No spatial partitioning was observed between the two phylotypes in A. pacifica in fluorescence in situ hybridization experiments. Stable isotopic analyses of carbon and sulfur indicated the chemoautotrophic nature of A. crypta and mixotrophic nature of A. pacifica. Molecular phylogenetic analyses of the host mussels showed that A. crypta constituted a monophyletic clade with other intracellular symbiotic (endosymbiotic mussels and that A. pacifica was the sister group of all endosymbiotic mussels. CONCLUSIONS/SIGNIFICANCE: These results strongly suggest that the symbiosis in A. pacifica is at an earlier stage in evolution than other endosymbiotic mussels. Whale falls and other modern biogenic reducing

  2. Molecular characterization of a deep-sea methanotrophic mussel symbiont that carries a RuBisCO gene

    OpenAIRE

    Elsaied, Hosam Easa; Kaneko, Ryo; Naganuma, Takeshi

    2006-01-01

    In our previous investigation on the genes of 1,5-bisphosphate carboxylase/oxygenase (RuBisCO; EC 4.1.1.39) in deep-sea chemoautotrophic and methanotrophic endosymbioses, the gene encoding the large subunit of RuBisCO form I (cbbL) had been detected in the gill of a mussel belonging to the genus Bathymodiolus from a western Pacific back-arc hydrothermal vent. This study further revealed the symbiont source of the RuBisCO cbbL gene along with the genes of 16S ribosomal RNA (16S rDNA), particul...

  3. The Carboxysome and Other Bacterial Microcompartments

    Energy Technology Data Exchange (ETDEWEB)

    Kerfeld, Cheryl A.; Greenleaf, William B.; Kinney, James N.

    2010-06-23

    - Carboxysomes are part of the carbon concentrating mechanism in cyanobacteria and chemoautotrophs. - Carboxysomes are a subclass of bacterial microcompartments (BMCs); BMCs can encapsulate a range of metabolic processes. - Like some viral particles, the carboxysome can be modeled as an icosahedron-in its case, having 4,000-5,000 hexameric shell subunits and 12 surface pentamers to generate curvature. - The threefold axis of symmetry of the CsoS1D protein in carboxysomes forms a pore that can open and close, allowing for selective diffusion. - Genetic modules encoding BMC shell proteins and the enzymes that they encapsulate are horizontally transferable, suggesting they enable bacteria to adapt to diverse environments.

  4. Massive expansion of marine archaea during a mid-Cretaceous oceanic anoxic event

    DEFF Research Database (Denmark)

    Kuypers, M.M.M.; Blokker, P.; Erbacher, J.;

    2001-01-01

    Biogeochemical and stable carbon isotopic analysis of black-shale sequences deposited during an Albian oceanic anoxic event (∼112 million years ago) indicate that up to 80 weight percent of sedimentary organic carbon is derived from marine, nonthermophilic archaea. The carbon-13 content of archaeal...... molecular fossils indicates that these archaea were living chemoautotrophically. Their massive expansion may have been a response to the strong stratification of the ocean during this anoxic event. Indeed, the sedimentary record of archaeal membrane lipids suggests that this anoxic event marks a time in...... Earth history at which certain hyperthermophilic archaea adapted to low-temperature environments....

  5. Methane Ice Worms: Hesiocaeca methanicola Colonizing Fossil Fuel Reserves

    Science.gov (United States)

    Fisher, C. R.; MacDonald, I. R.; Sassen, R.; Young, C. M.; Macko, S. A.; Hourdez, S.; Carney, R. S.; Joye, S.; McMullin, E.

    During a research cruise in July 1997 in the Gulf of Mexico we discovered a gas hydrate approximately 1m thick and over 2m in diameter which had recently breached the sea floor at a depth of 540m. The hydrate surface visible from the submarine was considerably greater than that of any other reported hydrate. Two distinct color bands of hydrate were present in the same mound, and the entire exposed surface of the hydrate was infested (2500 individuals/m2) with 2 to 4 cm-long worms, since described as a new species, Hesiocaecamethanicola, in the polychaete family Hesionidae (Desbruyères and Toulmond 1998). H.methanicola tissue stable isotope values are consistent with a chemoautotrophic food source. No evidence of chemoautotrophic symbionts was detected, but geochemical data support the presence of abundant free living bacteria on the hydrate. The activities of the polychaetes, grazing on the hydrate bacteria and supplying oxygen to their habitats, appears to contribute to the dissolution of hydrates in surface sediments.

  6. Toward an appreciation of hydrothennal-vent animals: Their environment, physiological ecology, and tissue stable isotope values

    Science.gov (United States)

    Fisher, Charles R.

    In the last few years several comprehensive reviews of the biology of hydrothermal vent organisms and communities have been published. In this contribution I will not attempt to exhaustively review the literature, list the fauna, or the known sites, but rather present a conceptual basis for understanding the relation between the dominant metazoan "primary producers" in hydrothermal vent communities and their environment. In addition to the other chapters in this volume, interested readers are encouraged to consult the following reviews for a more detailed discussion of particular aspects of vent biology. The community ecology of hydrothermal vents is reviewed by Grassle [1986], Tunnicliffe [1991], and Lutz and Kennish [1993]. Tunnicliffe [1991] contains the most complete species lists and general site descriptions currently available. Fisher [1990] reviews the literature on chemoautotrophic symbioses and presents species lists of the hosts to chemoautotrophic symbionts known at that time. Those lists are updated in Nelson and Fisher [1995] and the physiology of the associations reviewed from a distinctly bacterial (symbiont) viewpoint. The 1992 review by Childress and Fisher takes a detailed look at the physiology of vent fauna, with a full coverage of subjects such as rate processes, blood function, and chemical composition, which are not covered in depth in the other reviews, but are of special relevance to this contribution. Uses (and abuses) of stable isotopes are discussed in several of the above reviews, and are also reviewed specifically by Conway et al. [1994], Fiala-Médioni et al. [1993], and Kennicutt et al. [1992].

  7. Long-term performance of rapid oxidation of arsenite in simulated groundwater using a population of arsenite-oxidizing microorganisms in a bioreactor.

    Science.gov (United States)

    Li, Hao; Zeng, Xian-Chun; He, Zhong; Chen, Xiaoming; E, Guoji; Han, Yiyang; Wang, Yanxin

    2016-09-15

    A population of arsenite-oxidizing microorganisms enriched from the tailing of the Shimen realgar mine was used to generate biofilms on the surfaces of perlites. This bioreactor is able to completely oxidize 1100 μg/L As(III) dissolved in simulated groundwater into As(V) within 10 min; after 140 days of operation, approximately 20 min were required to completely oxidize the same concentration of As(III). Analysis for the 16S rRNA genes of the microbial community showed that Bacteroidetes and Proteobacteria are dominant in the reactor. Six different bacterial strains were randomly isolated from the reactor. Function and gene analysis indicated that all the isolates possess arsenite-oxidizing activity, and five of them are chemoautotrophic. Further analysis showed that a large diversity of AioAs and two types of RuBisCOs are present in the microbial community. This suggests that many chemoautotrophic arsenite-oxidizing microorganisms were responsible for quick oxidation of arsenite in the reactor. We also found that the reactor is easily regenerated and its number is readily expanded. To the best of our knowledge, the arsenite-oxidizing efficiency, which was expressed as the minimum time for complete oxidization of a certain concentration of As(III) under a single operation, of this bioreactor is the highest among the described bioreactors; it is also the most stable, economic and environment-friendly. PMID:27288673

  8. Auto- and heterotrophic acidophilic bacteria enhance the bioremediation efficiency of sediments contaminated by heavy metals.

    Science.gov (United States)

    Beolchini, Francesca; Dell'Anno, Antonio; De Propris, Luciano; Ubaldini, Stefano; Cerrone, Federico; Danovaro, Roberto

    2009-03-01

    This study deals with bioremediation treatments of dredged sediments contaminated by heavy metals based on the bioaugmentation of different bacterial strains. The efficiency of the following bacterial consortia was compared: (i) acidophilic chemoautotrophic, Fe/S-oxidising bacteria, (ii) acidophilic heterotrophic bacteria able to reduce Fe/Mn fraction, co-respiring oxygen and ferric iron and (iii) the chemoautotrophic and heterotrophic bacteria reported above, pooled together, as it was hypothesised that the two strains could cooperate through a mutual substrate supply. The effect of the bioremediation treatment based on the bioaugmentation of Fe/S-oxidising strains alone was similar to the one based only on Fe-reducing bacteria, and resulted in heavy-metal extraction yields typically ranging from 40% to 50%. The efficiency of the process based only upon autotrophic bacteria was limited by sulphur availability. However, when the treatment was based on the addition of Fe-reducing bacteria and the Fe/S oxidizing bacteria together, their growth rates and efficiency in mobilising heavy metals increased significantly, reaching extraction yields >90% for Cu, Cd, Hg and Zn. The additional advantage of the new bioaugmentation approach proposed here is that it is independent from the availability of sulphur. These results open new perspectives for the bioremediation technology for the removal of heavy metals from highly contaminated sediments. PMID:19118863

  9. Biosphere in 3.5 Ga submarine hydrothermal system

    International Nuclear Information System (INIS)

    Abundant organic matter (kerogen) was identified in ∼3.5 Ga hydrothermal silica dikes from the North Pole area in the Pilbara craton, Western Australia. The silica dikes developed in the uppermost 1000 m of the ancient oceanic crust. Thus, they would have been deposited in the 3.5 Ga sub-seafloor hydrothermal system. The carbon and nitrogen isotopic compositions of the kerogen were analyzed in this study. Their highly 13C-depleted isotopic compositions (δ13C = -38 to -33 per mille) strongly suggest that they are originally derived from biologically produced organic matter. The remarkable similarity of the δ13C values between the kerogen and modern hydrothermal vent organisms may suggest that the kerogen was derived from chemoautotrophic organisms. This idea is also consistent with their nitrogen isotopic compositions (δ15N = -4 to +4 per mille). The silica dikes consist mainly of fine-grained silica with minor pyrite and sphalerite. These mineral assemblages indicate that the silica dike was deposited from relatively low-temperature (probably less than 150degC) reducing hydrothermal fluid. Thus, anaerobic thermophilic/hyperthermophilic organisms could have survived in the hydrothermal fluid, which formed the silica dikes. Therefore, it is plausible that a chemoautotrophic-based biosphere (possibly methanogenesis) probably existed in the Early Archean sub-seafloor hydrothermal system. (author)

  10. Sulfur metabolisms in epsilon- and gamma-Proteobacteria in deep-sea hydrothermal fields

    Directory of Open Access Journals (Sweden)

    Masahiro eYamamoto

    2011-09-01

    Full Text Available In deep-sea hydrothermal systems, super hot and reduced vent fluids from the subseafloor blend with cold and oxidized seawater. Very unique and dense ecosystems are formed within these environments. Many molecular ecological studies showed that chemoautotrophic epsilon- and gamma-Proteobacteria are predominant primary producers in both free-living and symbiotic microbial communities in global deep-sea hydrothermal fields. Inorganic sulfur compounds are important substrates for the energy conservative metabolic pathways in these microorganisms. Recent genomic and metagenomic analyses and biochemical studies have contributed to the understanding of potential sulfur metabolic pathways for these chemoautotrophs. Epsilon-Proteobacteria use sulfur compounds for both electron-donors and -acceptors. On the other hand, gamma-Proteobacteria utilize two different sulfur-oxidizing pathways. It is hypothesized that differences between the metabolic pathways used by these two predominant proteobacterial phyla are associated with different ecophysiological strategies; extending the energetically feasible habitats with versatile energy metabolisms in the epsilon-Proteobacteria and optimizing energy production rate and yield for relatively narrow habitable zones in the gamma-Proteobacteria.

  11. Methanotrophy and chemoautotrophy within the redox gradient of a large and deep tropical lake (Lake Kivu, East Africa)

    Science.gov (United States)

    Morana, Cedric; Borges, Alberto V.; Darchambeau, François; Roland, Fleur; Montante, Laetitia; Descy, Jean-Pierre; Bouillon, Steven

    2014-05-01

    Lake Kivu (East Africa) is a large (2370 km2) and deep (maximum depth of 485 m) meromictic lake. Its vertical structure consists of an oxic and nutrient-poor mixed layer down to 70 m maximum, and a permanently anoxic monimolimnion rich in dissolved gases (methane and carbon dioxide) and inorganic nutrients. Seasonal variation of the vertical position of the oxic-anoxic interface is driven by contrasting precipitation and wind speed regimes between rainy (October-May) and dry (June-September) season, the latter being characterized by a deepening of the oxic zone, and an increased input of dissolved gases and inorganic nutrients. Our work aimed at quantifying methanotrophic and chemoautotrophic production within the redox gradient of Lake Kivu and identifying the micro-organisms involved in these processes using phospholipid-derived fatty acid markers and their carbon stable isotope composition. Our approach combined both natural stable isotope abundance analysis and 13C-labelling (13C-DIC ; 13C-CH4) experiments. Sampling was carried out at two stations in Lake Kivu during rainy (February 2012) and dry (September 2012) season conditions. Methanotrophic bacterial production rates were highly variable (from 0.1 to 7.0 μmol C L-1 d-1), but maximum values were always observed at the oxic-anoxic interface when the CH4:O2 ratio varied between 0.1 and 10, suggesting that the majority of methane was oxidized aerobically. Furthermore, strong stable isotope labelling of monounsaturated C16 fatty acids indicate that active methane oxidizers were related to the group of type I aerobic methanotrophs (gammaproteobacteria). Despite the dominance of aerobic methane oxidation, significant methanotrophic bacterial production rates were found below the oxic-anoxic interface during the rainy season, indicating that at least a fraction of the upcoming methane may be oxidized anaerobically. This observation was further confirmed by the strong labelling at these depths of the 10Me16

  12. Biogeochemistry of a low-activity cold seep in the Larsen B area, western Weddell Sea, Antarctica

    Directory of Open Access Journals (Sweden)

    J. Gutt

    2009-11-01

    Full Text Available First videographic indication of an Antarctic cold seep ecosystem was recently obtained from the collapsed Larsen B ice shelf, western Weddell Sea (Domack et al., 2005. Within the framework of the R/V Polarstern expedition ANTXXIII-8, we revisited this area for geochemical, microbiological and further videographical examinations. During two dives with ROV Cherokee (MARUM, Bremen, several bivalve shell agglomerations of the seep-associated, chemosynthetic clam Calyptogena sp. were found in the trough of the Crane and Evans glacier. The absence of living clam specimens indicates that the flux of sulphide and hence the seepage activity is diminished at present. This impression was further substantiated by our geochemical observations. Concentrations of thermogenic methane were moderately elevated with 2 μM in surface sediments of a clam patch, increasing up to 9 μM at a sediment depth of about 1 m in the bottom sections of the sediment cores. This correlated with a moderate decrease in sulphate from about 28 mM at the surface down to 23.4 mM, an increase in sulphide to up to 1.43 mM and elevated rates of the anaerobic oxidation of methane (AOM of up to 600 pmol cm−3 d−1 at about 1 m below the seafloor. Molecular analyses indicate that methanotrophic archaea related to ANME-3 are the most likely candidates mediating AOM in sediments of the Larsen B seep.

  13. Evidences of the Presence of Methane Seeps in the Colombian Caribbean Sea

    Science.gov (United States)

    Gracia, Adriana; Rangel-Buitrago, Nelson; Sellanes, Javier

    2010-05-01

    For the first time in the southern Caribbean Sea Margin of Colombia (between 450 - 700 m deep) we confirm the presence of methane seep communities near the deltas of the Magdalena and Sinu rivers. Some evidences of the occurrence of those communities include: i) bivalves constituents of marine chemosynthesis-based communities, which are indicators of reducing environments as vesicomyid and lucinid bivalves (Vesicomya caribbea, Calyptogena ponderosa, Ectenagena modioliforma, Lucinoma spp. and Graecina colombiensis), together with the rare solemyid clam Acharax caribbaea, ii) other seep-associated fauna such as the trochid snail Cataegis meroglypta, iii) the first report of vestimentiferan tubeworms for the area and, iv) the presence of authigenic carbonates; these constructions form hard substrates colonized by sessile fauna. Additionally, more than 20 species of benthic non-seep fauna were found associated in the area. The collected fauna exhibits an elevated taxonomic similarity to other modern and fossil seep communities from the Caribbean (Barbados Prism, Gulf of Mexico, Cenozoic seep taxa from Barbados, Trinidad and Venezuela). The presence of these chemosymbiotic species seems to be related to mud diapirism activity in the South West of the Colombian coast, this geologic characteristic indicates tectonic and depositional processes associated with the aforementioned deltas. Further research is necessary to establish biological and geological interactions, geochemical and geophysical controls, and organization of cold seeps communities in this unexplored area of the Caribbean. Keywords: Methane, Chemosynthesis-based communities,Bivalves, Mud diapirs, Colombian Caribbean Sea

  14. Efficiency of the benthic filter: Biological control of the emission of dissolved methane from sediments containing shallow gas hydrates at Hydrate Ridge

    Science.gov (United States)

    Sommer, S.; Pfannkuche, O.; Linke, P.; Luff, R.; Greinert, J.; Drews, M.; Gubsch, S.; Pieper, M.; Poser, M.; Viergutz, T.

    2006-06-01

    In marine sedimentary environments, microbial methanotrophy represents an important sink for methane before it leaves the seafloor and enters the water column. Using benthic observatories in conjunction with numerical modeling of pore water gradients, we investigated seabed methane emission rates at cold seep sites with underlying gas hydrates at Hydrate Ridge, Cascadia margin. Measurements were conducted at three characteristic sites which have variable fluid flow and sulfide flux and sustain distinct chemosynthetic communities. In sediments covered with microbial mats of Beggiatoa, seabed methane efflux ranges from 1.9 to 11.5 mmol m-2 d-1. At these sites of relatively high advective flow, total oxygen uptake was very fast, yielding rates of up to 53.4 mmol m-2 d-1. In sediments populated by colonies with clams of the genus Calyptogena and characterized by low advective flow, seabed methane emission was 0.6 mmol m-2 d-1, whereas average total oxygen uptake amounted to only 3.7 mmol m-2 d-1. The efficiency of methane consumption at microbial mat and clam field sites was 66 and 83%, respectively. Our measurements indicate a high potential capacity of aerobic methane oxidation in the benthic boundary layer. This layer potentially restrains seabed methane emission when anaerobic methane oxidation in the sediment becomes saturated or when methane is bypassing the sediment matrix along fractures and channels.

  15. alpha-Hydroxy and alpha-amino acids under possible Hadean, volcanic origin-of-life conditions.

    Science.gov (United States)

    Huber, Claudia; Wächtershäuser, Günter

    2006-10-27

    To test the theory of a chemoautotrophic origin of life in a volcanic, hydrothermal setting, we explored mechanisms for the buildup of bio-organic compounds by carbon fixation on catalytic transition metal precipitates. We report the carbon monoxide-dependent formation of carbon-fixation products, including an ordered series of alpha-hydroxy and alpha-amino acids of the general formula R-CHA-COOH (where R is H, CH3,C2H5,orHOCH2 and A is OH or NH2) by carbon fixation at 80 degrees to 120 degrees C, catalyzed by nickel or nickel,iron precipitates with carbonyl, cyano, and methylthio ligands as carbon sources, with or without sulfido ligands. Calcium or magnesium hydroxide was added as a pH buffer. The results narrow the gap between biochemistry and volcanic geochemistry and open a new gateway for the exploration of a volcanic, hydrothermal origin of life. PMID:17068257

  16. Partial resolution of sources of n-alkanes in the saline portion of the Parachute Creek Member, Green River Formation (Piceance Creek Basin, Colorado)

    Science.gov (United States)

    Collister, J. W.; Lichtfouse, E.; Hieshima, G.; Hayes, J. M.

    1994-01-01

    Systematic variations in the 13C contents of individual extractable n-alkanes (C16-C29) can be modelled quantitatively and interpreted as indicating contributions from at least five distinct sources. These appear to be cyanobacterial (C16-C18, delta 13C = -37% vs PDB), phytoplanktonic (C16-C23, delta = -32%), chemoautotrophic bacterial (C20-C29, delta = -38%), phytoplanktonic or heterotrophic bacterial (C20-C29, delta = -30%), and vascular plants (C23-C29, delta = -29%). Hydrous pyrolysis of related kerogens yields large quantities of additional n-alkanes with different and much more uniform delta values. The latter materials are apparently derived from the thermolysis of aliphatic biopolymers whose presence in the Green River Oil Shale has been recognized visually.

  17. Metabolic profiles of prokaryotic and eukaryotic communities in deep-sea sponge Lamellomorpha sp. indicated by metagenomics

    Science.gov (United States)

    Li, Zhi-Yong; Wang, Yue-Zhu; He, Li-Ming; Zheng, Hua-Jun

    2014-01-01

    The whole metabolism of a sponge holobiont and the respective contributions of prokaryotic and eukaryotic symbionts and their associations with the sponge host remain largely unclear. Meanwhile, compared with shallow water sponges, deep-sea sponges are rarely understood. Here we report the metagenomic exploration of deep-sea sponge Lamellomorpha sp. at the whole community level. Metagenomic data showed phylogenetically diverse prokaryotes and eukaryotes in Lamellomorpha sp.. MEGAN and gene enrichment analyses indicated different metabolic potentials of prokaryotic symbionts from eukaryotic symbionts, especially in nitrogen and carbon metabolisms, and their molecular interactions with the sponge host. These results supported the hypothesis that prokaryotic and eukaryotic symbionts have different ecological roles and relationships with sponge host. Moreover, vigorous denitrification, and CO2 fixation by chemoautotrophic prokaryotes were suggested for this deep-sea sponge. The study provided novel insights into the respective potentials of prokaryotic and eukaryotic symbionts and their associations with deep-sea sponge Lamellomorpha sp..

  18. Environmental genomics reveals a single species ecosystem deep within the Earth

    Energy Technology Data Exchange (ETDEWEB)

    Chivian, Dylan; Brodie, Eoin L.; Alm, Eric J.; Culley, David E.; Dehal, Paramvir S.; DeSantis, Todd Z.; Gihring, Thomas M.; Lapidus, Alla; Lin, Li-Hung; Lowry, Stephen R.; Moser, Duane P.; Richardson, Paul; Southam, Gordon; Wanger, Greg; Pratt, Lisa M.; Andersen, Gary L.; Hazen, Terry C.; Brockman, Fred J.; Arkin, Adam P.; Onstott, Tullis C.

    2008-09-17

    DNA from low biodiversity fracture water collected at 2.8 km depth in a South African gold mine was sequenced and assembled into a single, complete genome. This bacterium, Candidatus Desulforudis audaxviator, comprises>99.9percent of the microorganisms inhabiting the fluid phase of this particular fracture. Its genome indicates a motile, sporulating, sulfate reducing, chemoautotrophic thermophile that can fix its own nitrogen and carbon using machinery shared with archaea. Candidatus Desulforudis audaxviator is capable of an independent lifestyle well suited to long-term isolation from the photosphere deep within Earth?s crust, and offers the first example of a natural ecosystem that appears to have its biological component entirely encoded within a single genome.

  19. Metagenome of a Versatile Chemolithoautotroph from Expanding Oceanic Dead Zones

    Energy Technology Data Exchange (ETDEWEB)

    Walsh, David A.; Zaikova, Elena; Howes, Charles L.; Song, Young; Wright, Jody; Tringe, Susannah G.; Tortell, Philippe D.; Hallam, Steven J.

    2009-07-15

    Oxygen minimum zones (OMZs), also known as oceanic"dead zones", are widespread oceanographic features currently expanding due to global warming and coastal eutrophication. Although inhospitable to metazoan life, OMZs support a thriving but cryptic microbiota whose combined metabolic activity is intimately connected to nutrient and trace gas cycling within the global ocean. Here we report time-resolved metagenomic analyses of a ubiquitous and abundant but uncultivated OMZ microbe (SUP05) closely related to chemoautotrophic gill symbionts of deep-sea clams and mussels. The SUP05 metagenome harbors a versatile repertoire of genes mediating autotrophic carbon assimilation, sulfur-oxidation and nitrate respiration responsive to a wide range of water column redox states. Thus, SUP05 plays integral roles in shaping nutrient and energy flow within oxygen-deficient oceanic waters via carbon sequestration, sulfide detoxification and biological nitrogen loss with important implications for marine productivity and atmospheric greenhouse control.

  20. Predictive isotopic biogeochemistry of lipids from the Black Sea and Cariaco Trench

    International Nuclear Information System (INIS)

    Carbon isotopic compositions of autotrophic organisms can be predicted based on recently established relationships between [CO2(aq)] and var-epsilon p, the isotopic fractionation accompanying carbon fixation. In both the Black Sea and the Cariaco Trench, where [CO2(aq)] values are known and δ values for hydrocarbons were recently determined, predicted biomass δ values can be compared to those of biomarkers extracted from POM and sediment samples. The agreement is good, although a 5 per-thousand range in δ values is observed for the lipids, which may be due to ecological factors or to contributions from organisms that assimilate HCO3-. Lycopane and pentamethyleicosane apparently derive from planktonic organisms. Diploptene in the Black Sea apparently is derived from chemoautotrophic bacteria living at the oxic/anoxic interface. Some odd-C, long-chain n-alkanes have planktonic δ values, and the authors suggest they are not strict terrestrial indicators

  1. The Role of Seep Ecosystems in Distribution Patterns of Deep-Sea Megafauna

    Science.gov (United States)

    Wagner, J.; McKelvey, Z.; Jacobson, A.; Hoerauf, E.; Van Dover, C. L.

    2015-12-01

    One of the key questions about methane seeps is the sphere of influence on the surrounding area they provide in terms of habitat structure, food sources, and geochemical environment. Understanding the distribution of megafauna relative to the seep environment is an initial step toward understanding these ecosystem properties. Systematic photo surveys using AUV Sentry were conducted at 4 methane seeps at the Blake Ridge Diapir and a seep at Cape Fear Diapir. Distributions of dominant seep features (bivalves, carbonates, bacterial mats) were used to define the active seep site. Geospatial mapping indicates that non-seep-endemic taxa (those not hosting chemoautotrophic endosymbionts) either avoid (e.g., sea urchins, certain sea cucumbers), are attracted to (e.g., squat lobsters, cake urchins) or show no distributional bias to (e.g., sea stars, certain fish) the presence of a seep. Further investigation into these faunal relationships may improve understanding of services that seeps provide to the larger ocean ecosystem.

  2. The microbial case for Mars and its implication for human expeditions to Mars

    Science.gov (United States)

    Horneck, Gerda

    Mars is considered as key target for the search of life beyond the Earth. As well as carbon based chemistry and an adequate energy source, water in liquid phase has been considered a prerequisite for habitability. By analogy with terrestrial extremophilic microbial communities, e.g., those thriving in arid, cold, salty environments and/or those exposed to intense UV radiation, potential oases on Mars are suggested. They are connected with areas where liquid water still exists under the current conditions, but also sulfur rich subsurface areas for chemoautotrophic communities, rocks for endolithic communities, permafrost regions, hydrothermal vents, soil or evaporite crusts are of interest. The presence of humans on the surface of Mars will substantially increase the research potential; however, prior to any human exploratory mission the critical issues concerning human health and wellbeing as well as planetary protection issues need to be investigated.

  3. Improved method for screening mitochondrial cytochrome b markers to identify regional populations of the Old World screwworm fly and other myiasis agents.

    Science.gov (United States)

    Ready, P D; Wardhana, A H; Adams, Z J O; Sotiraki, S; Hall, M J R

    2014-10-01

    A new protocol was developed to overcome obstacles to the high-throughput sequence analysis of the 716-717 nucleotides at the carboxyl terminal of the mitochondrial gene cytochrome b (cyt b) of the myiasis flies Chrysomya bezziana and Wohlfahrtia magnifica. For both of these obligate parasites, cyt b haplotypes provide diagnostic markers for phylogeographic populations, markers that identify the origins of emerging populations causing economically important myiasis in livestock and, in the case of C. bezziana (Old World screwworm fly), could help select reproductively-compatible populations for use in the Sterile insect technique as part of area wide integrated pest management. High sequence quality is important for unambiguously detecting the few mutations that are diagnostic for regional cyt b haplotypes and their lineages. A key innovation is the design of a new forward primer for the specific PCR amplification and high-quality sequencing of cyt b. The improved protocol will facilitate the use of this established comparative cyt b sequence analysis, not only by teams lacking the resources for whole genome sequencing (WGS) but also by those requiring reference sequences for developing comparative mitogenomics based on WGS. PMID:25016294

  4. Antiproliferative, genotoxic and oxidant activities of cyclosativene in rat neuron and neuroblastoma cell lines

    Directory of Open Access Journals (Sweden)

    Toğar Başak

    2014-01-01

    Full Text Available Cyclosativene (CSV is a tetracyclic sesquiterpene found in the essential oils of Centaurea cineraria (Asteraceae and Abies magnifica A. Murray (Pinaceae plants. To the best of our knowledge, its cytotoxic, genotoxic and oxidant effects have never been studied on any cell lines. Therefore, we aimed to investigate the in vitro antiproliferative and/or cytotoxic properties, antioxidant/oxidant activity and genotoxic damage potential of CSV in healthy neurons and N2a neuroblastoma (N2a-NB cell cultures. After treatment with 10-400 μg/ml of CSV for 24 h, cell proliferation was measured by the MTT (3,(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide assay. The antioxidant activity was assessed by the total antioxidant capacity (TAC and total oxidative stress (TOS assays. To evaluate the level of DNA damage, single cell gel alkaline electrophoresis (SCGE was used. The MTT assay showed that the application of CSV significantly reduced cell viability in both cell types. CSV treatments at higher doses led to decreases of TAC levels and increases of TOS levels in neuron and N2a-NB cells. The mean values of the total scores of cells showing DNA damage were not found to be significantly different from the control values in both cells. In conclusion, this study suggests that CSV has weak anticancer potential.

  5. Diversity of mycorrhizal fungi of terrestrial orchids: compatibility webs, brief encounters, lasting relationships and alien invasions.

    Science.gov (United States)

    Bonnardeaux, Yumiko; Brundrett, Mark; Batty, Andrew; Dixon, Kingsley; Koch, John; Sivasithamparam, K

    2007-01-01

    The diversity of mycorrhizal fungi associated with an introduced weed-like South African orchid (Disa bracteata) and a disturbance-intolerant, widespread, native West Australian orchid (Pyrorchis nigricans) were compared by molecular identification of the fungi isolated from single pelotons. Molecular identification revealed both orchids were associated with fungi from diverse groups in the Rhizoctonia complex with worldwide distribution. Symbiotic germination assays confirmed the majority of fungi isolated from pelotons were mycorrhizal and a factorial experiment uncovered complex webs of compatibility between six terrestrial orchids and 12 fungi from Australia and South Africa. Two weed-like (disturbance-tolerant rapidly spreading) orchids - D. bracteata and the indigenous Australian Microtis media, had the broadest webs of mycorrhizal fungi. In contrast, other native orchids had relatively small webs of fungi (Diuris magnifica and Thelymitra crinita), or germinated exclusively with their own fungus (Caladenia falcata and Pterostylis sanguinea). Orchids, such as D. bracteata and M. media, which form relationships with diverse webs of fungi, had apparent specificity that decreased with time, as some fungi had brief encounters with orchids that supported protocorm formation but not subsequent seedling growth. The interactions between orchid mycorrhizal fungi and their hosts are discussed. PMID:17289365

  6. Reef fishes can recognize bleached habitat during settlement: sea anemone bleaching alters anemonefish host selection.

