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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. Assessment of Chemical Impact of Invasive Bryozoan Pectinatella magnifica on the Environment: Cytotoxicity and Antimicrobial Activity of P. magnifica Extracts

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    Peter Kollar

    2016-11-01

    Full Text Available Pectinatella magnifica, an invasive bryozoan, might significantly affect ecosystem balance due to its massive occurrence in many areas in Europe and other parts of the world. Biological and chemical analyses are needed to get complete information about the impact of the animal on the environment. In this paper, we aimed to evaluate in vitro cytotoxic effects of five extracts prepared from P. magnifica using LDH assay on THP-1 cell line. Antimicrobial activities of extracts against 22 different bacterial strains were tested by microdilution method. Our study showed that all extracts tested, except aqueous portion, demonstrated LD50 values below 100 μg/mL, which indicates potential toxicity. The water extract of P. magnifica with LD50 value of 250 μg/mL also shows potentially harmful effects. Also, an environmental risk resulting from the presence and increasing biomass of potentially toxic benthic cyanobacteria in old colonies should not be underestimated. Toxicity of Pectinatella extracts could be partially caused by presence of Aeromonas species in material, since we found members of these genera as most abundant bacteria associated with P. magnifica. Furthermore, P. magnifica seems to be a promising source of certain antimicrobial agents. Its methanolic extract, hexane, and chloroform fractions possessed selective inhibitory effect on some potential pathogens and food spoiling bacteria in the range of MIC 0.5–10 mg/mL. Future effort should be made to isolate and characterize the content compounds derived from P. magnifica, which could help to identify the substance(s responsible for the toxic effects of P. magnifica extracts.

  3. A Case of Gingival Myiasis Caused by Wohlfahrtia magnifica

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    T Mohammadzadeh

    2008-08-01

    Full Text Available A gingival myiasis in a four years old mental retarded boy with anorexia and weight loss is presented from southern part of Iran. Entomological studies on larvae showed the larvae as Wohlfartia magnifica which is a rare causative agent of gingival myiasis.

  4. Reintroduction of Tigridiopalma magnifica, a rare and critically endangered herb endemic to China

    Science.gov (United States)

    Hai Ren; Songjun Zeng; Longna Li; Qianmei Zhang; Long Yang; Jun Wang; Zhengfeng Wang; Qinfeng Guo

    2012-01-01

    Tigridiopalma magnifica, a perennial herb and the only species in the genus Tigridiopalma (Family Melastomataceae) is rare and endemic to China where it is categorized as Critically Endangered on the national Red List. Twelve locations with populations of T. magnifica have been identified (1 extinct, 11 extant...

  5. NMR studies of chalcones isolated from Neoraputia magnifica; Estudos por RMN de chalconas isoladas de Neoraputia magnifica

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    Tomazela, Daniela M.; Rodrigues Filho, Edson; Silva, M. Fatima das G. F. da; Fernandes, Joao B.; Vieira, Paulo C. [Sao Carlos Univ., SP (Brazil). Dept. de Quimica

    1997-12-31

    From Neoraputia magnifica (Rutaceae) we isolated two chalcones belonging to the 1,3-diarylprop-2-en-1-one group. The two chalcones presented two or three methoxyl groups at ring B; a dimethychromene between C-5`and O-6`and also an additional methoxyl at ring A. It has been noted that H-{beta} and C-{beta} of a chalcone are more deshielded than H-{alpha}. However, HMOC and HMBC experiments of the chalcones described here showed the opposite situation where H-{alpha} is more deshielded than H-{beta}. (author) 5 refs., 4 figs., 7 tabs.

  6. Calyptogena-cemented rocks and concretions from the eastern part of Nankai accretionary prism: Age and geochemistry of uranium

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    Lalou, Claude; Fontugne, Michel; Lallemand, Serge E.; Lauriat-Rage, Agnès

    1992-04-01

    Calyptogena valves included in a carbonate-rich cement, and fragments of a carbonate-rich chimney, have been examined for their stable isotopic (C and O) composition,14C activity and uranium series disequilibrium. The fossil shells were formed essentially with seawater carbon and a negligible contribution of cold seepage organic carbon, as shown by theirδ13C values. This allows the14C method to be used to determine their age. A fairly good concordance between the14C and230Th234U ages of the youngest shells gives confidence in the dating of the older samples using the latter technique. Thus, theCalyptogena are dated at ca. 150,000 and 20,000 yrs B.P. They have been preserved from dissolution by rapid cementation by a supersaturated carbonate solution. The cement is especially rich in uranium (as high as 75 ppm), whose source is seawater; the enrichment is due to local reducing conditions brought about by the bacterial decomposition of the soft tissues of the bivalves shortly after death. TheCalyptogena that probably developed between these two events (the events of ca. 20,000 and 150,000 yrs) have not been preserved from dissolution because, as is presently the case, the cold seepages were undersaturated with calcium carbonate. The two events probably represent periods of intense fluid venting connected with tectonic activity.

  7. [Wound myiasis due to Wohlfahrtia magnifica. First human case in Morocco].

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    Lmimouni, B E; Baba, N E; Yahyaoui, A; Khallaayoune, K; Dakkak, A; Sedrati, O; El Mellouki, W

    2004-11-01

    Wohlfahrtia magnifica is a frequent fly in countries with high breeding activity: Australia, South Africa or Arab country The parasitological infestation occurred essentially during the summer, favourable period to the biological evolution of the flies. In this work, we report one case of wound myiasis that complicates a cutaneous lesion caused by larvae of Wohlfahrtia magnifica. This observation constitutes the first human case in our country.

  8. Methods and systems for chemoautotrophic production of organic compounds

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    Fischer, Curt R.; Che, Austin J.; Shetty, Reshma P.; Kelly, Jason R.

    2013-01-08

    The present disclosure identifies pathways, mechanisms, systems and methods to confer chemoautotrophic production of carbon-based products of interest, such as sugars, alcohols, chemicals, amino acids, polymers, fatty acids and their derivatives, hydrocarbons, isoprenoids, and intermediates thereof, in organisms such that these organisms efficiently convert inorganic carbon to organic carbon-based products of interest using inorganic energy, such as formate, and in particular the use of organisms for the commercial production of various carbon-based products of interest.

  9. Methods and systems for chemoautotrophic production of organic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, Curt R.; Che, Austin J.; Shetty, Reshma P.; Kelly, Jason R.

    2018-02-27

    The present disclosure identifies pathways, mechanisms, systems and methods to confer chemoautotrophic production of carbon-based products of interest, such as sugars, alcohols, chemicals, amino acids, polymers, fatty acids and their derivatives, hydrocarbons, isoprenoids, and intermediates thereof, in organisms such that these organisms efficiently convert inorganic carbon to organic carbon-based products of interest using inorganic energy, such as formate, and in particular the use of organisms for the commercial production of various carbon-based products of interest.

  10. Cuticular structures on antennae of the bot fly, Portschinskia magnifica (Diptera: Oestridae).

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    Zhang, Dong; Wang, Qi-Ke; Hu, De-Fu; Li, Kai

    2012-10-01

    Portschinskia magnifica Pleske, 1926, is an endangered subcutaneous parasitic fly of voles that mimics bumblebees in appearance. Although the importance of antennae in Diptera has been repeatedly stressed, there is still a lack of morphology information of this group, let alone this species. Antennae of adult P. magnifica were studied with a stereoscopic microscope and scanning electron microscope. Six subtypes of antennal sensilla were observed on the funiculus and arista (one subtype of trichoid sensilla, one subtype of basiconic sensilla, and four subtypes of coeloconic sensilla). Sensilla on the antennal funiculus from one sample of both male and female flies were also mapped. Female P. magnifica bear a larger number of sensilla than males, and more sensilla were discovered on the posterior surface than on the anterior surface. However, what make this species special are the distinct structures and new morphological characteristics discovered in the antenna. The antennal funiculus of P. magnifica is completely enveloped by an antennal pedicel. A large number of branched or unbranched trichoid and basiconic sensilla are identified on the antennal funiculus. These two make the most numerous types of sensilla distributed all over the funicular surface. P. magnifica has the most coeloconic sensilla subtypes in previously studied oestrid flies. A total of four subtypes of coeloconic sensilla are found, with subtype I and subtype II on the proximal and middle part of the antennal funiculus and subtype III and subtype IV on the antennal arista. Two large bristles that resemble mechanoreceptors on the proximal two antennal segments located close to the arista are a unique feature. This has never been described in the oestrid funiculus. Interestingly, these bristles can appear as multi-tipped short structures in some individuals. P. magnifica lacks sensory pits that are usually abundant in other oestrid flies. The size, number, and distribution of sensilla on the male

  11. A forest health inventory assessment of red fir (Abies magnifica) in upper montane California

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    Leif Mortenson; Andrew N. Gray; David C. Shaw

    2015-01-01

    We investigated the forest health of red fir (Abies magnifica) and how it compared with commonly-associated species Jeffrey pine (Pinus jeffreyi), lodgepole pine (Pinus contorta) and white fir (Abies concolor) in the upper montane forests of California. We evaluated tree mortality rates...

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

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    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.

  13. An assemblage of the host anemone Heteractis magnifica in the northern Red Sea, and distribution of the resident anemonefish

    DEFF Research Database (Denmark)

    Brolund, Thea Marie; Tychsen, Anders; Nielsen, Lis Engdahl

    2004-01-01

    The Heteractis magnifica assemblage at the tip of the Sinai Peninsula was examined. The actinian size, location, and number of resident anemonefishes were recorded. The anemones were found at depths down to approximately 40 m and the sizes of clustering H. magnifica and clusters were positively c...... in very large numbers (approximately 250 and 1800 respectively) and the A. bicinctus home range size was positively correlated with depth....

  14. 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.

  15. 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.

  16. Genomic and population genetic analysis of deep-sea vent chemoautotrophs

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    Nakagawa, S.; Shimamura, S.; Takaki, Y.; Mino, S.; Makita, H.; Sawabe, T.; Takai, K.

    2012-12-01

    Deep-sea vents are the light-independent, highly productive ecosystems driven primarily by chemoautotrophs. Most of the invertebrates thrive there through their relationship with symbiotic chemoautotrophs. Chemoautotrophs are microorganisms that are able to fix inorganic carbon using a chemical energy obtained through the oxidation of reduced compounds. Following the discovery of deep-sea vent ecosystems in 1977, there has been an increasing knowledge that deep-sea vent chemoautotrophs display remarkable physiological and phylogenetic diversity. Recent microbiological studies have led to an emerging view that the majority of deep-sea vent chemoautotrophs have the ability to derive energy from multiple redox couples other than the conventional sulfur-oxygen couple. Genomic, metagenomic and postgenomic studies have considerably accelerated the comprehensive understanding of molecular mechanisms of deep-sea vent chemoautotrophy, even in unculturable endosymbionts of vent fauna. For example, genomic analysis suggested that there were previously unrecognized evolutionary links between deep-sea vent chemoautotrophs and important human/animal pathogens. However, relatively little is known about the genome of horizontally transmitted endosymbionts. In this study, we sequenced whole genomes of the probably horizontally transmitted endosymbionts of two different gastropod species from a deep-sea hydrothermal field, as an effort to address questions about 1) the genome evolution of horizontally transmitted, facultative endosymbionts, 2) their genomic variability, and 3) genetic differences among symbionts of various deep-sea vent invertebrates. Both endosymbiont genomes display features consistent with ongoing genome reduction such as large proportions of pseudogenes and transposable elements. The genomes encode multiple functions for chemoautotrophic respirations, probably reflecting their adaptation to their niches with continuous changes in environmental conditions. When

  17. 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.

  18. NCBI nr-aa BLAST: CBRC-HSAP-05-0051 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-HSAP-05-0051 ref|YP_903576.1| nicotinate (nicotinamide) nucleotide adenylyltra...nsferase [Candidatus Ruthia magnifica str. Cm (Calyptogena magnifica)] gb|ABL02105.1| nicotinate-nucleotide

  19. NCBI nr-aa BLAST: CBRC-PTRO-06-0046 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-PTRO-06-0046 ref|YP_903576.1| nicotinate (nicotinamide) nucleotide adenylyltra...nsferase [Candidatus Ruthia magnifica str. Cm (Calyptogena magnifica)] gb|ABL02105.1| nicotinate-nucleotide

  20. Traumatic myiasis in farmed animals caused by Wohlfahrtia magnifica in southern Italy (Diptera: Sarcophagidae

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    Teresa Bonacci

    2017-06-01

    Full Text Available Ten herds of sheep and goats (455 heads were inspected for the presence of traumatic myiasis between May and September 2013 in the province of Cosenza, Calabria, southern Italy. Nine cases were discovered in sheep, goats and a sheepdog. Infested body sites included external genitalia, wounds (sheep and sheepdog and hooves (goats. Larvae were removed from the infested body areas and reared to adult stage in the laboratory. Both the larvae and the adults were identified as belonging to the Mediterranean screwworm fly Wohlfahrtia magnifica (Schiner, 1862 (Diptera: Sarcophagidae, an obligatory parasite of humans and warm-blooded vertebrates. To our knowledge, these are the first cases of wohlfahrtiosis in sheep and goats to be reported from Calabria. The infested animals were living outdoors in spring and summer, and enclosed in sheds during the autumn and winter months. Observed effects of the myiases included severely impeded walking and tissue damage. Wohlfahrtiosis can cause significant economic loss to farmers. Data about the local distribution, seasonality and types of infestation caused by W. magnifica are useful to farmers and vets to improve control systems, in Calabria as elsewhere within the distributional range of the species

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

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

    2014-01-01

    Objective To study agents of animal wound myiasis in various geographical districts of Fars province. Methods This study has been done in Fars province, located in the southern part of Iran. Sums of 10 358 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 About 61% of all animal wound myiasis were caused by larvae of Wohlfahrtia magnifica. 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%. 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. PMID:25182946

  2. 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

  3. Human Urogenital Myiasis Caused by Lucilia sericata (Diptera: Calliphoridae) and Wohlfahrtia magnifica (Diptera: Sarcophagidae) in Markazi Province of Iran

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    Salimi, M; Goodarzi, D; Karimfar, MH; Edalat, H

    2010-01-01

    We report a case of human urogenital myiasis in an 86-year-old rural man with a penil ulcer and numerous alive and motile larvae from urethra and glans penis. Entomological studies on adult flies showed the larvae were Lucilia sericata and Wohlfahrtia magnifica. The clinical presentation and treatment strategies are discussed. PMID:22808392

  4. Venom present in sea anemone (Heteractis magnifica) induces apoptosis in non-small-cell lung cancer A549 cells through activation of mitochondria-mediated pathway.

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    Ramezanpour, Mahnaz; da Silva, Karen Burke; Sanderson, Barbara J S

    2014-03-01

    Lung cancer is a major cause of cancer deaths throughout the world and the complexity of apoptosis resistance in lung cancer is apparent. Venom from Heteractis magnifica caused dose-dependent decreases in survival of the human non-small-cell lung cancer cell line, as determined by the MTT and Crystal Violet assays. The H. magnifica venom induced cell cycle arrest and induced apoptosis of A549 cells, as confirmed by annexin V/propidium iodide staining. The venom-induced apoptosis in A549 cells was characterized by cleavage of caspase-3 and a reduction in the mitochondrial membrane potential. Interestingly, crude extracts from H. magnifica had less effect on the survival of non-cancer cell lines. In the non-cancer cells, the mechanism via which cell death occurred was through necrosis not apoptosis. These findings are important for future work using H. magnifica venom for pharmaceutical development to treat human lung cancer.

  5. PECTINATELLA MAGNIFICA LEIDY 1851 (PHYLACTOLAEMATES, UN BRYOZOAIRE INTRODUIT DANS LE NORD FRANCHE-COMTÉ.

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    RODRIGUEZ S.

    2002-04-01

    Full Text Available A partir de l’observation initiale d’une colonie du bryozoaire Pectinatella magnifica Leidy 1851 dans le nord Franche-Comté (été 1994 et d’une analyse bibliographique, un suivi de l’extension de l’espèce a été effectué sur le territoire franc-comtois et dans les régions limitrophes. La localisation des stations est assortie de valeurs de qualité d’eau mesurées sur le réseau hydrographique franc-comtois pour le compte de l’Agence de l’Eau Rhône-Méditerranée-Corse. La rédaction d’une fiche d’enquête nationale vise à collecter des informations sur ce bryozoaire afin d’en faciliter ultérieurement la gestion.

  6. Chemoautotrophic carbon fixation rates and active bacterial communities in intertidal marine sediments.

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    Henricus T S Boschker

    Full Text Available Chemoautotrophy has been little studied in typical coastal marine sediments, but may be an important component of carbon recycling as intense anaerobic mineralization processes in these sediments lead to accumulation of high amounts of reduced compounds, such as sulfides and ammonium. We studied chemoautotrophy by measuring dark-fixation of 13C-bicarbonate into phospholipid derived fatty acid (PLFA biomarkers at two coastal sediment sites with contrasting sulfur chemistry in the Eastern Scheldt estuary, The Netherlands. At one site where free sulfide accumulated in the pore water right to the top of the sediment, PLFA labeling was restricted to compounds typically found in sulfur and ammonium oxidizing bacteria. At the other site, with no detectable free sulfide in the pore water, a very different PLFA labeling pattern was found with high amounts of label in branched i- and a-PLFA besides the typical compounds for sulfur and ammonium oxidizing bacteria. This suggests that other types of chemoautotrophic bacteria were also active, most likely Deltaproteobacteria related to sulfate reducers. Maximum rates of chemoautotrophy were detected in first 1 to 2 centimeters of both sediments and chemosynthetic biomass production was high ranging from 3 to 36 mmol C m(-2 d(-1. Average dark carbon fixation to sediment oxygen uptake ratios were 0.22±0.07 mol C (mol O2(-1, which is in the range of the maximum growth yields reported for sulfur oxidizing bacteria indicating highly efficient growth. Chemoautotrophic biomass production was similar to carbon mineralization rates in the top of the free sulfide site, suggesting that chemoautotrophic bacteria could play a crucial role in the microbial food web and labeling in eukaryotic poly-unsaturated PLFA was indeed detectable. Our study shows that dark carbon fixation by chemoautotrophic bacteria is a major process in the carbon cycle of coastal sediments, and should therefore receive more attention in future

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

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    Boschker, Henricus T. S.; Vasquez-Cardenas, Diana; Bolhuis, Henk; Moerdijk-Poortvliet, Tanja W. C.; Moodley, Leon

    2014-01-01

    Chemoautotrophy has been little studied in typical coastal marine sediments, but may be an important component of carbon recycling as intense anaerobic mineralization processes in these sediments lead to accumulation of high amounts of reduced compounds, such as sulfides and ammonium. We studied chemoautotrophy by measuring dark-fixation of 13C-bicarbonate into phospholipid derived fatty acid (PLFA) biomarkers at two coastal sediment sites with contrasting sulfur chemistry in the Eastern Scheldt estuary, the Netherlands. At one site where free sulfide accumulated in the pore water right to the top of the sediment, PLFA labeling was restricted to compounds typically found in sulfur and ammonium oxidizing bacteria. At the other site, with no detectable free sulfide in the pore water, a very different PLFA labeling pattern was found with high amounts of label in branched i- and a-PLFA besides the typical compounds for sulfur and ammonium oxidizing bacteria. This suggests that other types of chemoautotrophic bacteria were also active, most likely Deltaproteobacteria related to sulfate reducers. Maximum rates of chemoautotrophy were detected in first 1 to 2 centimeters of both sediments and chemosynthetic biomass production was high ranging from 3 to 36 mmol C m−2 d−1. Average dark carbon fixation to sediment oxygen uptake ratios were 0.22±0.07 mol C (mol O2)−1, which is in the range of the maximum growth yields reported for sulfur oxidizing bacteria indicating highly efficient growth. Chemoautotrophic biomass production was similar to carbon mineralization rates in the top of the free sulfide site, suggesting that chemoautotrophic bacteria could play a crucial role in the microbial food web and labeling in eukaryotic poly-unsaturated PLFA was indeed detectable. Our study shows that dark carbon fixation by chemoautotrophic bacteria is a major process in the carbon cycle of coastal sediments, and should therefore receive more attention in future studies on

  8. Community structure and soil pH determine chemoautotrophic carbon dioxide fixation in drained paddy soils.

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    Long, Xi-En; Yao, Huaiying; Wang, Juan; Huang, Ying; Singh, Brajesh K; Zhu, Yong-Guan

    2015-06-16

    Previous studies suggested that microbial photosynthesis plays a potential role in paddy fields, but little is known about chemoautotrophic carbon fixers in drained paddy soils. We conducted a microcosm study using soil samples from five paddy fields to determine the environmental factors and quantify key functional microbial taxa involved in chemoautotrophic carbon fixation. We used stable isotope probing in combination with phospholipid fatty acid (PLFA) and molecular approaches. The amount of microbial (13)CO2 fixation was determined by quantification of (13)C-enriched fatty acid methyl esters and ranged from 21.28 to 72.48 ng of (13)C (g of dry soil)(-1), and the corresponding ratio (labeled PLFA-C:total PLFA-C) ranged from 0.06 to 0.49%. The amount of incorporationof (13)CO2 into PLFAs significantly increased with soil pH except at pH 7.8. PLFA and high-throughput sequencing results indicated a dominant role of Gram-negative bacteria or proteobacteria in (13)CO2 fixation. Correlation analysis indicated a significant association between microbial community structure and carbon fixation. We provide direct evidence of chemoautotrophic C fixation in soils with statistical evidence of microbial community structure regulation of inorganic carbon fixation in the paddy soil ecosystem.

  9. 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 (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 microbial carbon requirements in subice environments and may play a significant role in net carbon-fixation in polar systems.

  10. 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

  11. Aucula magnifica (Schaus, 1904 (Lepidoptera: Noctuidae: Agaristinae: morphology of egg and last instar larvae Aucula magnifica (Schaus, 1904 (Lepidoptera: Noctuidae: Agaristinae: morfologia do ovo e da larva de último ínstar

    Directory of Open Access Journals (Sweden)

    G. Poletto

    2010-05-01

    Full Text Available Aiming to contribute to knowledge of the immature instars of Neotropical Lepidoptera, this study details the morphology of the egg and last instar larvae of Aucula magnifica (Schaus, 1904 (Lepidoptera: Noctuidae: Agaristinae, emphasising the structures of the corium and the chaetotaxy. There is also a report of the occurrence of entomopathogenic action of Nomuraea rileyi (Farlow Samson fungi on the larva.Este estudo objetiva contribuir para o conhecimento dos estágios imaturos dos lepidópteros neotropicais. Nele é feito o detalhamento da morfologia das fases de ovo e de larva de Aucula magnifica (Schaus, 1904 (Lepidoptera: Noctuidae: Agaristinae, dando ênfase ao estudo das estruturas do córion e da quetotaxia da larva de último ínstar. Além disso é relatada a ocorrência da ação entomopatogênica do fungo Nomuraea rileyi (Farlow Samson sobre suas larvas.

  12. Peptide fingerprinting of the sea anemone Heteractis magnifica mucus revealed neurotoxins, Kunitz-type proteinase inhibitors and a new β-defensin α-amylase inhibitor.

    Science.gov (United States)

    Sintsova, Oksana; Gladkikh, Irina; Chausova, Victoria; Monastyrnaya, Margarita; Anastyuk, Stanislav; Chernikov, Oleg; Yurchenko, Ekaterina; Aminin, Dmitriy; Isaeva, Marina; Leychenko, Elena; Kozlovskaya, Emma

    2017-11-27

    Sea anemone mucus, due to its multiple and vital functions, is a valuable substance for investigation of new biologically active peptides. In this work, compounds of Heteractis magnifica mucus were separated by multistage liquid chromatography and resulting fractions were analyzed by MALDI-TOF MS. Peptide maps constructed according to the molecular masses and hydrophobicity showed presence of 326 both new and known peptides. Several major peptides from mucus were identified, including the sodium channel toxin RpII isolated earlier from H. magnifica, and four Kunitz-type proteinase inhibitors identical to H. crispa ones. Kunitz-type transcript diversity was studied and sequences of mature peptides were deduced. New β-defensin α-amylase inhibitor, a homolog of helianthamide from Stichodactyla helianthus, was isolated and structurally characterized. Overall, H. magnifica is a source of biologically active peptides with great pharmacological potential. Proteinase and α-amylase inhibitors along with toxins are major components of H. magnifica mucus which play an important role in the successful existence of sea anemones. Obtained peptide maps create a basis for more accurate identification of peptides during future transcriptomic/genomic studies of sea anemone H. magnifica. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Discovery of chemoautotrophic symbiosis in the giant shipworm Kuphus polythalamia (Bivalvia: Teredinidae) extends wooden-steps theory.