    Science.gov (United States)

    Scott, Anna; Dixson, Danielle L

    2016-05-25

    Understanding how bleaching impacts the settlement of symbiotic habitat specialists and whether there is flexibility in settlement choices with regard to habitat quality is essential given our changing climate. We used five anemonefishes (Amphiprion clarkii, Amphiprion latezonatus, Amphiprion ocellaris, Amphiprion percula and Premnas biaculeatus) and three host sea anemones (Entacmaea quadricolor, Heteractis crispa and Heteractis magnifica) in paired-choice flume experiments to determine whether habitat naive juveniles have the olfactory capabilities to distinguish between unbleached and bleached hosts, and how this may affect settlement decisions. All anemonefishes were able to distinguish between bleached and unbleached hosts, and responded only to chemical cues from species-specific host anemones irrespective of health status, indicating a lack of flexibility in host use. While bleached hosts were selected as habitat, this occurred only when unbleached options were unavailable, with the exception of A. latezonatus, which showed strong preferences for H. crispa regardless of health. This study highlights the potential deleterious indirect impacts of declining habitat quality during larval settlement in habitat specialists, which could be important in the field, given that bleaching events are becoming increasingly common. PMID:27226472

  7. A importância do treinamento da criança com baixa visão, com emprego dos auxílios ópticos, para capacitação educacional: relato de caso The value of optical aids' training for low vision child education: case report

    Directory of Open Access Journals (Sweden)

    Eduardo Toshio Sato

    2010-06-01

    Full Text Available O aprendizado do correto manuseio do auxílio óptico foi treinado: localização, focalização e seguimento com o telescópio de 8x de magnificação. Após essa etapa iniciou-se o aprendizado de cópia da lousa com o auxílio adaptado. Totalizaram-se 17 sessões para a criança receber a prescrição final devido às grandes dificuldades apresentadas pela baixa acentuada das funções visuais.Training of the proper handling of optical devices was performed: location, targeting and tracking with the 8x magnification telescope. After this step, learning to a copy from a blackboard with the adapted optical aid was initiated. Seventeen sessions were required for the child's final prescription due to severe low vision and loss of visual functions.

  8. High root concentration and uneven ectomycorrhizal diversity near Sarcodes sanguinea (Ericaceae): a cheater that stimulates its victims?

    Science.gov (United States)

    Bidartondo, M I; Kretzer, A M; Pine, E M; Bruns, T D

    2000-12-01

    Sarcodes sanguinea is a nonphotosynthetic mycoheterotrophic plant that obtains all of its fixed carbon from neighboring trees through a shared ectomycorrhizal fungus. We studied the spatial structuring of this tripartite symbiosis in a forest where Sarcodes is abundant, and its only fungal and photosynthetic plant associates are Rhizopogon ellenae and Abies magnifica, respectively. We found disproportionately high concentrations of Abies roots adjacent to Sarcodes roots compared to the surrounding soil. Rhizopogon ellenae colonizes the vast majority of those Abies roots (86-98%), and its abundance tends to decrease with increasing distance from Sarcodes plants. At 500 cm from Sarcodes plants we did not detect R. ellenae, and the ectomycorrhizal community instead was dominated by members of the Russulaceae and Thelephoraceae, which are commonly dominant in other California pinaceous forests. The highly clumped distribution of Abies-R. ellenae ectomycorrhizas indicates that Sarcodes plants either establish within pre-existing clumps, or they stimulate clump formation. Several lines of evidence favor the latter interpretation, suggesting an unexpected mutualistic aspect to the symbiosis. However, the mechanism involved remains unknown. PMID:11118414

  9. Plastid ultrastructure and photosynthesis in greening petaloid hypsophylls.

    Science.gov (United States)

    Weidner, M; Franz, A; Napp-Zinn, K

    1985-02-01

    The ultrastructural and biochemicalphysiological aspects of postfloral greening have been studied in hypsophylls of Heliconia aurantiaca Ghiesbr., Guzmania cf. x magnifica Richter and Spathiphyllum wallisii Regel. In all three species the greening of the hypsophylls is due to plastid transformation, chloroplast formation proceeding from the initially different types of plastids. The degradation process of the original plastid structures and the mode of thylakoid formation are distinct in each case. In none of the species do the transformed plastids look identical to the chloroplasts of the corresponding foliage leaves. On a chlorophyll basis, the rate of photosynthesis of the greened hypsophylls surpasses the rate of the leaves considerably in Spathiphyllum, but is much lower in Heliconia (no data for Guzmania). In all species, anatomy, plastid structure, pigments, 77° K-fluorescence emission, ribulose-1,5-bis-phosphate carboxylase activities and short-term photosynthesis (14)CO2-assimilation patterns prove the greened hypsophylls to be capable of providing additional carbon to the developing fruits, thus supplementing the import of organic matter from the foliage leaves. PMID:24249334

  10. Efficacy of three conditions of radiographic interpretation for assessment root canal length Eficácia de três condições de interpretação radiográfica em odontometria

    Directory of Open Access Journals (Sweden)

    Mitsuru Ogata

    2005-03-01

    , de arquivos foram medidas, em mm, da extremidade da lima ao ápice radiográfico, com a utilização de um paquímetro digital. Foram feitas três medidas em cada radiografia e em seguida foi calculada a média. Após um período de 12 dias, as medidas foram repetidas. As três condições experimentais de interpretação radiográfica foram: negatoscópio sem máscara e sem magnificação (Visual; 2 negatoscópio com lente de aumento de 2,5 X e com máscara (Magnificação e 3 bloqueador de luz e lente de aumento de 1,75 X (Bloqueador. As médias e os desvios-padrão das medidas foram calculados e realizada uma análise descritiva. Foi utilizada a análise de variância a dois critérios (ANOVA para avaliar a concordância intra-observador e intramétodo. O erro das medidas foi calculado pela fórmula de Dalhberg. RESULTADOS: O teste ANOVA não mostrou diferenças significantes entre as duas sessões de observação, métodos de interpretação ou interação entre as sessões de interpretação e método (p>0,05. A medida intra-observador foi 0,02 mm para os métodos Visual e Magnificação e 0,01 mm para o Bloqueador. CONCLUSÃO: Parece não haver qualquer vantagem realizar medidas da distância entre o ápice radicular e o extremo da lima endodôntica em dentes incisivos superiores utilizando máscara ou magnificação da imagem.

  11. The Sarcophagidae (Insecta: Diptera) described by Chien-ming Chao and Xue-zhong Zhang.

    Science.gov (United States)

    Zhang, Dong; Zhang, Ming; Li, Zijuan; Pape, Thomas

    2015-01-01

    The twenty-nine species-group names of Sarcophagidae proposed by Chien-ming Chao and Xue-zhong Zhang are reviewed. Of these names, twenty-four are available, while five are unavailable nomina nuda. Of the twenty-four available names, nine are considered valid, fifteen as invalid: thirteen junior synonyms, one unnecessary replacement name and one junior primary homonym. Holotypes of all species, and allotypes when available, are photographed and the species redescribed based on the type material. Eight new synonyms are proposed: Miltogramma tibita Chao & Zhang, 1988, syn. n. of Miltogramma taeniata Meigen, 1824; Sphenometopa luridimacula Chao & Zhang, 1988, syn. n. of Sphenometopa stackelbergiana Rohdendorf, 1967; Sphenometopa mesomelaenae Chao & Zhang, 1988, syn. n. of Sphenometopa stelviana (Brauer & Bergenstamm, 1891); Sphenometopa altajica Rohdendorf, 1971, syn. n. of Sphenometopa stelviana (Brauer & Bergenstamm, 1891); Sarcophila mongolica Chao & Zhang, 1988, syn. n. of Sarcophila latifrons (Fallén, 1817); Wohlfahrtia brevicornis Chao & Zhang, 1996, syn. n. of Wohlfahrtia grunini Rohdendorf, 1969; Wohlfahrtia hirtiparafacialis Chao & Zhang, 1996, syn. n. of Wohlfahrtia magnifica (Schiner, 1862); and Wohlfahrtiodes mongolicus Chao & Zhang, 1988, syn. n. of Asiosarcophila kaszabi Rohdendorf & Verves, 1978. The genus Asiosarcophila Rohdendorf & Verves, 1978 is herewith reported from China for the first time, along with the five species A. kaszabi, M. taeniata, S. stackelbergiana, S. stelviana and W. grunini. PMID:25947705

  12. Circumscription of Botryosphaeria species associated with Proteaceae based on morphology and DNA sequence data.

    Science.gov (United States)

    Denman, Sandra; Crous, Pedro W; Groenewald, J Z Ewald; Slippers, Bernard; Wingfield, Brenda D; Wingfield, Michael J

    2003-01-01

    Botryosphaeria spp. occur on and cause diseases of Proteaceae, but accurate identification has been problematic due to the lack of clear species circumscriptions of members of this genus. In this study, 46 isolates of Botryosphaeria from proteaceous hosts growing in various parts of the world were studied, using morphology, cultural characters and sequence data from the ITS region of the rDNA operon. Five Botryosphaeria spp. were found to be associated with Proteaceae. Botryosphaeria lutea was isolated from Banksia and Buckinghamia spp. in Australia, and a single isolate was obtained from Protea cynaroides in South Africa. Botryosphaeria proteae was associated only with South African Proteaceae, but occurred in many parts of the world. Another Botryosphaeria sp. that occurred exclusively on South African Proteaceae represents a new taxon that is described as B. protearum. This pathogen was found on South African Proteaceae cultivated in Australia; Hawaii; Portugal, including the Madeira Islands; and South Africa. Botryosphaeria ribis was associated with both South African and Australian Proteaceae and was isolated from material collected in Australia, Hawaii and Zimbabwe. A single occurrence of B. obtusa as an endophyte was recorded from P. magnifica in South Africa. In addition to providing a taxonomic overview of Botryosphaeria spp. associated with Proteaceae, this paper clarifies for the first time the global distribution of these species. A key also is provided to facilitate their identification. A large number of new host and distribution records are made and a new species of Botryosphaeria from Proteaceae is described. PMID:21156615

  13. Nectar Meals of a Mosquito-Specialist Spider

    Directory of Open Access Journals (Sweden)

    Josiah O. Kuja

    2012-01-01

    Full Text Available Evarcha culicivora, an East African jumping spider, is known for feeding indirectly on vertebrate blood by actively choosing blood-carrying mosquitoes as prey. Using cold-anthrone tests to detect fructose, we demonstrate that E. culicivora also feeds on nectar. Field-collected individuals, found on the plant Lantana camara, tested positive for plant sugar (fructose. In the laboratory, E. culicivora tested positive for fructose after being kept with L. camara or one of another ten plant species (Aloe vera, Clerodendron magnifica, Hamelia patens, Lantana montevideo, Leonotis nepetaefolia, Parthenium hysterophorus, Ricinus communis, Senna didymobotrya, Striga asiatica, and Verbena trivernia. Our findings demonstrate that E. culicivora acquires fructose from its natural diet and can ingest fructose directly from plant nectaries. However, experiments in the laboratory also show that E. culicivora can obtain fructose indirectly by feeding on prey that have fed on fructose, implying a need to consider this possibility when field-collected spiders test positive for fructose. In laboratory tests, 53.5% of 1,215 small juveniles, but only 3.4% of 622 adult E. culicivora, left with plants for 24 hours, were positive for fructose. These findings, along with the field data, suggest that fructose is especially important for early-instar juveniles of E. culicivora.

  14. Specific transformations of mineral forms of nitrogen in acid soils

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    MIRJANA KRESOVIC

    2009-01-01

    Full Text Available Investigations were performed on soils of different acidity, ranging in the pH interval 4.65–5.80 (in water. Changes of the mineral nitrogen forms in the examined soils were studied by applying short-term incubation experiments performed under aerobic conditions, with a humidity of 30 % and a temperature of 20 °C, both with and without the addition of 100 and 300 ppm NH4–N. The results of the incubation experiments showed that retarded nitrification was present in all the examined soils. Increased and toxic quantities of nitrites (35.7 ppm were formed during the incubation, which remained in the soil solution for several days, and even weeks, in spite of favorable conditions of moisture, aeration and temperature for the development of the process of chemo-autotrophic nitrification. Decelerated chemoautotrophic nitrification was the source of the occurrence of nitrite in the examined less acid soil (soil 1, while in soils of higher acidity (soils 2 and 3 after addition of 100 and 300 ppm NH4–N, nitrite occurred due to chemical denitrification (chemodenitrification. Nitrites formed in the process of chemodenitrification underwent spontaneous chemical oxidation resulting in nitrate formation (chemical nitrification. The content of mineral nitrogen (NH4 + NO3 + NO2–N decreased during the incubation period, proving gaseous losses from the examined soils. Application of lower doses of nitrogen fertilizers could decrease nitrogen losses by denitrification as well as the occurrence of nitrite in toxic quantities in the investigated pseudogley soil.

  15. Endosymbioses between bacteria and deep-sea siboglinid tubeworms from an Arctic Cold Seep (Haakon Mosby Mud Volcano, Barents Sea).

    Science.gov (United States)

    Lösekann, Tina; Robador, Alberto; Niemann, Helge; Knittel, Katrin; Boetius, Antje; Dubilier, Nicole

    2008-12-01

    Siboglinid tubeworms do not have a mouth or gut and live in obligate associations with bacterial endosymbionts. Little is currently known about the phylogeny of frenulate and moniliferan siboglinids and their symbionts. In this study, we investigated the symbioses of two co-occurring siboglinid species from a methane emitting mud volcano in the Arctic Ocean (Haakon Mosby Mud Volcano, HMMV): Oligobrachia haakonmosbiensis (Frenulata) and Sclerolinum contortum (Monilifera). Comparative sequence analysis of the host-specific 18S and the symbiont-specific 16S rRNA genes of S. contortum showed that the close phylogenetic relationship of this host to vestimentiferan siboglinids was mirrored in the close relationship of its symbionts to the sulfur-oxidizing gammaproteobacterial symbionts of vestimentiferans. A similar congruence between host and symbiont phylogeny was observed in O. haakonmosbiensis: both this host and its symbionts were most closely related to the frenulate siboglinid O. mashikoi and its gammaproteobacterial symbiont. The symbiont sequences from O. haakonmosbiensis and O. mashikoi formed a clade unaffiliated with known methane- or sulfur-oxidizing bacteria. Fluorescence in situ hybridization indicated that the dominant bacterial phylotypes originated from endosymbionts residing inside the host trophosome. In both S. contortum and O. haakonmosbiensis, characteristic genes for autotrophy (cbbLM) and sulfur oxidation (aprA) were present, while genes diagnostic for methanotrophy were not detected. The molecular data suggest that both HMMV tubeworm species harbour chemoautotrophic sulfur-oxidizing symbionts. In S. contortum, average stable carbon isotope values of fatty acids and cholesterol of -43 per thousand were highly negative for a sulfur oxidizing symbiosis, but can be explained by a (13)C-depleted CO(2) source at HMMV. In O. haakonmosbiensis, stable carbon isotope values of fatty acids and cholesterol of -70 per thousand are difficult to reconcile with

  16. Population structure of deep-sea chemolithoautotrophs: identification of phenotypic and genotypic correlations

    Science.gov (United States)

    Mino, S.; Nakagawa, S.; Sawabe, T.; Miyazaki, J.; Makita, H.; Nunoura, T.; Yamamoto, M.; Takai, K.

    2012-12-01

    Deep-sea hydrothermal fields are areas on the seafloor of high biological productivity fueled primarily by microbial chemosynthesis. Chemolithoautotrophic Epsilonproteobacteria and Persephonella with an ability to utilize inorganic substrates such as elemental sulfur and hydrogen are important members in wide range of temperature conditions in deep-sea hydrothermal vents. However, little is known about their population genetic structure such as intraspecific genetic diversity, distribution pattern, and phenotypic characteristics. Previously, using genetic approach based on multi-locus sequence analysis (MLSA), we clarified that Epsilonproteobacteria Group A, B, F, and Persephonella populations were geographically separated, and Epsilonproteobacteria appeared to diverge by mutation rather than recombination. Contrary to genetic evidence for allopatric segregation in deep-sea chemoautotrophs, however, phenotypic evidence has never been found. In addition, analyzing such a phenotypic characteristic may lead to a better understanding of the interactions microbes have with their environment. In this study, we present a metabolomic approach based on matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) to reveal phenotypic biogeographical discrimination. We demonstrated the whole-cell MALDI-TOF MS method on Epsilonproteobacteria and Persephonella populations. These chemoautotrophic strains used in this study were isolated from chimney structures, vent fluids, and hydrothermal sediments. These hydrothermal samples were collected from geographically separated hydrothermal areas of the South Mariana Trough, Okinawa Trough and Central Indian Ridge. Based on mass peaks (signal/noise >10) within the m/z range of 2000-14000, phenotypic analysis was carried out by cluster analysis. The result of phenotypic analysis was compared with the genotypic clusters. The whole-cell MALDI-TOF MS revealed that Persephonella population was identified to

  17. Expression of genes involved in the uptake of inorganic carbon in the gill of a deep-sea vesicomyid clam harboring intracellular thioautotrophic bacteria.

    Science.gov (United States)

    Hongo, Yuki; Ikuta, Tetsuro; Takaki, Yoshihiro; Shimamura, Shigeru; Shigenobu, Shuji; Maruyama, Tadashi; Yoshida, Takao

    2016-07-10

    Deep-sea vesicomyid clams, including the genus Phreagena (formerly Calyptogena), harbor thioautotrophic bacterial symbionts in the host symbiosome, which consists of cytoplasmic vacuoles in gill epithelial cells called bacteriocytes. The symbiont requires inorganic carbon (Ci), such as CO2, HCO3(-), and CO3(2-), to synthesize organic compounds, which are utilized by the host clam. The dominant Ci in seawater is HCO3(-), which is impermeable to cell membranes. Within the bacteriocyte, cytoplasmic carbonic anhydrase (CA) from the host, which catalyzes the inter-conversion between CO2 and HCO3(-), has been shown to be abundant and is thought to supply intracellular CO2 to symbionts in the symbiosome. However, the mechanism of Ci uptake by the host gill from seawater is poorly understood. To elucidate the influx pathway of Ci into the bacteriocyte, we isolated the genes related to Ci uptake via the pyrosequencing of cDNA from the gill of Phreagena okutanii, and investigated their expression patterns. Using phylogenetic and amino acid sequence analyses, three solute carrier family 4 (SLC4) bicarbonate transporters (slc4co1, slc4co2, and slc4co4) and two membrane-associated CAs (mcaco1 and mcaco2) were identified as candidate genes for Ci uptake. In an in situ hybridization analysis of gill sections, the expression of mcaco1 and mcaco2 was detected in the bacteriocytes and asymbiotic non-ciliated cells, respectively, and the expression of slc4co1 and slc4co2 was detected in the asymbiotic cells, including the intermediate cells of the inner area and the non-ciliated cells of the external area. Although subcellular localizations of the products of these genes have not been fully elucidated, they may play an important role in the uptake of Ci into the bacteriocytes. These findings will improve our understanding of the Ci transport system in the symbiotic relationships of chemosynthetic bivalves. PMID:27016297

  18. Biogeochemistry of a low-activity cold seep in the Larsen B area, western Weddell Sea, Antarctica

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    H. Niemann

    2009-06-01

    Full Text Available First videographic indication of an Antarctic cold seep ecosystem was recently obtained from the collapsed Larsen B ice shelf, western Weddell Sea (Domack et al., 2005. Within the framework of the R/V Polarstern expedition ANTXXIII-8, we revisited this area for geochemical, microbiological and further videographical examinations. During two dives with ROV Cherokee (MARUM, Bremen, several bivalve shell agglomerations of the seep-associated, chemo syntheticclam Calyptogena sp. were found in the trough of the Crane and Evans glacier. The absence of living clam specimens indicates that the flux of sulphide and hence the seepage activity is diminished at present. This impression was further substantiated by our geochemical observations. Concentrations of thermogenic methane were moderately elevated with 2 μM in surface sediments of a clam patch, increasing up to 9 μM at a sediment depth of about 1 m in the bottom sections of the sediment cores. This correlated with a moderate decrease in sulphate from 28 mM at the surface down to 23.4 mM, an increase in sulphide to up to 1.43 mM and elevated rates of the anaerobic oxidation of methane (AOM of up to 600 pmol cm−3 d−1 at about 1 m below the seafloor. Molecular analyses indicate that methanotrophic archaea related to ANME-3 are the most likely candidates mediating AOM in sediments of the Larsen B seep (Domack et al., 2005; EOS 86, 269–276.

  19. Tectonic context of fluid venting at the toe of the eastern Nankai accretionary prism: Evidence for a shallow detachment fault

    Science.gov (United States)

    Chamot-Rooke, N.; Lallemant, S. J.; Le Pichon, X.; Henry, P.; Sibuet, M.; Boulègue, J.; Foucher, J.-P.; Furuta, T.; Gamo, T.; Glaçon, G.; Kobayashi, K.; Kuramoto, S.; Ogawa, Y.; Schultheiss, P.; Segawa, J.; Takeuchi, A.; Tarits, P.; Tokuyama, H.

    1992-04-01

    During the Kaiko-Nankai diving cruise the peak of the venting activity was located near the top of the very first anticline. The most prominent morphological feature between the mid-slope (3870 m) and the apex of the fold (3770 m) is a 20 m high cliff cutting through subhorizontal massive mudstones affected by numerous joints. The trend of this scarp is oblique to the fold axis and structurally controlled along two sharply defined NNE-SSE and E-W directions. Fresh talus and blocks found locally suggest active tectonics and recent erosion. Intense deformation is evident from strongly tilted strata restricted to the base of the cliff that we interpret as an upslope thrust. At the scale of Seabeam mapping, this thrust can be followed eastward for more than 5 km along the 3820 m isobath. Two seismic lines recorded during one of the pre-site surveys show deformation at shallow depth, including small-scale folding and thrusting affecting only the wedge-shaped top sequence. Deeper layers can be traced continuously below this sequence. We conclude that the boundary between the "piggy-back" basin and the frontal fold turbidites acts as a shallow detachment fault, and interpret the base of the cliff as the outcrop of the fault. Dense colonies ofCalyptogena clams and strongly nonlinear thermal gradients locate the major peak of fluid activity at the edge of the plateau above the main cliff. Scattered biological colonies as well as white bacterial mats and cemented chimneys were also found in a narrow belt along the base of the cliff. Fluid activity is thus closely related to the shallow detachment fault, fluid being expelled both at the outcrop of the fault and above it through the overlying strata, possibly using the very dense joint network.

  20. Complementação por coagulação com plasma de argônio após a ressecção endoscópica completa pela técnica de fatiamento para grandes adenomas colorretais

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    Walton Albuquerque

    2013-10-01

    Full Text Available OBJETIVO: avaliar a eficácia da complementação por coagulação com plasma de argônio para reduzir a taxa de neoplasia residual ou recorrente após ressecção endoscópica completa fragmentada de grandes adenomas sésseis colorretais. MÉTODOS: critérios de inclusão: pacientes com grandes adenomas colorretais sésseis, > 20mm, sem sinais morfológicos de infiltração profunda, submetidos à ressecção endoscópica completa fragmentada estudada com cromoendoscopia e magnificação de imagens. Os pacientes foram randomizados em dois grupos: grupo 1 - nenhum procedimento adicional e, grupo 2 - complementação por coagulação com plasma de argônio. O seguimento por colonoscopia foi realizado em três, seis e 12 meses de pós-operatório. Foi avaliada a taxa de neoplasia residual ou recidiva local. RESULTADOS: foram incluídos no estudo um total de 21 lesões. Onze lesões no grupo 1 e dez no grupo 2. Ocorreram duas neoplasias residuais ou recorrências locais em cada grupo, detectadas em três meses de acompanhamento. CONCLUSÃO: a complementação por coagulação com plasma de argônio após uma aparente ressecção endoscópica completa em fragmentos de grandes adenomas sésseis colorretais não parece reduzir a ocorrência de lesão adenomatosa residual ou recidiva local.

  1. Sede de organizaciones internacionales y centro de conferencias, Viena - Austria

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    Staber, Johann

    1979-11-01

    Full Text Available This complex on one bank of the Danube, is located between Wagramer Street and the Danube Park, a beautiful area overlooking the City and surrounded by greenery. It includes: — Six Y-shaped buildings, four of them housing the administrative centers of two international organizations AIEA and UNODI and the other two used for common services. — One circular building used for international congresses. — One hexagon congress hall attached to a circular hotel building. In addition, the complex includes a multilevel car park, elevated pedestrian walks, two access plazas and full network of roads at different levels. The congress centre is the most essential element of the complex and, similarly as the circular international congress hall was designed with flexibility in mind, permitting a number of different floor arrangements using movable partitions.

    Este complejo, construido a orillas del Danubio, está situado entre la calle Wagramer y el parque del Danubio, en una zona de gran belleza, con magnificas vistas de la ciudad y con amplias zonas verdes. Consta de: —Seis edificios con plantas en forma de Y, cuatro de ellos utilizados para sedes administrativas de las Organizaciones Internacionales AIEA y UNODI, y los otros dos para servicios comunes. —Un edificio de planta circular destinado a Conferencias Internacionales. —Un Centro de Conferencias de planta hexagonal, adosado a un hotel de planta circular. El conjunto se completa con estacionamientos de varias plantas, pasarelas para peatones, dos plazas de acceso y un completo trazado viario con calles a distintos niveles. El Centro de Conferencias es la parte esencial del complejo y, al igual que el edificio circular para Conferencias Internacionales, admite distintas variantes en la distribución del espacio para salas mediante la utilización de tabiques móviles de separación.

  2. Yeast identification in floral nectar of Mimulus aurantiacus (Invited)

    Science.gov (United States)

    Kyauk, C.; Belisle, M.; Fukami, T.

    2009-12-01

    Nectar is such a sugar-rich resource that serves as a natural habitat in which microbes thrive. As a result, yeasts arrive to nectar on the bodies of pollinators such as hummingbirds and bees. Yeasts use the sugar in nectar for their own needs when introduced. This research focuses on the identification of different types of yeast that are found in the nectar of Mimulus aurantiacus (commonly known as sticky monkey-flower). Unopened Mimulus aurantiacus flower buds were tagged at Jasper Ridge and bagged three days later. Floral nectar was then extracted and plated on potato dextrose agar. Colonies on the plates were isolated and DNA was extracted from each sample using QIAGEN DNeasy Plant Mini Kit. The DNA was amplified through PCR and ran through gel electrophoresis. The PCR product was used to clone the nectar samples into an E.coli vector. Finally, a phylogenetic tree was created by BLAST searching sequences in GenBank using the Internal Transcribed Space (ITS) locus. It was found that 18 of the 50 identified species were Candida magnifica, 14 was Candida rancensis, 6 were Crytococcus albidus and there were 3 or less of the following: Starmella bombicola, Candida floricola, Aureobasidium pullulans, Pichia kluyvera, Metschnikowa cibodaserisis, Rhodotorua colostri, and Malassezia globosa. The low diversity of the yeast could have been due to several factors: time of collection, demographics of Jasper Ridge, low variety of pollinators, and sugar concentration of the nectar. The results of this study serve as a necessary first step for a recently started research project on ecological interactions between plants, pollinators, and nectar-living yeast. More generally, this research studies the use of the nectar-living yeast community as a natural microcosm for addressing basic questions about the role of dispersal and competitive and facilitative interactions in ecological succession.

  3. The Prevalence of Sheep Traumatic Myiasis in Three Counties from the West Side of Romania and Bacteria Isolated from the Insects Maggots

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    Daniela Marina Mot

    2013-10-01

    Full Text Available Myiasis represents an infestation of animals and humans caused by the maggots of certain fly species of Diptera order, Insecta class, which feed on the hosts' living or dead tissues or body fluids. In sheep, myiasis is a major animal welfare issue developing serious pain, suffering and in untreated cases may result in tissue injuries, reproduction and productivity losses and even death. There are two most important fly species which cause traumatic cutaneous myiasis of sheep in Europe: Wohlfahrtia magnifica (Sarcophagidae implicated in etiology of wound myiasis in southern and eastern Europe and Lucilia sericata (Calliphoridae, implicated in etiology of sheep strike, mainly in the middle latitudes of Europe continent. A few farmers from Timiş, Arad and Caraş-Severin counties were been asked to response to a questionnaire on the prevalence of traumatic myiasis which evolved in their sheep flock in April-September period of year 2012. From a total number of 2206 sheep taken into study were been discovered 1658 healthy sheep (75.16% and 548 sheep with myiasis (24.84%. From identified lesions with myiasis were been collected insects maggots from all three stages of development and were been prepared in Microbiology laboratory in the view to obtain data on the culturable bacteria isolated under aerobic conditions. Bacteria detected from maggots samples were: Staphylococcus aureus, Bacillus subtilis, Proteus vulgaris, Micrococcus luteus and Escherichia coli. The myasis insects maggots in sheep infestation can acquire many bacteria from their host or from their surroundings, all these can, together another bacteria, complicate the lesions and without treatment may lead to animals death.

  4. Restauración del Teatro Español Madrid-España

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    Editorial, Equipo

    1980-04-01

    Full Text Available In October 1975 the Spanish National Theatre was destroyed by a fire which started on stage and reached a large part of the theatre and the ceiling which, with its great candelabra, collapsed onto the parterre. The Madrid Town Hall, with the cooperation of the Ministry of Culture, performed magnificent restoration work and converted this theatre in one of the most advances in our country, not only regarding its scenery technique — taking maximum advantage of the stage, deepening the pits, establishing new borders and stage machinery, etc. — but also adding some magnificent installations, such as the air conditioning and the sophisticated electronic heat and smoke detector system.

    El Teatro Español, en octubre de 1975, se destruyó por un incendio iniciado en el escenario y que alcanzó una gran parte de la sala y del techo, el cual, con su gran lámpara, se derrumbo sobre el patio de butacas. El Ayuntamiento de Madrid, con la colaboración del Ministerio de Cultura, realizó una magnífica labor de restauración y convirtió este teatro en uno de los más avanzados de nuestro país, no sólo en cuanto a su técnica escénica —aprovechando al máximo el escenario, profundizando los fosos, estableciendo nuevas bambalinas y tramoyas, etc.— sino además añadiéndole unas magnificas instalaciones, tales como la de aire acondicionado y el sofisticado sistema de detectores electrónicos de calor y humo.

  5. Cloning and Characterization Analysis of the Genes Encoding Precursor of Mast Cell Degranulating Peptide From 2 Honeybee and 3 Wasp Species%2种蜜蜂和3种胡蜂蜂毒前肥大细胞脱粒肽原基因的克隆及同源性分析

    Institute of Scientific and Technical Information of China (English)

    张素方; 施婉君; 程家安; 张传溪

    2003-01-01

    The precursors of mast cell degranulating peptide (MCDP) genes were amplified by RT-PCR from the total RNA of venom gland of two honeybee species,Apis mellifera ligustica,Apis cerana cerana,and three wasp species,Vespa magnifica,Vespa velutina nigrothorax and Polistes hebraeus,respectively.Their PCR products were ligated into pGEM ((R))T-easy vector and the nucleotide sequences were analyzed.The length of five fragments was the same,it was 341 bp containing an ORF of 153 bp coding the precursor of MCDP and 188 bp 3′ noncoding region.They have more than 90% homologues with each other in nucleotide sequences.The precursors of MCDP of A.cerana cerana,V.magnifica,V.velutina nigrothorax and P.hebraeus shared 96%,100%,94% and 98% homology with A.mellifera ligustica,respectively.The two species of wasps,V.magnifica and V.velutina nigrothorax,contained the same MCDP as A.mellifera ligustica,though they belong to different families with quite different biological properties,while A.cerana cerana contained the different MCDP in their venom as A.mellifera ligustica though they belong to the same genus.The fifth amino acid residue of MCDP in A.cerana cerana and P.hebraeus is arginine,replacing the cysteine,an important disulfide bridges element,in the position as in A.mellifera ligustica.%从中华蜜蜂、意大利蜜蜂、大胡蜂、墨胸胡蜂和亚非马蜂5种雌成蜂毒腺中快速抽提总RNA,用RT-PCR方法分别扩增各得到大小约为350 bp的cDNA片段,进一步将这5个片段克隆入pGEM ((R))T-easy载体,进行测序和序列分析.结果表明:所扩增得到的5个片段长度均为341 bp,均包含一个完整的开放阅读框和3′端未编码区的188 bp核苷酸序列,证实为5种蜂的蜂毒前肥大细胞脱粒肽原的cDNA.经序列比较,意大利蜜蜂、中华蜜蜂、大胡蜂、墨胸胡蜂和亚非马蜂前肥大细胞脱粒肽原核苷酸序列彼此间的同源性都为90%以上.中华蜜蜂、大胡蜂、墨胸胡蜂和亚非马蜂

  6. Carbon and nitrogen isotopic ratios of suspended particulate organic matter (SPOM) in the Black Sea water column

    Science.gov (United States)

    Çoban-Yıldız, Yeşim; Altabet, Mark A.; Yılmaz, Ayşen; Tuğrul, Süleyman

    2006-08-01

    Carbon and nitrogen isotopic ratios ( δ15N and δ13C) of suspended particulate organic matter (SPOM) in the water column of the Black Sea were measured at a total of nine stations in September-October (autumn) 1999 and May 2001. For comparison, a station in the Mediterranean Sea and one in the Sea of Marmara were sampled in October 1999. Large-sized particle samples, as well as samples of surface sediment were also collected for N and C isotopic analysis. The results revealed important vertical and regional variations in N and C isotopic composition. Seasonal variations in SPOM δ15N and δ13C were not apparent. SPOM in the euphotic zone (EZ), oxycline, and suboxic/anoxic interface layers of the water column was characterized by distinct isotopic composition. In the EZ, the N and C isotopic ratios of SPOM were in the range typically observed for plankton-derived SPOM in the surface ocean (EZ means ranged from 2.7‰ to 5.9‰ for δ15N and from -24.0‰ to -21.5‰ for δ13C). Shelf region SPOM had higher δ15N and lower δ13C (EZ means of 5.9‰ and -24.0‰, respectively). Large-sized particles (LPOM) collected by zooplankton net tows had ˜3‰ higher δ15N values compared to SPOM, indicating fractionation during trophic transfer of nitrogen. SPOM in the oxycline increased by 3-6‰ for δ15N, while δ13C decreased by -2‰ to -4‰, which may be attributed to greater lipid content. In the suboxic/anoxic interface zone, SPOM isotopic ratios ( δ15N as low as 0.0‰ to -8.0‰) suggest chemoautotrophic production leading to dominance of new, in situ produced organic matter. The location of the most negative δ15N values indicates that chemoautotrophic production is most intense at the shelf-break regions, possibly enhanced by mixing of oxygenated and nitrate-rich Mediterranean inflow waters with suboxic/anoxic Black Sea water.

  7. Microbiological and geochemical dynamics in simulated-heap leaching of a polymetallic sulfide ore.

    Science.gov (United States)

    Wakeman, Kathryn; Auvinen, Hannele; Johnson, D Barrie

    2008-11-01

    The evolution of microbial populations involved in simulated-heap leaching of a polymetallic black schist sulfide ore (from the recently-commissioned Talvivaara mine, Finland) was monitored in aerated packed bed column reactors over a period of 40 weeks. The influence of ore particle size (2-6.5 mm and 6.5-12 mm) on changes in composition of the bioleaching microflora and mineral leaching dynamics in columns was investigated and compared to fine-grain (manganese and nickel and 68% of zinc being leached within 6 weeks, though relatively little of the copper present in the ore was solubilised. The microbial consortium that emerged from the original inoculum was relatively simple in shake flasks, and was dominated by the iron-oxidizing autotroph Leptospirillum ferriphilum, with smaller numbers of Acidimicrobium ferrooxidans, Acidithiobacillus caldus and Leptospirillum ferrooxidans. Both metal recovery and (for the most part) total numbers of prokaryotes were greater in the column reactor containing the medium-grain than that containing the coarse-grain ore. The bioleaching communities in the columns displayed temporal changes in composition and differed radically from those in shake flask cultures. While iron-oxidizing chemoautotrophic bacteria were always the most numerically dominant bacteria in the medium-grain column bioreactor, there were major shifts in the most abundant species present, with the type strain of Acidithiobacillus ferrooxidans dominating in the early phase of the experiment and other bacteria (At. ferrooxidans NO37 and L. ferriphilum) dominating from week 4 to week 40. With the coarse-grain column bioreactor, similar transitions in populations of iron-oxidizing chemoautotrophs were observed, though heterotrophic acidophiles were often the most abundant bacteria found in mineral leach liquors. Four bacteria not included in the mixed culture used to inoculate the columns were detected by biomolecular techniques and three of these (all

  8. Dynamic drivers of a shallow-water hydrothermal vent ecogeochemical system (Milos, Eastern Mediterranean)

    Science.gov (United States)

    Yücel, Mustafa; Sievert, Stefan; Giovanelli, Donato; Foustoukos, Dionysis; DeForce, Emelia; Thomas, François; Vetriani, Constantino; Le Bris, Nadine

    2014-05-01

    Shallow-water hydrothermal vents share many characteristics with their deep-sea analogs. However, despite ease of access, much less is known about the dynamics of these systems. Here, we report on the spatial and temporal chemical variability of a shallow-water vent system at Paleochori Bay, Milos Island, Greece, and on the bacterial and archaeal diversity of associated sandy sediments. Our multi-analyte voltammetric profiles of dissolved O2 and hydrothermal tracers (e.g. Fe2+, FeSaq, Mn2+) on sediment cores taken along a transect in hydrothermally affected sediments indicate three different areas: the central vent area (highest temperature) with a deeper penetration of oxygen into the sediment, and a lack of dissolved Fe2+ and Mn2+; a middle area (0.5 m away) rich in dissolved Fe2+ and Mn2+ (exceeding 2 mM) and high free sulfide with potential for microbial sulfide oxidation as suggested by the presence of white mats at the sediment surface; and, finally, an outer rim area (1-1.5 m away) with lower concentrations of Fe2+ and Mn2+ and higher signals of FeSaq, indicating an aged hydrothermal fluid contribution. In addition, high-frequency temperature series and continuous in situ H2S measurements with voltammetric sensors over a 6-day time period at a distance 0.5 m away from the vent center showed substantial temporal variability in temperature (32 to 46 ºC ) and total sulfide (488 to 1329 µM) in the upper sediment layer. Analysis of these data suggests that tides, winds, and abrupt geodynamic events generate intermittent mixing conditions lasting for several hours to days. Despite substantial variability, the concentration of sulfide available for chemoautotrophic microbes remained high. These findings are consistent with the predominance of Epsilonproteobacteria in the hydrothermally influenced sediments Diversity and metagenomic analyses on sediments and biofilm collected along a transect from the center to the outer rim of the vent provide further insights on

  9. Serine 363 of a Hydrophobic Region of Archaeal Ribulose 1,5-Bisphosphate Carboxylase/Oxygenase from Archaeoglobus fulgidus and Thermococcus kodakaraensis Affects CO2/O2 Substrate Specificity and Oxygen Sensitivity.

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    Nathan E Kreel

    Full Text Available Archaeal ribulose 1, 5-bisphospate carboxylase/oxygenase (RubisCO is differentiated from other RubisCO enzymes and is classified as a form III enzyme, as opposed to the form I and form II RubisCOs typical of chemoautotrophic bacteria and prokaryotic and eukaryotic phototrophs. The form III enzyme from archaea is particularly interesting as several of these proteins exhibit unusual and reversible sensitivity to molecular oxygen, including the enzyme from Archaeoglobus fulgidus. Previous studies with A. fulgidus RbcL2 had shown the importance of Met-295 in oxygen sensitivity and pointed towards the potential significance of another residue (Ser-363 found in a hydrophobic pocket that is conserved in all RubisCO proteins. In the current study, further structure/function studies have been performed focusing on Ser-363 of A. fulgidus RbcL2; various changes in this and other residues of the hydrophobic pocket point to and definitively establish the importance of Ser-363 with respect to interactions with oxygen. In addition, previous findings had indicated discrepant CO2/O2 specificity determinations of the Thermococcus kodakaraensis RubisCO, a close homolog of A. fulgidus RbcL2. It is shown here that the T. kodakaraensis enzyme exhibits a similar substrate specificity as the A. fulgidus enzyme and is also oxygen sensitive, with equivalent residues involved in oxygen interactions.

  10. Purification and biochemical characterization of the F1-ATPase from Acidithiobacillus ferrooxidans NASF-1 and analysis of the atp operon.

    Science.gov (United States)

    Wakai, Satoshi; Ohmori, Asami; Kanao, Tadayoshi; Sugio, Tsuyoshi; Kamimura, Kazuo

    2005-10-01

    ATPase was purified 51-fold from a chemoautotrophic, obligately acidophilic iron-oxidizing bacterium, Acidithiobacillus ferrooxidans NASF-1. The purified ATPase showed the typical subunit pattern of the F1-ATPase on a polyacrylamide gel containing sodium dodecyl sulfate, with 5 subunits of apparent molecular masses of 55, 50, 33, 20, and 18 kDa. The enzyme hydrolyzed ATP, GTP, and ITP, but neither UTP nor ADP. The K(m) value for ATP was 1.8 mM. ATPase activity was optimum at pH 8.5 at 45 degrees C, and was activated by sulfite. Azide strongly inhibited the enzyme activity, whereas the enzyme was relatively resistant to vanadate, nitrate, and N,N'-dicyclohexylcarbodiimide. The genes encoding the subunits for the F1F(O)-ATPase from A. ferrooxidans NASF-1 were cloned as three overlapping fragments by PCR cloning and sequenced. The molecular masses of the alpha, beta, gamma, delta, and epsilon subunits of the F1 portion were deduced from the amino acid sequences to be 55.5, 50.5, 33.1, 19.2, and 15.1 kDa, respectively. PMID:16244438

  11. Differential processing of anthropogenic carbon and nitrogen in benthic food webs of A Coruña (NW Spain) traced by stable isotopes

    Science.gov (United States)

    Bode, Antonio; Fernández, Consolación; Mompeán, Carmen; Parra, Santiago; Rozada, Fernando; Valencia-Vila, Joaquín; Viana, Inés G.

    2014-08-01

    In this study the effect of inputs of organic matter and anthropogenic nitrogen at small spatial scales were investigated in the benthos of the Ria of A Coruña (NW Spain) using stable carbon and nitrogen isotopes. This ria is characteristically enriched in nutrients provided either by marine processes (as coastal upwelling) or by urban and agricultural waste. Stable isotope composition in trophic guilds of infaunal benthos revealed spatial differences related to their nutrient inputs. The main difference was the presence of an additional chemoautotrophic food web at the site with a large accumulation of organic matter. The enrichment in heavy nitrogen isotopes observed in most compartments suggests the influence of sewage-derived nitrogen, despite large inputs of marine nitrogen. Macroalgae (Fucus vesiculosus) resulted significantly enriched at the site influenced by estuarine waters. In contrast, no differences were found in mussels (Mytilus galloprovincialis), thus suggesting a major dependence on marine nutrient sources for this species. However, the estimations of anthropogenic influence were largely dependent on assumptions required to model the different contributions of sources. The measurement of stable isotope signatures in various compartments revealed that, despite anthropogenic nutrients are readily incorporated into local food webs, a major influence of natural marine nutrient sources cannot be discarded.

  12. Lipids of Prokaryotic Origin at the Base of Marine Food Webs

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    Maria José Caramujo

    2012-11-01

    Full Text Available In particular niches of the marine environment, such as abyssal trenches, icy waters and hot vents, the base of the food web is composed of bacteria and archaea that have developed strategies to survive and thrive under the most extreme conditions. Some of these organisms are considered “extremophiles” and modulate the fatty acid composition of their phospholipids to maintain the adequate fluidity of the cellular membrane under cold/hot temperatures, elevated pressure, high/low salinity and pH. Bacterial cells are even able to produce polyunsaturated fatty acids, contrarily to what was considered until the 1990s, helping the regulation of the membrane fluidity triggered by temperature and pressure and providing protection from oxidative stress. In marine ecosystems, bacteria may either act as a sink of carbon, contribute to nutrient recycling to photo-autotrophs or bacterial organic matter may be transferred to other trophic links in aquatic food webs. The present work aims to provide a comprehensive review on lipid production in bacteria and archaea and to discuss how their lipids, of both heterotrophic and chemoautotrophic origin, contribute to marine food webs.

  13. Comparison of Vertical Distributions of Prokaryotic Assemblages in the Anoxic Cariaco Basin and Black Sea by Use of Fluorescence In Situ Hybridization†

    Science.gov (United States)

    Lin, Xueju; Wakeham, Stuart G.; Putnam, Isabell F.; Astor, Yrene M.; Scranton, Mary I.; Chistoserdov, Andrei Y.; Taylor, Gordon T.

    2006-01-01

    Individual prokaryotic cells from two major anoxic basins, the Cariaco Basin and the Black Sea, were enumerated throughout their water columns using fluorescence in situ hybridization (FISH) with the fluorochrome Cy3 or horseradish peroxidase-modified oligonucleotide probes. For both basins, significant differences in total prokaryotic abundance and phylogenetic composition were observed among oxic, anoxic, and transitional (redoxcline) waters. Epsilon-proteobacteria, Crenarchaeota, and Euryarchaeota were more prevalent in the redoxclines, where previous studies reported high rates of chemoautotrophic production relative to those in waters above and below the redoxclines. Relative abundances of Archaea in both systems varied between 1% and 28% of total prokaryotes, depending on depth. The prokaryotic community composition varied between the two anoxic basins, consistent with distinct geochemical and physical conditions. In the Black Sea, the relative contributions of group I Crenarchaeota (median, 5.5%) to prokaryotic communities were significantly higher (P < 0.001; n = 20) than those of group II Euryarchaeota (median, 2.9%). In contrast, their proportions were nearly equivalent in the Cariaco Basin. Beta-proteobacteria were unexpectedly common throughout the Cariaco Basin's water column, accounting for an average of 47% of 4′,6′-diamidino-2-phenylindole (DAPI)-stained cells. This group was below the detection limit (<1%) in the Black Sea samples. Compositional differences between basins may reflect temporal variability in microbial populations and/or systematic differences in environmental conditions and the populations for which they select. PMID:16597973

  14. Hydrogen consumption by methanogens on the early Earth

    Science.gov (United States)

    Kral, T. A.; Brink, K. M.; Miller, S. L.; McKay, C. P.; Bada, J. L. (Principal Investigator)

    1998-01-01

    It is possible that the first autotroph used chemical energy rather than light. This could have been the main source of primary production after the initial inventory of abiotic organic material had been depleted. The electron acceptor most readily available for use by this first chemoautotroph would have been CO2. The most abundant electron donor may have been H2 that would have been outgassing from volcanoes at a rate estimated to be as large as 10(12) moles yr-1, as well as from photo-oxidation of Fe+2. We report here that certain methanogens will consume H2 down to partial pressures as low as 4 Pa (4 x 10(-5) atm) with CO2 as the sole carbon source at a rate of 0.7 ng H2 min-1 microgram-1 cell protein. The lower limit of pH2 for growth of methanogens can be understood on the basis that the pH2 needs to be high enough for one ATP to be synthesized per CO2 reduced. The pH2 values needed for growth measured here are consistent with those measured by Stevens and McKinley for growth of methanogens in deep basalt aquifers. H2-consuming autotrophs are likely to have had a profound effect on the chemistry of the early atmosphere and to have been a dominant sink for H2 on the early Earth after life began rather than escape from the Earth's atmosphere to space.

  15. Trophosome of the Deep-Sea Tubeworm Riftia pachyptila Inhibits Bacterial Growth

    Science.gov (United States)

    Klose, Julia; Aistleitner, Karin; Horn, Matthias; Krenn, Liselotte; Dirsch, Verena; Zehl, Martin; Bright, Monika

    2016-01-01

    The giant tubeworm Riftia pachyptila lives in symbiosis with the chemoautotrophic gammaproteobacterium Cand. Endoriftia persephone. Symbionts are released back into the environment upon host death in high-pressure experiments, while microbial fouling is not involved in trophosome degradation. Therefore, we examined the antimicrobial effect of the tubeworm’s trophosome and skin. The growth of all four tested Gram-positive, but only of one of the tested Gram-negative bacterial strains was inhibited by freshly fixed and degrading trophosome (incubated up to ten days at either warm or cold temperature), while no effect on Saccharomyces cerevisiae was observed. The skin did not show antimicrobial effects. A liquid chromatography-mass spectrometric analysis of the ethanol supernatant of fixed trophosomes lead to the tentative identification of the phospholipids 1-palmitoleyl-2-lyso-phosphatidylethanolamine, 2-palmitoleyl-1-lyso-phosphatidylethanolamine and the free fatty acids palmitoleic, palmitic and oleic acid, which are known to have an antimicrobial effect. As a result of tissue autolysis, the abundance of the free fatty acids increased with longer incubation time of trophosome samples. This correlated with an increasing growth inhibition of Bacillus subtilis and Listeria welshimeri, but not of the other bacterial strains. Therefore, the free fatty acids produced upon host degradation could be the cause of inhibition of at least these two bacterial strains. PMID:26730960

  16. Life at the hyperarid margin: novel bacterial diversity in arid soils of the Atacama Desert, Chile

    Science.gov (United States)

    Neilson, Julia W.; Quade, Jay; Ortiz, Marianyoly; Nelson, William M.; Legatzki, Antje; Tian, Fei; LaComb, Michelle; Betancourt, Julio L.; Wing, Rod A.; Soderlund, Carol A.; Maier, Raina M.

    2012-01-01

    Nearly half the earth's surface is occupied by dryland ecosystems, regions susceptible to reduced states of biological productivity caused by climate fluctuations. Of these regions, arid zones located at the interface between vegetated semiarid regions and biologically unproductive hyperarid zones are considered most vulnerable. The objective of this study was to conduct a deep diversity analysis of bacterial communities in unvegetated arid soils of the Atacama Desert, to characterize community structure and infer the functional potential of these communities based on observed phylogenetic associations. A 454-pyrotag analysis was conducted of three unvegetated arid sites located at the hyperarid-arid margin. The analysis revealed communities with unique bacterial diversity marked by high abundances of novel Actinobacteria and Chloroflexi and low levels of Acidobacteria and Proteobacteria, phyla that are dominant in many biomes. A 16S rRNA gene library of one site revealed the presence of clones with phylogenetic associations to chemoautotrophic taxa able to obtain energy through oxidation of nitrite, carbon monoxide, iron, or sulfur. Thus, soils at the hyperarid margin were found to harbor a wealth of novel bacteria and to support potentially viable communities with phylogenetic associations to non-phototrophic primary producers and bacteria capable of biogeochemical cycling.

  17. Structural analysis of CsoS1A and the protein shell of the Halothiobacillus neapolitanus carboxysome.

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    Yingssu Tsai

    2007-06-01

    Full Text Available The carboxysome is a bacterial organelle that functions to enhance the efficiency of CO2 fixation by encapsulating the enzymes ribulose bisphosphate carboxylase/oxygenase (RuBisCO and carbonic anhydrase. The outer shell of the carboxysome is reminiscent of a viral capsid, being constructed from many copies of a few small proteins. Here we describe the structure of the shell protein CsoS1A from the chemoautotrophic bacterium Halothiobacillus neapolitanus. The CsoS1A protein forms hexameric units that pack tightly together to form a molecular layer, which is perforated by narrow pores. Sulfate ions, soaked into crystals of CsoS1A, are observed in the pores of the molecular layer, supporting the idea that the pores could be the conduit for negatively charged metabolites such as bicarbonate, which must cross the shell. The problem of diffusion across a semiporous protein shell is discussed, with the conclusion that the shell is sufficiently porous to allow adequate transport of small molecules. The molecular layer formed by CsoS1A is similar to the recently observed layers formed by cyanobacterial carboxysome shell proteins. This similarity supports the argument that the layers observed represent the natural structure of the facets of the carboxysome shell. Insights into carboxysome function are provided by comparisons of the carboxysome shell to viral capsids, and a comparison of its pores to the pores of transmembrane protein channels.

  18. The vent microbiome: patterns and drivers

    Science.gov (United States)

    Pachiadaki, M.

    2015-12-01

    Microbial processes within deep-sea hydrothermal vents affect the global biogeochemical cycles. Still, there are significant gaps in our understanding of the microbiology and the biogeochemistry of deep-sea hydrothermal systems. Vents differ in temperature, host rock composition and fluid chemistry; factors that are hypothesized to shape the distribution of the microbial communities, their metabolic capabilities and their activities. Using large-scale single cell genomics, we obtained insights into the genomic content of several linkages of a diffuse flow vent. The genomes show high metabolic versatility. Sulfur oxidation appears to be predominant but there is the potential of using a variety of e- donors and acceptors to obtain energy. To further assess the ecological importance of the vent auto- and heterotrophs, the global biogeography of the analyzed lineages will be investigated by fragment recruitment of metagenomes produced from the same site as well as other hydrothermal systems. Metatranscriptomic and metaproteomic data will be integrated to examine the expression of the predominant metabolic pathways and thus the main energy sources driving chemoautotrophic production. The comparative analysis of the key players and associated pathways among various vent sites that differ in physicochemical characteristics is anticipated to decipher the patterns and drivers of the global dispersion and the local diversification of the vent microbiome.

  19. Resource utilization and trophic position of nematodes and harpacticoid copepods in and adjacent to Zostera noltii beds

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    A.-M. Vafeiadou

    2014-01-01

    Full Text Available This study examines the resource use and trophic position of nematodes and harpacticoid copepods at the genus/species level in an estuarine food web in Zostera noltii beds and in adjacent bare sediments, using the natural abundance of stable carbon and nitrogen isotopes. Microphytobenthos is among the main resources of most taxa, but seagrass-associated resources (i.e. seagrass detritus and epiphytes also contribute to meiobenthos nutrition, with seagrass detritus being available also in deeper sediments and in unvegetated patches close to seagrass beds. A predominant dependence on chemoautotrophic bacteria was demonstrated for the nematode genus Terschellingia and the copepod family Cletodidae. A predatory feeding mode is illustrated for Paracomesoma and other Comesomatidae, which were previously considered first-level consumers (deposit feeders according to their buccal morphology. The considerable variation found in both resource use and trophic level among nematode genera from the same feeding type, and even among congeneric nematode species, shows that interpretation of nematode feeding ecology based purely on mouth morphology should be avoided.

  20. Assembly, function and evolution of cyanobacterial carboxysomes.

    Science.gov (United States)

    Kerfeld, Cheryl A; Melnicki, Matthew R

    2016-06-01

    All cyanobacteria contain carboxysomes, RuBisCO-encapsulating bacterial microcompartments that function as prokaryotic organelles. The two carboxysome types, alpha and beta, differ fundamentally in components, assembly, and species distribution. Alpha carboxysomes share a highly-conserved gene organization, with evidence of horizontal gene transfer from chemoautotrophic proteobacteria to the picocyanobacteria, and seem to co-assemble shells concomitantly with aggregation of cargo enzymes. In contrast, beta carboxysomes assemble an enzymatic core first, with an encapsulation peptide playing a critical role in formation of the surrounding shell. Based on similarities in assembly, and phylogenetic analysis of the pentameric shell protein conserved across all bacterial microcompartments, beta carboxysomes appear to be more closely related to the microcompartments of heterotrophic bacteria (metabolosomes) than to alpha carboxysomes, which appear deeply divergent. Beta carboxysomes can be found in the basal cyanobacterial clades that diverged before the ancestor of the chloroplast and have recently been shown to be able to encapsulate functional RuBisCO enzymes resurrected from ancestrally-reconstructed sequences, consistent with an ancient origin. Alpha and beta carboxysomes are not only distinct units of evolution, but are now emerging as genetic/metabolic modules for synthetic biology; heterologous expression and redesign of both the shell and the enzymatic core have recently been achieved. PMID:27060669

  1. Iron oxide deposits associated with the ectosymbiotic bacteria in the hydrothermal vent shrimp Rimicaris exoculata

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    P. Compère

    2008-09-01

    Full Text Available The Rimicaris exoculata shrimp is considered as a primary consumer that dominates the fauna of most Mid-Atlantic Ridge (MAR hydrothermal ecosystems. These shrimps harbour in their gill chambers an important ectosymbiotic community of chemoautotrophic bacteria associated with iron oxide deposits. The structure and elemental composition of the mineral concretions associated with these bacteria have been investigated by using LM, ESEM, TEM STEM and EDX microanalyses. The nature of the iron oxides in shrimps obtained from the Rainbow vent field has also been determined by Mössbauer spectroscopy. This multidisciplinary approach has revealed that the three layers of mineral crust in the Rimicaris exoculata shrimps consist of large concretions formed by aggregated nanoparticles of two-line ferrihydrite and include other minor elements as Si, Ca, Mg, S and P, probably present as silicates cations, sulphates or phosphates respectively that may contribute to stabilise the ferrihydrite form of iron oxides. TEM-observations on the bacteria have revealed their close interactions with these minerals. Abiotic and biotic precipitation could occur within the gill chamber of Rimicaris exoculata, suggesting the biologically-mediated formation of the iron oxide deposits. The difference of the bacterial density in the three-mineral crust layers could be correlated to the importance of the iron oxide concretions and suggest that the first mineral particles precipitates on the lower layer which could be considered as the most likely location of iron-oxidizing bacteria.

  2. Food Web Structure at South Su, Solwara 1 and Solwara 8 Hydrothermal Vent Sites (Manus Basin)

    Science.gov (United States)

    Honig, D. L.; Hsing, P.; Jones, R.; Schultz, T.; Sobel, A.; Thaler, A.; van Dover, C. L.

    2008-12-01

    A robust understanding of food webs in chemoautotrophically based hydrothermal vent ecosystems requires quantifying the input of local bacterial chemoautoptrophic production vs. photosynthetically derived debris from surface waters. As an initial step towards this goal for vent communities in Papua New Guinea's Manus Basin, we use isotopic ratios of carbon, nitrogen and sulfur to describe trophic relations among 17 invertebrate genera collected in July 2008 at the Solwara 1, Solwara 8 and South Su hydrothermal vent beds. Prior stable isotope work by Erickson, Macko and Van Dover (unpublished) at Manus Basin vent sites suggests that we will see relatively depleted ä13C and ä15N values for the primary consumers Ifremeria, Alviniconcha and Olgasolaris compared to secondary consumers like the mobile, scavenging genera Munidopsis, Austinograea, Alvinocaris and Chorocaris, sessile suspension feeders of the genera Eochinolasmus and Vulcanolepas, and the predatory sponge Abyssocladia. We further hypothesize that mobile fauna will exhibit greater within-genus variance of ä13C, ä15N and ä34S values than sessile genera due to mobile organisms' ability to forage for photosynthetically derived detritus.

  3. Major role of microbes in carbon fluxes during Austral winter in the Southern Drake Passage.

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    Maura Manganelli

    Full Text Available Carbon cycling in Southern Ocean is a major issue in climate change, hence the need to understand the role of biota in the regulation of carbon fixation and cycling. Southern Ocean is a heterogeneous system, characterized by a strong seasonality, due to long dark winter. Yet, currently little is known about biogeochemical dynamics during this season, particularly in the deeper part of the ocean. We studied bacterial communities and processes in summer and winter cruises in the southern Drake Passage. Here we show that in winter, when the primary production is greatly reduced, Bacteria and Archaea become the major producers of biogenic particles, at the expense of dissolved organic carbon drawdown. Heterotrophic production and chemoautotrophic CO(2 fixation rates were substantial, also in deep water, and bacterial populations were controlled by protists and viruses. A dynamic food web is also consistent with the observed temporal and spatial variations in archaeal and bacterial communities that might exploit various niches. Thus, Southern Ocean microbial loop may substantially maintain a wintertime food web and system respiration at the expense of summer produced DOC as well as regenerate nutrients and iron. Our findings have important implications for Southern Ocean ecosystem functioning and carbon cycle and its manipulation by iron enrichment to achieve net sequestration of atmospheric CO(2.

  4. Heterotrophic and Autotrophic Microbial Populations in Cold Perennial Springs of the High Arctic ▿ †

    Science.gov (United States)

    Perreault, Nancy N.; Greer, Charles W.; Andersen, Dale T.; Tille, Stefanie; Lacrampe-Couloume, Georges; Lollar, Barbara Sherwood; Whyte, Lyle G.

    2008-01-01

    The saline springs of Gypsum Hill in the Canadian high Arctic are a rare example of cold springs originating from deep groundwater and rising to the surface through thick permafrost. The heterotrophic bacteria and autotrophic sulfur-oxidizing bacteria (up to 40% of the total microbial community) isolated from the spring waters and sediments were classified into four phyla (Actinobacteria, Bacteroidetes, Firmicutes, and Proteobacteria) based on 16S rRNA gene analysis; heterotrophic isolates were primarily psychrotolerant, salt-tolerant, facultative anaerobes. Some of the isolates contained genes for thiosulfate oxidation (soxB) and anoxygenic photosynthesis (pufM), possibly enabling the strains to better compete in these sulfur-rich environments subject to long periods of illumination in the Arctic summer. Although leucine uptake by the spring water microbial community was low, CO2 uptake was relatively high under dark incubation, reinforcing the idea that primary production by chemoautotrophs is an important process in the springs. The small amounts of hydrocarbons in gases exsolving from the springs (0.38 to 0.51% CH4) were compositionally and isotopically consistent with microbial methanogenesis and possible methanotrophy. Anaerobic heterotrophic sulfur oxidation and aerobic autotrophic sulfur oxidation activities were demonstrated in sediment slurries. Overall, our results describe an active microbial community capable of sustainability in an extreme environment that experiences prolonged periods of continuous light or darkness, low temperatures, and moderate salinity, where life seems to rely on chemolithoautotrophy. PMID:18805995

  5. An Early Carboniferous seep community and hydrocarbon-derived carbonates from the Harz Mountains, Germany

    Science.gov (United States)

    Peckmann, Jörn; Gischler, Eberhard; Oschmann, Wolfgang; Reitner, Joachim

    2001-03-01

    Early Carboniferous (latest Visean) seep deposits occur on top of the drowned Middle Devonian Late Devonian Iberg atoll reef, Harz Mountains, Germany. These deposits include limestone with a low-diversity but high-abundance fauna of rhynchonellid brachiopods and rare solemyid bivalves, as well as microbial limestone. Rhynchonellids form dense, autochthonous shell accumulations and are generally articulated. They are closely associated with hydrocarbon-derived carbonates. The carbonates exhibit δ13C values as low as -32‰, relative to the Peedee belemnite standard, revealing that they are predominantly hydrocarbon derived. The fauna, carbonate fabrics, and isotope signatures provide unequivocal evidence for a seep origin of the Visean deposit. The occurrence of solemyid bivalves supports this interpretation as members of this family (1) are well known for their relationship with chemoautotrophic bacteria and (2) have been reported from ancient and modern seeps. Possible hydrocarbon sources are thermogenic methane derived from the volcanic base of the Iberg reef or methane from a petroleum reservoir.

  6. Variation in the diets of hydrothermal vent gastropods

    Science.gov (United States)

    Govenar, Breea; Fisher, Charles R.; Shank, Timothy M.