    Science.gov (United States)

    Distel, Daniel L; Altamia, Marvin A; Lin, Zhenjian; Shipway, J Reuben; Han, Andrew; Forteza, Imelda; Antemano, Rowena; Limbaco, Ma Gwen J Peñaflor; Tebo, Alison G; Dechavez, Rande; Albano, Julie; Rosenberg, Gary; Concepcion, Gisela P; Schmidt, Eric W; Haygood, Margo G

    2017-05-02

    The "wooden-steps" hypothesis [Distel DL, et al. (2000) Nature 403:725-726] proposed that large chemosynthetic mussels found at deep-sea hydrothermal vents descend from much smaller species associated with sunken wood and other organic deposits, and that the endosymbionts of these progenitors made use of hydrogen sulfide from biogenic sources (e.g., decaying wood) rather than from vent fluids. Here, we show that wood has served not only as a stepping stone between habitats but also as a bridge between heterotrophic and chemoautotrophic symbiosis for the giant mud-boring bivalve Kuphus polythalamia This rare and enigmatic species, which achieves the greatest length of any extant bivalve, is the only described member of the wood-boring bivalve family Teredinidae (shipworms) that burrows in marine sediments rather than wood. We show that K. polythalamia harbors sulfur-oxidizing chemoautotrophic (thioautotrophic) bacteria instead of the cellulolytic symbionts that allow other shipworm species to consume wood as food. The characteristics of its symbionts, its phylogenetic position within Teredinidae, the reduction of its digestive system by comparison with other family members, and the loss of morphological features associated with wood digestion indicate that K. polythalamia is a chemoautotrophic bivalve descended from wood-feeding (xylotrophic) ancestors. This is an example in which a chemoautotrophic endosymbiosis arose by displacement of an ancestral heterotrophic symbiosis and a report of pure culture of a thioautotrophic endosymbiont.

  14. 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

  15. The conundrum between chemoautotrophic production and reductant and oxidant supply: A case study from the Cariaco Basin

    Science.gov (United States)

    Li, Xiaona N.; Taylor, Gordon T.; Astor, Yrene; Varela, Ramon; Scranton, Mary I.

    2012-03-01

    Since 1996, two or three profiles per year of chemoautotrophic production, oxygen, nitrate, ammonium, sulfide and methane have been obtained at the CARIACO Time-Series station and less frequently, at three other stations in the Cariaco Basin. Rates of 14C-bicarbonate assimilation (chemoautotrophy) are consistently elevated in the suboxic and upper anoxic zones. In this paper, we present estimates of vertical fluxes of biologically-important reductants and oxidants over a ten year period (1998-2008) using a simple one dimensional (1-D) model, and compare them to chemoautotrophic production rates. In general, downward oxidant fluxes from major species (in electron-equivalents) balanced well with upward electron fluxes from inorganic reductants. However, vertical fluxes of electron donors/acceptors calculated using typical mixing constants only explained a small fraction (less than 10%) of the measured chemoautotrophic production, if we assume a simplified stoichiometry of 1H2S:1CO2:1O2. Laboratory cultures of sulfide oxidizers typically require 2.4-7.2 mol H2S to fix one mole of C, which would make the mismatch between fluxes and chemoautotrophy measurements even more extreme. Inclusion of other reductants (methane, ammonium, etc.) does not resolve this problem. In addition, we found no relationship between diffusive flux of reductants/oxidants and integrated chemoautotrophic production with data from 19 cruises, suggesting that the diffusive flux of reactants is not the direct source to fuel the chemoautotrophic production. In exploring this imbalance, we considered other sulfide sources: sulfide from vertical or horizontal advective transport, and in situ sulfide production within the upper part of the anoxic water column. Based on the spatial sampling we have done, we do not believe that horizontal transport is supplying enough sulfide to the Cariaco time series station. Sulfide budget in the anoxic water column suggests that sulfide supply from the vertical

  16. 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

  17. Purification of a 19-kDa pore-forming cytolysin from the sea anemone Heteractis magnifica

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    S Karthikayalu

    2010-01-01

    Full Text Available Pore-forming cytolysins of 19 kDa from sea anemones present a remarkable cytolytic property. In the present work, a purified 19-kDa cytolysin was obtained from the sea anemone Heteractis magnifica. The purification steps involved ammonium sulfate precipitation and subsequently desalting by dialysis against 10 mM sodium phosphate buffer (pH 7.4, followed by anion exchange chromatography in DEAE-Sepharose® column (GE Healthcare, Sweden and gel filtration chromatography using Sephadex® G-50 matrix (GE Healthcare, Sweden. The active fractions from the gel filtration chromatography were pooled and rechromatographed in the same column. The final active fraction showed a prominent protein band of molecular mass of 19 kDa when analyzed by SDS-PAGE.

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

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    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.

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

    Science.gov (United States)

    2010-01-01

    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. PMID:20534131

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

    Energy Technology Data Exchange (ETDEWEB)

    Dastidar, Aniruddha, E-mail: andy.dastidar@ky.gov [USEPA Research Participant, Division of Water, Frankfort, KY 40601 (United States); Wang, Yi-Tin, E-mail: ywang@engr.uky.edu [Department of Civil Engineering, University of Kentucky, Lexington (United States)

    2012-08-15

    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 K{sub s} = 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 K{sub s}. -- Highlights: Black-Right-Pointing-Pointer As (III) oxidation. Black-Right-Pointing-Pointer Biokinetic parameters. Black-Right-Pointing-Pointer Model validation

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

    Directory of Open Access Journals (Sweden)

    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.

  2. Comparison of the protein-coding genomes of three deep-sea, sulfur-oxidising bacteria: "Candidatus Ruthia magnifica", "Candidatus Vesicomyosocius okutanii" and Thiomicrospira crunogena.

    Science.gov (United States)

    McGill, Susan E; Barker, Daniel

    2017-07-20

    " Candidatus Ruthia magnifica", "Candidatus Vesicomyosocius okutanii" and Thiomicrospira crunogena are all sulfur-oxidising bacteria found in deep-sea vent environments. Recent research suggests that the two symbiotic organisms, "Candidatus R. magnifica" and "Candidatus V. okutanii", may share common ancestry with the autonomously living species T. crunogena. We used comparative genomics to examine the genome-wide protein-coding content of all three species to explore their similarities. In particular, we used the OrthoMCL algorithm to sort proteins into groups of putative orthologs on the basis of sequence similarity. The OrthoMCL inflation parameter was tuned using biological criteria. Using the tuned value, OrthoMCL delimited 1070 protein groups. 63.5% of these groups contained one protein from each species. Two groups contained duplicate protein copies from all three species. 123 groups were unique to T. crunogena and ten groups included multiple copies of T. crunogena proteins but only single copies from the other species. "Candidatus R. magnifica" had one unique group, and had multiple copies in one group where the other species had a single copy. There were no groups unique to "Candidatus V. okutanii", and no groups in which there were multiple "Candidatus V. okutanii" proteins but only single proteins from the other species. Results align with previous suggestions that all three species share a common ancestor. However this is not definitive evidence to make taxonomic conclusions and the possibility of horizontal gene transfer was not investigated. Methodologically, the tuning of the OrthoMCL inflation parameter using biological criteria provides further methods to refine the OrthoMCL procedure.

  3. Dataset of traumatic myiasis observed for three dominant screw worm species in North West Pakistan with first report of Wohlfahrtia magnifica (Schiner

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    Farrah Zaidi

    2016-09-01

    Full Text Available Regional surveys were carried out in different parts of North West Pakistan among domestic animals (N=57,921 including pets and livestock identifying cases of traumatic myiasis (n=1037. A total of four surveys focused general livestock population during Eid ul Adha (Eid surveys; incidence=1.21% while another four surveys (Miscellaneous surveys; incidence=7.34% targeted animal population brought to veterinary hospitals and dispensaries. Timeframe spanned four years from 2012 to 2015. Maggots were sampled and location of the wound was recorded for each host. Taxonomic identification used light and electron microscopic techniques. Our dataset shows three species as principle agents of myiasis (n=882 including Chrysomya bezziana Villeneuve (n=394, Wohlfahrtia magnifica (n=244 and Lucilia cuprina Wiedemann (n=244. Others (n=155 including Chrysomya megacephala (Fabricius, Chrysomya rufifacies (Macquart, Lucilia sericata (Meigen, Lucilia illustris (Meigen, Lucilia porphyrina (Walker, Hemipyrellia ligguriens (Wiedemann, Calliphora vicina (Robineau-Desvoidy, Sarcophaga crassipalpalis (Macquart and Sarcophaga species were identified as species of minor importance. The obligatory screwworm species W. magnifica is a first report from Pakistan. The results based on this dataset are presented in a recent publication “Distribution Modeling of three screwworm species in the ecologically diverse landscape of North West Pakistan” (Zaidi et al., 2016 [1].

  4. Diversity of Total Bacterial Communities and Chemoautotrophic Populations in Sulfur-Rich Sediments of Shallow-Water Hydrothermal Vents off Kueishan Island, Taiwan.

    Science.gov (United States)

    Wang, Li; Cheung, Man Kit; Liu, Rulong; Wong, Chong Kim; Kwan, Hoi Shan; Hwang, Jiang-Shiou

    2017-04-01

    Shallow-water hydrothermal vents (HTVs) are an ecologically important habitat with a geographic origin similar to that of deep-sea HTVs. Studies on shallow-water HTVs have not only facilitated understanding of the influences of vents on local ecosystems but also helped to extend the knowledge on deep-sea vents. In this study, the diversity of bacterial communities in the sediments of shallow-water HTVs off Kueishan Island, Taiwan, was investigated by examining the 16S ribosomal RNA gene as well as key functional genes involved in chemoautotrophic carbon fixation (aclB, cbbL and cbbM). In the vent area, Sulfurovum and Sulfurimonas of Epsilonproteobacteria appeared to dominate the benthic bacterial community. Results of aclB gene analysis also suggested involvement of these bacteria in carbon fixation using the reductive tricarboxylic acid (rTCA) cycle. Analysis of the cbbM gene showed that Alphaproteobacterial members such as the purple non-sulfur bacteria were the major chemoautotrophic bacteria involving in carbon fixation via the Calvin-Benson-Bassham (CBB) cycle. However, they only accounted for cycle is the major chemoautotrophic carbon fixation pathway in sediments of the shallow-water HTVs off Kueishan Island.

  5. LECTOTIPIFICACIÓN PARA SCHWARTZIA MAGNIFICA (COMPLEJO NORANTEA, MARCGRAVIACEAE Y REVISIÓN DEL GÉNERO PARA BOLIVIA Y PERÚ

    Directory of Open Access Journals (Sweden)

    GIRALDO-CAÑAS DIEGO

    2006-12-01

    Full Text Available Se presenta un estudio taxonómico de las especies peruanas y bolivianas del géneroSchwartzia de la familia neotropical Marcgraviaceae. Schwartzia está representadoen la flora peruana por dos especies, unas de las cuales es endémica, mientras que enBolivia sólo se ha documentado la presencia de una especie. Se presentan la clave parareconocer las especies así como sus descripciones, sus sinónimos, sus ilustraciones,su distribución geográfica y se comentan algunas observaciones morfológicas yecológicas. Por último, se propone la lectotipificación para Schwartzia magnifica,para la cual se destaca, además, su redescubrimiento.

  6. A new species of Copepoda Harpacticoida, Xylora calyptogenae spec. n., with a carnivorous life-style from a hydrothermally active submarine volcano in the New Ireland Fore-Arc system (Papua New Guinea) with notes on the systematics of the Donsiellinae Lang, 1948

    Science.gov (United States)

    Willen, Elke

    2006-12-01

    A new species of harpacticoid copepods, Xylora calyptogenae spec. n., from Edison Seamount, a hydrothermally active submarine volcano in the New Ireland Fore-Arc system (Papua New Guinea) is described. The new species belongs to the Donsiellinae Lang, 1944, a highly specialised taxon, the members of which have previously been encountered only in association with decaying wood and/or wood-boring isopods. A closer relationship of the Donsiellinae with the Pseudotachidiidae Lang, 1936, can be stated on the basis of characteristics concerning the setation and/or segmentation of A1, A2, Mxl, Mxp, the shape of the female P5, anal somite, sexual dimorphisms on P2 and P3 and missing caudal seta I. Within the Pseudotachidiidae, the Donsiellinae again can be well characterized, e.g. by the setation and segmentation of A2, Mxl, swimming-legs, the shape of P1, female P5, male P2, sexual dimorphism and male P5. The Donsiellinae share some apomorphies with the pseudotachidiid subtaxon Paranannopinae Por, 1986: setation/segmentation of Mx, P1, A1. X. calyptogenae spec. n. is more closely related to Xylora bathyalis Hicks 1988 living in the deep sea wood substrata in New Zealand waters. Some traits of the evolutionary history of the Donsiellinae become evident, probably starting from the more primitive deep sea taxa X .calyptogenae spec. n., which lives in the hydrothermal seafloor in the absence of decaying wood, and X. bathyalis, which is found in decaying wood but not necessarily associated with the wood-boring isopod Limnoria Leach, 1814, towards the more advanced genera such as Donsiella Stephensen, 1936, which invades shallow waters and, further, clings to Limnoria, forming a close and, for the copepod, probably obligatory association. The specialised mouthparts of X. calyptogenae spec. n. seem to facilitate the grabbing and fixing of larger and/or active food items. This is confirmed by the presence of a large prey organism, presumably a copepod, consumed either alive or

  7. Development and characterization of new polymorphic microsatellite markers in four sea anemones: Entacmaea quadricolor, Heteractis magnifica, Stichodactyla gigantea, and Stichodactyla mertensii

    KAUST Repository

    Gatins, Remy

    2016-10-08

    Relatively few studies have investigated the genetic population structure of sea anemones. This is particularly true for sea anemones that host some of the most iconic fishes on coral reefs, the anemonefishes. One of the main reasons for this knowledge gap is the lack of appropriate genetic markers. We developed and characterized a total of 47 novel polymorphic microsatellite markers for four host sea anemone species from the Indo-Pacific: Entacmaea quadricolor (n = 16 microsatellite markers), Heteractis magnifica (n = 8), Stichodactyla mertensii (n = 13), and Stichodactyla gigantea (n = 10). Here, we report genetic diversity statistics from two different sampling locations for each anemone species. Overall, we found that most markers were highly polymorphic. On average, we found a mean of seven alleles per locus. Observed and expected heterozygosities displayed high variation among loci, ranging from 0.033 to 0.980 and from 0.038 to 0.927, respectively. Only four loci showed deviations of Hardy–Weinberg equilibrium in both populations and were identified as having null alleles. Additionally, two pairs of loci were identified to be in linkage disequilibrium in only one population. Host anemones are highly sought after in the marine aquarium trade and are susceptible to thermal bleaching. Although most studies focus on their obligate symbionts (the anemonefish), genetic analyses of host sea anemones can expand our understanding of the biology, connectivity, and population structure of these organisms and potentially help develop conservation strategies that will aid both the host and its symbionts.

  8. 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

  9. 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

  10. Colonoscopia com magnificação de imagem: análise da variação interobservadores para os padrões de criptas e comparação das imagens endoscópicas com os achados histopatológicos Magnification colonoscopy images: analysis of variation interobservers for pit patern and comparison of endoscopy and histopatologic findings

    Directory of Open Access Journals (Sweden)

    Esdras Camargo Andrade Zanoni

    2006-12-01

    Full Text Available A colonoscopia com magnificação de imagem (CMI é considerada uma técnica que possibilita o diagnóstico diferencial entre lesões colorretais neoplásicas e não-neoplásicas. Este estudo avaliou a variação da concordância interobservadores para os padrões de criptas através de três endoscopistas experientes com a classificação de Kudo, e correlacionou esses aspectos morfológicos com os achados histopatológicos. Um total de 213 imagens de lesões magnificadas (polipóides e planas forma coletadas de 161 pacientes consecutivos e apresentadas a três observadores independentes que expressaram opinião sobre o padrão de criptas predominante. Todas as lesões foram completamente excisadas e enviadas para estudo histopatológico. A estatística estimada de Kappa mostrou que o índice de concordância geral para padrões de criptas entre os três observadores foi bom (0,561. Com relação aos resultados histapatológicos, quando comparados aos padrões de criptas, observou-se: acuária de 84%; sensibilidade de 91,4%; especifidade de 67,2%; valor preditivo positivo de 86,6% valor preditivo negativo de 79,3% e índice de Kappa de 0,61. Embora a reprodutilidade interobservadores dos padrões de criptas seja boa, a CMI não deve substituir o estudo histopatológico, pois não diferencia com a necessária segurança lesões neoplásicas de lesões não-neoplásicas.Colonoscopy with magnified view is the most reliable nonbiopsy method for distinguishing non-neoplastic from neoplastic colorectal lesions. This study analysed lhe interobserver concordance in diagnosis of pit patem, with 3 experients endoscopists using Kudo Classification and correlating the this aspects with histological ones. A total of 213 magnificated images injuries (polipoides and plain had been collected of 161 independent observing patients consecutive and presented tres that had expressed opinion on the predominant standard of criptas. All the injuries had been

  11. Estudo comparativo entre MBI (FICE® e a magnificação com índigo-carmin no diagnóstico diferencial de lesões neoplásicas e não-neoplásicas de cólon e reto Comparative study between MBI (FICE® and magnification chromoendoscopy with indigo carmine in the differential diagnosis of neoplastic and non-neoplastic lesions of the colorectum

    Directory of Open Access Journals (Sweden)

    Carlos Eduardo Oliveira dos Santos

    2009-06-01

    Full Text Available CONTEXTO: O uso da cromoscopia virtual com sistema de imagem multibanda poderia auxiliar no diagnóstico in vivo de neoplasias colônicas. Objetivo - Avaliar a exatidão da magnificação associada à cromoendoscopia eletrônica ou com índigo-carmin na distinção entre lesões neoplásicas e não-neoplásicas do cólon e reto. MÉTODOS: Foram avaliadas prospectivamente 157 lesões colorretais em 75 pacientes. Empregou-se o sistema FICE® para a análise dos padrões de capilares, com a malha capilar negativa sendo considerada padrão de lesões não-neoplásicas, e a malha capilar positiva, o padrão das neoplasias. Após esta avaliação, ainda usando o sistema FICE®, o padrão de criptas foi definido conforme a classificação de Kudo. Por fim, instilou-se índigo-carmin à 0,8% e outro estudo das criptas foi realizado. RESULTADOS: Entre as 157 lesões colorretais, classificou-se 116 como malha capilar positiva, sendo 115 confirmadas histologicamente como neoplasias. Já entre as 41 lesões com malha capilar negativa, 32 eram não-neoplásicas. A sensibilidade foi de 92,7%, a especificidade de 97% e a precisão de 93,6%. Os padrões de criptas tipo I e II representaram as lesões não-neoplásicas e os tipos III-V, as neoplásicas. Com a utilização da cromoscopia eletrônica, observou-se sensibilidade de 94,4%, especificidade de 97% e precisão de 94,9%. Já com o uso da magnificação associada ao índigo-carmin, a sensibilidade foi de 97,6%, a especificidade de 93,9% e a precisão de 96,8%. CONCLUSÕES: Tanto a cromoendoscopia eletrônica, quanto o uso do índigo-carmin, associados à magnificação de imagens, apresentaram precisão elevada quanto ao diagnóstico histopatológico e não houve diferença estatística entre ambos os métodos.CONTEXT: Multiband imaging (MBI/Fuji Intelligent Color Enhancement (FICE® is a spectral image processing technology that helps in vivo diagnosis of colorectal neoplasias. OBJECTIVE: To compare the

  12. Regulation of carbon dioxide fixation in the chemoautotroph Xanthobacter flavus

    NARCIS (Netherlands)

    Keulen, Geertje van

    2000-01-01

    Autotrophic bacteria and plants are able to convert the greenhouse gas carbon dioxide, CO2, into cell material. Although there are a number of metabolic pathways supporting autotrophic growth, the Calvin cycle is the most widely distributed of these. CO2 fixation requires a large amount of energy

  13. Autecological study of the chemoautotroph Nitrobacter by immunofluorescence.

    Science.gov (United States)

    Fliermans, C B; Bohlool, B B; Schmidt, E L

    1974-01-01

    Fluorescent antibodies (FA) prepared for Nitrobacter agilis and N. winogradskyi were highly reactive in homologous staining. Low-level cross-reactions between the two species were removed by adsorption. All 15 pure-culture isolates of Nitrobacter tested reacted strongly with either N. agilis FA or N. winogradskyi FA. All pure-culture isolates from soils were determined to be N. winogradskyi; those from Mammoth Cave sediments and a cattle waste oxidation ditch were N. agilis. No cross-reaction was found in extensive tests that included five isolates of Nitrosomonas europaea and 668 heterotrophic aerobic and anaerobic bacteria isolated from soil, sewage, and cave sites. The FA preparations were used to detect Nitrobacter species in Mammoth Cave sediments, in a cattle waste oxidation ditch, and in surface waters and sediments of a river and to observe that N. winogradskyi can outgrow N. agilis in enrichment culture.

  14. 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

  15. Microbial methane oxidation and chemoauthotrophic communities at the North Alex mud volcano, Eastern Mediterranean

    Science.gov (United States)

    Treude, T.; Reischke, S.; Feseker, T.; Hensen, C.

    2009-04-01

    North Alex mud volcano, located on the upper slope of the western Nile deep-sea fan, is characterized by an active seepage center transporting pore fluids and gases from deep subsurface sources to the sediment-water interface. We sampled different locations between the center and rim of the mud volcano with ROV and multicorer to study the activity of benthic microorganisms involved in aerobic and anaerobic oxidation of methane as well as associated chemoautotrophic communities. Highest methanotrophic activity was found in the mud volcano center, where sediments exhibited high methane and sulfide concentrations. Chemoauthotrophic organisms included filamentous sulfur bacteria (Beggiatoa spp.) and symbiont bivalves (Calyptogena spp., Acharax spp.). In the vicinity of the southern mud volcano rim a large tubeworm field (Lamellibrachia spp.) was discovered. The field was associated with authigenic carbonate precipitates and chemoautotrophic bivalves of the family Lucinidae. Abundant ray eggs placed within the tubeworm field as well as the presence of small fish, shrimp and squid indicated that this habitat was utilized as a nursery ground by marine organisms that are not typically related to seepage activity. Preliminary data on benthic microbial methane turnover, geochemical gradients as well as temperature profiles across the sediment-water interface will be presented.

  16. Geomicrobiology of the ocean crust: a role for chemoautotrophic Fe-bacteria.

    Science.gov (United States)

    Edwards, Katrina J; Bach, Wolfgang; Rogers, Daniel R

    2003-04-01

    The delicate balance of the major global biogeochemical cycles greatly depends on the transformation of Earth materials at or near its surface. The formation and degradation of rocks, minerals, and organic matter are pivotal for the balance, maintenance, and future of many of these cycles. Microorganisms also play a crucial role, determining the transformation rates, pathways, and end products of these processes. While most of Earth's crust is oceanic rather than terrestrial, few studies have been conducted on ocean crust transformations, particularly those mediated by endolithic (rock-hosted) microbial communities. The biology and geochemistry of deep-sea and sub-seafloor environments are generally more complicated to study than in terrestrial or near-coastal regimes. As a result, fewer, and more targeted, studies usually homing in on specific sites, are most common. We are studying the role of endolithic microorganisms in weathering seafloor crustal materials, including basaltic glass and sulfide minerals, both in the vicinity of seafloor hydrothermal vents and off-axis at unsedimented (young) ridge flanks. We are using molecular phylogenetic surveys and laboratory culture studies to define the size, diversity, physiology, and distribution of microorganisms in the shallow ocean crust. Our data show that an unexpected diversity of microorganisms directly participate in rock weathering at the seafloor, and imply that endolithic microbial communities contribute to rock, mineral, and carbon transformations.