    2015-11-01

    A prevailing paradigm of hydrothermal vent ecology is that primary consumers feed on chemoautotrophic bacteria. However, for the purposes of reconstructing vent food webs and for tracking energy flow from the generation of rock and fluid chemistry through primary/ secondary productivity and consumption to the overlying water column, it remains unclear which consumers feed on which bacteria. In paired analyses of carbon and nitrogen tissue stable isotope values with unique 16S rRNA sequences from the stomach contents, we determined that two species of gastropod grazers appear to feed on epsilon-proteobacteria, while two other species have more diverse diets, including one species that consumes alpha-proteobacteria, planctomycetes, and non-green sulfur bacteria. Different carbon fixation pathways used by epsilon- and alpha-proteobacteria may account for the variation in the carbon stable isotope values among the consumers. Furthermore, our results indicate that trophic specialization and niche partitioning may contribute to the distribution and abundance of vent-endemic gastropods and support the hypothesis that consumers in the warmer habitats commonly feed on epsilon-proteobacteria that use the rTCA cycle, while in the cooler habitats they feed on additional bacteria that use the CBB cycle. These results suggest that the phylogenetic and metabolic diversity of free-living bacteria may play an important and previously overlooked role in facilitating species coexistence among primary consumers at hydrothermal vents and other chemosynthesis-based ecosystems.

  7. Shifts in the meso- and bathypelagic archaea communities composition during recovery and short-term handling of decompressed deep-sea samples.

    Science.gov (United States)

    La Cono, Violetta; Smedile, Francesco; La Spada, Gina; Arcadi, Erika; Genovese, Maria; Ruggeri, Gioacchino; Genovese, Lucrezia; Giuliano, Laura; Yakimov, Michail M

    2015-06-01

    Dark ocean microbial communities are actively involved in chemoautotrophic and anaplerotic fixation of bicarbonate. Thus, aphotic pelagic realm of the ocean might represent a significant sink of CO2 and source of primary production. However, the estimated metabolic activities in the dark ocean are fraught with uncertainties. Typically, deep-sea samples are recovered to the sea surface for downstream processing on deck. Shifts in ambient settings, associated with such treatments, can likely change the metabolic activity and community structure of deep-sea adapted autochthonous microbial populations. To estimate influence of recovery and short-term handling of deep-sea samples, we monitored the succession of bathypelagic microbial community during its 3 days long on deck incubation. We demonstrated that at the end of exposition, the deep-sea archaeal population decreased threefold, whereas the bacterial fraction doubled in size. As revealed by phylogenetic analyses of amoA gene transcripts, dominance of the active ammonium-oxidizing bathypelagic Thaumarchaeota groups shifted over time very fast. These findings demonstrated the simultaneous existence of various 'deep-sea ecotypes', differentially reacting to the sampling and downstream handling. Our study supports the hypothesis that metabolically active members of meso- and bathypelagic Thaumarchaeota possess the habitat-specific distribution, metabolic complexity and genetic divergence at subpopulation level. PMID:25682761

  8. Reconstruction of redox processes in the water column of Lake Greifen by means of 13C analyses of individual organic compounds from sediments

    International Nuclear Information System (INIS)

    Lake Greifen, an eutrophic lake in northeastern Switzerland, has become increasingly productive and its bottom waters have become anoxic. Isotopic compositions of the total organic carbon in sediments reflect this change but do not allow determination of specific chemical environments. Carbon-isotopic compositions of individual organic compounds, which here range at least from -35 to -75 per-thousand PDB, can be more informative in this regard. The n-alkanes have δ13C values between -35 and -46 per-thousand. Those with 12 to 22 carbon atoms have isotopic compositions corresponding to the lipid component of the phytoplankton currently in the surface waters of the lake. C23 - C31 n-alkanes are more depleted in 13C. Carbon isotopic compositions of hopanes range from -53 to -75 per-thousand. These compounds must derive at least partially from methanotrophs growing at the oxycline, and possibly from chemoautotrophs with utilize CO2 strongly depleted in 13C. Detailed carbon isotopic flow pathways which existed during different times in the history of the lake can be suggested. These results indicate that the organic matter in Lake Greigen sediments must have multiple origins, and that diverse organisms residing in strongly contrasting chemical environments can contribute organic materials with the potential to be preserved over geologic time scales

  9. Polymersomes Containing Iron Sulfide (FeS) as Primordial Cell Model. For the investigation of energy providing redox reactions

    Science.gov (United States)

    Alpermann, Theodor; Rüdel, Kristin; Rüger, Ronny; Steiniger, Frank; Nietzsche, Sandor; Filiz, Volkan; Förster, Stephan; Fahr, Alfred; Weigand, Wolfgang

    2011-04-01

    According to Wächtershäuser's "Iron-Sulfur-World" one major requirement for the development of life on the prebiotic Earth is compartmentalization. Vesicles spontaneously formed from amphiphilic components containing a specific set of molecules including sulfide minerals may have lead to the first autotrophic prebiotic units. The iron sulfide minerals may have been formed by geological conversions in the environment of deep-sea volcanos (black smokers), which can be observed even today. Wächtershäuser postulated the evolution of chemical pathways as fundamentals of the origin of life on earth. In contrast to the classical Miller-Urey experiment, depending on external energy sources, the "Iron-Sulfur-World" is based on the catalytic and energy reproducing redox system FeS + {H_2}S to FeS{}_2 + {H_2} . The energy release out of this redox reaction (∆RG° = -38 kJ/mol, pH 0) could be the cause for the subsequent synthesis of complex organic molecules and the precondition for the development of more complex units similar to cells known today. Here we show the possibility for precipitating iron sulfide inside vesicles composed of amphiphilic block-copolymers as a model system for a first prebiotic unit. Our findings could be an indication for a chemoautotrophic FeS based origin of life.

  10. Metagenomic Analysis from the Interior of a Speleothem in Tjuv-Ante's Cave, Northern Sweden.

    Science.gov (United States)

    Zepeda Mendoza, Marie Lisandra; Lundberg, Johannes; Ivarsson, Magnus; Campos, Paula; Nylander, Johan A A; Sallstedt, Therese; Dalen, Love

    2016-01-01

    Speleothems are secondary mineral deposits normally formed by water supersaturated with calcium carbonate percolating into underground caves, and are often associated with low-nutrient and mostly non-phototrophic conditions. Tjuv-Ante's cave is a shallow-depth cave formed by the action of waves, with granite and dolerite as major components, and opal-A and calcite as part of the speleothems, making it a rare kind of cave. We generated two DNA shotgun sequencing metagenomic datasets from the interior of a speleothem from Tjuv-Ante's cave representing areas of old and relatively recent speleothem formation. We used these datasets to perform i) an evaluation of the use of these speleothems as past biodiversity archives, ii) functional and taxonomic profiling of the speleothem's different formation periods, and iii) taxonomic comparison of the metagenomic results to previous microscopic analyses from a nearby speleothem of the same cave. Our analyses confirm the abundance of Actinobacteria and fungi as previously reported by microscopic analyses on this cave, however we also discovered a larger biodiversity. Interestingly, we identified photosynthetic genes, as well as genes related to iron and sulphur metabolism, suggesting the presence of chemoautotrophs. Furthermore, we identified taxa and functions related to biomineralization. However, we could not confidently establish the use of this type of speleothems as biological paleoarchives due to the potential leaching from the outside of the cave and the DNA damage that we propose has been caused by the fungal chemical etching. PMID:26985997

  11. Metagenomic Analysis from the Interior of a Speleothem in Tjuv-Ante's Cave, Northern Sweden.

    Directory of Open Access Journals (Sweden)

    Marie Lisandra Zepeda Mendoza

    Full Text Available Speleothems are secondary mineral deposits normally formed by water supersaturated with calcium carbonate percolating into underground caves, and are often associated with low-nutrient and mostly non-phototrophic conditions. Tjuv-Ante's cave is a shallow-depth cave formed by the action of waves, with granite and dolerite as major components, and opal-A and calcite as part of the speleothems, making it a rare kind of cave. We generated two DNA shotgun sequencing metagenomic datasets from the interior of a speleothem from Tjuv-Ante's cave representing areas of old and relatively recent speleothem formation. We used these datasets to perform i an evaluation of the use of these speleothems as past biodiversity archives, ii functional and taxonomic profiling of the speleothem's different formation periods, and iii taxonomic comparison of the metagenomic results to previous microscopic analyses from a nearby speleothem of the same cave. Our analyses confirm the abundance of Actinobacteria and fungi as previously reported by microscopic analyses on this cave, however we also discovered a larger biodiversity. Interestingly, we identified photosynthetic genes, as well as genes related to iron and sulphur metabolism, suggesting the presence of chemoautotrophs. Furthermore, we identified taxa and functions related to biomineralization. However, we could not confidently establish the use of this type of speleothems as biological paleoarchives due to the potential leaching from the outside of the cave and the DNA damage that we propose has been caused by the fungal chemical etching.

  12. Metabolic engineering of Cupriavidus necator for heterotrophic and autotrophic alka(e)ne production.

    Science.gov (United States)

    Crépin, Lucie; Lombard, Eric; Guillouet, Stéphane E

    2016-09-01

    Alkanes of defined carbon chain lengths can serve as alternatives to petroleum-based fuels. Recently, microbial pathways of alkane biosynthesis have been identified and enabled the production of alkanes in non-native producing microorganisms using metabolic engineering strategies. The chemoautotrophic bacterium Cupriavidus necator has great potential for producing chemicals from CO2: it is known to have one of the highest growth rate among natural autotrophic bacteria and under nutrient imbalance it directs most of its carbon flux to the synthesis of the acetyl-CoA derived polymer, polyhydroxybutyrate (PHB), (up to 80% of intracellular content). Alkane synthesis pathway from Synechococcus elongatus (2 genes coding an acyl-ACP reductase and an aldehyde deformylating oxygenase) was heterologously expressed in a C. necator mutant strain deficient in the PHB synthesis pathway. Under heterotrophic condition on fructose we showed that under nitrogen limitation, in presence of an organic phase (decane), the strain produced up to 670mg/L total hydrocarbons containing 435mg/l of alkanes consisting of 286mg/l of pentadecane, 131mg/l of heptadecene, 18mg/l of heptadecane, and 236mg/l of hexadecanal. We report here the highest level of alka(e)nes production by an engineered C. necator to date. We also demonstrated the first reported alka(e)nes production by a non-native alkane producer from CO2 as the sole carbon source. PMID:27212691

  13. Volumetric measurements of bacterial cells and extracellular polymeric substance glycoconjugates in biofilms.

    Science.gov (United States)

    Staudt, C; Horn, H; Hempel, D C; Neu, T R

    2004-12-01

    In this study an enrichment culture developed from activated sludge was used to investigate the architecture of fully hydrated multispecies biofilms. The assessment of biofilm structure and volume was carried out using confocal laser scanning microscopy (CLSM). Bacterial cell distribution was determined with the nucleic acid-specific stain SYTO 60, whereas glycoconjugates of extracellular polymeric substances (EPS) were stained with the Alexa-488-labeled lectin of Aleuria aurantia. Digital image analysis was employed for visualization and quantification of three-dimensional CLSM data sets. The specific volumes of the polymeric and cellular biofilm constituents were quantified. In addition, gravimetric measurements were done to determine dry mass and thickness of the biofilms. The data recorded by the CLSM technique and the gravimetric data were then compared. It was shown that the biofilm thicknesses determined with both methods agree well for slow-growing heterotrophic and chemoautotrophic biofilms. In addition, for slow-growing biofilms, the volumes and masses calculated from CLSM and the biomass calculated from gravimetric measurements were also comparable. For fast-growing heterotrophic biofilms cultivated with high glucose concentrations the data sets fit to a lesser degree, but still showed the same common trend. Compared with traditional gravimetric measurements, CLSM allowed differential recording of multiple biofilm parameters with subsequent three-dimensional visualization and quantification. The quantitative three-dimensional results recorded by CLSM are an important basis for understanding, controlling, exploiting, and modeling of biofilms. PMID:15470707

  14. Carboxysomal carbonic anhydrases: Structure and role in microbial CO2 fixation

    Energy Technology Data Exchange (ETDEWEB)

    Cannon, Gordon C.; Heinhorst, Sabine; Kerfeld, Cheryl A.

    2010-06-23

    Cyanobacteria and some chemoautotrophic bacteria are able to grow in environments with limiting CO2 concentrations by employing a CO2-concentrating mechanism (CCM) that allows them to accumulate inorganic carbon in their cytoplasm to concentrations several orders of magnitude higher than that on the outside. The final step of this process takes place in polyhedral protein microcompartments known as carboxysomes, which contain the majority of the CO2-fixing enzyme, RubisCO. The efficiency of CO2 fixation by the sequestered RubisCO is enhanced by co-localization with a specialized carbonic anhydrase that catalyzes dehydration of the cytoplasmic bicarbonate and ensures saturation of RubisCO with its substrate, CO2. There are two genetically distinct carboxysome types that differ in their protein composition and in the carbonic anhydrase(s) they employ. Here we review the existing information concerning the genomics, structure and enzymology of these uniquely adapted carbonic anhydrases, which are of fundamental importance in the global carbon cycle.

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

    Science.gov (United States)

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

    1997-01-01

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

  16. Predictive isotopic biogeochemistry: hydrocarbons from anoxic marine basins

    Science.gov (United States)

    Freeman, K. H.; Wakeham, S. G.; Hayes, J. M.

    1994-01-01

    Carbon isotopic compositions were determined for individual hydrocarbons in water column and sediment samples from the Cariaco Trench and Black Sea. In order to identify hydrocarbons derived from phytoplankton, the isotopic compositions expected for biomass of autotrophic organisms living in surface waters of both localities were calculated based on the concentrations of CO2(aq) and the isotopic compositions of dissolved inorganic carbon. These calculated values are compared to measured delta values for particulate organic carbon and for individual hydrocarbon compounds. Specifically, we find that lycopane is probably derived from phytoplankton and that diploptene is derived from the lipids of chemoautotrophs living above the oxic/anoxic boundary. Three acyclic isoprenoids that have been considered markers for methanogens, pentamethyleicosane and two hydrogenated squalenes, have different delta values and apparently do not derive from a common source. Based on the concentration profiles and isotopic compositions, the C31 and C33 n-alkanes and n-alkenes have a similar source, and both may have a planktonic origin. If so, previously assigned terrestrial origins of organic matter in some Black Sea sediments may be erroneous.

  17. Effects of inorganic carbon limitation on anaerobic ammonium oxidation (anammox) activity.

    Science.gov (United States)

    Kimura, Yuya; Isaka, Kazuichi; Kazama, Futaba

    2011-03-01

    Anammox bacteria are chemoautotrophic bacteria that oxidize ammonium with nitrite as the electron acceptor and with CO(2) as the main carbon source. The effects of inorganic carbon (IC) limitation on anammox bacteria were investigated using continuous feeding tests. In this study, a gel carrier with entrapped anammox sludge was used. It was clearly shown that the anammox activity deteriorated with a decrease in the influent IC concentration. The relationship between the influent IC concentration and the anammox activity was analyzed using Michaelis-Menten kinetics, and the apparent K(m) was determined to be 1.2mg-C/L. The activity could be recovered by adding IC to the influent. The consumption ratio of IC to ammonium was not constant and mainly depended on the influent ratio of the IC to ammonium concentrations (inf.IC/inf.NH(4)-N). The results indicated that an inf.IC/inf.NH(4)-N ratio of 0.2 in the anammox reactor was ideal for the anammox process using gel cubes. PMID:21256745

  18. Carbon isotopes in biological carbonates: Respiration and photosynthesis

    Science.gov (United States)

    McConnaughey, T.A.; Burdett, J.; Whelan, J.F.; Paull, C.K.

    1997-01-01

    Respired carbon dioxide is an important constituent in the carbonates of most air breathing animals but is much less important in the carbonates of most aquatic animals. This difference is illustrated using carbon isotope data from freshwater and terrestrial snails, ahermatypic corals, and chemoautotrophic and methanotrophic pelecypods. Literature data from fish otoliths and bird and mammal shell and bone carbonates are also considered. Environmental CO2/O2 ratios appear to be the major controlling variable. Atmospheric CO2/O2 ratios are about thirty times lower than in most natural waters, hence air breathing animals absorb less environmental CO2 in the course of obtaining O2. Tissue CO2 therefore, does not isotopically equilibrate with environmental CO2 as thoroughly in air breathers as in aquatic animals, and this is reflected in skeletal carbonates. Animals having efficient oxygen transport systems, such as vertebrates, also accumulate more respired CO2 in their tissues. Photosynthetic corals calcify mainly during the daytime when photosynthetic CO2 uptake is several times faster than respiratory CO2 release. Photosynthesis, therefore, affects skeletal ??13C more strongly than does respiration. Corals also illustrate how "metabolic" effects on skeletal isotopic composition can be estimated, despite the presence of much larger "kinetic" isotope effects. Copyright ?? 1997 Elsevier Science Ltd.

  19. The microbial arsenic cycle in Mono Lake, California.

    Science.gov (United States)

    Oremland, Ronald S; Stolz, John F; Hollibaugh, James T

    2004-04-01

    Significant concentrations of dissolved inorganic arsenic can be found in the waters of a number of lakes located in the western USA and in other water bodies around the world. These lakes are often situated in arid, volcanic terrain. The highest concentrations of arsenic occur in hypersaline, closed basin soda lakes and their remnant brines. Although arsenic is a well-known toxicant to eukaryotes and prokaryotes alike, some prokaryotes have evolved biochemical mechanisms to exploit arsenic oxyanions (i.e., arsenate and arsenite); they can use them either as an electron acceptor for anaerobic respiration (arsenate), or as an electron donor (arsenite) to support chemoautotrophic fixation of CO(2) into cell carbon. Unlike in freshwater or marine ecosystems, these processes may assume quantitative significance with respect to the carbon cycle in arsenic-rich soda lakes. For the past several years our research has focused on the occurrence and biogeochemical manifestations of these processes in Mono Lake, a particularly arsenic-rich environment. Herein we review some of our findings concerning the biogeochemical arsenic cycle in this lake, with the hope that it may broaden the understanding of the influence of microorganisms upon the speciation of arsenic in more common, less "extreme" environments, such as drinking water aquifers. PMID:19712427

  20. Polymersomes containing iron sulfide (FeS) as primordial cell model : for the investigation of energy providing redox reactions.

    Science.gov (United States)

    Alpermann, Theodor; Rüdel, Kristin; Rüger, Ronny; Steiniger, Frank; Nietzsche, Sandor; Filiz, Volkan; Förster, Stephan; Fahr, Alfred; Weigand, Wolfgang

    2011-04-01

    According to Wächtershäuser's "Iron-Sulfur-World" one major requirement for the development of life on the prebiotic Earth is compartmentalization. Vesicles spontaneously formed from amphiphilic components containing a specific set of molecules including sulfide minerals may have lead to the first autotrophic prebiotic units. The iron sulfide minerals may have been formed by geological conversions in the environment of deep-sea volcanos (black smokers), which can be observed even today. Wächtershäuser postulated the evolution of chemical pathways as fundamentals of the origin of life on earth. In contrast to the classical Miller-Urey experiment, depending on external energy sources, the "Iron-Sulfur-World" is based on the catalytic and energy reproducing redox system FeS+H2S-->FeS2+H2. The energy release out of this redox reaction (∆RG°=-38 kJ/mol, pH 0) could be the cause for the subsequent synthesis of complex organic molecules and the precondition for the development of more complex units similar to cells known today. Here we show the possibility for precipitating iron sulfide inside vesicles composed of amphiphilic block-copolymers as a model system for a first prebiotic unit. Our findings could be an indication for a chemoautotrophic FeS based origin of life. PMID:20697814

  1. The microbial world and the case for Mars

    Science.gov (United States)

    Horneck, Gerda

    2000-09-01

    Microbial prokaryotes have flourished on Earth for more than 3.5 Ga. They dominated the Earth's biosphere during the first 2 Ga of its history before the first unicellular mitotic eukaryotes appeared. Therefore, in a search for extant life beyond the Earth, microorganisms are the most likely candidates for a putative biota of an extraterrestrial habitat. On Earth, life has developed strategies to cope with the so-called extreme conditions, such as hot vents, permafrost, permanent ice, subsurface regions, high atmosphere, rocks or salt crystals. By analogy with terrestrial extremophile communities, potential protected niches have been postulated for Mars, such as sulfur-rich sub-surface areas for chemoautotrophic communities, rocks for endolithic communities, permafrost regions, hydrothermal vents, soil, or evaporite crystals. Several methods exist to trace and identify microbial communities on Earth. Some of these biogenic signatures and biomarkers may also be applicable in attempts to search for life on Mars. However, the search for signatures indicative for putative extant life on Mars can only be the final steps in a research strategy in the quest for extraterrestrial life. In particular, prior to any "search for extant life" experiment, more data are required on the geology (paleolakes, volcanism, hydrothermal vents, carbonates), climate (hydrosphere, duration of phases which allow liquid water) and radiation environment, present state and past evolution as well as organic molecules in sediments. The search for possible biological oases will be connected with the detection of areas where liquid water still exists under the current conditions on that planet.

  2. Stable carbon isotope fractionation by methanogens growing on different Mars regolith analogs

    Science.gov (United States)

    Sinha, Navita; Kral, Timothy A.

    2015-07-01

    In order to characterize stable carbon (13C/12C) isotope fractionation of metabolically produced methane by methanogens in martian settings, Methanothermobacter wolfeii, Methanosarcina barkeri, and Methanobacterium formicicum were cultured on four different Mars regolith analogs - JSC Mars-1, Artificial Mars Simulant, montmorillonite, and Mojave Mars Simulant - and also in their growth supporting media. These chemoautotrophic methanogens utilize CO2 for their carbon source and H2 for their energy source. When compared to the carbon isotope signature of methane when grown on their respective growth media, M. wolfeii and M. barkeri demonstrated variability in carbon isotope fractionation values during methanogenesis on the Mars analogs, while M. formicicum showed subtle or negligible difference in carbon isotope fractionation values. Interestingly, M. wolfeii and M. barkeri have shown relatively consistent enriched values of 12C on montmorillonite, a kind of clay found on Mars, compared to other Mars regolith analogs. In general, M. barkeri showed large carbon isotope fractionation compared to M. wolfeii and M. formicicum during methanognesis on various kinds of analogs. Stable carbon isotope fractionation is one of the techniques used to infer different origins, environments, and pathways of methanogensis. The results obtained in this novel research can provide clues to determine ambiguous sources of methane on Mars.

  3. Comparative genomics of vesicomyid clam (Bivalvia: Mollusca chemosynthetic symbionts

    Directory of Open Access Journals (Sweden)

    Girguis Peter R

    2008-12-01

    Full Text Available Abstract Background The Vesicomyidae (Bivalvia: Mollusca are a family of clams that form symbioses with chemosynthetic gamma-proteobacteria. They exist in environments such as hydrothermal vents and cold seeps and have a reduced gut and feeding groove, indicating a large dependence on their endosymbionts for nutrition. Recently, two vesicomyid symbiont genomes were sequenced, illuminating the possible nutritional contributions of the symbiont to the host and making genome-wide evolutionary analyses possible. Results To examine the genomic evolution of the vesicomyid symbionts, a comparative genomics framework, including the existing genomic data combined with heterologous microarray hybridization results, was used to analyze conserved gene content in four vesicomyid symbiont genomes. These four symbionts were chosen to include a broad phylogenetic sampling of the vesicomyid symbionts and represent distinct chemosynthetic environments: cold seeps and hydrothermal vents. Conclusion The results of this comparative genomics analysis emphasize the importance of the symbionts' chemoautotrophic metabolism within their hosts. The fact that these symbionts appear to be metabolically capable autotrophs underscores the extent to which the host depends on them for nutrition and reveals the key to invertebrate colonization of these challenging environments.

  4. The Biological Deep Sea Hydrothermal Vent as a Model to Study Carbon Dioxide Capturing Enzymes

    Directory of Open Access Journals (Sweden)

    Premila D. Thongbam

    2011-04-01

    Full Text Available Deep sea hydrothermal vents are located along the mid-ocean ridge system, near volcanically active areas, where tectonic plates are moving away from each other. Sea water penetrates the fissures of the volcanic bed and is heated by magma. This heated sea water rises to the surface dissolving large amounts of minerals which provide a source of energy and nutrients to chemoautotrophic organisms. Although this environment is characterized by extreme conditions (high temperature, high pressure, chemical toxicity, acidic pH and absence of photosynthesis a diversity of microorganisms and many animal species are specially adapted to this hostile environment. These organisms have developed a very efficient metabolism for the assimilation of inorganic CO2 from the external environment. In order to develop technology for the capture of carbon dioxide to reduce greenhouse gases in the atmosphere, enzymes involved in CO2 fixation and assimilation might be very useful. This review describes some current research concerning CO2 fixation and assimilation in the deep sea environment and possible biotechnological application of enzymes for carbon dioxide capture.

  5. The spatial scale of genetic subdivision in populations of Ifremeria nautilei, a hydrothermal-vent gastropod from the southwest Pacific

    Directory of Open Access Journals (Sweden)

    Thaler Andrew D

    2011-12-01

    Full Text Available Abstract Background Deep-sea hydrothermal vents provide patchy, ephemeral habitats for specialized communities of animals that depend on chemoautotrophic primary production. Unlike eastern Pacific hydrothermal vents, where population structure has been studied at large (thousands of kilometres and small (hundreds of meters spatial scales, population structure of western Pacific vents has received limited attention. This study addresses the scale at which genetic differentiation occurs among populations of a western Pacific vent-restricted gastropod, Ifremeria nautilei. Results We used mitochondrial and DNA microsatellite markers to infer patterns of gene flow and population subdivision. A nested sampling strategy was employed to compare genetic diversity in discrete patches of Ifremeria nautilei separated by a few meters within a single vent field to distances as great as several thousand kilometres between back-arc basins that encompass the known range of the species. No genetic subdivisions were detected among patches, mounds, or sites within Manus Basin. Although I. nautilei from Lau and North Fiji Basins (~1000 km apart also exhibited no evidence for genetic subdivision, these populations were genetically distinct from the Manus Basin population. Conclusions An unknown process that restricts contemporary gene flow isolates the Manus Basin population of Ifremeria nautilei from widespread populations that occupy the North Fiji and Lau Basins. A robust understanding of the genetic structure of hydrothermal vent populations at multiple spatial scales defines natural conservation units and can help minimize loss of genetic diversity in situations where human activities are proposed and managed.

  6. Validating the Incorporation of 13C and 15N in a Shorebird That Consumes an Isotopically Distinct Chemosymbiotic Bivalve.

    Science.gov (United States)

    van Gils, Jan A; Ahmedou Salem, Mohamed Vall

    2015-01-01

    The wealth of field studies using stable isotopes to make inferences about animal diets require controlled validation experiments to make proper interpretations. Despite several pleas in the literature for such experiments, validation studies are still lagging behind, notably in consumers dwelling in chemosynthesis-based ecosystems. In this paper we present such a validation experiment for the incorporation of 13C and 15N in the blood plasma of a medium-sized shorebird, the red knot (Calidris canutus canutus), consuming a chemosymbiotic lucinid bivalve (Loripes lucinalis). Because this bivalve forms a symbiosis with chemoautotrophic sulphide-oxidizing bacteria living inside its gill, the bivalve is isotopically distinct from 'normal' bivalves whose food has a photosynthetic basis. Here we experimentally tested the hypothesis that isotope discrimination and incorporation dynamics are different when consuming such chemosynthesis-based prey. The experiment showed that neither the isotopic discrimination factor, nor isotopic turnover time, differed between birds consuming the chemosymbiotic lucinid and a control group consuming a photosynthesis-based bivalve. This was true for 13C as well as for 15N. However, in both groups the 15N discrimination factor was much higher than expected, which probably had to do with the birds losing body mass over the course of the experiment. PMID:26458005

  7. Validating the Incorporation of 13C and 15N in a Shorebird That Consumes an Isotopically Distinct Chemosymbiotic Bivalve.

    Directory of Open Access Journals (Sweden)

    Jan A van Gils

    Full Text Available The wealth of field studies using stable isotopes to make inferences about animal diets require controlled validation experiments to make proper interpretations. Despite several pleas in the literature for such experiments, validation studies are still lagging behind, notably in consumers dwelling in chemosynthesis-based ecosystems. In this paper we present such a validation experiment for the incorporation of 13C and 15N in the blood plasma of a medium-sized shorebird, the red knot (Calidris canutus canutus, consuming a chemosymbiotic lucinid bivalve (Loripes lucinalis. Because this bivalve forms a symbiosis with chemoautotrophic sulphide-oxidizing bacteria living inside its gill, the bivalve is isotopically distinct from 'normal' bivalves whose food has a photosynthetic basis. Here we experimentally tested the hypothesis that isotope discrimination and incorporation dynamics are different when consuming such chemosynthesis-based prey. The experiment showed that neither the isotopic discrimination factor, nor isotopic turnover time, differed between birds consuming the chemosymbiotic lucinid and a control group consuming a photosynthesis-based bivalve. This was true for 13C as well as for 15N. However, in both groups the 15N discrimination factor was much higher than expected, which probably had to do with the birds losing body mass over the course of the experiment.

  8. Landscape-scale effects of fire severity on mixed-conifer and red fir forest structure in Yosemite National Park

    Science.gov (United States)

    Kane, Van R.; Lutz, James A.; Roberts, Susan L.; Smith, Douglas F.; McGaughey, Robert J.; Povak, Nicholas A.; Brooks, Matthew L.

    2013-01-01

    While fire shapes the structure of forests and acts as a keystone process, the details of how fire modifies forest structure have been difficult to evaluate because of the complexity of interactions between fires and forests. We studied this relationship across 69.2 km2 of Yosemite National Park, USA, that was subject to 32 fires ⩾40 ha between 1984 and 2010. Forests types included ponderosa pine (Pinus ponderosa), white fir-sugar pine (Abies concolor/Pinus lambertiana), and red fir (Abies magnifica). We estimated and stratified burned area by fire severity using the Landsat-derived Relativized differenced Normalized Burn Ratio (RdNBR). Airborne LiDAR data, acquired in July 2010, measured the vertical and horizontal structure of canopy material and landscape patterning of canopy patches and gaps. Increasing fire severity changed structure at the scale of fire severity patches, the arrangement of canopy patches and gaps within fire severity patches, and vertically within tree clumps. Each forest type showed an individual trajectory of structural change with increasing fire severity. As a result, the relationship between estimates of fire severity such as RdNBR and actual changes appears to vary among forest types. We found three arrangements of canopy patches and gaps associated with different fire severities: canopy-gap arrangements in which gaps were enclosed in otherwise continuous canopy (typically unburned and low fire severities); patch-gap arrangements in which tree clumps and gaps alternated and neither dominated (typically moderate fire severity); and open-patch arrangements in which trees were scattered across open areas (typically high fire severity). Compared to stands outside fire perimeters, increasing fire severity generally resulted first in loss of canopy cover in lower height strata and increased number and size of gaps, then in loss of canopy cover in higher height strata, and eventually the transition to open areas with few or no trees. However

  9. Developing a Long-Term Forest Gap Model to Predict the Behavior of California Pines, Oaks, and Cedars Under Climate Change and Other Disturbance Scenarios

    Science.gov (United States)

    Davis, S. L.; Moran, E.

    2015-12-01

    Many predictions about how trees will respond to climate change have been made, but these often rely on extrapolating into the future one of two extremes: purely correlative factors like climate, or purely physiological factors unique to a particular species or plant functional group. We are working towards a model that combines both phenotypic and genotypic traits to better predict responses of trees to climate change. We have worked to parameterize a neighborhood dynamics, individual tree forest-gap model called SORTIE-ND, using open data from both the USDA Forest Service Forest Inventory & Analysis (FIA) datasets in California and 30-yr old permanent plots established by the USGS. We generated individual species factors including stage-specific mortality and growth rates, and species-specific allometric equations for ten species, including Abies concolor, A. magnifica, Calocedrus decurrens, Pinus contorta, P. jeffreyi, P. lambertiana, P. monticola, P. ponderosa, and the two hardwoods Quercus chrysolepis and Q. kelloggii. During this process, we also developed two R packages to aid in parameter development for SORTIE-ND in other ecological systems. MakeMyForests is an R package that parses FIA datasets and calculates parameters based on the state averages of growth, light, and allometric parameters. disperseR is an R package that uses extensive plot data, with individual tree, sapling, and seedling measurements, to calculate finely tuned mortality and growth parameters for SORTIE-ND. Both are freely available on GitHub, and future updates will be available on CRAN. To validate the model, we withheld several plots from the 30-yr USGS data while calculating parameters. We tested for differences between the actual withheld data and the simulated forest data, in basal area, seedling density, seed dispersal, and species composition. The similarity of our model to the real system suggests that the model parameters we generated with our R packages accurately represent

  10. Atmospheric deposition and solute export in giant sequoia: mixed conifer watersheds in the Sierra Nevada, California

    Science.gov (United States)

    Stohlgren, Thomas J.; Melack, John M.; Esperanza, Anne M.; Parsons, David J.