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

    Science.gov (United States)

    Khan, Nymul E; Myers, John A; Tuerk, Amalie L; Curtis, Wayne R

    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® 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¢/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. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Inhibition of Chemoautotrophic Nitrification by Sodium Chlorate and Sodium Chlorite: a Reexamination

    OpenAIRE

    Hynes, Russell K.; Knowles, Roger

    1983-01-01

    The oxidation of NH4+ by Nitrosomonas europaea was insensitive to 10 mM NaClO3 (sodium chlorate) but was strongly inhibited by NaClO2 (sodium chlorite; Ki, 2 μM). The oxidation of NO2− by Nitrobacter winogradskyi was inhibited by both ClO3− and ClO2− (Ki for ClO2−, 100 μM). N. winogradskyi reduced ClO3− to ClO2− under both aerobic and anaerobic conditions, and as much as 0.25 mM ClO2− was detected in the culture filtrate. In mixed N. europaea-N. winogradskyi cell suspensions, the oxidation of...

  19. Inhibition of chemoautotrophic nitrification by sodium chlorate and sodium chlorite: a reexamination.

    Science.gov (United States)

    Hynes, R K; Knowles, R

    1983-04-01

    The oxidation of NH(4) by Nitrosomonas europaea was insensitive to 10 mM NaClO(3) (sodium chlorate) but was strongly inhibited by NaClO(2) (sodium chlorite; K(i), 2 muM). The oxidation of NO(2) by Nitrobacter winogradskyi was inhibited by both ClO(3) and ClO(2) (K(i) for ClO(2), 100 muM). N. winogradskyi reduced ClO(3) to ClO(2) under both aerobic and anaerobic conditions, and as much as 0.25 mM ClO(2) was detected in the culture filtrate. In mixed N. europaea-N. winogradskyi cell suspensions, the oxidation of both NH(4) and NO(2) was inhibited in the presence of 10 mM ClO(3) after a 2-h lag period, despite the fact that, under these conditions, ClO(2) was not detected in the filtrate. The data are consistent with the hypothesis that, in mixed culture, NH(4) oxidation is inhibited by ClO(2) produced by reduction of ClO(3) by the NO(2) oxidizer. The use of ClO(3) inhibition of NO(2) oxidation in assays of nitrification by mixed populations necessitates cautious interpretation unless it can be shown that the oxidation of NH(4) is not affected.

  20. Whole-genome shotgun sequence of the sulfur-oxidizing chemoautotroph Pseudaminobacter salicylatoxidans KCT001.

    Science.gov (United States)

    Alam, Masrure; Roy, Chayan; Pyne, Prosenjit; Agarwal, Atima; George, Ashish; Ghosh, Wriddhiman

    2012-09-01

    The facultatively sulfur-oxidizing chemolithoautotrophic alphaproteobacterium Pseudaminobacter salicylatoxidans KCT001 (MTCC 7265) belongs to the family Phyllobacteriaceae of the order Rhizobiales. Analysis of its genome offers valuable insight into the adaptive specializations and evolution of free-living soil bacteria that are phylogenetically closely related to symbiotic and invasive rhizobacteria.

  1. The bivalve Thyasira cf. gouldi hosts chemoautotrophic symbiont populations with strain level diversity

    Directory of Open Access Journals (Sweden)

    Bonita McCuaig

    2017-07-01

    Full Text Available Invertebrates from various marine habitats form nutritional symbioses with chemosynthetic bacteria. In chemosynthetic symbioses, both the mode of symbiont transmission and the site of bacterial housing can affect the composition of the symbiont population. Vertically transmitted symbionts, as well as those hosted intracellularly, are more likely to form clonal populations within their host. Conversely, symbiont populations that are environmentally acquired and extracellular may be more likely to be heterogeneous/mixed within host individuals, as observed in some mytilid bivalves. The symbionts of thyasirid bivalves are also extracellular, but limited 16S rRNA sequencing data suggest that thyasirid individuals contain uniform symbiont populations. In a recent study, Thyasira cf. gouldi individuals from Bonne Bay, Newfoundland, Canada were found to host one of three 16S rRNA phylotypes of sulfur-oxidizing gammaproteobacteria, suggesting environmental acquisition of symbionts and some degree of site-specificity. Here, we use Sanger sequencing of both 16S RNA and the more variable ribulose-1,5-bisphosphate carboxylase (RuBisCO PCR products to further examine Thyasira cf. gouldi symbiont diversity at the scale of host individuals, as well as to elucidate any temporal or spatial patterns in symbiont diversity within Bonne Bay, and relationships with host OTU or size. We obtained symbiont 16S rRNA and RuBisCO Form II sequences from 54 and 50 host individuals, respectively, during nine sampling trips to three locations over four years. Analyses uncovered the same three closely related 16S rRNA phylotypes obtained previously, as well as three divergent RuBisCO phylotypes; these were found in various pair combinations within host individuals, suggesting incidents of horizontal gene transfer during symbiont evolution. While we found no temporal patterns in phylotype distribution or relationships with host OTU or size, some spatial effects were noted, with some phylotypes only found within particular sampling sites. The sequencing also revealed symbiont populations within individual hosts that appeared to be a mixture of different phylotypes, based on multiple base callings at divergent sites. This work provides further evidence that Thyasira cf. gouldi acquires its symbionts from the environment, and supports the theory that hosts can harbour symbiont populations consisting of multiple, closely related bacterial phylotypes.

  2. 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

  3. Aerobic and Anaerobic Thiosulfate Oxidation by a Cold-Adapted, Subglacial Chemoautotroph

    National Research Council Canada - National Science Library

    Harrold, Zoë R; Skidmore, Mark L; Hamilton, Trinity L; Desch, Libby; Amada, Kirina; van Gelder, Will; Glover, Kevin; Roden, Eric E; Boyd, Eric S

    2016-01-01

    Geochemical data indicate that protons released during pyrite (FeS2) oxidation are important drivers of mineral weathering in oxic and anoxic zones of many aquatic environments, including those beneath glaciers...

  4. Aerobic and Anaerobic Thiosulfate Oxidation by a Cold-Adapted, Subglacial Chemoautotroph

    Science.gov (United States)

    Harrold, Zoë R.; Skidmore, Mark L.; Hamilton, Trinity L.; Desch, Libby; Amada, Kirina; van Gelder, Will; Glover, Kevin; Roden, Eric E.

    2015-01-01

    Geochemical data indicate that protons released during pyrite (FeS2) oxidation are important drivers of mineral weathering in oxic and anoxic zones of many aquatic environments, including those beneath glaciers. Oxidation of FeS2 under oxic, circumneutral conditions proceeds through the metastable intermediate thiosulfate (S2O32−), which represents an electron donor capable of supporting microbial metabolism. Subglacial meltwaters sampled from Robertson Glacier (RG), Canada, over a seasonal melt cycle revealed concentrations of S2O32− that were typically below the limit of detection, despite the presence of available pyrite and concentrations of the FeS2 oxidation product sulfate (SO42−) several orders of magnitude higher than those of S2O32−. Here we report on the physiological and genomic characterization of the chemolithoautotrophic facultative anaerobe Thiobacillus sp. strain RG5 isolated from the subglacial environment at RG. The RG5 genome encodes genes involved with pathways for the complete oxidation of S2O32−, CO2 fixation, and aerobic and anaerobic respiration with nitrite or nitrate. Growth experiments indicated that the energy required to synthesize a cell under oxygen- or nitrate-reducing conditions with S2O32− as the electron donor was lower at 5.1°C than 14.4°C, indicating that this organism is cold adapted. RG sediment-associated transcripts of soxB, which encodes a component of the S2O32−-oxidizing complex, were closely affiliated with soxB from RG5. Collectively, these results suggest an active sulfur cycle in the subglacial environment at RG mediated in part by populations closely affiliated with RG5. The consumption of S2O32− by RG5-like populations may accelerate abiotic FeS2 oxidation, thereby enhancing mineral weathering in the subglacial environment. PMID:26712544

  5. Evaluation of fungicides for the control of Botryosphaeria protearum on Protea magnifica in the Western Cape Province of South Africa

    NARCIS (Netherlands)

    Denman, S.; Crous, P.W.; Sadie, A.; Wingfield, M.J.

    2004-01-01

    A range of fungicides was tested in vitro for their effect on mycelial inhibition. Selected products showing potential for disease control were then further tested under field conditions. The most effective fungicides in the in vitro tests were tebuconazole, benomyl, prochloraz me, iprodione and

  6. 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.

  7. Sulfurimonas gotlandica sp. nov., a chemoautotrophic and psychrotolerantepsilonproteobacterium isolated from a pelagicredoxcline, and an emended description of the genus Sulfurimonas

    NARCIS (Netherlands)

    Labrenz, M.; Grote, J.; Mammitzsch, K.; Boschker, H.T.S.; Laue, M.; Jost, G.; Glaubitz, S.; Jürgens, K.

    2013-01-01

    A psychro- and aerotolerant bacterium was isolated from the sulfidic water of a pelagic redox zone of the central Baltic Sea. The slightly curved rod- or spiral-shaped cells were motile by one polar flagellum or two bipolar flagella. Growth was chemolithoautotrophic, with nitrate or nitrite as

  8. An assemblage of the host anemone Heteractis magnifica in the northern Res Sea, and distribution of the resident anemonefish

    DEFF Research Database (Denmark)

    Brolund, Thea Marie; Tychsen, Anders; Nielsen, Lis Engdahl

    2004-01-01

    The Heteractis magni¢ca assemblage at the tip of the Sinai Peninsula was examined. The actinian size, location, and number of resident anemone¢shes were recorded. The anemones were found at depths down to approximately 40m and the sizes of clustering H. magni¢ca and clusters were positively...

  9. 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. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Newly discovered hydrothermal system on the Alarcón Rise, Mexico

    Science.gov (United States)

    Paduan, J. B.; Clague, D. A.; Caress, D. W.; Lundsten, L.; Martin, J. F.; Nieves-Cardoso, C.

    2012-12-01

    The Alarcón Rise lies at the mouth of the Gulf of California, and is the last segment of the East Pacific Rise before the plate boundary redirects into the gulf. As part of MBARI's expedition to the gulf in 2012, the neovolcanic zone of the entire ridge segment was mapped by MBARI's mapping AUV. 110 potential hydrothermal chimneys were identified in the new high resolution maps, and 70 were visited with the ROV Doc Ricketts, after having been sought in vain without the maps on an expedition in 2003. Two active vent fields were found, and have been named Meyibó and Ja sít from local native languages. They lie 2.5km apart at ~2300m depth, and are associated with a large, young sheet flow 1/3 of the way along the ridge from the south, on the most inflated part of the ridge. The southern field, Meyibó, contains 14 active chimneys (confirmed with ROV observations) nestled in grabens of several highly fractured cones surrounded by the sheet flow, and generally aligned with its discontinuous, 8km-long fissure system. The northern field, Ja sít, is a broad cluster of 8 active chimneys (also confirmed) rising above the sheet flow's channel system, more than 150m from the fissure. The chimneys stand as tall as 18 m. The most vigorous vent "black smoke" (mineral-rich fluid) >300°C and others are bathed in "white smoke". The active chimneys are populated with bacterial mat and dense clumps of Riftia pachyptila with tubes as long as 1.5m. Abundant limpets, Bythograea thermydron and galatheid crabs, and the pink vent fish Thermarces cerberus were on and near the giant tube worms. Alvinellid worms were observed at 2 chimneys. Some cracks in nearby lava flows vented clear fluid and were populated with tubeworms or Calyptogena magnifica clams. Several chimneys exhibited signs of waning activity: dead tubeworms were still attached and only a minor portion of the edifice supported bacterial mat and live tubeworms. Inactive chimneys are more numerous (48 were confirmed with ROV

  11. Geology of the Alarcón Rise Based on 1-m Resolution Bathymetry and ROV Observations and Sampling

    Science.gov (United States)

    Clague, D. A.; Caress, D. W.; Lundsten, L.; Martin, J. F.; Paduan, J. B.; Portner, R. A.; Bowles, J. A.; Castillo, P. R.; Dreyer, B. M.; Guardado-France, R.; Nieves-Cardoso, C.; Rivera-Huerta, H.; Santa Rosa-del Rio, M.; Spelz-Madero, R.

    2012-12-01

    in two areas within the large sheet flow on the inflated portion of the ridge. Fluid temperatures exceed 300°C and the chimneys are surrounded by extensive vent communities that superficially resemble those at 21°N with robust clumps of Riftia pachyptila and fields of mostly dead Calyptogena magnifica. Samples from some of the inactive chimneys are Cu-rich (abundant chalcopyrite), but most of the 37 chimney and sulfide mound samples are Fe- and Zn-rich. The rims of the two central calderas on Alarcón Seamount are aphyric channelized sheet flows, but the rim on the western and largest caldera is comprised of limu-o Pele rich volcaniclastic deposits. Foraminifera ooze with hydrothermal clay component has accumulated inside the calderas.

  12. La costa del rio Parana: cultura, naturaleza y territorio: apuntes para su interpretacion y proyecto

    National Research Council Canada - National Science Library

    Bertuzzi, Maria Laura

    2009-01-01

    ...: un fragmento de la costa fluvial del rio Parana. Esta area fue historicamente desplazada del interes provincial convirtiendose en periferia de produccion y comunicacion a pesar de sus magnificas condiciones medioambientales...

  13. Chemoautotrophy in the ocean

    NARCIS (Netherlands)

    Middelburg, J.J.

    2011-01-01

    Organic matter recycling releases ammonium, and under anoxic conditions, other reduced metabolites that can be used by chemoautotrophs to fix inorganic carbon. Here I present an estimate for the global rate of oceanic carbon fixation by chemoautotrophs (0.77 Pg C y−1). Near-shore and shelf sediments

  14. Seasonally varying nitrogen isotope biogeochemistry of particulate organic matter in Lake Kinneret, Israel

    Digital Repository Service at National Institute of Oceanography (India)

    Hadas, O.; Altabet, M.A; Agnihotri, R.

    processes. The lowest delta sup(15) N POM values (- 5.5 ppt) were observed in early winter, a consequence of isotopic fractionation by chemoautotrophic microbial NH sup(+) sub(4) assimilation, and during the first phase of the nitrification period...

  15. Morfología de semillas y desarrollo post-seminal de especies de Comanthera (Eriocaulaceae)

    OpenAIRE

    Dugarte Corredor, Blanca Auxiliadora; Escobar Escobar, Diego Fernando; Scatena, Vera Lúcia

    2015-01-01

    Comanthera brasiliana, C. magnifica y C. suberosa (Eriocaulaceae) forman parte de la lista de especies amenazadas de extinción en Brasil, debido a su alto grado de endemismo y a la recolecta indiscriminada. Estas tres especies junto con C. brunnea y C. linearis constituyen el clado de Comanthera magnifica. Se estudió la germinación, la morfología de semillas y el desarrollo post-seminal de las cinco especies, buscando caracterizar morfológica y anatómicamente las semillas y estadios posterior...

  16. Macrobenthic abundance in the vicinity of spreading ridge environment in Central Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Ingole, B.S.

    Genus Locations/Status Coelenterata Actinostolid (sea anemone) Beds on the bare rocks as close as 1 ? 2 m from black smokers Mollusca Bivalvia Calyptogena North of triple junction (heap of dead shells..., only a very small fraction (1% or less) of surface pro - ductivity reaches the deep ocean floor 2 and therefore the deep - sea benthos may not necessarily depend on the surface primary productivity as was generally argued 3 ? 6 . Tight coupling...

  17. Nouvelles espèces d’Orchomene s.l. (Crustacea-Amphipoda) des fonds abyssaux. Affinités avec les autres Orchomene profonds

    NARCIS (Netherlands)

    Bellan-Santini, D.

    1990-01-01

    Deux espèces d’ Orchomene aveugles appartenant aux communautés benthiques abyssales sont décrites. O. kaikoi a été récolté dans le grand bivalve Calyptogena (Ectenagena) phaseoliformis provenant des fosses de subduction du Japon. O. stocki provient du lavage d’épongés du genre Cladorhiza récoltées

  18. An enigmatic hawker dragonfly from the Middle Jurassic of China (Odonata, Aeshnoptera)

    OpenAIRE

    Huang, Di-Ying; Nel, André; Cai, Chenyang

    2017-01-01

    International audience; The aeshnopteran Propecymatophlebia magnifica gen. et sp. nov. is described from the Middle Jurassic Hiafanggou Formation of Inner Mongolia in China, on the basis of a complete forewing. It confirms the remarkable palaeodiversity of the stem group of the hawker dragonflies in Central Asia in the period between the Middle Jurassic and the Early Cretaceous.

  19. The oldest accurate record of Scenopinidae in the Lowermost Eocene amber of France (Diptera: Brachycera).

    Science.gov (United States)

    Garrouste, Romain; Azar, Dany; Nel, Andre

    2016-03-22

    Eocenotrichia magnifica gen. et sp. nov. (Diptera: Scenopinidae: Metatrichini) is described and illustrated from the Lowermost Eocene amber of Oise (France) and represents the oldest definitive window fly fossil. The present discovery in the Earliest Eocene supports the Late Cretaceous-Paleocene age currently proposed for the emergence of Metatrichini.

  20. Rooting cuttings from douglas-fir, white-fir, and California red fir christmas trees

    Science.gov (United States)

    C. M. Blankensop; R. Z. Callaham

    1960-01-01

    Christmas tree growers in California have asked geneticists to help improve the characteristics of the - wild species they are cultivating. The preferred Christmas trees of California are Shasta red fir (Abies magnifica A. Murr.), white fir (A. concolor (Gord. & Glend.) Lindl.), and Douglas-fir (Pseudotsuga...

  1. Population dynamics of dwarf mistletoe on young true firs in the central Sierra Nevada, California

    Science.gov (United States)

    Robert E Scharpf; J. R. Jr. Parmeter

    1982-01-01

    Young red firs (Abies magnifica A. Murr.) and white firs (A. concolor [Gord. & Glend.] Lindl. ex Hildebr.) on the Stanislaus National Forest, California, were inoculated with seeds of dwarf mistletoe (Arceuthobium abietinum) for 5 successive years. Only 3 to 4 percent of about 7000 seeds placed on branches...

  2. Pharmacological effects of two cytolysins isolated from the sea ...

    Indian Academy of Sciences (India)

    Prakash

    2009-12-07

    Dec 7, 2009 ... Katz A M 1996 Protein families that mediate Ca2+ signalling in the cardiovascular system; Am. J. Cardiol. 28 522–529. Khoo H E, Lim J P C and Tan C H 1995 Effects of sea anemone. Heterantis magnifica and Actinia equina cytolisins on synaptosomal uptake of GABA and choline; Toxicon 33. 1365–1373.

  3. Growth of California red fir advance regeneration after overstory removal and thinning

    Science.gov (United States)

    William W. Oliver

    1985-01-01

    Advance regeneration is common under decadent, old-growth stands of California red fir (Abies magnifica A. Murr.). Intense competition for the site's resources can create sapling stands of poor vigor and advanced age. When competition is reduced by overstory removal and thinning, suppressed advance regeneration has been shown to respond with...

  4. Dwarf Mistletoe on Red Fir . . . infection and control in understory stands

    Science.gov (United States)

    Robert F. Scharpf

    1969-01-01

    Height and age of understory red fir (Abies magnifica A. Murr.) were related to dwarf mistletoe (Arceuthobiilm campylopodum f. abietinum) infection from the surrounding overstory red fir on four National Forests in California. Percentage of trees infected and intensity of infection increased significantly as height of understory...

  5. Early verification of a hybrid between noble and California red firs

    Science.gov (United States)

    Roy R. Silen; William B. Critchfield; Jerry F. Franklin

    1965-01-01

    Hybrids between Abies procera Rehd., and Abies magnifica A. Murr., made reciprocally at Marys Peak near Corvallis, Oreg., and near Placerville, Calif., suggest that no significant genetic barriers prevent crossing of the two species where ranges overlap. Hence, maintenance of species differences must be looked for in other factors...

  6. Eocene deep-sea communities in localized limestones formed by subduction-related methane seeps, southwestern Washington

    Science.gov (United States)

    Goedert, James L.; Squires, Richard L.

    1990-12-01

    Densely populated communities of soft-bottom-dwelling taxa similar to those found today along subduction zones off the coasts of Japan and Oregon have been discovered in very localized deep-water limestones of late middle to late Eocene age along the southwestern margin of Washington. Subduction was prevalent in this area during this time, and compressive forces squeezed subsurface methanerich waters onto the ocean floor, where opportunistic bivalves (especially Modiolus, Calyptogena, and Thyasira), vestimentiferan? tube worms, serpufid tube worms, siliceous sponges, very small limpets, trochid and turbinid archaeogastropods, and other macrobenthos colonized. These assemblages are the earliest recorded biologic communities formed in response to methane seeps in subduction zones.

  7. Gene flow between Atlantic and Pacific Ocean basins in three lineages of deep-sea clams (Bivalvia: Vesicomyidae: Pliocardiinae) and subsequent limited gene flow within the Atlantic

    Science.gov (United States)

    LaBella, Abigail Leavitt; Van Dover, Cindy L.; Jollivet, Didier; Cunningham, Clifford W.

    2017-03-01

    Pliocardiin (vesicomyid) clams rely on microbial symbionts for nutrition and are obligate inhabitants of deep-sea chemosynthetic ecosystems. Unlike many other invertebrate hosts of chemosynthetic microbes, pliocardiin clams are found in every ocean in a variety of reducing habitats, including hydrothermal vents, cold seeps, organic falls and deep-sea fans. The global distribution of pliocardiin clams suggests historical gene flow between ocean basins. We focus on 3 pliocardiin genera-'Pliocardia' I, Calyptogena and Abyssogena-each of which has a pair of sister clades in the Atlantic and Pacific. Our work tests the hypothesis that historical gene flow between the Atlantic and Pacific Oceans within these genera was interrupted by the closure of the Panamanian seaway and tests whether isolation between the ocean basins is the result of vicariance or past colonization. These questions are investigated in the context of fossil evidence, biogeography and phylogenetics. This study revealed a set of substitution rates consistent with other invertebrate studies (μ=0.8%/My/lineage), and a set consistent with much lower rates often attributed to deep-sea organisms (μ=0.3%/My/lineage). Among the Pacific/Atlantic sister pairs, 'Pliocardia' I COI divergence per lineage is intermediate (2.5%), Calyptogena is the highest (6.1%) and Abyssogena the lowest (0.8%). The substitution rates suggest that 'Pliocardia' I and Calyptogena have histories of at least 2.8 My in the Atlantic, with Calyptogena likely older. The slower rate, however, is inconsistent with both the maximum age of the family and several well studied fossils: leaving the faster rate preferred. With the faster rate, the Abyssogena southwardae clade diverged from its Pacific sister clade around 1 Mya, which likely post-dates the closure of the Isthmus of Panama and the opening of the Bering Strait. In light of this recent divergence, we test the previously proposed hypothesis that there is a high level of ongoing gene

  8. New Middle Permian palaeopteran insects from Lod?ve Basin in southern France (Ephemeroptera, Diaphanopterodea, Megasecoptera)

    OpenAIRE

    Jakub Prokop; André Nel

    2011-01-01

    Three new palaeopteran insects are described from the Middle Permian (Guadalupian) of Salagou Formation in the Lodève Basin (South of France), viz. the diaphanopterodean Alexrasnitsyniidae fam. n., based on Alexrasnitsynia permiana gen. et sp. n., the Parelmoidae Permelmoa magnifica gen. et sp. n., and Lodevohymen lapeyriei gen. et sp. n. (in Megasecoptera or Diaphanopterodea, family undetermined). In addition the first record of mayflies attributed to family Syntonopteridae (Ephemerop...

  9. A new phyllocarid (Crustacea: Malacostraca) from the Silurian Fossil-Lagerstätte of Herefordshire, UK.

    Science.gov (United States)

    Briggs, Derek E G; Sutton, Mark D; Siveter, David J; Siveter, Derek J

    2004-01-22

    A new three-dimensionally preserved arthropod, Cinerocaris magnifica, from the Wenlock Series (Silurian) of Herefordshire, UK, is described and assigned to the Phyllocarida (Crustacea). The description and reconstruction are based on specimens that have been serially ground, reconstructed by computer and rendered in three dimensions as coloured virtual models. Cinerocaris magnifica displayed the tagmosis characteristic of phyllocarids, with eight thoracic and seven abdominal somites, terminating in a telson with furca. The remarkable preservation of the appendages makes this the earliest completely known malacostracan crustacean. Two pairs of antennae (the first with two flagella) were followed by a mandible and first maxilla, each with a slender palp-like ramus. The second maxilla consisted of a limb stem with endites and an endopod that tapered distally. There was no exopod. The thoracopods comprised a limb stem with six or seven endites, an arrangement previously known only in entomostracans, and an endopod with about five endites. Flap-like outer rami correspond to an exopod and epipods. The pleopods bore two long slender oar-blade-like rami. Cladistic analysis places C. magnifica as a plesion within the Echinocaridina. It provides critical evidence of the limb morphology of an early malacostracan, which will be important in understanding crustacean evolution.