    1991-01-01

    Atmospheric depostion and stream discharge and solutes were measured for three years (September 1984 - August 1987) in two mixed conifer watersheds in Sequoia National Park, in the southern Sierra Nevada of California. The Log Creek watershed (50 ha, 2067-2397 m elev.) is drained by a perennial stream, while Tharp's Creek watershed (13 ha, 2067-2255 m elev.) contains an intermittent stream. Dominant trees in the area include Abies concolor (white fir), Sequoiadendron giganteum (giant sequoia), A. magnifica (red fir), and Pinus lambertiana (sugar pine). Bedrock is predominantly granite and granodiorite, and the soils are mostly Pachic Xerumbrepts. Over the three year period, sulfate (SO42-), nitrate (NO3-), and chloride (Cl-) were the major anions in bulk precipitation with volume-weighted average concentrations of 12.6, 12.3 and 10.0 μeq/1, respectively. Annual inputs of NO3-N, NH4-N and SO4-S from wet deposition were about 60 to 75% of those reported from bulk deposition collectors. Discharge from the two watersheds occurs primarily during spring snowmelt. Solute exports from Log and Tharp's Creeks were dominated by HCO3-, Ca2+ and Na+, while H+, NO3-, NH4+ and PO43- outputs were relatively small. Solute concentrations were weakly correlated with instantaneous stream flow for all solutes (r2 3- (Log Cr. r2=0.72; Tharp's Cr. r2=0.38), Na+ (Log Cr. r2=0.56; Tharp's Cr. r2=0.47), and silicate (Log Cr. r2=0.71; Tharp's Cr. r2=0.49). Mean annual atmospheric contributions of NO3-N (1.6 kg ha-1), NH4-N (1.7 kg ha-1), and SO4-S (1.8 kg ha-1), which are associated with acidic deposition, greatly exceed hydrologic losses. Annual watershed yields (expressed as eq ha-1) of HCO3- exceeded by factors of 2.5 to 37 the annual atmospheric deposition of H+.

  11. MICROTOMOGRAFIA DE ALTA RESOLUÇÃO NO SETOR MINERAL

    Directory of Open Access Journals (Sweden)

    Daniel Uliana

    2014-07-01

    Full Text Available A técnica de microscopia por tomografia de raios X (MRX oferece uma capacidade única para análise de associações, morfologia e liberação de múltiplas fases através da aquisição direta de imagens tridimensionais de alta resolução. Trata-se de uma técnica de análise 3D não invasiva atualmente utilizada no setor mineral para caracterização de carvão, minerais industriais e de base, além de metais preciosos, complementando técnicas de microscopia já existentes como MLA e QEMSCAN. A técnica já é empregada há algum tempo na indústria do petróleo para a caracterização de tamanho e distribuição de poros, permitindo simular o fluxo de óleo em rochas reservatório. Além disso, a caracterização de poros em 3D permite a simulação de fluxo em processos de lixiviação. Requerendo pouca ou nenhuma preparação da amostra, comparativamente às técnicas de microscopia bi ou unidimensionais proporciona vantagens como a preparação muito mais ágil da amostra, aquisição direta de dados volumétricos, análise quantitativa em 3D e menor tempo de análise aliado a maior representatividade do material analisado. Particularmente em estudos de metais preciosos, tem-se um significativo aumento na probabilidade de detecção dos minerais de interesse. Recentes avanços com o emprego de dupla magnificação – projeção cônica aliada à utilização de lentes ópticas - possibilitam a aquisição de imagens com resolução submicrométrica com sensível melhoria no contraste entre as fases.

  12. Influence of increasing dissolved inorganic carbon concentrations and decreasing pH on chemolithoautrophic bacteria from oxic-sulfidic interfaces

    Science.gov (United States)

    Mammitzsch, K.; Jost, G.; Jürgens, K.

    2012-12-01

    Increases in the dissolved inorganic carbon (DIC) concentration are expected to cause a decrease in the pH of ocean waters, a process known as ocean acidification. In oxygen-deficient zones this will add to already increased DIC and decreased pH values. It is not known how this might affect microbial communities and microbially mediated processes. In this study, the potential effects of ocean acidification on chemolithoautotrophic prokaryotes of marine oxic-anoxic transition zones were investigated, using the chemoautotrophic denitrifying ɛ-proteobacterium "Sulfurimonas gotlandica" strain GD1 as a model organism. This and related taxa use reduced sulfur compounds, e.g. sulfide and thiosulfate, as electron donors and were previously shown to be responsible for nitrate removal and sulfide detoxification in redox zones of the Baltic Sea water column but occur also in other oxygen-deficient marine systems. Bacterial cell growth within a broad range of DIC concentrations and pH values was monitored and substrate utilization was determined. The results showed that the DIC saturation concentration for growth was already reached at 800 μM, which is well below in situ DIC levels. The pH optimum was between 6.6 and 8.0. Within a pH range of 6.6-7.1 there was no significant difference in substrate utilization; however, at lower pH values cell growth decreased sharply and cell-specific substrate consumption increased. These findings suggest that a direct effect of ocean acidification, with the predicted changes in pH and DIC, on chemolithoautotrophic bacteria such as "S. gotlandica" str. GD1 is generally not very probable.

  13. Biostimulation induces syntrophic interactions that impact C, S and N cycling in a sediment microbial community

    Energy Technology Data Exchange (ETDEWEB)

    Handley, KM [University of California, Berkeley; Verberkmoes, Nathan C [ORNL; Steefel, Carl I [Lawrence Berkeley National Laboratory (LBNL); Sharon, I [University of California, Berkeley; Williams, Ken [Lawrence Berkeley National Laboratory (LBNL); Miller, CS [University of California, Berkeley; Frischkorn, Kyle C [University of California, Berkeley; Chourey, Karuna [ORNL; Thomas, Brian [University of California, Berkeley; Shah, Manesh B [ORNL; Long, Phil [Pacific Northwest National Laboratory (PNNL); Hettich, Robert {Bob} L [ORNL; Banfield, Jillian F. [University of California, Berkeley

    2013-01-01

    Stimulation of subsurface microorganisms to induce reductive immobilization of metals is a promising approach for bioremediation, yet the overall microbial community response is typically poorly understood. Here we used community proteogenomics to test the hypothesis that excess input of acetate activates syntrophic interactions among autotrophs and heterotrophs. A flow-through sediment column was incubated in a groundwater well of an acetate-amended aquifer. Genomic sequences from the community recovered during microbial sulfate reduction were used to econstruct, de novo, near-complete genomes for Desulfobacter (Deltaproteobacteria) and relatives of Sulfurovum and Sulfurimonas (Epsilonproteobacteria), and Bacteroidetes. Partial genomes were obtained for Clostridiales (Firmicutes) and Desulfuromonadales-like Deltaproteobacteria. The majority of proteins identified by mass spectrometry corresponded to Desulfobacter-like species, and demonstrate the role of this organism in sulfate reduction (Dsr and APS), nitrogen-fixation (Nif) and acetate oxidation to CO2 during amendment. Results suggest less abundant Desulfuromonadales and Bacteroidetes also actively contributed to CO2 production via the TCA cycle. Proteomic data indicate that sulfide was partially re-oxidized by Epsilonproteobacteria through nitrate-dependent sulfide oxidation (using Nap, Nir, Nos, SQR and Sox), with CO2 fixed using the reverse TCA cycle. Modeling shows that this reaction was thermodynamically possible, and kinetically favorable relative to acetate-dependent denitrification. We conclude that high-levels of carbon amendment aimed to stimulate anaerobic heterotrophy led to carbon fixation in co-dependent chemoautotrophs. These results have implications for understanding complex ecosystem behavior, and show that high levels of organic carbon supplementation can expand the range of microbial functionalities accessible for ecosystem manipulation.

  14. The genome of the intracellular bacterium of the coastal bivalve, Solemya velum: A blueprint for thriving in and out of symbiosis

    Energy Technology Data Exchange (ETDEWEB)

    Dmytrenko, Oleg; Russell, Shelbi L.; Loo, Wesley T.; Fontanez, Kristina M.; Liao, Li; Roeselers, Guus; Sharma, Raghav; Stewart, Frank J.; Newton, Irene L. G.; Woyke, Tanja; Wu, Dongying; Lang, Jenna Morgan; Eisen, Jonathan A.; Cavanaugh, Colleen M.

    2014-09-25

    Background: Symbioses between chemoautotrophic bacteria and marine invertebrates are rare examples of living systems that are virtually independent of photosynthetic primary production. These associations have evolved multiple times in marine habitats, such as deep-sea hydrothermal vents and reducing sediments, characterized by steep gradients of oxygen and reduced chemicals. Due to difficulties associated with maintaining these symbioses in the laboratory and culturing the symbiotic bacteria, studies of chemosynthetic symbioses rely heavily on culture independent methods. The symbiosis between the coastal bivalve, Solemya velum, and its intracellular symbiont is a model for chemosynthetic symbioses given its accessibility in intertidal environments and the ability to maintain it under laboratory conditions. To better understand this symbiosis, the genome of the S. velum endosymbiont was sequenced. Results: Relative to the genomes of obligate symbiotic bacteria, which commonly undergo erosion and reduction, the S. velum symbiont genome was large (2.86 Mb), GC-rich (50.4percent), and contained a large number (78) of mobile genetic elements. Comparative genomics identified sets of genes specific to the chemosynthetic lifestyle and necessary to sustain the symbiosis. In addition, a number of inferred metabolic pathways and cellular processes, including heterotrophy, branched electron transport, and motility, suggested that besides the ability to function as an endosymbiont, the bacterium may have the capacity to live outside the host. Conclusions: The physiological dexterity indicated by the genome substantially improves our understanding of the genetic and metabolic capabilities of the S. velum symbiont and the breadth of niches the partners may inhabit during their lifecycle

  15. Assessment of biotechnological strategies for the valorization of metal bearing wastes

    International Nuclear Information System (INIS)

    Highlights: ► We examine biological strategies to valorize different metal rich solid waste. ► Bacteria play a key role in the mobilization of Zn and Y from fluorescent powders. ► Ferrous iron is crucial for the bioleaching of Ni, V, Mo from spent catalysts. ► No biological effect is observed for Ni, Zn, As, Cr mobilisation from sediments. - Abstract: The present work deals with the application of biotechnology for the mobilization of metals from different solid wastes: end of life industrial catalysts, heavy metal contaminated marine sediments and fluorescent powders coming from a cathode ray tube glass recycling process. Performed experiments were aimed at assessing the performance of acidophilic chemoautotrophic Fe/S-oxidizing bacteria for such different solid matrices, also focusing on the effect of solid concentration and of different substrata. The achieved results have evidenced that metal solubilization seems to be strongly influenced by the metal speciation and partitioning in the solid matrix. No biological effect was observed for Ni, Zn, As, Cr mobilization from marine sediments (34%, 44%, 15%, 10% yields, respectively) due to metal partitioning. On the other hand, for spent refinery catalysts (Ni, V, Mo extractions of 83%, 90% and 40%, respectively) and fluorescent powders (Zn and Y extraction of 55% and 70%, respectively), the improvement in metal extraction observed in the presence of a microbial activity confirms the key role of Fe/S oxidizing bacteria and ferrous iron. A negative effect of solid concentration was in general observed on bioleaching performances, due to the toxicity of dissolved metals and/or to the solid organic component.

  16. Subsurface Organics in Aseptic Cores From the MARTE Robotic Drilling Experiment: Ground truth and Contamination Issues

    Science.gov (United States)

    Bonaccorsi, R.; Stoker, C. R.

    2006-12-01

    The subsurface is the key environment for searching for life on planets lacking surface life. This includes the search for past/present life on Mars where possible subsurface life could exist [1]. The Mars-Analog-Rio-Tinto-Experiment (MARTE) performed a simulation of a Mars robotic drilling at the RT Borehole#7 Site ~6.07m, atop a massive-pyrite deposit from the Iberian Pyritic Belt. The RT site is considered an important analog of Sinus Meridiani on Mars, an ideal model analog for a subsurface Martian setting [2], and a relevant example of deep subsurface microbial community including aerobic and anaerobic chemoautotrophs [4-5]. Searching for microbes or bulk organics of biological origin in a subsurface sample from a planet is a key scientific objective of Robotic drilling missions. During the 2005 Field experiment 28 minicores were robotically handled and subsampled for life detection experiments under anti-contamination protocols. Ground truth included visual observation of cores and lab based Elemental and Isotope Ratios Mass Spectrometry analysis (EA-IRMS) of bulk organics in Hematite and Gohetite-rich gossanized tuffs, gossan and clay layers within 0-6m-depth. C-org and N-tot vary up to four orders of magnitude among the litter (~11Wt%, 0-1cm) and the mineralized (~3Wt%, 1-3cm) layers, and the first 6 m-depth (C-org=0.02-0.38Wt%). Overall, the distribution/ preservation of plant and soil-derived organics (d13C-org = 26 per mil to 24 per mil) is ten times higher (C-org=0.33Wt%) that in hematite-poor clays, or where rootlets are present, than in hematite- rich samples (C-org=marte.arc.nasa.gov; [3] Stoker, C., et al., 2006 AbSciCon, [4] Stoker et al., submitted; [5] Bonaccorsi., et al., 2006 AbSciCon.

  17. Relevance of the Halocline in the Diet of the Troglobic Shrimp T.mitchelli in the Yucatan Peninsula

    Science.gov (United States)

    Cruz de La Garza, Y.; Escobar Briones, E.

    2007-05-01

    The anchihaline cave systems are characterized by subsurface connections with the sea and the sinkholes, have polyhaline underground water masses and are locally influenced by the rainforest organic input during the rainy season. The specific physical characteristics of the two water masses (fresh and marine) define the presence of karst fauna and their diet, the halocline represents a physicochemical barrier for many organisms and retains suspended particles creating food source storage along a cline of geochemical reactions. We studied the occurrence of the shrimp Typhatya mitchelli, an endemic Decapod Crustacean from the Yucatan Peninsula anchihaline ecosystems. We analyzed its presence in the two water masses and related its muscle d13C and d15N stable isotopic composition to its diet and specific habitat preference. The presence of specialized setae in P1 and P2 and depleted C and N values (d13C -43.11 min. -21.05 max.; d15N -0.54 min. 9.34 max.) confirm a diet sustained on bacteria with similar signatures as those from chemoautotrophic environments where the dominant morphological structures show that scraping on the cave walls, cave floor and the halocline are the prevailing feeding strategy. The density differences of water masses (rainwater rho 0.996 to 0.997 kg m-3, halocline rho 0.997 to 1.009 kg m-3; marine water rho 1.09 to 1.024 kg m-3) at the halocline allow the species (rho 1.12 to 1.13) to find the interface as a suitable substrate where organic matter can concentrate and sustain a dense population of shrimps.

  18. Influence of increasing dissolved inorganic carbon concentrations and decreasing pH on chemolithoautrophic bacteria from oxic-sulfidic interfaces

    Directory of Open Access Journals (Sweden)

    K. Mammitzsch

    2012-12-01

    Full Text Available Increases in the dissolved inorganic carbon (DIC concentration are expected to cause a decrease in the pH of ocean waters, a process known as ocean acidification. In oxygen-deficient zones this will add to already increased DIC and decreased pH values. It is not known how this might affect microbial communities and microbially mediated processes. In this study, the potential effects of ocean acidification on chemolithoautotrophic prokaryotes of marine oxic-anoxic transition zones were investigated, using the chemoautotrophic denitrifying ε-proteobacterium "Sulfurimonas gotlandica" strain GD1 as a model organism. This and related taxa use reduced sulfur compounds, e.g. sulfide and thiosulfate, as electron donors and were previously shown to be responsible for nitrate removal and sulfide detoxification in redox zones of the Baltic Sea water column but occur also in other oxygen-deficient marine systems. Bacterial cell growth within a broad range of DIC concentrations and pH values was monitored and substrate utilization was determined. The results showed that the DIC saturation concentration for growth was already reached at 800 μM, which is well below in situ DIC levels. The pH optimum was between 6.6 and 8.0. Within a pH range of 6.6–7.1 there was no significant difference in substrate utilization; however, at lower pH values cell growth decreased sharply and cell-specific substrate consumption increased. These findings suggest that a direct effect of ocean acidification, with the predicted changes in pH and DIC, on chemolithoautotrophic bacteria such as "S. gotlandica" str. GD1 is generally not very probable.

  19. Influence of chemosynthetic ecosystems on nematode community structure and biomass in the deep eastern Mediterranean Sea

    Science.gov (United States)

    Lampadariou, N.; Kalogeropoulou, V.; Sevastou, K.; Keklikoglou, K.; Sarrazin, J.

    2013-08-01

    Mud volcanoes are a~special type of cold seeps where life is based on chemoautotrophic processes. They are considered to be extreme environments and are characterized by unique megafaunal and macrofaunal communities. However, very few studies on mud volcanoes taking into account the smaller meiobenthic communities have been carried out. Two mud volcanoes were explored during the MEDECO (MEditerranean Deep-sea ECOsystems) cruise (2007) with the remotely operated vehicle (ROV) Victor-6000: Amsterdam, located south of Turkey between 1700 and 2000 m depth (Anaximander mud field); and Napoli, south of Crete, located along the Mediterranean Ridge at about 2000 m depth (Olimpi mud field). The major aim of this study was to describe distributional patterns of meiofaunal communities and nematode assemblages from different seep microhabitats. Meiofaunal taxa and nematode assemblages at both mud volcanoes differed significantly from other Mediterranean sites in terms of standing stocks, dominance and species diversity. Density and biomass values were significantly higher at the seep sites, particularly at Amsterdam. Patterns of nematode diversity, the dominant meiofaunal taxon, varied, displaying both very high or very low species richness and dominance, depending on the microhabitat studied. The periphery of the Lamellibrachia and bivalve shell microhabitats of Napoli exhibited the highest species richness, while the reduced sediments of Amsterdam yielded a species-poor nematode community dominated by two successful species, one belonging to the genus Aponema and the other to the genus Sabatieria. Analysis of β-diversity showed that microhabitat heterogeneity of mud volcanoes contributed substantially to the total nematode species richness in the eastern Mediterranean Sea. These observations indicate a strong influence of mud volcanoes and cold-seep ecosystems on the meiofaunal communities and nematode assemblages.

  20. Exploring the Habitability of Ice-covered Waterworlds: The Deep-Sea Hydrothermal System of the Aurora Mount at Gakkel Ridge, Arctic Ocean (82°54' N, 6°15W, 3900 m)

    Science.gov (United States)

    Boetius, A.; Bach, W.; Borowski, C.; Diehl, A.; German, C. R.; Kaul, N. E.; Koehler, J.; Marcon, Y.; Mertens, C.; Molari, M.; Schlindwein, V. S. N.; Tuerke, A.; Wegener, G.

    2014-12-01

    The geographic remoteness of the ultraslow Gakkel Ridge in the ice-covered Arctic Ocean raises many questions about the nature and biogeography of its habitats. In 2001, the two-ice-breaker mission AMORE (RV POLARSTERN and USCGC HEALY) detected hydrothermal plumes and evidence for seafloor venting associated with volcanic ridges rising from the rift valley floor of 4.2 km depth (Edmonds et al., 2003; Michael et al., 2003). The AURORA expedition in July 2014 (RV POLARSTERN Cruise PS86) targeted this "Aurora" field at the SW limit of Gakkel Ridge, to investigate its habitats, communities and their energy sources. No robots can yet be deployed through ice-cover to explore such deep habitats and ice-breaking research vessels cannot hold position in the thick multiyear ice. Instead, we estimated ice-drift to predict suitable start positions, then attached POLARSTERN to a matching ice floe, to achieve the bottom trajectories that we required for targeted exploration. The Aurora mount is volcanic in origin formed from mounded pillow basalts overlain by about a meter of sediment and cut through by steep cliffs revealing basalt pillows in outcrop and in talus piles. We identified persistent plume activity in the water column above the mount at 3100-3600 m (800-300 m off-bottom of its top) characterized by anomalies in turbidity, Eh, methane, temperature, density, and elevated microbial chemoautotrophic activity. Using a towed camera-, and multisensor- platform (OFOS) we located active venting as the source of this plume together with inactive chimneys and associated craters on the SW flank of Mt.Aurora. Its dominantly filter-feeding fauna is apparently sustained by venting of energy-rich fluids and microbial transfer of this geofuel into nutrition. This communication presents first results of our recent fieldwork and experimental investigations in Summer 2014 to explore deep-sea ecosystems in ice-covered oceans.

  1. Vesicomyidae (bivalvia: current taxonomy and distribution.

    Directory of Open Access Journals (Sweden)

    Elena M Krylova

    Full Text Available Vesicomyid bivalves are a consistent component of communities of sulphide-rich reducing environments distributed worldwide from 77 degrees N to 70 degrees S at depths from 100 to 9050 m. Up-to-now the taxonomy of the family has been uncertain. In this paper, the current state of vesicomyid taxonomy and distribution at the generic rank are considered. This survey is founded on a database including information both from literature sources and also unpublished data of the authors on all recent species of vesicomyids. We suggest that the Vesicomyidae is not a synonym of Kelliellidae, and is therefore a valid family name. We propose to divide the family Vesicomyidae into two subfamilies: Vesicomyinae and Pliocardiinae. The Vesicomyinae includes one genus, Vesicomya, which comprises small-sized bivalves characterized by non-reduced gut and the absence of subfilamental tissue in gills. Symbiosis with chemoautotrophic bacteria has, so far, not been proved for Vesicomya and the genus is not restricted to sulphide-rich reducing habitats. The subfamily Pliocardiinae currently contains about 15 genera with mostly medium or large body size, characterized by the presence of subfilamental tissue in the gills. The Pliocardiinae are highly specialized for sulphide-rich reducing environments, harbouring chemoautrophic bacteria in their gills. This is the first summary of the generic structure of the family Vesicomyidae that allow us to analyze the distribution of vesicomyids at the generic level. We recognize here five different distribution patterns that are related to the specific environmental demands. The general trends in the distribution patterns of the vesicomyids are an occurrence of the majority of genera in broad geographical ranges and the prevalence of near continental type of distribution.

  2. Optimized inhibition assays reveal different inhibitory responses of hydroxylamine oxidoreductases from beta- and gamma-proteobacterial ammonium-oxidizing bacteria.

    Science.gov (United States)

    Nishigaya, Yuki; Fujimoto, Zui; Yamazaki, Toshimasa

    2016-07-29

    Ammonia-oxidizing bacteria (AOB), ubiquitous chemoautotrophic bacteria, convert ammonia (NH3) to nitrite (NO2(-)) via hydroxylamine as energy source. Excessive growth of AOB, enhanced by applying large amounts of ammonium-fertilizer to the farmland, leads to nitrogen leaching and nitrous oxide gas emission. To suppress these unfavorable phenomena, nitrification inhibitors, AOB specific bactericides, are widely used in fertilized farmland. However, new nitrification inhibitors are desired because of toxicity and weak-effects of currently used inhibitors. Toward development of novel nitrification inhibitors that target hydroxylamine oxidoreductase (HAO), a key enzyme of nitrification in AOB, we established inhibitor evaluation systems that include simplified HAO purification procedure and high-throughput HAO activity assays for the purified enzymes and for the live AOB cells. The new assay systems allowed us to observe distinct inhibitory responses of HAOs from beta-proteobacterial AOB (βAOB) Nitrosomonas europaea (NeHAO) and gamma-proteobacterial AOB (γAOB) Nitrosococcus oceani (NoHAO) against phenylhydrazine, a well-known suicide inhibitor for NeHAO. Consistently, the live cells of N. europaea, Nitrosomonas sp. JPCCT2 and Nitrosospira multiformis of βAOB displayed higher responses to phenylhydrazine than those of γAOB N. oceani. Our homology modeling studies suggest that different inhibitory responses of βAOB and γAOB are originated from different local environments around the substrate-binding sites of HAOs in these two classes of bacteria due to substitutions of two residues. The results reported herein strongly recommend inhibitor screenings against both NeHAO of βAOB and NoHAO of γAOB to develop HAO-targeting nitrification inhibitors with wide anti-AOB spectra. PMID:27173879

  3. Strong pathways for incorporation of terrestrially derived organic matter into benthic communities

    Science.gov (United States)

    McLeod, Rebecca J.; Wing, Stephen R.

    2009-05-01

    In Fiordland, New Zealand, large volumes of organic matter are deposited into the marine environment from pristine forested catchments. Analyses of δ15N, δ13C and δ34S were employed to determine whether these inputs were contributing to marine food webs via assimilation by common macroinvertebrates inhabiting the inner reaches of the fjords. Terrestrially derived organic matter (TOM) had values of δ15N, δ13C and δ34S that were distinct from other carbon source pools, providing sufficient power to quantify the contribution of TOM to the benthic food web. Isotopic values among macroinvertebrates varied significantly, with consistently low values of δ15N, δ13C and δ34S for the abundant deposit feeders Echinocardium cordatum (Echinodermata) and Pectinaria australis (Annelida), indicating assimilation of TOM. High concentrations of bacterial fatty acid biomarkers in E. cordatum, and values of δ13C of these biomarkers similar to TOM (-27 to -30‰) confirmed that TOM is indirectly assimilated by these sea urchins via heterotrophic bacteria. TOM was also found to enter the infaunal food web via chemoautotrophic bacteria that live symbiotically within Solemya parkinsonii (Bivalvia). Echinocardium cordatum, Pectinaria australis and S. parkinsonii comprised up to 33.5% of the biomass of the macroinfaunal community, and thus represent strong pathways for movement of organic matter from the forested catchments into the benthic food web. This demonstration of connectivity among adjacent marine and terrestrial habitats has important implications for coastal land management, and highlights the importance of intact coastal forests to marine ecosystem function.

  4. To clone the ammonia monooxygenase gene of autotrophic bacteria ammonium oxidation capacity%化能自养菌氨单加氧酶基因的克隆

    Institute of Scientific and Technical Information of China (English)

    龚国利; 张甜; 史政豪; 魏选明; 王磊

    2015-01-01

    氨氧化细菌是一类革兰氏阴性的化能自养菌.也是生物脱氮工艺中不可缺少的一类细菌.本研究通过以土壤为材料富集氨氧化细菌,并从富集土样的全基因组中成功扩增到amoA全长基因,与NCBI标准菌株 Nitrosomonas sp .GH22序列同源性达到99%,并用amoA 全长基因构建得克隆载体,经菌落PC R和双酶切鉴定正确,为后期构建新型的生物脱氮基因工程菌奠定基础.%Ammonia oxidizing bacteria is a class of gram negative chemoautotrophic bacteria , and it is also a kind of indispensable in the process of biological removal of nitrogen .In this study ,the amoA gene was successfully amplified from the whole genome of the enriched soil sample ,then put this amoA gene sequence blasted in Genbank through Internet online;at last ,we get a result that it has high homology with the amoA gene of Nitrosomonas sp . GH22(99% ) .According to the amoA full‐length gene constructed a cloned vector ,through the identification of colony PCR and restriction analysis were correct ,to lay the foundation for the later construction of a new biological nitrogen removal genetically engineered bacteri‐a.

  5. 古菌氨氧化与amoA基因的扩增%Archaeal Ammonia Oxidation and Amplification of amoA Gene

    Institute of Scientific and Technical Information of China (English)

    蒋敏芝; 黄秋雨

    2012-01-01

    Ammonia oxidation is a obligate aerobic: chemoautotrophic process taken by a small part bacterial community of Hymenomycetes. Ammonia-oxidizing bacteria (AOB) is a inorganic: autntrophic micro-organism, responsible for converting NH4+ to NO2- in the nitrification reaction, ammonia oxidizing archaea (AOA) is independent of the AOB clade. The paper introduced discovery and ammonia oxidation of AOA, extracted, purified and amplified amoA genes according to its features. The results confirmed exist of AOA, and provided basis for follow-up study.%氨氧化过程是由变形菌纲中的一小部分细菌类群所进行的专性好氧的化能自养过程,氨氧化细菌(AOB)是硝化反应中负责将NH4+转化为NO2-的一类无机自养微生物,氨氧化古菌(AOA)是独立于AOB进化枝之外的能进行氨氧化作用的古菌。介绍了AOA古菌的发现过程及其氨氧化作用,提取、纯化了amoA基因并利用amoA基因的特征,对它进行扩增,证实了AOA古菌的存在,并为后续研究提供了依据。

  6. Making a living while starving in the dark: metagenomic insights into the energy dynamics of a carbonate cave.

    Science.gov (United States)

    Ortiz, Marianyoly; Legatzki, Antje; Neilson, Julia W; Fryslie, Brandon; Nelson, William M; Wing, Rod A; Soderlund, Carol A; Pryor, Barry M; Maier, Raina M

    2014-02-01

    Carbonate caves represent subterranean ecosystems that are largely devoid of phototrophic primary production. In semiarid and arid regions, allochthonous organic carbon inputs entering caves with vadose-zone drip water are minimal, creating highly oligotrophic conditions; however, past research indicates that carbonate speleothem surfaces in these caves support diverse, predominantly heterotrophic prokaryotic communities. The current study applied a metagenomic approach to elucidate the community structure and potential energy dynamics of microbial communities, colonizing speleothem surfaces in Kartchner Caverns, a carbonate cave in semiarid, southeastern Arizona, USA. Manual inspection of a speleothem metagenome revealed a community genetically adapted to low-nutrient conditions with indications that a nitrogen-based primary production strategy is probable, including contributions from both Archaea and Bacteria. Genes for all six known CO2-fixation pathways were detected in the metagenome and RuBisCo genes representative of the Calvin-Benson-Bassham cycle were over-represented in Kartchner speleothem metagenomes relative to bulk soil, rhizosphere soil and deep-ocean communities. Intriguingly, quantitative PCR found Archaea to be significantly more abundant in the cave communities than in soils above the cave. MEtaGenome ANalyzer (MEGAN) analysis of speleothem metagenome sequence reads found Thaumarchaeota to be the third most abundant phylum in the community, and identified taxonomic associations to this phylum for indicator genes representative of multiple CO2-fixation pathways. The results revealed that this oligotrophic subterranean environment supports a unique chemoautotrophic microbial community with potentially novel nutrient cycling strategies. These strategies may provide key insights into other ecosystems dominated by oligotrophy, including aphotic subsurface soils or aquifers and photic systems such as arid deserts. PMID:24030597

  7. Prominent bacterial heterotrophy and sources of 13C-depleted fatty acids to the interior Canada Basin

    Directory of Open Access Journals (Sweden)

    S. R. Shah

    2013-04-01

    Full Text Available In recent decades, the Canada Basin of the Arctic Ocean has experienced rapidly decreasing summer sea ice coverage and freshening of surface waters. It is unclear how these changes translate to depth, particularly as our baseline understanding of organic carbon cycling in the deep basin is limited. In this study, we describe full-depth profiles of the abundance, distribution and carbon isotopic composition of fatty acids from suspended particulate matter at a seasonally ice-free station and a semi-permanently ice-covered station. Fatty acids, along with suspended particulate organic carbon (POC, are more concentrated under ice cover than in ice-free waters. But this influence, apparent at 50 m depth, does not propagate downward below 150 m depth, likely due to the weak biological pump in the central Canada Basin. Branched fatty acids have δ13C values that are similar to suspended POC at all depths and are 13C-enriched compared to even-numbered saturated fatty acids at depths above 3000 m. These are likely to be produced in situ by heterotrophic bacteria incorporating organic carbon that is isotopically similar to total suspended POC. A source of saturated even-numbered fatty acids is also suggested below surface waters which could represent contributions from laterally advected organic carbon or from chemoautotrophic bacteria. At 3000 m depth and below, a greater relative abundance of long-chain (C20–24, branched and unsaturated fatty acids is consistent with a stronger influence of re-suspended sedimentary organic carbon on benthic particulate matter. At these deep depths, two individual fatty acids (C12 and iso-C17 are significantly depleted in 13C, allowing for the possibility that methane oxidizing bacteria contribute fatty acids, either directly to suspended particulate matter or to shallow sediments that are subsequently mobilized and incorporated into suspended particulate matter within the deep basin.