  10. Major role of nitrite-oxidizing bacteria in dark ocean carbon fixation

    NARCIS (Netherlands)

    Pachiadaki, M.G.; Sintes, E.; Bergauer, K.; Brown, J.M.; Record, N.R.; Swan, B.K.; Mathyer, M.E.; Hallam, S.J.; López-Garcìa, P.; Takaki, Y.; Nunoura, T.; Woyke, T.; Herndl, G.J.; Stepanauskas, R.

    2017-01-01

    Carbon fixation by chemoautotrophic microorganisms in the dark ocean has a major impact on global carbon cycling and ecological relationships in the ocean’s interior, but the relevant taxa and energy sources remain enigmatic.We show evidence that nitrite-oxidizing bacteria affiliated with the

  11. Bacteria and Acidic Drainage from Coal Refuse: Inhibition by Sodium Lauryl Sulfate and Sodium Benzoate

    OpenAIRE

    Dugan, Patrick R.; Apel, William A.

    1983-01-01

    The application of an aqueous solution of sodium lauryl sulfate and sodium benzoate to the surface of high-sulfur coal refuse resulted in the inhibition of iron-and sulfur-oxidizing chemoautotrophic bacteria and in the decrease of acidic drainage from the refuse, suggesting that acid drainage can be abated in the field by inhibiting iron- and sulfur-oxidizing bacteria.

  12. Characteristics of pendent heliconia for use in landscape and as cut flower

    Directory of Open Access Journals (Sweden)

    Vivian Loges

    2016-10-01

    Full Text Available The Heliconia species with pendent inflorescences and colorful bracts is a good option for landscaping in tropical gardens and cut flowers market. In Brazil only a few species of Heliconia are commercially produced eg. H. rostrata, H. rauliniana and H. chartacea. Aiming to increase the use of outstanding native plants and the knowledge of these products for enthusiasts of tropical flowers, this work was carried out to characterize H. chartacea, H. collinsiana, H. magnifica, H. pendula, H. platystachys, H. pogonantha, H. rostrata, H. rauliniana and H. vellerigera for use in landscaping and as cut flower. The evaluations were performed on plants belonging to the Germplasm Collection of the Instituto Agronômico (IAC, in Ubatuba Unit of Research and Development, located in Ubatuba, São Paulo State, growing in partial shade conditions. Qualitative and quantitative characteristics related to clump and flower stem aspects were analyzed. A point scoring system was used to determine the species most suitable as landscape plant or as cut flower. The plant height range from 2.3 (H. rostrata to 7.0 m (H. pogonantha, having inflorescence with vibrant and different colors, varying between yellow, orange, red, pink, green and two color combinations. The inflorescences from most of the species were visible in the clump and remain in good conditions for two (H. platystachys to five months (H. magnifica, H. rostrata and H. pogonantha and present six (H. platystachys and H. pendula to 40 (H. pogonantha open bracts. White wax in leaves or inflorescences were observed in H. collinsiana, H. chartacea, H. pendula and H. platystachys. On the other hand, H. magnifica, H. rostrata, H. pogonantha and H. vellerigera exhibit a hairy surface, pubescent to lanuginose. The postharvest durability longer than 10 days was observed only in H. platystachys, H. rostrata, H. chartacea, and H. rauliniana. This characterization and scoring system were important to indicate and

  13. Genetic tools link long-term demographic and life-history traits of anemonefish to their anemone hosts

    KAUST Repository

    Salles, Océane C.

    2016-07-26

    The life-history traits and population dynamics of species are increasingly being attributed to the characteristics of their preferred habitats. While coral reef fish are often strongly associated with particular habitats, long-term studies establishing the demographic and life-history consequences of occupying different reef substrata are rare and no studies have monitored individuals in situ over their lifetime and determined the fate of their offspring. Here, we documented a quasi-turnover and local reproductive success for an entire population of orange clownfish (Amphiprion percula) from Kimbe Island, Papua New Guinea, by taking bi-annual samples of DNA over a 10-yr period (2003–2013). We compared demographic and life-history traits of individuals living on two host anemone species, Heteractis magnifica and Stichodactyla gigantea, including female size, adult continued presence (a proxy for relative longevity range), early post-settlement growth, the number of eggs per clutch and ‘local’ reproductive success (defined for each adult as the number of offspring returning to the natal population). Our results indicate that while the relative longevity of adults was similar on both host anemone species, females living in H. magnifica were larger than females in S. gigantea. However, despite females growing larger and producing more eggs on H. magnifica, we found that local reproductive success was significantly higher for clownfish living in S. gigantea. Life-history traits also exhibited local spatial variation, with higher local reproductive success recorded for adults living on S. gigantea on the eastern side of the island. Our findings support a ‘silver-spoon’ hypothesis that predicts individuals that are fortunate enough to recruit into good habitat and location will be rewarded with higher long-term reproductive success and will make a disproportionate contribution to population renewal. © 2016 Springer-Verlag Berlin Heidelberg

  14. 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.

  15. 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 ...

  16. 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...

  17. 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.

  18. 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...

  19. 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.

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

    Science.gov (United States)

    Pešić, Vladimir; Chatterjee, Tapas; Alfaro, Monica; Schizas, Nikolaos V

    2014-01-01

    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.

  1. Acquisition of epibiotic bacteria along the life cycle of the hydrothermal shrimp Rimicaris exoculata

    OpenAIRE

    Guri, Mathieu; Durand, Lucile; Cueff-Gauchard, Valérie; Zbinden, Magali; Crassous, Philippe; Shillito, Bruce; Cambon-Bonavita, Marie-Anne

    2012-01-01

    The caridean shrimp Rimicaris exoculata dominates the fauna at several Mid-Atlantic Ridge hydrothermal vent sites. This shrimp has an enlarged gill chamber, harboring a dense ectosymbiotic community of chemoautotrophic bacteria associated with mineral oxide deposits. Until now, their acquisition is not fully understood. At three hydrothermal vent sites, we analyzed the epibionts diversity at different moult stages and also in the first stages of the shrimp life (eggs, hatched eggs (with larva...

  2. Life in a ligand sphere.

    OpenAIRE

    Wächtershäuser, G.

    1994-01-01

    The most fundamental divide in biology is that between heterotrophic and autotrophic ways of life. Two of the leading proponents of a heterotrophic origin of life ("hetero-origin") in a prebiotic broth, C. de Duve and S. L. Miller, have criticized my theory of a pyrite-pulled chemo-autotrophic origin of life ("auto-origin") [De Duve, C. & Miller, S. L. (1991) Proc. Natl. Acad. Sci. USA 88, 10014-10017]. This criticism is now answered.

  3. Post-drilling changes in seabed landscape and megabenthos in a deep-sea hydrothermal system, the Iheya North field, Okinawa Trough.

    Directory of Open Access Journals (Sweden)

    Ryota Nakajima

    Full Text Available There has been an increasing interest in seafloor exploitation such as mineral mining in deep-sea hydrothermal fields, but the environmental impact of anthropogenic disturbance to the seafloor is poorly known. In this study, the effect of such anthropogenic disturbance by scientific drilling operations (IODP Expedition 331 on seabed landscape and megafaunal habitation was surveyed for over 3 years using remotely operated vehicle video observation in a deep-sea hydrothermal field, the Iheya North field, in the Okinawa Trough. We focused on observations from a particular drilling site (Site C0014 where the most dynamic change of landscape and megafaunal habitation was observed among the drilling sites of IODP Exp. 331. No visible hydrothermal fluid discharge had been observed at the sedimentary seafloor at Site C0014, where Calyptogena clam colonies were known for more than 10 years, before the drilling event. After drilling commenced, the original Calyptogena colonies were completely buried by the drilling deposits. Several months after the drilling, diffusing high-temperature hydrothermal fluid began to discharge from the sedimentary subseafloor in the area of over 20 m from the drill holes, 'artificially' creating a new hydrothermal vent habitat. Widespread microbial mats developed on the seafloor with the diffusing hydrothermal fluids and the galatheid crab Shinkaia crosnieri endemic to vents dominated the new vent community. The previously soft, sedimentary seafloor was hardened probably due to barite/gypsum mineralization or silicification, becoming rough and undulated with many fissures after the drilling operation. Although the effects of the drilling operation on seabed landscape and megafaunal composition are probably confined to an area of maximally 30 m from the drill holes, the newly established hydrothermal vent ecosystem has already lasted 2 years and is like to continue to exist until the fluid discharge ceases and thus the

  4. 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.

  5. Vochysia Aubl. do Estado do Paraná, Brasil - DOI: 10.4025/actascibiolsci.v29i1.124 Vochysia Aubl. from the state of Paraná, Brazil

    Directory of Open Access Journals (Sweden)

    Claudinei Pedroso Ribas

    2007-11-01

    Full Text Available Apresentam-se resultados de levantamento florístico das espécies de Vochysia Aubl. (Vochysiaceae St. Hil. no Estado do Paraná, baseado em material fresco coletado nas diversas regiões fitogeográficas deste Estado e em material exsicatado, depositado em herbários nacionais e estrangeiros. Foram registradas três espécies: V. tucanorum Mart., V. bifalcata Warm. e V. magnifica Warm. Inclui-se chave dicotômica para identificação, assim como descrições, nomes populares, usos, fenologia, distribuição geográfica e ilustrações para cada espécie identificada.The results of a floristic survey of Vochysia Aubl in the state of Paraná are presented. The analysis was based on fresh material collected in different regions of the state as well as on dried material from several national and foreign herbaria. Three species were registered: V. tucanorum Mart., V. bifalcata Warm . and V. magnifica Warm. A key to differentiate the species is presented and for each species, the botanical description, common names, phenology data, the geographic distribution, uses and illustrations are included.

  6. Contrasting responses in the growth and energy utilization properties of sympatric Populus and Salix to different altitudes: implications for sexual dimorphism in Salicaceae.

    Science.gov (United States)

    Lei, Yanbao; Chen, Ke; Jiang, Hao; Yu, Lei; Duan, Baoli

    2017-01-01

    An interesting ecological and evolutionary puzzle arises from the observations of male-biased sex ratios in genus Populus, whereas in the taxonomically related Salix, females are generally more dominant. In the present study, we combined results from a field investigation into the sex ratios of the Salicaceous species along an altitudinal gradient on Gongga Mountain, and a pot experiment by monitoring growth and energy utilization properties to elucidate the mechanisms governing sexual dimorphism. At middle altitudes 2000 and 2300 m, the sex ratios were consistent with a 1:1 equilibrium in sympatric Populus purdomii and Salix magnifica. However, at the lower and higher ends of the altitudinal gradient, skewed sex ratios were observed. For example, the male:female ratios were 1.33 and 2.36 in P. purdomii at 1700 and 2600 m respectively; for S. magnifica the ratio was 0.62 at 2600 m. At 2300 m, the pot-grown seedlings of both species exhibited the highest biomass accumulation and total leaf area, simultaneously with the balanced sex ratios in the field. At 3300 m, the specific leaf area in male P. purdomii was 23.9% higher than that of females, which may be the morphological cause for the observed 19.3% higher nitrogen allocation to Rubisco, and 20.6% lower allocation to cell walls. As such, male P. purdomii showed a 32.9% higher foliar photosynthetic capacity, concomitant with a 12.0% lower construction cost. These properties resulted in higher photosynthetic nitrogen- and energy-use efficiencies, and shorter payback time (24.4 vs 40.1 days), the time span that a leaf must photosynthesize to amortize the carbon investment. Our results thus suggested that male P. purdomii evolved a quicker energy-return strategy. Consequently, these superior energy gain-cost related traits and the higher total leaf area contributed to the higher growth rate and tolerance in stress-prone environments, which might, in part, shed new light on the male-biased sex ratios in

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

    Science.gov (United States)

    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 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 environments may act as refugia

  8. Evolution and biogeography of deep-sea vent and seep invertebrates.

    Science.gov (United States)

    Van Dover, C L; German, C R; Speer, K G; Parson, L M; Vrijenhoek, R C

    2002-02-15

    Deep-sea hydrothermal vents and cold seeps are submarine springs where nutrient-rich fluids emanate from the sea floor. Vent and seep ecosystems occur in a variety of geological settings throughout the global ocean and support food webs based on chemoautotrophic primary production. Most vent and seep invertebrates arrive at suitable habitats as larvae dispersed by deep-ocean currents. The recent evolution of many vent and seep invertebrate species (<100 million years ago) suggests that Cenozoic tectonic history and oceanic circulation patterns have been important in defining contemporary biogeographic patterns.