  8. Cancer and Toxicology Section

    International Nuclear Information System (INIS)

    The Cancer and Toxicology Section is concerned with the investigation of the mechanisms by which chemicals, radiation, and viruses cause the changes broadly identified as cancer. In addition, the study of mechanisms has been extended to include the nontumorigenic effects of various agents associated with fossil energy and fuels. Research in molecular genetics of carcinogenesis focuses largely on the transposon properties of the genomes of retroviruses. The transposon structure of the DNA genomes of endogenous murine N-tropic and B-tropic type C retroviruses is being elucidated, and their chromosomal location mapped in hamster-mouse cell hybrids. A model of the mechanism of retrovirus induction by radiation and chemicals is being developed, and experiments have established that compounds such as hydroxyurea act as inducer. There is the possibility that transposition of sequences of this endogenous virus may be linked to leukemogenesis. Research in regulation of gene expression aims at defining in molecular terms the mechanisms determining expression of specific genes, how these are regulated by hormones, and the events responsible for dysfunction of gene expression in cancer. In corollary work, a library of cloned cDNAs specific for products of genes of special interest to regulation is being developed. Improvement of reversed-phase chromatography as a means of isolating bacterial plasmids and restriction fragments of DNA is underway. Newly developed techniques permit the isolation of supercoiled plasmid DNA directly from bacterial extracts. The technology has been developed recently for the photosynthetic growth of the chemo-autotrophic organism Rhodospirillum rubrum and the enzyme ribulosebisphosphate carboxylase has been produced in quantity

  9. An extensive reef system at the Amazon River mouth

    Science.gov (United States)

    Moura, Rodrigo L.; Amado-Filho, Gilberto M.; Moraes, Fernando C.; Brasileiro, Poliana S.; Salomon, Paulo S.; Mahiques, Michel M.; Bastos, Alex C.; Almeida, Marcelo G.; Silva, Jomar M.; Araujo, Beatriz F.; Brito, Frederico P.; Rangel, Thiago P.; Oliveira, Braulio C. V.; Bahia, Ricardo G.; Paranhos, Rodolfo P.; Dias, Rodolfo J. S.; Siegle, Eduardo; Figueiredo, Alberto G.; Pereira, Renato C.; Leal, Camille V.; Hajdu, Eduardo; Asp, Nils E.; Gregoracci, Gustavo B.; Neumann-Leitão, Sigrid; Yager, Patricia L.; Francini-Filho, Ronaldo B.; Fróes, Adriana; Campeão, Mariana; Silva, Bruno S.; Moreira, Ana P. B.; Oliveira, Louisi; Soares, Ana C.; Araujo, Lais; Oliveira, Nara L.; Teixeira, João B.; Valle, Rogerio A. B.; Thompson, Cristiane C.; Rezende, Carlos E.; Thompson, Fabiano L.

    2016-01-01

    Large rivers create major gaps in reef distribution along tropical shelves. The Amazon River represents 20% of the global riverine discharge to the ocean, generating up to a 1.3 × 106–km2 plume, and extensive muddy bottoms in the equatorial margin of South America. As a result, a wide area of the tropical North Atlantic is heavily affected in terms of salinity, pH, light penetration, and sedimentation. Such unfavorable conditions were thought to imprint a major gap in Western Atlantic reefs. We present an extensive carbonate system off the Amazon mouth, underneath the river plume. Significant carbonate sedimentation occurred during lowstand sea level, and still occurs in the outer shelf, resulting in complex hard-bottom topography. A permanent near-bottom wedge of ocean water, together with the seasonal nature of the plume’s eastward retroflection, conditions the existence of this extensive (~9500 km2) hard-bottom mosaic. The Amazon reefs transition from accretive to erosional structures and encompass extensive rhodolith beds. Carbonate structures function as a connectivity corridor for wide depth–ranging reef-associated species, being heavily colonized by large sponges and other structure-forming filter feeders that dwell under low light and high levels of particulates. The oxycline between the plume and subplume is associated with chemoautotrophic and anaerobic microbial metabolisms. The system described here provides several insights about the responses of tropical reefs to suboptimal and marginal reef-building conditions, which are accelerating worldwide due to global changes. PMID:27152336

  10. Pan-genome analyses identify lineage- and niche-specific markers of evolution and adaptation in Epsilonproteobacteria

    Directory of Open Access Journals (Sweden)

    Ying eZhang

    2014-03-01

    Full Text Available The rapidly increasing availability of complete bacterial genomes has created new opportunities for reconstructing bacterial evolution, but it has also highlighted the difficulty to fully understand the genomic and functional variations occurring among different lineages. Using the class Epsilonproteobacteria as a case study, we investigated the composition, flexibility, and function of its pan-genomes. Models were constructed to extrapolate the expansion of pan-genomes at three different taxonomic levels. The results show that, for Epsilonproteobacteria the seemingly large genome variations among strains of the same species are less noticeable when compared with groups at higher taxonomic ranks, indicating that genome stability is imposed by the potential existence of taxonomic boundaries. The analyses of pan-genomes has also defined a set of universally conserved core genes, based on which a phylogenetic tree was constructed to confirm that thermophilic species from deep-sea hydrothermal vents represent the most ancient lineages of Epsilonproteobacteria. Moreover, by comparing the flexible genome of a chemoautotrophic deep-sea vent species to 1 genomes of species belonging to the same genus, but inhabiting different environments, and 2 genomes of other vent species, but belonging to different genera, we were able to delineate the relative importance of lineage-specific versus niche-specific genes. This result not only emphasizes the overall importance of phylogenetic proximity in shaping the variable part of the genome, but also highlights the adaptive functions of niche-specific genes. Overall, by modeling the expansion of pan-genomes and analyzing core and flexible genes, this study provides snapshots on how the complex processes of gene acquisition, conservation, and removal affect the evolution of different species, and contribute to the metabolic diversity and versatility of Epsilonproteobacteria.

  11. Spatial differences in East scotia ridge hydrothermal vent food webs: influences of chemistry, microbiology and predation on trophodynamics.

    Directory of Open Access Journals (Sweden)

    William D K Reid

    Full Text Available The hydrothermal vents on the East Scotia Ridge are the first to be explored in the Antarctic and are dominated by large peltospiroid gastropods, stalked barnacles (Vulcanolepas sp. and anomuran crabs (Kiwa sp. but their food webs are unknown. Vent fluid and macroconsumer samples were collected at three vent sites (E2, E9N and E9S at distances of tens of metres to hundreds of kilometres apart with contrasting vent fluid chemistries to describe trophic interactions and identify potential carbon fixation pathways using stable isotopes. δ(13C of dissolved inorganic carbon from vent fluids ranged from -4.6‰ to 0.8‰ at E2 and from -4.4‰ to 1.5‰ at E9. The lowest macroconsumer δ(13C was observed in peltospiroid gastropods (-30.0‰ to -31.1‰ and indicated carbon fixation via the Calvin-Benson-Bassham (CBB cycle by endosymbiotic gamma-Proteobacteria. Highest δ(13C occurred in Kiwa sp. (-19.0‰ to -10.5‰, similar to that of the epibionts sampled from their ventral setae. Kiwa sp. δ(13C differed among sites, which were attributed to spatial differences in the epibiont community and the relative contribution of carbon fixed via the reductive tricarboxylic acid (rTCA and CBB cycles assimilated by Kiwa sp. Site differences in carbon fixation pathways were traced into higher trophic levels e.g. a stichasterid asteroid that predates on Kiwa sp. Sponges and anemones at the periphery of E2 assimilated a proportion of epipelagic photosynthetic primary production but this was not observed at E9N. Differences in the δ(13C and δ(34S values of vent macroconsumers between E2 and E9 sites suggest the relative contributions of photosynthetic and chemoautotrophic carbon fixation (rTCA v CBB entering the hydrothermal vent food webs vary between the sites.

  12. Genetic connectivity between north and south Mid-Atlantic Ridge chemosynthetic bivalves and their symbionts.

    Directory of Open Access Journals (Sweden)

    Karina van der Heijden

    Full Text Available Transform faults are geological structures that interrupt the continuity of mid-ocean ridges and can act as dispersal barriers for hydrothermal vent organisms. In the equatorial Atlantic Ocean, it has been hypothesized that long transform faults impede gene flow between the northern and the southern Mid-Atlantic Ridge (MAR and disconnect a northern from a southern biogeographic province. To test if there is a barrier effect in the equatorial Atlantic, we examined phylogenetic relationships of chemosynthetic bivalves and their bacterial symbionts from the recently discovered southern MAR hydrothermal vents at 5°S and 9°S. We examined Bathymodiolus spp. mussels and Abyssogena southwardae clams using the mitochondrial cytochrome c oxidase subunit I (COI gene as a phylogenetic marker for the hosts and the bacterial 16S rRNA gene as a marker for the symbionts. Bathymodiolus spp. from the two southern sites were genetically divergent from the northern MAR species B. azoricus and B. puteoserpentis but all four host lineages form a monophyletic group indicating that they radiated after divergence from their northern Atlantic sister group, the B. boomerang species complex. This suggests dispersal of Bathymodiolus species from north to south across the equatorial belt. 16S rRNA genealogies of chemoautotrophic and methanotrophic symbionts of Bathymodiolus spp. were inconsistent and did not match the host COI genealogy indicating disconnected biogeography patterns. The vesicomyid clam Abyssogena southwardae from 5°S shared an identical COI haplotype with A. southwardae from the Logatchev vent field on the northern MAR and their symbionts shared identical 16S phylotypes, suggesting gene flow across the Equator. Our results indicate genetic connectivity between the northern and southern MAR and suggest that a strict dispersal barrier does not exist.

  13. Organic nutrient enrichment in the oligotrophic ocean: Impacts on remineralization, carbon sequestration, and community structure

    Science.gov (United States)

    Mackey, K. R.; Paytan, A.; Post, A. F.

    2007-12-01

    In oligotrophic seas where inorganic nitrogen (N) and phosphorus (P) are below the limits of detection, organic forms of these nutrients may constitute greater than 90% of the total N and P in the euphotic zone. The combined enzymatic activity of phytoplankton and heterotrophic bacteria determines the rate of nutrient remineralization, thereby influencing phytoplankton growth rates and carbon sequestration in these regions. In this study we investigated the effects of fertilization with ammonium (NH4), nitrate (NO3), nitrite (NO2), and phosphate (PO4) as well as various forms of organic N (urea, glycine) and P (deoxyribonucleic acid, 2- aminoethyl phosphonic acid, phytic acid) on the growth and taxonomic composition of the phytoplankton community in the Gulf of Aqaba, Red Sea. The impacts of these changes on nutrient cycling and biological assimilation were also assessed. Organic N additions led to phytoplankton growth when given together with PO4, yielding 2-3 fold increases in chlorophyll a (Chl a) and cell density relative to initial levels. Moreover, our results show that addition of NH4 or NO3 led to accumulation of extra-cellular NO2, suggesting that incomplete assimilatory reduction of NO3 by phytoplankton as well as chemoautotrophic oxidation of NH4 by ammonium oxidizing microbes contributed to NO2 formation. These findings conflict with earlier studies in the Gulf that attributed NO2 formation solely to the phytoplankton community. Organic P additions also led to 2-3 fold increases in Chl a and cell density relative to initial levels when given together with NH4 and NO3. Compared to other P additions, DNA led to the rapid accumulation of extra-cellular PO4, indicating substantial nucleotidase activity in excess of the amount needed to meet phytoplankton growth requirements. These results show the importance and interconnectivity of phytoplankton and heterotrophic bacteria communities in contributing to nutrient cycling and carbon sequestration in

  14. Sources of organic carbon for Rimicaris hybisae: Tracing individual fatty acids at two hydrothermal vent fields in the Mid-Cayman rise

    Science.gov (United States)

    Streit, Kathrin; Bennett, Sarah A.; Van Dover, Cindy L.; Coleman, Max

    2015-06-01

    Hydrothermal vents harbor ecosystems mostly decoupled from organic carbon synthesized with the energy of sunlight (photosynthetic carbon source) but fueled instead by oxidation of reduced compounds to generate a chemosynthetic carbon source. Our study aimed to disentangle photosynthetic and chemosynthetic organic carbon sources for the shrimp species Rimicaris hybisae, a primary consumer presumed to obtain its organic carbon mainly from ectosymbiotic chemoautotrophic bacteria living on its gill cover membrane. To provide ectosymbionts with ideal conditions for chemosynthesis, these shrimp live in dense clusters around vent chimneys; they are, however, also found sparsely distributed adjacent to diffuse vent flows, where they might depend on alternative food sources. Densely and sparsely distributed shrimp were sampled and dissected into abdominal tissue and gill cover membrane, covered with ectosymbiotic bacteria, at two hydrothermal vent fields in the Mid-Cayman rise that differ in vent chemistry. Fatty acids (FA) were extracted from shrimp tissues and their carbon isotopic compositions assessed. The FA data indicate that adult R. hybisae predominantly rely on bacteria for their organic carbon needs. Their FA composition is dominated by common bacterial FA of the n7 family (~41%). Bacterial FA of the n4 FA family are also abundant and found to constitute good biomarkers for gill ectosymbionts. Sparsely distributed shrimp contain fractions of n4 FA in gill cover membranes ~4% lower than densely packed ones (~18%) and much higher fractions of photosynthetic FA in abdominal tissues, ~4% more (compared with 1.6%), suggesting replacement of ectosymbionts along with exoskeletons (molt), while they take up alternative diets of partly photosynthetic organic carbon. Abdominal tissues also contain photosynthetic FA from a second source taken up presumably during an early dispersal phase and still present to c. 3% in adult shrimp. The contribution of photosynthetic carbon to

  15. Spatial and temporal diversity of microbial mats in the shallow-water hydrothermal system of Milos Island (Greece)

    Science.gov (United States)

    Giovannelli, D.; Foustoukos, D.; Le Bris, N.; Sievert, S. M.; Yucel, M.; Vetriani, C.

    2014-12-01

    Shallow-water hydrothermal vents are ubiquitous but poorly studied geothermal environments. The shallow-water hydrothermal system of Milos Island is a unique study site with vents exhibiting steep geothermal gradients in the presence of light that allows the co-occurrence of photosynthesis and chemosynthesis. The active hydrothermal emissions of the Milos hydrothermal system support complex microbial mats, which are fundamental in engineering the environmental niche in which extremophiles thrive. Because of the shallow depth, the mat community is wiped out during every major storm, when swell and wave action increase, and then it reconstitutes itself over a brief period of time (days). While most studies are focused on the diversity of the community residing in the underlying sediments, little information is available on the diversity and functioning of the mat community, and how it responds to abrupt geodynamic events. Here we report the results of a joint geochemical and microbiological survey of the microbial mats of Milos island, and analyze the spatial and temporal evolution of the mat community following a major storm. Our results show that the community is dominated by Epsilonproteobacteria, although significant variability is present within the systemm. The observed variability correlates with spatial profiles and in situ measurement of temperature and sulfide carried out over a 6 days periods, showing that tides, winds, and abrupt geodynamic events generate intermittent mixing conditions lasting for several hours to days. Diversity and metagenomic analyses of the mature mat provide further information on the metabolic potential of the community and on the influence of environmental factors on ecosystem functioning. Our work lays the basis for studies aimed at resolving the spatial and temporal dynamics of chemoautotrophic microbial communities in shallow-water hydrothermal systems.

  16. An overview of the latest results of cold seep research along the Hikurangi Margin, New Zealand

    Science.gov (United States)

    Greinert, J.; Faure, K.; Bialas, J.; Linke, P.; Pecher, I.; Rowden, A.

    2008-12-01

    Prior to 2006, the knowledge about cold seeps around New Zealand was based mainly on accidental recovery of seep fauna or methane-derived carbonates by fishermen and flares in echo sounders. Lewis and Marshall (1996) compiled these findings, providing the first details on 13 seep sites. Four of those are located at the Hikurangi Margin along the east coast of New Zealand's North Island. Since then, three international cruises in 2006 and 2007 enhanced our knowledge considerably about methane seepage along the Hikurangi Margin, an area which has in places very strong BSRs. Two cruises on RV TANGAROA in 2006 focused on extensive reconnaissance work as well as fauna sampling, geochemical pore water analyses and CTD casts including water sampling for methane analyses. Several new seep sites were discovered during these cruises. Using these data, very detailed investigations in four main working areas could be performed during a 10-weeks expedition with RV SONNE (SO191). All research topics currently discussed in the scientific community were addressed using state-of-the-art equipment (e.g. deep- tow side-scan and ROV-deployments). Fourteen institutes from seven countries were involved. Echosounder and sidescan surveys unmistakably revealed active seep sites by detecting bubbles in the water column and carbonate precipitation at the seafloor forming massive chemoherm complexes. These complexes are associated with typical seep fauna like tube worms, bivalve mollusk species (Calyptogena, Bathymodiolus),and bacterial mats. At the fringe of these chemoherms dark sediment patches were observed which exihibit a novel seep habitat dominated by dense beds of two new species of heterotrophic ampharetid polychaetes. Bubble release was visually observed at several sites and recorded in the backscatter of various acoustic devices. At one site (680m water depth) very strong, pulsing outbursts could be observed repeatedly with methane fluxes of 20 to 25 l/min (60 to 74 mol

  17. An overview of gas hydrate and cold seep research along the Hikurangi Margin, New Zealand (2006 & 2007)

    Science.gov (United States)

    Greinert, J.; Faure, K.; Naudts, L.; de Batist, M.; Bialas, J.; Linke, P.; Pecher, I.; Rowden, R.

    2009-04-01

    Prior to 2006, the knowledge about cold seeps around New Zealand was based mainly on accidental recovery of seep fauna or methane-derived carbonates by fishermen and the detection of flares in fish-finding sonars. Lewis and Marshall (1996; NZJGG) compiled these findings, providing the first details on 13 seep sites. Four of those are located at the Hikurangi Margin along the east coast of New Zealand's North Island. Since then, three international cruises in 2006 and 2007 enhanced our knowledge considerably about methane seepage along the Hikurangi Margin, an area which has widely distributed and in places very strong BSR. Two cruises on the RV TANGAROA (led by GNS Science and NIWA, NZ) in 2006 focused on extensive reconnaissance work (multibeam mapping, seismic surveys, flare imaging, visual observations) as well as fauna sampling, geochemical pore water analyses and CTD casts including water sampling for methane analyses. Several new seep sites were discovered during these cruises. Using these data, very detailed investigations in four main working areas could be performed during a 10-week expedition with RV SONNE (SO191, led by IFM-GEOMAR, Germany). All research topics currently discussed in the scientific community were addressed using state-of-the-art equipment (e.g. deep-tow side-scan, TV-guided sampling, lander and ROV-deployments). Fourteen institutes from seven countries were involved (Australia, Belgium, Germany, New Zealand, United Kingdom, United States, Switzerland). Echosounder and sidescan surveys unmistakably revealed active seep sites by detecting bubbles in the water column and carbonate precipitation at the seafloor forming massive chemoherm complexes. These complexes are associated with typical seep fauna like tube worms, bivalve mollusk species (Calyptogena, Bathymodiolus),and bacterial mats. At the fringe of these chemoherms dark sediment patches were observed which exihibit a novel seep habitat dominated by dense beds of two new species of

  18. Methane seepage along the Hikurangi Margin offshore New Zealand: 6 years of multidisciplinary studies

    Science.gov (United States)

    Greinert, J.; Bialas, J.; Klaucke, I.; Crutchley, G.; Dale, A.; Linke, P.; Sommer, S.; Bowden, D.; Rowden, A.; de Haas, H.; de Stigter, H.; Faure, K.

    2012-12-01

    Detailed studies in 2006, 2007 and 2011 along the east coast of New Zealand's North Island highlighted the close link of sub-bottom fluid pathways and seafloor expressions of methane seepage such as clam fields, carbonate build-ups, tubeworms, bacterial mats and methane release (Marine Geology 272). Prior to our studies, only accidental observations of hydroacoustic anomalies, recoveries of calyptogena shells and methane-derived carbonate chimneys indicated active seepage. Wide areas of the sub-seafloor show BSR structures, gas migration pathways, gas chimneys and blanking zones, which are closely linked to actual seep sites. Sidescan surveys showed four prominent seep areas at Omakere Ridge in 1120m water depth, three of them perfectly matching the shapes and locations of faults seen in high resolution 3D-seismic surveys. The fourth seep, Bear's Paw, on its western side represents an old seep which developed into a cold water coral habitat. At the actively seeping eastern part, gas hydrates could be retrieved and bubble release was observed hydroacoustically and confirmed by high dissolved methane values (380nM). No strong microbial oxidation effects could be found in δ13C values plotting along a mixing curve between pure seep (-70 ‰PDB) and atmospheric methane (-47 ‰PDB). Lander deployments show a tide-influenced gas discharge with sometimes eruptive bubble release with possible plume development transporting methane-charged water higher up into the water column. Rock Garden, with just above 600m water depth at its top outside the gas hydrate stability zone, hosts two main seep areas. ROV observations at Faure Site document eruptive releases of free gas from decimeter-wide craters at the seafloor. Flux estimates show peak releases of 420ml/min with bubbles up to 9mm in diameter. Concentrations of dissolved methane reach up to 3500nM close to the bottom, but higher concentrations are limited to below 400m of water depth; here, methane is transported towards

  19. Discovery of Nascent Vents and Recent Colonization Associated with(Re)activated Hydrothermal Vent Fields by the GALREX 2011 Expedition on the Galápagos Rift

    Science.gov (United States)

    Shank, T. M.; Holden, J. F.; Herrera, S.; Munro, C.; Muric, T.; Lin, J.; Stuart, L.

    2011-12-01

    GALREX 2011 was a NOAA OER telepresence cruise that explored the diverse habitats and geologic settings of the deep Galápagos region. The expedition made12 Little Hercules ROV dives in July 2011.Abundant corals and a strong depth zonation of species (including deepwater coral communities) were found near 500 m depth on Paramount Seamount, likely influenced by past low sea level states, wave-cut terrace processes, and the historical presence of shallow reef structures. At fresh lava flows with associated (flocculent) hydrothermal venting near 88° W, now known as Uka Pacha and Pegasus Vent Fields, rocks were coated with white microbial mat and lacked sessile fauna, with few mobile fauna (e.g., bythograeid crabs, alvinocarid shrimp, polynoid worms, zoarcid fish, and dirivultid copepods). This suggests a recent creation of hydrothermal habitats through volcanic eruptions and/or diking events, which may have taken place over a 15 km span separating the two vent fields. The Rosebud vent field at 86°W was not observed and may have been covered with lava since last visited in 2005. A hydrothermal vent field near 86°W was discovered that is one of the largest vent fields known on the Rift (120m by 40m). Low-temperature vent habitats were colonized by low numbers of tubeworms including Riftia, Oasisia, and a potential Tevnia species (the latter not previously observed on the Galapagos Rift). Patches of tubeworms were observed with individuals less than 2cm in length, and the relatively few large Riftia had tube lengths near 70cm long. Large numbers of small (microbial communities were observed on the underside and vertical surfaces of basalt rock surfaces. There were at least 13 species of vent-endemic fauna. The active colonization was observed on relatively older basalt pillows and lobate lavas ringed by and amidst a large dead bed of Calyptogena clams (most with broken and dissolving shells greater than 25 cm in length, with a few of the same size living amongst the

  20. The radiation resistance and cobalt biosorption activity of yeast strains isolated from the Lanyu low-level radioactive waste repository in Taiwan

    International Nuclear Information System (INIS)

    The ubiquitous nature of microbes has made them the pioneers in radionuclides adsorption and transport. In this study, the radiation resistance and nuclide biosorption capacity of microbes isolated from the Lanyu low-level radioactive waste (LLRW) repository in Taiwan was assessed, the evaluation of the possibility of using the isolated strain as biosorbents for 60Co and Co (II) from contaminated aqueous solution and the potential impact on radionuclides release. The microbial content of solidified waste and broken fragments of containers at the Lanyu LLRW repository reached 105 CFU/g. Two yeast strains, Candida guilliermondii (CT1) and Rhodotorula calyptogenae (RT1) were isolated. The radiation dose necessary to reduce the microbial count by one log cycle of CT1 and RT1 was 2.1 and 0.8 kGy, respectively. Both CT1 and RT1 can grow under a radiation field with dose rate of 6.8 Gy/h, about 100 times higher than that on the surface of the LLRW container in Lanyu repository. CT1 and RT1 had the maximum 60Co biosorption efficiency of 99.7 ± 0.1% and 98.3 ± 0.2%, respectively in 60Co aqueous solution (700 Bq/mL), and the 60Co could stably retained for more than 30 days in CT 1. Nearly all of the Co was absorbed and reached equilibrium within 1 h by CT1 and RT1 in the 10 μg/g Co (II) aqueous solution. Biosorption efficiency test showed almost all of the Co (II) was adsorbed by CT1 in 20 μg/g Co (II) aqueous solution, the efficiency of biosorption by RT1 in 10 μg/g of Co (II) was lower. The maximum Co (II) sorption capacity of CT1 and RT1 was 5324.0 ± 349.0 μg/g (dry wt) and 3737.6 ± 86.5 μg/g (dry wt), respectively, in the 20 μg/g Co (II) aqueous solution. Experimental results show that microbial activity was high in the Lanyu LLRW repository in Taiwan. Two isolated yeast strains, CT1 and RT1 have high potential for use as biosorbents for 60Co and Co (II) from contaminated aqueous solution, on the other hand, but may have the impact on

  1. Avaliação da espessura da camada de fibras nervosas da retina e mácula em pacientes com ambliopia Thickness of the retinal nerve fiber layer, macular thickness, in patients with amblyopia

    Directory of Open Access Journals (Sweden)

    Juliana Mitre

    2010-02-01

    Full Text Available OBJETIVO: Avaliar a espessura da camada de fibras nervosas da retina em olhos amblíopes e comparar com olhos normais e certificar se há correlação com a redução da acuidade visual. Além disso, este estudo se propõe avaliar a eficácia e eficiência em uma série de casos do protótipo de um equipamento nacional de magnificação para leitura. MÉTODOS: Participaram deste estudo 30 pacientes na faixa etária entre 9 e 80 anos (17 do sexo masculino. Foi desenvolvido um aparelho portátil, patenteado pela Unifesp (PI#020050145260, com um sistema de captura de imagens acoplado a um monitor de 5,6 polegadas proporcionando um aumento de 15 x. Foram analisadas a eficácia da acuidade visual e a eficiência de leitura após a utilização do protótipo proposto. RESULTADOS: Seis pacientes (20% apresentaram AV 8M, 12 pacientes (40% apresentaram AV 6M, 7 pacientes (23,3% apresentaram 5 M, 5 pacientes (16,7% apresentaram 4M. A média de acuidade visual antes da utilização do SLP medida pela tabela LHNV-1 logMAR foi de 5,75M e após a utilização 100% dos pacientes atingiram a eficácia de AV J1. CONCLUSÃO: O protótipo do SLP mostrou-se um recurso alternativo no processo de inclusão social das pessoas com baixa visão com diferentes níveis de resíduo visual. Também pode proporcionar incentivo psicológico, permitir conforto, mobilidade e independência àqueles que necessitam de uma leitura mais prolongada e maior distância de trabalho.OBJECTIVE: To compare the thickness of the retinal nerve fiber layer (RNFLand the macular thickness of the amblyopic eye with those of the non-amblyopic eye in patients with unilateral amblyopia using optical coherence tomography (OCT. METHODS: OCT was performed for13 patients with unilateral amblyopia who had no neurologic disease. Nine male andfour female patients, whose ages ranged from 23 to 63 years, were enrolled in the study. The RNFL thickness average analysis program was used to evaluate mean

  2. One-bottle adhesives: in vitro analysis of solvent volatilization and sealing ability Adesivos de frasco único: análise in vitro da volatilização do solvente e do selamento marginal

    Directory of Open Access Journals (Sweden)

    Fábio Garcia Lima

    2005-12-01

    inicial (PI e, após 10 min, seu peso final (PF. A razão PI/PF foi utilizada para determinar a taxa de volatilização do solvente. Os frascos com os maiores níveis de evaporação (SB Controle e PB Controle e com os menores níveis de evaporação (SB Teste e PB Teste foram aplicados em restaurações Classe V com margens em dentina. Os espécimes foram termociclados e imersos em solução de fucsina básica a 0,5%. A penetração do corante foi avaliada sob magnificação e os dados foram submetidos ao teste de Kruskal-Wallis. A volatilização do solvente foi mais rápida para o adesivo à base de acetona. As razões PI/PF variaram de 1,239 a 1,515 para SB e de 3,488 a 6,476 para PB. PB-Controle e SB-Controle exibiram vedamento similar. Os maiores escores de penetração foram encontrados para o PB-Teste (p < 0,05. Os resultados indicam que a habilidade de selamento pode ser afetada pela repetida utilização dos frascos de adesivo à base de acetona.

  3. Racionalidad del terror

    Directory of Open Access Journals (Sweden)

    Sauquillo, Julián

    2012-06-01

    ío de esa potencia difusa que conocemos como el Occidente desarrollado. Al Qaeda no duda en presentar su guerra con Occidente como una «guerra sin cuartel» hasta eliminar a los cristianos infieles y someter al mundo al Islam. Mientras tanto, en similar sentido conflictual, la campaña teórica de Samuel Huntington por todo el planeta, responde con un paradigma postguerra fría capaz de inflamar el conflicto internacional en un sentido no menos beligerante con anti-Occidente que el empleado por los imanes radicales. Como ha señalado Amartya Sen, al priorizar de esta forma la identidad religiosa, la respuesta de Occidente al terrorismo internacional como «terrorismo islámico» es muy torpe pues se magnifica la importancia de las autoridades religiosas en detrimento de los cauces gubernativos en la resolución de los problemas.

  4. Caracterização físico-química do enxerto de osso bovino liofilizado Physicochemical characterization of lyophilized bovine bone grafts

    Directory of Open Access Journals (Sweden)

    Carlos Roberto Galia

    2011-01-01

    Full Text Available OBJETIVO: Avaliar as características físico-químicas do enxerto bovino liofilizado manufaturado em escala semi-industrial (OrthoGen, Baumer S/A* de acordo com protocolo previamente desenvolvido pelos autores. MÉTODOS: A caracterização do enxerto de osso bovino liofilizado foi feita por meio de microscopia eletrônica de varredura (MEV, energy dispersive spectroscopy (EDS, difratometria de raios-X, análise por termogravimetria, análise de calorimetria exploratória diferencial (DSC e espectroscopia por infravermelho Fourier-transform (FT-IR. RESULTADOS: Ca foi o principal componente (60% encontrado nas amostras, seguido por P (28% e O (5%. O tamanho médio (dp dos poros foi 316µm (146,7, variando de 91,2 a 497,8µm, e 333,5µm (304,8, variando de 87,2 a 963,9µm com 50x e 150x magnificação, respectivamente. Picos de hidroxiapatita foram a 26ºC e 32ºC, e perda de massa foi observada entre 250ºC e 640ºC, correspondendo material orgânico e água. Duas transições de temperatura (45,67°C e 91,89°C mostraram desnaturação de colágeno tipo I e desidratação da hidroxiapatita. CONCLUSÃO: A avaliação físico-química do enxerto de osso bovino liofilizado, de acordo com o protocolo desenvolvido em escala semi-industrial, confirma que este produto apresenta excelente biocompatibilidade, com características semelhantes ao osso in natura.OBJECTIVE: To evaluate the physicochemical characteristics of lyophilized bovine grafts manufactured on a semi-industrial scale (Orthogen; Baumer S/A* in accordance with a protocol previously developed by the authors. METHODS: The lyophilized bovine bone grafts were characterized by means of scanning electron microscopy (SEM, energy dispersive spectroscopy (EDS, X-ray diffractometry (XRD, thermogravimetric (TG analysis, differential exploratory scanning calorimetry (DSC and Fourier-transform infrared (FT-IR spectroscopy. RESULTS: Ca was the main component (60% found in the samples, followed by P (28

  5. A importância do controle de qualidade em serviços de hemodinâmica e cardiologia intervencionista The relevance of quality control in services of hemodynamics and interventional cardiology

    Directory of Open Access Journals (Sweden)

    Eara de Souza Luz

    2007-02-01

    Full Text Available OBJETIVO: Avaliar o desempenho de um equipamento de raios X utilizado em radiologia intervencionista e a qualidade de imagem produzida, aplicando alguns testes de controle de qualidade. MATERIAIS E MÉTODOS: O equipamento de raios X testado foi da marca Philips (Integris H3000, do serviço de hemodinâmica de um hospital do Rio de Janeiro. Foram utilizados objetos de teste de Leeds para avaliar a qualidade da imagem, e um sistema Radcal 9015 para medições dosimétricas. RESULTADOS: Nos modos high e normal, os valores medidos das taxas de kerma no ar foram diferentes dos esperados. Em alguns casos, os valores das taxas medidas não foram afetados pelo uso de diferentes modos de magnificação. A avaliação da qualidade da imagem apresentou resultados diferentes dos valores recomendados pelas normas. Isto pode levar à obtenção de imagens de menor qualidade e ao aumento da exposição à radiação de pacientes e profissionais. CONCLUSÃO: Os resultados mostraram a importância da aplicação periódica de testes de controle de qualidade, que permitem monitorar o desempenho do equipamento e estimar a exposição dos pacientes e trabalhadores. Os resultados obtidos sugerem a necessidade de uma revisão no sistema de aquisição de imagens do equipamento.OBJECTIVE: To evaluate the performance and quality of images of a x-ray equipment utilized in interventional radiology, by means of some tests of quality control. MATERIALS AND METHODS: Measurements have been performed on a Philips Integris H3000 x-ray equipment dedicated to interventional procedures in the hemodynamics laboratory of a hospital in Rio de Janeiro, RJ, Brazil. Leeds test objects have been used to evaluate the image quality. Dosimetric measurements have been developed with a Radcal 9015 dosimetric system. RESULTS: In high and normal modes, the air kerma rates have been different from the expected results. In some cases, values have not been affected by the use of different

  6. DUSEL and the future of deep terrestrial microbiology (Invited)

    Science.gov (United States)

    Onstott, T. C.; Peters, C. A.; Murdoch, L. C.; Elsworth, D.; Sonnenthal, E. L.; Kieft, T.; Boutt, D. F.; Germanovich, L.; Glaser, S. D.; Wang, H. F.; Roggenthen, B.; Lesko, K.; Cushman, P.; Stetler, L. D.; Bang, S.; Anderson, C.

    2009-12-01

    subsurface chemoautotrophic activity is regulated by tectonic episodicity. The DUSEL CO2 Facility will investigate how microbial activity is impacted by CO2 injection and whether microbial activity has a significant impact upon long-term sequestration of CO2. These three experiments represent a subset of the integrated suite of experiments planned for the first 5 years, but many more microbial experiments can be accommodated within DUSEL. With its unique experimental assets, km-scale spatial access and multi-decade observational lifetime, DUSEL will usher in the next generation of exploration into the deep terrestrial biosphere and not only reveal the answers to many of its well-hidden secrets, but perhaps to the origin of life itself.

  7. Evidence for a Methane-Fueled Ecosystem within Anchialine Caves of the Yucatan Peninsula, Mexico

    Science.gov (United States)

    Brankovits, D.; Pohlman, J.; Niemann, H.; Leigh, M. B.; Lehmann, M. F.; Iliffe, T. M.

    2014-12-01

    Anchialine caves within coastal karst terrains of the tropics contain distinct mixtures of fresh and marine water separated by a sharp pycnocline. The Caribbean coast of Mexico's Yucatan Peninsula contains over 1000 km of mapped cave passages, the densest known accumulation of anchialine caves in the world. Deep within the caves and beyond where vegetative detritus from the entrance pool (or cenote) is present, a surprising diversity of higher-order animals (mostly crustaceans) is found. How these ecosystems thrive in an environment where no obvious sources of food are visible is enigmatic. A decades-old study based on the simple observation of 13C-depleted biomass in the stygobitic (cave-adapted) fauna suggested biogeochemical processes related to methane-linked carbon cycling and/or other chemoautotrophic pathways as a source of energy and carbon, but was unable to identify the exact source of this material. In this study, we investigate the biogeochemistry of four anchialine caves along an 8 km transect running perpendicular to the coastline. We measured the distribution, concentration and isotopic composition of biotic and abiotic components of the ecosystem to identify the energetic sources and microbial processes that sustain life in this subsurface aquifer. High concentrations of methane (5 µM) and evidence for methane oxidation in the fresh water portion of the water column suggest methane availability and consumption. Furthermore, the presence of 13C-depleted fatty acids (e.g., C16:1ω7c with δ13C-values as low as -54.1‰) and deuterium-depleted δD values (e.g., as low as δD = -225‰) from tissues of an atyid shrimp provide evidence that methanotrophic bacteria were a substantial fraction of its diet. Molecular microbial community analyses of shrimp guts and the water column are underway to identify the methanotrophs. These findings have the potential to reframe the carbon cycle and ecosystem dynamics for an isolated, yet widespread habitat within

  8. A multiproxy approach to understanding the "enhanced" flux of organic matter through the oxygen-deficient waters of the Arabian Sea

    Science.gov (United States)

    Keil, Richard G.; Neibauer, Jacquelyn A.; Biladeau, Christina; van der Elst, Kelsey; Devol, Allan H.

    2016-04-01

    Free-drifting sediment net traps were deployed 14 times at depths between 80 and 500 m for 1-3 days each during the late monsoon-intermonsoon transition in the central Arabian Sea. Two locations (19.5 and 15.5° N) were within the permanently oxygen-deficient zone (ODZ), and a third (11° N) had a shallow and thin oxygen minimum. The secondary nitrite maximum, which serves as a tracer of the ODZ, thinned from ˜ 250 m thick at stations 19.5 and 15.5° N to ˜ 50 m thick at station 11° N. Overall, organic carbon fluxes ranged from 13.2 g m2 yr-1 at 80 m to a minimum of 1.1 g m2 yr-1 at 500 m. Fluxes at the more oxygenated 11° N station attenuate faster than within the permanent ODZ. Martin curve attenuation coefficients for 19.5 and 15.5° N are respectively 0.59 and 0.63 and for 11° N it is 0.98. At least six potential mechanisms might explain why particles sinking through the ODZ are more effectively transferred to depth: (M1) oxygen effects, (M2) microbial loop efficiencies and chemoautotrophy, (M3) changes in zooplankton dynamics, (M4) additions of ballast that might sorb and protect organic matter from decay (M4a) or change sinking speeds (M4b), (M5) inputs of refractory organic matter and (M6) temperature effects. These mechanisms are intertwined, and they were explored using a combination of mineral (XPS) and organic matter characterizations of the sinking material, shipboard incubation experiments, and evaluations of existing literature. Direct evidence was found supporting an oxygen effect and/or changes in the efficiency of the microbial loop including the addition of chemoautotrophic carbon to the sinking flux in the upper 500 m. Less direct evidence was found for the other potential mechanisms. A simple conceptual model consistent with our and other recent data suggests that the upper ODZ microbial community determines the initial flux attenuation, and that zooplankton and sinking speed become more important deeper in the water column. The exact

  9. The Geobiochemistry of Methanogen Proteins

    Science.gov (United States)

    Prasad, A.; Shock, E.

    2013-12-01

    A principle of geobiochemistry is that adaptation over evolutionary time includes a thermodynamic drive to minimize costs of making biomolecules like proteins and lipids. If so, then biomolecule abundances will reflect, at least in part, their relative stabilities at the conditions imposed by external environments. We tested this hypothesis by comparing relative stabilities of 138 orthologous proteins between a representative lake-sediment methanogen (Methanoculleus marisnigri) and a representative rumen methanogen (Methanospirillum hungatei) at the compositional constraints of their respective environments. Chemical affinities of the proteins were calculated based on pH, temperature, and concentrations of dissolved hydrogen, bicarbonate, ammonia, and hydrogen sulfide, together with standard Gibbs energies of formation of proteins from the elements predicted with a group additivity algorithm for unfolded proteins [1]. Methanogens were chosen as they are chemoautotrophs and their metabolism proceeds at relatively small affinities. Also, they are found in a variety of compositionally varying habitats like rumen, sediments, hydrothermal systems and sewage. The methanogens selected belong to the same order of taxonomy and are closely related. Preliminary results show that a majority of the proteins belonging to the rumen methanogen (66%) are more stable in the rumen environment, while a majority of the proteins belonging to the lake-sediment methanogen (58%) are more stable at sediment conditions. In a separate observation, it was noted that while the complete protein ';proteasome subunit alpha' of another rumen methanogen (Methanobrevibacter smithii) was less stable in its more reducing habitat as compared to a sewage methanogen (Methanothermobacter thermoautotophicus), its first 26 amino acid residues (N terminal) were in fact more stable in its own environment. These 26 residues are reported to be unique as compared to other proteasome proteins and are suggested to

  10. Distribution of mega fauna on sulfide edifices on the Eastern Lau Spreading Center and Valu Fa Ridge

    Science.gov (United States)

    Sen, Arunima; Becker, Erin L.; Podowski, Elizabeth L.; Wickes, Leslie N.; Ma, Shufen; Mullaugh, Katherine M.; Hourdez, Stéphane; Luther, George W.; Fisher, Charles R.

    2013-02-01

    Hydrothermal vent sulfide edifices contain some of the most extreme thermal and chemical conditions in which animals are able to live. As a result, sulfide edifices in the East Pacific Rise, Juan de Fuca Ridge, and Mid Atlantic Ridge vent systems often contain distinct faunal assemblages. In this study, we used high-resolution imagery and in-situ physico-chemical measurements within the context of a Geographic Information System (GIS) to examine community structure and niche differentiation of dominant fauna on sulfide edifices in the Eastern Lau Spreading Center (ELSC) and Valu Fa Ridge (VFR) in the Western Pacific Ocean. Our results show that ELSC and VFR sulfide edifices host two distinct types of communities. One type, that covers the majority of sulfide edifice faces, is overall very similar to nearby lava communities and biomass is dominated by the same chemoautotrophic symbiont-containing molluscs that dominate lava communities, namely the provannid gastropods Alviniconcha spp. and Ifremeria nautilei and the mytilid bivalve Bathymodiolus brevior. The spatial distribution of the dominant molluscs is often a variation of the pattern of concentric rings observed on lavas, with Alviniconcha spp. at the tops of edifices where exposure to vent flow is the highest, and I. nautilei and B. brevior below. Our physico-chemical measurements indicate that because of rapid dispersion of vent fluid, habitable area for symbiont-containing fauna is quite limited on sulfide edifices, and the realized niches of the mollusc groups are narrower on sulfide edifices than on lavas. We suggest that competition plays an important role in determining the realized distributions of the mollusc groups on edifices. The other habitat, present in small patches of presumably hot, new anhydrite, is avoided by the dominant symbiont-containing molluscs and inhabited by crabs, shrimp and polynoids that are likely more heat tolerant. The ratio of sulfide concentration to temperature anomaly of

  11. Organic and Inorganic Carbon in the Rio Tinto (Spain) Deep Subsurface System: a Possible Model for Subsurface Carbon and Lithoautotrophs on Mars.

    Science.gov (United States)

    Bonaccorsi, R.; Stoker, C. R.; MARTE Science Team

    2007-12-01

    The subsurface is the key environment for searching for life on planets lacking surface life. Subsurface ecosystems are of great relevance to astrobiology including the search for past/present life on Mars. Conditions on the Martian surface do not support biological activity but the subsurface might preserve organics and host subsurface life [1]. A key requirement for the analysis of subsurface samples on Mars is the ability to characterize organic vs. inorganic carbon pools. This information is needed to determine if the sample contains organic material of biological origin and/ or to establish if pools of inorganic carbon can support subsurface biospheres. The Mars Analog Rio Tinto Experiment (MARTE) performed deep drilling of cores i.e., down to 165-m depth, in a volcanically-hosted-massive-sulfide deposit at Rio Tinto, Spain, which is considered an important analog of the Sinus Meridiani site on Mars. Results from MARTE suggest the existence of a relatively complex subsurface life including aerobic and anaerobic chemoautotrophs, and strict anaerobic methanogens sustained by Fe and S minerals in anoxic conditions, which is an ideal model analog for a deep subsurface Martian environment. We report here on the distribution of organic (C-org: 0.01-0.3Wt% and inorganic carbon (IC = 0.01-7.0 Wt%) in a subsurface rock system including weathered/oxidized i.e., gossan, and unaltered pyrite stockwork. Cores were analyzed from 3 boreholes (BH-4, BH-7, and BH-8) that penetrated down to a depth of ~165 m into massive sulfide. Nearsurface phyllosilicate rich-pockets contain the highest amounts of organics (0.3Wt%) [2], while the deeper rocks contain the highest amount of carbonates. Assessing the amount of C pools available throughout the RT subsurface brings key insight on the type of trophic system sustaining its microbial ecosystem (i.e., heterotrophs vs. autotrophs) and the biogeochemical relationships that characterize a new type of subsurface biosphere at RT. This

  12. Metagenomic Assembly of the Dominant Zetaproteobacteria in an Iron-oxidizing Hydrothermal Microbial Mat

    Science.gov (United States)

    Moyer, C. L.; Fullerton, H.

    2013-12-01

    TCA cycle. The presence of Molybdopterin oxidoreductase, ferric uptake regulation protein, cytochromes, thioredoxin, RuBisCo and other TCA related genes support our hypothesis of chemoautotrophic primary production with the notion that Zetaproteobacteria act as ecosystem engineers driving microbial mat formation and maintenance of their habitat.

  13. Carbon isotopic composition of branched tetraether membrane lipids in soils suggest a rapid turnover and a heterotrophic life style of their source organism(s)

    Science.gov (United States)

    Weijers, J. W. H.; Wiesenberg, G. L. B.; Bol, R.; Hopmans, E. C.; Pancost, R. D.

    2010-09-01

    Branched Glycerol Dialkyl Glycerol Tetraethers (GDGTs) are membrane spanning lipids synthesised by as yet unknown bacteria that thrive in soils and peat. In order to obtain more information on their ecological niche, the stable carbon isotopic composition of branched GDGT-derived alkanes, obtained upon ether bond cleavage, has been determined in a peat and various soils, i.e. forest, grassland and cropland, covered by various vegetation types, i.e., C3- vs. C4-plant type. These δ13C values are compared with those of bulk organic matter and higher plant derived n-alkanes from the same soils. With average δ13C values of -28‰, branched GDGTs in C3 soils are only slightly depleted (ca. 1‰) relative to bulk organic carbon and on average 8.5‰ enriched relative to plant wax-derived long-chain n-alkanes ( nC29-nC33). In an Australian soil dominantly covered with C4 type vegetation, the branched GDGTs have a δ13C value of -18‰, clearly higher than observed in soils with C3 type vegetation. As with C3 vegetated soils, branched GDGT δ13C values are slightly depleted (1‰) relative to bulk organic carbon and enriched (ca. 5‰) relative to n-alkanes in this soil. The δ13C values of branched GDGT lipids being similar to bulk organic carbon and their co-variation with those of bulk organic carbon and plant waxes, suggest a heterotrophic life style and assimilation of relatively heavy and likely labile substrates for the as yet unknown soil bacteria that synthesise the branched GDGT lipids. However, a chemoautotrophic lifestyle, i.e. consuming respired CO2, could not be fully excluded based on these data alone. Based on a natural labelling experiment of a C3/C4 crop change introduced on one of the soils 23 years before sampling and based on a free-air CO2 enrichment experiment with labelled CO2 on another soil, a turnover time of ca. 18 years has been estimated for branched GDGTs in these arable soils.

  14. Metagenomics, single cell genomics, and steady-state free energy flux provide insight into the biogeochemical cycling of deep, meteoric water

    Science.gov (United States)

    Magnabosco, C.; Lau, C. M.; Ryan, K.; Kieft, T. L.; Snyder, L.; Sherwood Lollar, B.; Lacrampe Couloume, G.; Hendrickson, S.; Pullin, M. J.; Slater, G. F.; Simkus, D.; Borgonie, G.; van Heerden, E.; Kuloyo, O.; Maleke, M.; Tlalajoe, T.; Vermeulen, J.; Vermeulen, F.; Munro, A.; Pienaar, M.; Stepanauskas, R.; Grim, S. L.; Onstott, T. C.

    2013-12-01

    Prior to the onset of high-throughput sequencing, the study of biogeochemical cycling in the terrestrial deep subsurface was limited to geochemical, thermodynamic, culture dependent microbial and low-throughput molecular analyses. Here, we present an integration of these traditional methods with high-throughput metagenomic and single cell analysis of 3.1 km deep water collected from a borehole (TT107) located in AngloGold Ashanti's TauTona Au Mine of South Africa and intersecting a fracture within a Witwatersrand Supergroup quartzite. The low salinity fracture water encountered at this depth is meteoric in origin and has a subsurface residence time on the order of a few thousand years. Aqueous geochemistry and estimated steady-state free energy flux values suggest that redox reactions are driven by the oxidation of abundant, energy-rich substrates including H2, CO, CH4, formate, and propanoate. The majority of the metagenome's sequences related to the phyla Firmicutes and Proteobacteria, which contain several bacterial species that are likely to exhibit chemoautotrophic metabolism. Sequence data confirms that many of these bacteria have the ability reduce of sulfur and nitrogen species via dissimilatory pathways. Thermincola were the most abundant firmicutes at this location and were sequenced at the single cell level. Notably, Thermincola sp. are capable of reducing metals and may utilize energy rich manganese reduction pathways at TT107. The CH4 at this site is of abiological origin (δ13C-C1-3 = -43.5 to -44.3 VPDB; δ2H-C1-3 = -345 to -200 VSMOW) despite the metagenome containing several sequences that are closely related to methanogens in the archaeal phyla Euryarchaeota. Alternatively, these archaea may belong to a group of euryarchaetoa commonly referred to as anaerobic mehanotrophic archaea (ANME) - suggesting that anaerobic oxidation (AOM) of abiogenic CH4 coupled to the reduction of sulfate species may be occurring at this site. Sequences for pmoA and s

  15. Methane and Dissolved Organic Carbon Sustain an Ecosystem within a Density Stratified Coastal Aquifer of the Yucatan Peninsula, Mexico. Evidence for a Subterranean Microbial Loop?

    Science.gov (United States)

    Brankovits, David; Pohlman, John W.; Niemann, Helge; Leigh, Mary Beth; Casso, Michael; Alvarez Noguera, Fernando; Lehmann, Moritz F.; Iliffe, Thomas M.

    2016-04-01

    In coastal karst terrains, anchialine caves that meander in density stratified aquifers provide an exceptional opportunity for scientists to study in situ biogeochemical processes within the groundwater. The Caribbean coast of Mexico's Yucatan Peninsula contains over 1000 km of mapped cave passages, the densest known accumulation of anchialine caves in the world. A decades-old study based on the simple observation of 13C-depleted biomass in the cave-adapted fauna suggested biogeochemical processes related to methane-linked carbon cycling and/or other chemoautotrophic pathways as a source of energy and carbon. In this study, we utilized cave diving and a novel sampling device (the Octopipi) to obtain cm-scale water column profiles of methane, DOC and DIC concentrations and stable carbon isotope ratios to identify the energy sources and microbial processes that sustain life in these subterranean estuaries. High concentrations (up to 9522 nM) low-δ13C (as low as -67.5 permil) methane near the ceiling of the cave (in the fresh water section of the stratified water column) and evidence for methane oxidation in the brackish water portion of the water column suggest methane availability and consumption. Profiles obtained by the Octopipi demonstrate that virtually all of the methane (˜99%) is oxidized at the interface of anoxic freshwater and hypoxic brackish water masses. The high-methane water mass near the ceiling also contained elevated concentrations of DOC (851 μM) that displayed comparatively high δ13C (-27.8 to -28.2 permil), suggesting terrestrial organic matter input from the overlying soils. Low-methane brackish and saline water was characterized by lower DOC concentration (15 to 97 μM), yet with similar δ13C (-25.9 to -27.2 permil), suggesting significant terrestrial organic matter consumption or removal with increasing depth, from fresh to saline water, within the water column. The presence of 13C-depleted fatty acids (e.g., C16:1ω7c with δ13C

  16. Arsenic, Prokaryotes, and Closed Basin Soda Lakes of the Western USA.

    Science.gov (United States)

    Oremland, R. S.

    2006-12-01

    A number of saline, alkaline soda lakes in the Great Basin and Mojave Desert of the United States have unusually high concentrations of inorganic arsenic dissolved in their brine-waters. The arsenic originates from natural rather than anthropogenic sources, namely volcanic hydrothermal inputs. When this influx is coupled with evapo-concentration and the unique chemical behavior of arsenic oxyanions in alkaline waters, it results in extremely elevated As concentrations. For example, the salinity and arsenate levels of 3 comparable soda lakes (pH 9.8) are: Big Soda Lake, NV (27 g/L; 20 uM), Mono Lake, CA (90 g/L; 200 uM), and Searles Lake, CA (340 g/L; 3,900 uM). The arsenic oxidation state changes from As5+ (arsenate) to As3+ (arsenite) with vertical transition from their oxygenated surface water to their anoxic bottom water. Similar phenomena occur in their littoral sediments. These lakes also harbor active populations of prokaryotes that achieve these As redox changes either by using arsenate as an electron acceptor for respiration, or by employing arsenite as a chemoautotrophic electron donor. Diverse microorganisms have been identified in these systems that are involved in the biogeochemical cycling of arsenic therein, and in situ studies made with radiotracer (73As) and other means showed that these redox reactions occur at rapid rates. However, other than their use for waterfowl hunting (Big Soda Lake), as a region of scenic beauty (Mono Lake), or as a resource for the chemical industry (Searles Lake), there is little concern about the arsenic in these systems because the waters are not potable and their chemistry is too extreme to allow for the presence of fish. Nonetheless, microbial processes that govern arsenic biogeochemistry can greatly influence the hydrologic mobility and toxicity of this element in freshwater systems, such as drinking water aquifers. Moreover, anthropogenic inputs of arsenic can also occur in closed basin lakes in this region, such as

  17. Carbon isotopic composition of branched tetraether membrane lipids in soils suggest a rapid turnover and a heterotrophic life style of their source organism(s

    Directory of Open Access Journals (Sweden)

    J. W. H. Weijers

    2010-09-01

    Full Text Available Branched Glycerol Dialkyl Glycerol Tetraethers (GDGTs are membrane spanning lipids synthesised by as yet unknown bacteria that thrive in soils and peat. In order to obtain more information on their ecological niche, the stable carbon isotopic composition of branched GDGT-derived alkanes, obtained upon ether bond cleavage, has been determined in a peat and various soils, i.e. forest, grassland and cropland, covered by various vegetation types, i.e., C3- vs. C4-plant type. These δ13C values are compared with those of bulk organic matter and higher plant derived n-alkanes from the same soils. With average δ13C values of −28‰, branched GDGTs in C3 soils are only slightly depleted (ca. 1‰ relative to bulk organic carbon and on average 8.5‰ enriched relative to plant wax-derived long-chain n-alkanes ( nC29nC33. In an Australian soil dominantly covered with C4 type vegetation, the branched GDGTs have a δ13C value of −18‰, clearly higher than observed in soils with C3 type vegetation. As with C3 vegetated soils, branched GDGT δ13C values are slightly depleted (1‰ relative to bulk organic carbon and enriched (ca. 5‰ relative to n-alkanes in this soil. The δ13C values of branched GDGT lipids being similar to bulk organic carbon and their co-variation with those of bulk organic carbon and plant waxes, suggest a heterotrophic life style and assimilation of relatively heavy and likely labile substrates for the as yet unknown soil bacteria that synthesise the branched GDGT lipids. However, a chemoautotrophic lifestyle, i.e. consuming respired CO2, could not be fully excluded based on these data alone. Based on a natural labelling experiment of a C3/C4 crop change introduced on one of the soils 23 years before sampling and based

  18. Carbon isotopic composition of branched tetraether membrane lipids in soils suggest a rapid turnover and a heterotrophic life style of their source organism(s

    Directory of Open Access Journals (Sweden)

    J. W. H. Weijers

    2010-05-01

    Full Text Available Branched Glycerol Dialkyl Glycerol Tetraethers (GDGTs are membrane spanning lipids synthesised by as yet unknown bacteria that thrive in soils and peat. In order to obtain more information on their ecological niche, the stable carbon isotopic composition of branched GDGT-derived alkanes, obtained upon ether bond cleavage, has been determined in various soils, i.e. peat, forest, grassland and cropland, covered by various vegetation types, i.e., C3- vs. C4-plant type. These δ13C values are compared with those of bulk organic matter and higher plant derived n-alkanes from the same soils. With average δ13C values of −28‰, branched GDGTs in C3 soils are only slightly depleted (ca. 1‰ relative to bulk organic carbon and on average 8.5‰ enriched relative to plant wax-derived long-chain n-alkanes (nC29nC33. In an Australian soil covered with C4 type vegetation, the branched GDGTs have a δ13C value of −18‰, clearly higher than observed in soils with C3 type vegetation. As with C3 vegetated soils, branched GDGT δ13C values are slightly depleted (1‰ relative to bulk organic carbon and enriched (ca. 5‰ relative to n-alkanes in this soil. The δ13C values of branched GDGT lipids being similar to bulk organic carbon and their co-variation with those of bulk organic carbon and plant waxes, suggest a heterotrophic life style and assimilation of relatively heavy and likely labile substrates for the as yet unknown soil bacteria that synthesise the branched GDGT lipids. However, a chemoautotrophic lifestyle, i.e. consuming respired CO2, could not be fully excluded based on these data alone. Based on a natural labelling experiment of a C3/C4 crop change introduced on one of the soils 23 years before sampling and based on a free air CO

  19. Microbially mediated carbon cycling as a control on the δ 13C of sedimentary carbon in eutrophic Lake Mendota (USA): new models for interpreting isotopic excursions in the sedimentary record

    Science.gov (United States)

    Hollander, David J.; Smith, Michael A.

    2001-12-01

    An isotopic study of various carbon phases in eutrophic Lake Mendota (Wisconsin, USA) indicates that the δ 13C composition of sedimentary organic and inorganic carbon has become more negative in response to increasing microbially mediated carbon cycling and processes associated with the intensification of seasonal and long-term eutrophication. Progressive increases in the contributions of isotopically depleted chemoautotrophic and methanotrophic biomass (reflected in the -40 to -90‰ values of hopanols and FAMES), attributed to seasonal and long-term increases in production and expansion of the anaerobic water mass, accounts for carbon isotopic trends towards depleted δ 13C values observed in both seasonal varves and over the past 100 years. Changes in the intensities of certain microbial processes are also evident in the sedimentary geochemical record. During the period of most intense cultural eutrophication, when the oxic-anoxic interface was located close to the surface, methanogenesis/methanotrophy and the oxidation of biogenic methane increased to the extent that significant quantities of 13C-depleted CO 2 were added into the epilimnion. This depleted CO 2 was subsequently utilized by phytoplankton and incorporated into CaCO 3 during biogenically induced calcite precipitation. A comparative study between eutrophic Lakes Mendota and Greifen, further indicate that the extent of nutrient loading in the epilimnion determines whether the δ 13C record of sedimentary organic carbon reflects intensification of microbial processes in the hypolimnion and sediments, or changes in the primary productivity in the photic zone. From this comparison, a series of eutrophication models are developed to describe progressive transitions through thresholds of microbial and eukaryotic productivity and their influence on the δ 13C record of sedimentary carbon. With increasing eutrophication, the models initially predict a negative and then a subsequent positive carbon isotopic

  20. Identification of proteins involved in the functioning of Riftia pachyptila symbiosis by Subtractive Suppression Hybridization

    Directory of Open Access Journals (Sweden)

    Lallier François H

    2007-09-01

    Full Text Available Abstract Background Since its discovery around deep sea hydrothermal vents of the Galapagos Rift about 30 years ago, the chemoautotrophic symbiosis between the vestimentiferan tubeworm Riftia pachyptila and its symbiotic sulfide-oxidizing γ-proteobacteria has been extensively studied. However, studies on the tubeworm host were essentially targeted, biochemical approaches. We decided to use a global molecular approach to identify new proteins involved in metabolite exchanges and assimilation by the host. We used a Subtractive Suppression Hybridization approach (SSH in an unusual way, by comparing pairs of tissues from a single individual. We chose to identify the sequences preferentially expressed in the branchial plume tissue (the only organ in contact with the sea water and in the trophosome (the organ housing the symbiotic bacteria using the body wall as a reference tissue because it is supposedly not involved in metabolite exchanges in this species. Results We produced four cDNA libraries: i body wall-subtracted branchial plume library (BR-BW, ii and its reverse library, branchial plume-subtracted body wall library (BW-BR, iii body wall-subtracted trophosome library (TR-BW, iv and its reverse library, trophosome-subtracted body wall library (BW-TR. For each library, we sequenced about 200 clones resulting in 45 different sequences on average in each library (58 and 59 cDNAs for BR-BW and TR-BW libraries respectively. Overall, half of the contigs matched records found in the databases with good E-values. After quantitative PCR analysis, it resulted that 16S, Major Vault Protein, carbonic anhydrase (RpCAbr, cathepsin and chitinase precursor transcripts were highly represented in the branchial plume tissue compared to the trophosome and the body wall tissues, whereas carbonic anhydrase (RpCAtr, myohemerythrin, a putative T-Cell receptor and one non identified transcript were highly specific of the trophosome tissue. Conclusion Quantitative PCR

  1. Influence of seep emission on the non-symbiont-bearing fauna and vagrant species at an active giant pockmark in the Gulf of Guinea (Congo-Angola margin)

    Science.gov (United States)

    Olu, K.; Caprais, J. C.; Galéron, J.; Causse, R.; von Cosel, R.; Budzinski, H.; Ménach, K. Le; Roux, C. Le; Levaché, D.; Khripounoff, A.; Sibuet, M.

    2009-12-01

    Detailed surveying with an ROV found that a dense and diverse cold-seep community colonises a giant pockmark located at 3200 m depth, 8 km north from the deep Congo channel. Several types of assemblages, either dominated by Mytilidae and Vesicomyidae bivalves or Siboglinidae polychaetes, are distributed on the 800-m diameter active area. The site is characterised by a most active central zone in a depression with abundant carbonate concretions and high methane fluxes where high-density clusters of mussels and siboglinids dominate. In contrast, the peripheral zones display large fields of dead and live vesicomyids on soft sediment, with a lower mean density and lower methane concentration in seawater. The associated megafauna includes Alvinocarididae shrimps, echinoids, holothurians of the family Synaptidae, several species of gastropods, two species of galatheids, and Zoarcidae and Ophidiidae fishes. Multivariate analyses of video transect data show that the distribution of these major megafauna species at the pockmark scale is influenced by the habitat heterogeneity due to fluid or gas emission, occurrence of hydrates, substratum variability and by the presence of large symbiont-bearing species. Several assemblages dominated either by mytilids, vesicomyids, or siboglinids have been sampled for megafauna densities and biomass estimations and stable isotope measurements ( δ13C and δ15N) of dominant species and food sources. The highest estimates of megafauna densities have been obtained in mytilid beds. According to their stable isotopes values, non-symbiont-bearing species mainly rely on chemosynthesis-originated carbon, either as primary consumers of chemoautotrophic microorganisms, or at higher trophic level recycling organic matter, or relying on bivalve and tubeworm production. Most of them likely feed on different sources like shrimps, but differences according to habitat have been evidenced. Carbon and nitrogen isotope ratios of galatheids and benthic or

  2. Present-day serpentinization in the Tablelands, Gros Morne National Park, Newfoundland: a Mars Analogue Site

    Science.gov (United States)

    Szponar, N.; Morrill, P. L.; Brazelton, W. J.; Schrenk, M. O.; Bower, D. M.; Steele, A.

    2010-12-01

    Serpentinization - a reaction between water and ultramafic rock (derived from the mantle) - is suspected to be a source of hydrocarbons such as methane on Mars. Through the hydration of ultramafic rock, this reaction produces hydrogen (H2) gas and reducing conditions necessary for abiogenic hydrocarbon synthesis, while also producing conditions amendable for the production of methane through microbial chemoautotrophic pathways. Mars analogue sites of present-day serpentinization can be used to determine what geochemical measurements are required for determining the reactions responsible for the methane in the Martian atmosphere. On Earth few locations that are known to exhibit active serpentinization are easily accessible. One such location is found in the Tablelands at Gros Morne National Park, Newfoundland. Peridotite rocks similar to those found on Mars dominate the Tablelands thus making the Tablelands an important analogue site for potential ecosystems on Mars. Present-day serpentinization is evidenced by fluid seeps characterized by highly alkaline (pH 11 to 12) and highly reducing (as low as -820 mV) conditions, travertine and the presence of dissolved methane. These fluids contain high concentrations of Ca2+ (~5.00x104ppb) compared to freshwater inputs (~ 1.00x103) and react at the surface with atmospheric CO2 producing travertine deposits (as CaCO3 precipitate). Dissolved H2 gas produced abiogenically through the serpentinization reaction also provides copious geofuels, which can be used for chemosynthesis. Preliminary data has shown that microbial life lives in the high pH springs of the Tablelands. Ongoing studies of targeted compounds including phospholipid fatty acids and ether-linked lipids are being used to determine the microbial community compositions and verify the occurrence of Bacteria and Archaea in these fluids. An important question is also the source of the serpentinized fluid seeps. Hydrogen (δ2H) and oxygen (δ18O) isotopes of these

  3. Volcanic degassing, hydrothermal circulation and the flourishing of early life on Earth: A review of the evidence from c. 3490-3240 Ma rocks of the Pilbara Supergroup, Pilbara Craton, Western Australia

    Science.gov (United States)

    Van Kranendonk, Martin J.

    2006-02-01

    Formation of the Warrawoona Group are intimately associated with barite and chert precipitates from hydrothermal vents, suggesting that component microbes may have been chemoautotrophic hyperthermophiles. Evidence of shallow water to periodically exposed conditions, active growth faulting and soft sediment deformation indicates that the volcanogenic emissions were erupted into a shallow water, tectonically active caldera and concentrated therein to produce an extreme habitat for early life. Widespread conical and pseudocolumnar stromatolites in the c. 3400 Ma, Strelley Pool Chert at the base of the unconformably overlying Kelly Group occur in shallow marine platform carbonates. Silicification was the result of later hydrothermal circulation driven by heat from the overlying, newly erupted Euro Basalt. The markedly different morphology and geological setting of these only slightly younger stromatolites, compared with the Dresser Formation, suggests a diversity of microbial life on early Earth. The biogenicity of putative microfossils from this and younger hydrothermal silica veins in the Warrawoona Group remains controversial and requires further detailed study.

  4. Biomineralization and biosignatures of coralloid-type speleothems from lava tubes of Galapagos Islands: evidences on the fossil record of prokaryotes

    Science.gov (United States)

    Miller, Ana Z.; Garcia-Sanchez, Angela M.; Pereira, Manuel F. C.; Gazquez, Fernando; Calaforra, José M.; Forti, Paolo; Toulkeridis, Theofilos; Martínez-Frías, Jesús; Saiz-Jimenez, Cesareo

    2016-04-01

    , whereas the final stage mainly consists of low crystalline calcite. FESEM-EDS analysis revealed mineralized bacterial filaments rich in Si on the coralloid samples, as well as minerals precipitation associated with extracellular polymeric substances (EPS), which serve as nuclei for preferential precipitation on the extracellular sheaths. This suggests that biological activity played a major role in the development of these speleothems. In addition, imprints of filamentous cells and microboring readily preserved on siliceous minerals were observed on the coralloid speleothems. These features are recognized as biosignatures valuable for astrobiology and may represent modern analogs of the fossil record of prokaryotes. DNA-based analyses showed that bacteria belonging to Actinobacteria (31%) Gemmatimonadetes (25%) and Proteobacteria (24%) phyla dominated in this cave ecosystem, followed by Acidobacteria, Firmicutes and Nitrospirae. Most of the identified phylotypes were affiliated to chemoautotrophs, including thermophilic bacteria such as Ferrithrix thermotolerans, and other mineral utilizing microorganisms like Aciditerrimonas ferrireducens, Desulfuromonas sp. and Desulfovibrio sp., indicating that Galapagos lava tubes host highly specialized subsurface biosphere dominated by microorganisms able to interact with minerals and promote biomineralization. Acknowledgments: This work has been supported by the project PC-65-14 from the Ministry of Environment of Ecuador. AZM acknowledges the support from the Marie Curie Fellowship of the 7th EC Framework Programme (PIEF-GA-2012-328689-DECAVE). The authors acknowledge the Spanish Ministry of Economy and Competitiveness (project CGL2013-41674-P) and FEDER funds for financial support.

  5. Origin and flow dynamic of groundwater in Movile cave area, Romania, based on environmental isotopes

    International Nuclear Information System (INIS)

    The stable isotope content of waters collected from the investigated area provided important information about the unusual underground ecosystem of Movile Cave that is based on chemoautotrophic conditions. As a conservative tracer in carbonate rocks deuterium was used to determine the un-elucidated problems of the water origin in cave. The cave developed into hydrogeologic complex of South-Dobrogea and is located near the Mangalia City. Rocks classified according to their hydrological function include the unconfined aquifer in the Sarmatian karstic limestones and the confined aquifer in the Mesozoic limestones which are fractured and karstic and represent a unitary complex interconnected with upper lying aquifer. The tectonic structure indicates three faults: a fault orientated by NS lineament intersects the Kara Oban Fault orientated on NW-SE direction and the Movile-Aurora Fault in the Mangalia Swamp. The values of δ2H and δ18O plotted on GMWL (Craig line) indicate the meteoric origin of groundwater in Movile Cave area. The average value of δ2H for all samples is -85 0/00, for the most samples (76%) the δ2H values are lower than -80 0/00 and the water is isotopically more light than the waters from the semiarid lowland of the Dobrogea district (over -76 0/00). The δ2H-Δdens correlation of samples delineated three isotopically water types: groundwater with low deuterium content (0/00), water with deuterium content of about mean value and waters with higher δ2H (> -78 0/00). Time series of the deuterium concentration from groundwater samples both from the aquifer in Mesozoic limestone and from the unconfined aquifer in Sarmatian limestone exhibits a distinct seasonal effect, indicating a strong link with isotopic composition of precipitation, but a lower deuterium concentration in summer than in winter. This six-month phase shift of the isotopic composition variations with respect to normal succession of seasonal maximum and minimum values of precipitation

  6. The Arsenic Cycle in Searles Lake, California: An Arsenic-Rich, Salt-Saturated Soda Lake. II. Isolation of Arsenic-Metabolizing Microbes.

    Science.gov (United States)

    Switzer Blum, J.; Hoeft, S. E.; Stolz, J. F.; Langley, S.; Beveridge, T. J.; Kulp, T. R.; Oremland, R. S.

    2004-12-01

    dioxide. Preliminary evidence suggests that the culture consists of a lactate-oxidizing sulfate-reducer growing in synthrophy with a chemoautotrophic, sulfide-oxidizing As(V)-respirer. Terminal restriction length polymorphism analysis has indicated the presence of both bacterial and archaeal components in the Serl-Ab enrichment, although it is not yet known which is responsible for the observed As(V)-reduction and sulfate-reduction. Efforts are ongoing to resolve Serl-Ab by using classical isolation procedures for a heterotrophic sulfate reducer and an autotrophic As(V)-respirer. In addition, new efforts are being undertaken to isolate hydrogen-oxidizing As(V)-respirers, as well as aerobic As(III)-oxidizers from the extreme environment of Searles Lake.

  7. A lander mission to probe subglacial water on Saturn's moon Enceladus for life

    Science.gov (United States)

    Konstantinidis, Konstantinos; Flores Martinez, Claudio L.; Dachwald, Bernd; Ohndorf, Andreas; Dykta, Paul; Bowitz, Pascal; Rudolph, Martin; Digel, Ilya; Kowalski, Julia; Voigt, Konstantin; Förstner, Roger

    2015-01-01

    The plumes discovered by the Cassini mission emanating from the south pole of Saturn's moon Enceladus and the unique chemistry found in them have fueled speculations that Enceladus may harbor life. The presumed aquiferous fractures from which the plumes emanate would make a prime target in the search for extraterrestrial life and would be more easily accessible than the moon's subglacial ocean. A lander mission that is equipped with a subsurface maneuverable ice melting probe will be most suitable to assess the existence of life on Enceladus. A lander would have to land at a safe distance away from a plume source and melt its way to the inner wall of the fracture to analyze the plume subsurface liquids before potential biosignatures are degraded or destroyed by exposure to the vacuum of space. A possible approach for the in situ detection of biosignatures in such samples can be based on the hypothesis of universal evolutionary convergence, meaning that the independent and repeated emergence of life and certain adaptive traits is wide-spread throughout the cosmos. We thus present a hypothetical evolutionary trajectory leading towards the emergence of methanogenic chemoautotrophic microorganisms as the baseline for putative biological complexity on Enceladus. To detect their presence, several instruments are proposed that may be taken aboard a future subglacial melting probe. The "Enceladus Explorer" (EnEx) project funded by the German Space Administration (DLR), aims to develop a terrestrial navigation system for a subglacial research probe and eventually test it under realistic conditions in Antarctica using the EnEx-IceMole, a novel maneuverable subsurface ice melting probe for clean sampling and in situ analysis of ice and subglacial liquids. As part of the EnEx project, an initial concept study is foreseen for a lander mission to Enceladus to deploy the IceMole near one of the active water plumes on the moon's South-Polar Terrain, where it will search for

  8. Spatial distribution of diverse cold seep communities living on various diapiric structures of the southern Barbados prism

    Science.gov (United States)

    Olu, K.; Sibuet, M.; Harmegnies, F.; Foucher, J.-P.; Fiala-Médioni, A.

    Three sectors of the south Barbados prism between 1000 and 2000 m depth were explored by the French submersible Nautile. Chemosynthesis-based benthic communities were discovered on several structures affected by diapirism, including mud volcanoes, domes and an anticlinal ridge. The communities are associated with the expulsion of methane-rich fluids which is a wide-spread process in the area. These communities are dominated by large bivalves and vestimentiferans which harbour chemoautotrophic symbiotic bacteria. The symbiotic bivalves include two species of Mytilidae and one of Vesicomyidae, with dominance of a methanotrophic mussel. Cartography of the benthic communities, interpretation of thermal measurements and observation of sedimentary patterns have been used to define the life habits of each of the three species of symbiotic bivalves. Each species has a characteristic preference for different conditions of edaphic and fluid flow: the dominant methanotrophic mussel appears to require high velocity vents and hard substratum. The vesicomyids and the other species of mussel are able to take up sulfide from the sediments, and so are associated with low seepages, but also require soft sediment. The three bivalve species are assumed successively to colonize the top of a diapiric ridge, in a succession related to the temporal evolution of fluid flow and sedimentation. The composition of the bivalve assemblages, their densities and biomasses all differ between the several mud volcanoes and domes studied, and these parameters are thought to be related to the spatial and temporal variations of fluid expulsion through the structures, and the lithification processes linked to fluid expulsion. One very active dome is at present colonized by an exceptionally large and dense population of the methanotrophic mussel. In contrast, communities in another area, on the domes and volcanoes that are currently inactive, were colonized by only a few living vesicomyids and mussels

  9. The Origin of Life in a Terrestrial Hydrothermal Pool? The Importance of a Catalytic Surface

    Science.gov (United States)

    Sydow, L. A.; Bennett, P.

    2013-12-01

    A premise of one chemoautotrophic theory for the origin of life is that a recurring reaction catalyzed on the charged surfaces of pyrite served as the first metabolism and was later enveloped by a primitive cellular membrane. This proposed 'surface metabolism' is analogous to the reductive acetyl-CoA pathway (Wächtershäuser 1988) and requires the abiotic formation of methanethiol (CH3SH), the simplest of the alkyl thiols, which would serve the role of coenzyme-A in the surface metabolism. Abiogenic CH3SH has not previously been identified in terrestrial hot springs, but it has been produced in the laboratory under hydrothermal conditions in the presence of a catalyst, usually FeS. Its formation would occur via the following reactions, with reaction 2 requiring catalysis: CO2 + 2H2S --> CS2 + 2H2O (1) CS2 + 3H2 --> CH3SH + H2S (2) We have identified CH3SH in Cinder Pool, an acid-sulfate-chloride hot spring in Yellowstone National Park. This spring is unusual in that it contains a subaqueous molten sulfur layer (~18 m depth) and thousands of iron-sulfur-spherules floating on the surface, which are created by gas bubbling through the molten floor of the spring. Analysis with EDS has shown that cinder material, largely composed of elemental sulfur, also contains trace iron sulfide minerals, meaning it could serve as a reactive and catalytic surface for abiogenic CH3SH formation in Cinder Pool. Furthermore, the cinders themselves are highly porous, and these void spaces could trap necessary reactants near the catalytic surface. Gas samples were collected from Cinder pool in fall of 2011 using the bubble strip method. One sample contained measurable quantities of CH3SH, and all samples contained related reactant sulfur gases such as large amounts of H2S, and smaller amounts of CS2 and dimethyl disulfide. Laboratory microcosm experiments were conducted to replicate these findings in a sterile environment to ensure CH3SH generation was abiotic. Analog Cinder Pool water

  10. Continental subsurface waters support unique but diverse C-acquisition strategies

    Science.gov (United States)

    Lau, C. M.; Magnabosco, C.; Brown, C. T.; Grim, S. L.; Lacrampe Couloume, G.; Wilkie, K. M.; Sherwood Lollar, B.; Simkus, D.; Slater, G. F.; Hendrickson, S.; Pullin, M. J.; Kieft, T. L.; Li, L.; Snyder, L.; Kuloyo, O.; Linage, B.; Borgonie, G.; Vermeulen, J.; Maleke, M.; Tlalajoe, N.; Moloantoa, K.; van Heerden, E.; Vermeulen, F.; Pienaar, M.; Munro, A.; Joubert, L.; Ackerman, J.; van Jaarsveld, C.; Onstott, T. C.

    2013-12-01

    Terrestrial subsurface environments generally support two orders of magnitude fewer microorganisms than submarine environments where energy and C sources are more abundant. However, our research on the geochemistry and stable isotopes has suggested that the microbial communities residing in the continental subsurface waters, aged more than thousands of years, do not live by a monotypic metabolic network across sites. We evaluated the taxonomic and functional diversity of microbial communities from three localities in South Africa and their relationship to the environmental parameters associated with each fracture water. The borehole at Tau Tona Au mine (TT107; 3,100 mbls), Masimong Au mine (MM5; 1,900 mbls) and Zondereinde Pt mine (NO14; 2,100 mbls) contain saline fracture water of paleometeroic origin but the anaerobic ecosystems were driven by distinctive C-assimilation strategies. Archaea and Bacteria are present in all samples with the latter being dominant (>75%). The similarity between the Δ14C and δ13C-PLFA with those of the DIC indicates that the majority of cellular C in the TT107 sample was derived from the DIC (0.6 mM), even though dissolved CH4 (8.8 mM) is more available. The DIC may have supported a wide variety of chemoautotrophs including the predominant firmicutes, e.g. Thermincola sp. and Ca. Desulforudis audaxviator. Interestingly, a considerable percentage of sequences related to oligotrophic α-proteobacteria Caulobacter sp. was detected, which warrants further investigation as the aerobic heterotrophic microorganism has a unique dimorphic life cycle. For the MM5 sample, the δ13C and δ2H of the CH4 indicate it was produced via CO2 reduction from DIC, which is consistent with the relatively high abundance of hydrogenotrophic methanogen Methanothermobacter sp. that scavenged the abiogenic H2 and utilized the DIC (0.43 mM) leading to its enriched δ13C signature. In contrast to the TT107 sample, the much-depleted δ13C-CH4 indicates that the

  11. Oxic-anoxic conditions in the water column of a tropical freshwater reservoir (Pena-Larga dam, NW Venezuela)

    International Nuclear Information System (INIS)

    photosynthetic organisms and land-derived detritus, that either reflect the contribution of microbial biomass (chemoautotrophic and/or methanotrophic bacteria) or the selective degradation of more labile organic compounds in the water column. The hypoxic to anoxic conditions displayed in the major part of the water column extend to the first cm of lake bottom sediments. A simplified budget based on the main redox processes active in the hypolimnion and on average water residence times, supports drastic differences in mineralization rate: 83-444 μmol C L-1 a-1 for the oxic reservoir and only 43 μmol C L-1 a-1 for the hypoxic to anoxic reservoir. This study shows that, if water renewal is not sufficient, tropical freshwater lakes may be subject to severe dissolved O2 depletion conditions at shallow depths, comparable to those observed in deep sections of the water column of temperate eutrophic lakes

  12. Arsenic release from shallow aquifers of the Hetao Basin, Inner Mongolia: Evidence from bacterial community in aquifer sediments and groundwater

    Science.gov (United States)

    Li, Y.; Guo, H.

    2013-12-01

    Indigenous microbes play crucial roles in arsenic mobilization in high arsenic groundwater systems. Databases concerning the presence and the activity of microbial communities are very useful in evaluating the potential of microbe-mediated arsenic mobilization in shallow aquifers hosting high arsenic groundwater. This study characterized microbial communities in groundwaters at different depths with different arsenic concentrations by DGGE and one sediment by 16S rDNA gene clone library, and evaluated arsenic mobilization in microcosm batches with the presence of indigenous bacteria. DGGE fingerprints revealed that the community structure changed substantially with depth at the same location. It indicated that a relatively higher bacterial diversity was present in the groundwater sample with lower arsenic concentration. The clone library of sediment sample 2009M1 and DGGE profiles of microbial community structures of groundwater samples indicated NO3-, Fe(III) and SO42- reducing bacteria are abundant in the As-affected aquifer, which are facultative or anaerobic chemoautotrophic bacteria. Pseudomonas that was rich in both high arsenic groundwater and sediment included a great number of denitrifying bacterium strains that may contribute to the low concentration of nitrate in the groundwater. Fe(III)-reducing bacteria belonging to different species, such as Aquabacterium sp., Thauera sp., Georgfuchsia sp., Methyloversatilis sp., Clostridium sp., were widely found in the community. The genus Desulfosporosinus observed in the sediment sample of 2009M1 was believed to be sulfate reducer. These results offered direct evidences that anaerobic reducing bacteria play a role in the formation of toxic, mobile As(III) in the groundwater of the Hetao basin, especially Fe(III)-reducing bacteria. Incubation of sediments without the addition of organic carbon source showed a significant release of arsenic (predominantly as As(III)). By contrast, sterile incubations and incubations

  13. Exploring the controls of soil biogeochemistry in a restored coastal wetland using object-oriented computer simulations of uptake kinetics and thermodynamic optimization in batch reactors

    Science.gov (United States)

    Payn, R. A.; Helton, A. M.; Poole, G.; Izurieta, C.; Bernhardt, E. S.; Burgin, A. J.

    2012-12-01

    Many hypotheses have been proposed to predict patterns of biogeochemical redox reactions based on the availability of electron donors and acceptors and the thermodynamic theory of chemistry. Our objective was to develop a computer model that would allow us to test various alternatives of these hypotheses against data gathered from soil slurry batch reactors, experimental soil perfusion cores, and in situ soil profile observations from the restored Timberlake Wetland in coastal North Carolina, USA. Software requirements to meet this objective included the ability to rapidly develop and compare different hypothetical formulations of kinetic and thermodynamic theory, and the ability to easily change the list of potential biogeochemical reactions used in the optimization scheme. For future work, we also required an object pattern that could easily be coupled with an existing soil hydrologic model. These requirements were met using Network Exchange Objects (NEO), our recently developed object-oriented distributed modeling framework that facilitates simulations of multiple interacting currencies moving through network-based systems. An initial implementation of the object pattern was developed in NEO based on maximizing growth of the microbial community from available dissolved organic carbon. We then used this implementation to build a modeling system for comparing results across multiple simulated batch reactors with varied initial solute concentrations, varied biogeochemical parameters, or varied optimization schemes. Among heterotrophic aerobic and anaerobic reactions, we have found that this model reasonably predicts the use of terminal electron acceptors in simulated batch reactors, where reactions with higher energy yields occur before reactions with lower energy yields. However, among the aerobic reactions, we have also found this model predicts dominance of chemoautotrophs (e.g., nitrifiers) when their electron donor (e.g., ammonium) is abundant, despite the

  14. Engineering and Coordination of Regulatory Networks and Intracellular Complexes to Maximize Hydrogen Production by Phototrophic Microorganisms

    Energy Technology Data Exchange (ETDEWEB)

    James C. Liao

    2012-05-22

    This project is a collaboration with F. R. Tabita of Ohio State. Our major goal is to understand the factors and regulatory mechanisms that influence hydrogen production. The organisms to be utilized in this study, phototrophic microorganisms, in particular nonsulfur purple (NSP) bacteria, catalyze many significant processes including the assimilation of carbon dioxide into organic carbon, nitrogen fixation, sulfur oxidation, aromatic acid degradation, and hydrogen oxidation/evolution. Our part of the project was to develop a modeling technique to investigate the metabolic network in connection to hydrogen production and regulation. Organisms must balance the pathways that generate and consume reducing power in order to maintain redox homeostasis to achieve growth. Maintaining this homeostasis in the nonsulfur purple photosynthetic bacteria is a complex feat with many avenues that can lead to balance, as these organisms possess versatile metabolic capabilities including anoxygenic photosynthesis, aerobic or anaerobic respiration, and fermentation. Growth is achieved by using H{sub 2} as an electron donor and CO{sub 2} as a carbon source during photoautotrophic and chemoautotrophic growth, where CO{sub 2} is fixed via the Calvin-Benson-Bassham (CBB) cycle. Photoheterotrophic growth can also occur when alternative organic carbon compounds are utilized as both the carbon source and electron donor. Regardless of the growth mode, excess reducing equivalents generated as a result of oxidative processes, must be transferred to terminal electron acceptors, thus insuring that redox homeostasis is maintained in the cell. Possible terminal acceptors include O{sub 2}, CO{sub 2}, organic carbon, or various oxyanions. Cells possess regulatory mechanisms to balance the activity of the pathways which supply energy, such as photosynthesis, and those that consume energy, such as CO{sub 2} assimilation or N{sub 2} fixation. The major route for CO{sub 2} assimilation is the CBB

  15. Massive Expansion of Marine Archaea During The Early Albian Oceanic Anoxic Event 1B

    Science.gov (United States)

    Kuypers, M. M.; Kuypers, M. M.; Blokker, P.; Erbacher, J.; Kinkel, H.; Pancost, R. D.; Pancost, R. D.; Schouten, S.; Sinninghe Damsté, J. S.

    2001-12-01

    environments. We can only speculate about the causes of this unprecedented massive expansion of marine planktonic archaea during the mid-Cretaceous OAE1b. Prolonged periods of enhanced hydrothermal activity would have significantly altered the ocean chemistry during the mid-Cretaceous, providing the necessary reduced compounds like ammonium to sustain a large community of chemoautotrophic archaea. In addition pronounced water stratification and anoxic conditions such as existed during the OAE1b could have provided a competitive advantage for archaea over phytoplankton utilising ammonium, allowing a diverse community of nitrifying non-thermophilic archaea to evolve. In any case our data show that there seems to be no unifying mechanism for black shale deposition during the mid-Cretaceous OAEs. Although there are apparent similarities (distinct lamination, 13C-enrichment of OC) between the black shales of OAE1b and other OAEs, our detailed molecular work shows that the origin of the OM (archaeal versus phytoplanktonic) and causes for 13C-enrichment of OC are completely different.

  16. Diabetes mellitus en adultos mexicanos: resultados de la Encuesta Nacional de Salud 2000 Diabetes mellitus in Mexican adults: results from the 2000 National Health Survey

    Directory of Open Access Journals (Sweden)

    Gustavo Olaiz-Fernández

    2007-01-01

    xico. Su efecto se magnifica al afectar con mayor frecuencia a grupos de población cuyos factores sociales o económicos limitan su acceso al tratamiento. Los datos informados son útiles para la institución de programas de escrutinio y prevención. Los resultados confirman que la diabetes debe ser motivo de investigación en familiares de primer grado e individuos que tengan uno o más de los componentes del síndrome metabólico (hipertensión, dislipidemia, obesidad y microalbuminuria.OBJECTIVE: To show the prevalence of diabetes mellitus (DM and its associated factors in adults, using data derived from the 2000 National Health Survey (NHS. MATERIAL AND METHODS: The 2000 NHS was conducted between November 1999 and June 2000. An adult questionnaire was administered to 45 294 subjects 20 years of age and older. Capillary glucose levels, weight, height and blood pressure were obtained. Individual weighted factors were considered in the statistical analysis, as was the survey's complex sampling design to obtain variances using SUDAAN 7.5.6. RESULTS: The national prevalence of DM in adults ages 20 years and older was 7.5% (95% CI: 7.1-7.9. The prevalence was 7.8% in women and 7.2% in men. It was higher according to age: 2.3% in adults 40 years or younger and 21.2% in those older than 60 years of age. In the urban population, prevalence was 8.1% and in the rural population it was 6.5%. The disease was more frequent in the northern region of the country (8.4% and in the Mexico City metropolitan area (8.1%. DM was more frequent in the population with the least amount of schooling (9.9%, the lowest income (8.1%, high blood pressure (13.7%, hypercholesterolemia (23.3% microalbuminuria (15.5% and renal disease (12.3%. Using multivariate logistic regression, stratified by gender, variables associated with DM were identified: age, little schooling, family history of DM, high blood pressure, renal disease or hypercholesterolemia in both genders. Abdominal obesity was associated

  17. Ergonomics: a study of influence on productivity Ergonomía: un estudio de su influencia en la productividad Ergonomia: um estudo sobre sua influência na produtividade

    Directory of Open Access Journals (Sweden)

    Carlos Rodrigues da Silva

    2009-12-01

    Full Text Available Companies, governments and society are showing an increasing interest in ergonomics as applied to productive activities. Therefore the Brazilian government has issued Norma Regulamentadora 17 - Ergonomia to establish parameters for adapting working conditions to the psycho-physiologic characteristics of workers. This work evaluated ergonomics, productivity and work stations at “Magnifica Confecções” in Paranaíba, where most machines are operated in a seated position with repetitive movements. Therefore ergonomic concepts aspects are decisive to improve productivity and well-being of collaborators. Ergonomics is used at the work stations in a constructive and participative problem solving process requiring understanding of the tasks, activities, problems and performance demanded. For this reason, resultant data was supported by questionnaires answered by the diverse participants that developed these activities resolving these problems.Es creciente el interés de las empresas, los gobiernos y la sociedad por el estudio de la ergonomía aplicada a las actividades productivas. En este sentido, el gobierno brasileño ha publicado la “Norma Reglamentaria 17 - Ergonomía”, que tiene por objeto establecer los parámetros para la adecuación de las condiciones de trabajo a las características psicofisiológicas de los trabajadores. Este trabajo tiene como objetivo evaluar los puestos de trabajo de la empresa “Magnífica Confecções”, en Paranaíba, MS, Brasil, en relación a su ergonomía, y determinar su influencia en la productividad. El uso constante de las máquinas, la posición sentada y la repetición de los movimientos implicados en la actividad industrial son característicos del puesto de trabajo de la organización. Por estas características, la atención a las exigencias ergonómicas es un factor decisivo para aumentar la productividad y mejorar el bienestar de las participantes. La aplicación de los conceptos de ergonom

  18. Development of biological platform for the autotrophic production of biofuels

    Science.gov (United States)

    Khan, Nymul

    of the current status of metabolic engineering of chemolithoautotrophs is carried out in order to identify the challenges and likely routes to overcome them. This is presented in Chapter 3 of this dissertation. The initial metabolic engineering and bioreactor studies was carried out using a number of gene-constructs on R. capsulatus and R. eutropha. The gene-constructs consisted of Plac promoter followed by the triterpene synthase genes (SS or BS) and other upstream genes. A comparison of the production of triterpenes were done in the different growth modes that R. capsulatus was capable of growing---aerobic heterotrophic, anaerobic photoheterotrophic and aerobic chemoautotrophic. Autotrophic productivity could likely be improved much further by increasing the available mass-transfer of the reactor. These efforts are presented in Chapter 4 of this dissertation. (Abstract shortened by UMI.).

  19. 长期施肥对稻田土壤固碳功能菌群落结构和数量的影响%Abundance and composition of CO2fixating bacteria in relation to long-term fertilization of paddy soils

    Institute of Scientific and Technical Information of China (English)

    袁红朝; 秦红灵; 刘守龙; 童成立; 葛体达; 魏文学; 吴金水

    2012-01-01

    CO2 fixation is the central mechanism of primary production in almost all ecosystems, and plays a major role in regulating the concentration of atmospheric CO2. Carbon dioxide accounts for about 50% of the current global wanning potential. Soil microorganisms that assimilate CO2 are widely distributed, and have a great ability to adapt to environmental extremes, such as within volcanic sediments, lake wetlands and the submarine realm. Microbial CO2 assimilation is of great significance to climate change mitigation and sustainable development for human beings.It has now been well established that atmospheric concentration of CO2 can be reduced significantly by adopting management practices to enhance CO2 sequestration (storage) in cropland soils. Among the approaches for increasing CO2 sequestration of croplands are soil fertilization management practices, such as returning crop residues to the soil, plantingtemporarily retired land with grass for stabilization, and integrating nutrient management strategies to diversified cropping systems.Paddy soils are distributed widely throughout the world, and generally are known for their production of greenhouse gasses ( N2 O and CH4 ). Numerous studies have used molecular techniques to investigate these microbial driving mechanisms. However, few studies have addressed the importance of microbial CO2 fixation processes in paddy soils. Investigation of the impacts of long-term fertilization on the structure and abundance of CO2 assimilating bacteria in paddy soils can provide a theoretical basis for the application of information on fertilization of paddy-rice fields. This type of research also may benefit the reduction of greenhouse gas emissions and increase carbon sequestration.Although carbon fixating microorganisms exhibit a wide range of physiological and ecological traits, most photo- and chemoautotrophic bacteria use ribulose-1,5-biphosphate carboxylase/oxygenase (RubisCO) , which catalyzes the first rate