  9. Thinking of biology: asteroid impacts, microbes, and the cooling of the atmosphere

    Science.gov (United States)

    Oberbeck, V. R.; Mancinelli, R. L.

    1994-01-01

    The authors examine the cooling of the Earth's surface from 3.75 to 1 billion years ago. Three effects of the bombardment of Earth by asteroids and comets that may have delayed surface cooling include time to form continents, volatilization of carbonate rocks which released carbon dioxide into the atmosphere, and inability of microbes to inhabit land masses during large impact events. Continental microbes may have helped reduce high temperatures from 3.75 to 3.5 billion years ago. If so, the evolutionary sequence of microbes is proposed to be anaerobic heterotrophs, chemoautotrophs, and then photoautotrophs.

  10. Inorganic carbon fixation by chemosynthetic ectosymbionts and nutritional transfers to the hydrothermal vent host-shrimp Rimicaris exoculata

    OpenAIRE

    Ponsard, J.; Cambon Bonavita, M.-A.; Zbinden, M.; Lepoint, G.; Joassin, A.; Corbari, L.; Shillito, B.; Durand, L.; Cueff-Gauchard, V.; Compère, P.

    2013-01-01

    The shrimp Rimicaris exoculata dominates several hydrothermal vent ecosystems of the Mid-Atlantic Ridge and is thought to be a primary consumer harbouring a chemoautotrophic bacterial community in its gill chamber. The aim of the present study was to test current hypotheses concerning the epibiont’s chemoautotrophy, and the mutualistic character of this association. In-vivo experiments were carried out in a pressurised aquarium with isotope-labelled inorganic carbon (NaH13CO3 and NaH14CO3) in...

  11. Inorganic carbon fixation by chemosynthetic ectosymbionts and nutritional transfers to the hydrothermal vent host-shrimp Rimicaris exoculata

    OpenAIRE

    Ponsard, Julie; Cambon-Bonavita, Marie-Anne; Zbinden, Magali; Lepoint, Gilles; Joassin, André; Corbari, Laure; Shillito, Bruce; Durand, Lucile; Cueff-Gauchard, Valérie; Compère, Philippe

    2012-01-01

    The shrimp Rimicaris exoculata dominates several hydrothermal vent ecosystems of the Mid-Atlantic Ridge and is thought to be a primary consumer harbouring a chemoautotrophic bacterial community in its gill chamber. The aim of the present study was to test current hypotheses concerning the epibiont's chemoautotrophy, and the mutualistic character of this association. In-vivo experiments were carried out in a pressurised aquarium with isotope-labelled inorganic carbon (NaH13CO3 and NaH14CO3) in...

  12. Oxidoreductase mimic activity of natural pyrrhotite

    Science.gov (United States)

    Ibáñez de Aldecoa, A. L.; Velasco, F.; Menor-Salván, C.

    2012-09-01

    The theory of the chemo-autotrophic origin of life, also called the "iron-sulfur world hypothesis", proposes that the system FeS/FeS2 present in the primitive Earth crust gave the reductive power necessary to conduct the first protometabolic redox reactions. Some experimental studies demonstrated the redox activity of the FeS/SH2 system, but none of them used natural FeS. Here, we show that the iron sulfide mineral pyrrhotite is able to mimic the redox activity of the enzyme lactate dehydrogenase, which reversibly reduces the pyruvate in lactate, under prebiotic conditions with pyrite formation.

  13. Isolation from soils ofNitrobacter and evidence for novel serotypes using immunofluorescence.

    Science.gov (United States)

    Josserand, A; Cleyet-Marel, J C

    1979-09-01

    To study the ecology of chemoautotrophic nitrifying bacteria (Nitrobacter), the immunofluorescence technique has been used. Fluorescent antibodies againstNitrobacter winogradskyi andNitrobacter agilis, the two known serotypes, have not labeled strains isolated from soils of the Lyon region (pH 8.1 and pH 4.7). The pure-culture isolates appeared to belong to the same genus, but to be serologically different from the reference strains. These results led us to question the diversity of strains ofNitrobacter in soils.

  14. 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.

  15. 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...

  16. Strategy for modeling putative multilevel ecosystems on Europa.

    Science.gov (United States)

    Irwin, Louis N; Schulze-Makuch, Dirk

    2003-01-01

    A general strategy for modeling ecosystems on other worlds is described. Two alternative biospheres beneath the ice surface of Europa are modeled, based on analogous ecosystems on Earth in potentially comparable habitats, with reallocation of biomass quantities consistent with different sources of energy and chemical constituents. The first ecosystem models a benthic biosphere supported by chemoautotrophic producers. The second models two concentrations of biota at the top and bottom of the subsurface water column supported by energy harvested from transmembrane ionic gradients. Calculations indicate the plausibility of both ecosystems, including small macroorganisms at the highest trophic levels, with ionotrophy supporting a larger biomass than chemoautotrophy.

  17. Bicarbonate uptake by marine Crenarchaeota.

    Science.gov (United States)

    Wuchter, Cornelia; Schouten, Stefan; Boschker, Henricus T S; Sinninghe Damsté, Jaap S

    2003-02-28

    Biphytanyl membrane lipids and 16S rRNA sequences derived from marine Crenarchaeota were detected in shallow North Sea surface water in February 2002. To investigate the carbon fixation mechanism of these uncultivated archaea in situ (13)C bicarbonate tracer experiments were performed with this water in the absence of light. About 70% of the detected (13)C incorporation into lipids (including fatty acids and sterols) is accounted for by the crenarchaeotal biphytanyl membrane lipids. This finding indicates that marine Crenarchaeota can utilize bicarbonate or CO(2) derived thereof in the absence of light and are chemoautotrophic organisms.

  18. Validação da escala de pensamentos castróficos e associação do catastrofismo com marcadores biológicos

    OpenAIRE

    Francislea Cristina Sehn

    2012-01-01

    Base teórica: A dor crônica decorre de alterações estruturais e funcionais mal adaptativas que influenciam a resposta ao estímulo ou que sustentam os processos de excitabilidade. Um dos sintomas que permeia grande número de pacientes com dor crônica é a catastrofização, cujas características são um conjunto de pensamentos negativos, deseperança e magnificação do sintoma ou condição. Este sintoma é mensurado por meio de uma escala de catastrofização usada em vários países. No entanto não dispo...

  19. Termoterapia transpupilar como opção terapêutica para hemangioma circunscrito de coróide: relato de caso

    Directory of Open Access Journals (Sweden)

    Roizenblatt Jaime

    2002-01-01

    Full Text Available Os autores descrevem um caso de hemangioma circunscrito de coróide, com descolamento de retina associado, tratado por meio de termoterapia transpupilar com laser de diodo. Os parâmetros utilizados foram: 900 mW, mira de 4,2 mm, tempo de 3 minutos, lente QuadrAspheric (Volkâ com fator de magnificação de 1,97. Um mês após o tratamento ocorreu redução significativa do hemangioma, com recuperação integral da visão deste olho. São feitas considerações a respeito do método, o qual mostra-se promissor no tratamento destes tumores vasculares.

  20. Sea anemones modify their hiding time based on their commensal damselfish.

    Science.gov (United States)

    Lim, Alexandra N; De La Guerra, Justin A; Blumstein, Daniel T

    2016-08-01

    Animals often retreat to refugia when alarmed and the time they spend hiding reflects an economic decision that trades off reducing predation risk with other beneficial activities. Typically, refugia such as burrows are static, but some refugia are dynamic. For species with defensive mutualisms, hiding might be contingent on their mutualist's behaviour. We disturbed and quantified hiding time in magnificent sea anemones, Heteractis magnifica, and their associated domino damselfish, Dascyllus trimaculatus. We found that sea anemone hiding behaviour was dependent on the number and behaviour of their commensal fish: anemones emerged sooner when they had more associated fish and faster returning fish. Together, these results demonstrate that hiding behaviour can be influenced by the behaviour of a commensal; such dynamic mutualisms may be found in other systems.

  1. LEVANTAMENTO POPULACIONAL E ANÁLISE FAUNÍSTICA DE LEPIDOPTERA EM Eucalyptus spp. NO MUNICÍPIO DE PINHEIRO MACHADO, RS

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    Oderlei Bernardi

    2011-01-01

    Full Text Available The objective of this research was to collect, to study and to characterize the fauna of lepidopterous associated with Eucalyptus spp., plantation in the Municipality of Pinheiro Machado, in RS state. In the period of October 2005 to October 2007, every 15 days, collections of insects were accomplished with three light traps. After selection and transfixion procedures, the lepidopterous were identified based on entomological collections and specialized literature. Two thousand and twenty individuals belonging to 14 families, 106 genera and 220 species were collected. The families with the highest number of species collected were: Noctuidae (59, Geometridae (30, Arctiidae (28 and Saturniidae (14. According to the fauna classification the most species were considered not dominant, uncommon, rare and accidental. Among the species identified, there were some whose larvae are defoliators of the eucalypts: Oxydia agliata, (Geometridae, Sarsina violascens (Lymantriidae, Automeris illustris, Eacles imperialis magnifica and Lonomia obliqua (Saturniidae, which needs to have their populations monitored.

  2. Orígenes y expansión de la dehesa en el término de Cáceres

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    María Dolores GARCÍA OLIVA

    2009-11-01

    Full Text Available La formación de las dehesas en el territorio extremeño apenas ha atraído la atención de los historiadores, a pesar de que constituyen un rasgo característico del paisaje rural extremeño. S. Zapata Blanco denuncia esta situación en «El análisis histórico de la dehesa: Elemento clave para la comprensión de la Historia de Extremadura», título de un epígrafe de un artículo de este autor bastante elocuente y que en absoluto magnifica el papel de la dehesa en la historia socioeconómica de la región.

  3. El control constitucional en el trópico

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    Hugo Palacios Mejía

    2001-12-01

    Full Text Available Propósito. El control constitucional sobre los actos legislativos y las leyes es un instrumento excelente para hacer el Estado de Derecho. Pero en Colombia ha adquirido cierta hipertrofia tropical, por razón de las características de la acción y el proceso de inconstitucionalidad, y por vitud de la jurisprudencia de la primera Corte Constitucional. Esa hipertrofia magnifica los problemas de todo control constitucional; hace que los "grupos de presión" encuentren muy atractivo y fácil "capturar" la Corte; y que las sentencias de la Corte se conviertan en una fuente de "ineficiencias" en el sistema económico. Este documento explica esos problemas y presenta algunas sugerencias de reforma constitucional para superarlos.

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

    Science.gov (United States)

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

    2017-11-01

    For the first decade following its description in 1954, the Calvin-Benson cycle was considered the sole pathway of autotrophic CO2 assimilation. In the early 1960s, experiments with fermentative bacteria uncovered reactions that challenged this concept. Ferredoxin was found to donate electrons directly for the reductive fixation of CO2 into alpha-keto acids via reactions considered irreversible. Thus, pyruvate and alpha-ketoglutarate could be synthesized from CO2, reduced ferredoxin and acetyl-CoA or succinyl-CoA, respectively. This work opened the door to the discovery that reduced ferredoxin could drive the Krebs citric acid cycle in reverse, converting the pathway from its historical role in carbohydrate breakdown to one fixing CO2. Originally uncovered in photosynthetic green sulfur bacteria, the Arnon-Buchanan cycle has since been divorced from light and shown to function in a variety of anaerobic chemoautotrophs. In this retrospective, colleagues who worked on the cycle at its inception in 1966 and those presently working in the field trace its development from a controversial reception to its present-day inclusion in textbooks. This pathway is now well established in major groups of chemoautotrophic bacteria, instead of the Calvin-Benson cycle, and is increasingly referred to as the Arnon-Buchanan cycle. In this retrospective, separate sections have been written by the authors indicated. Bob Buchanan wrote the abstract and the concluding comments.

  5. 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].

  6. 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.

  7. Evolutionary and geologic consequences of organic carbon fixing in the primitive anoxic ocean

    Science.gov (United States)

    Berry, W. B. N.; Wilde, P.

    1983-03-01

    Steps leading to development of the modern photic-based marine food web are postulated as the result of modifications of the environment, enhanced by the activity of Archean sulfur chemoautotrophs. Such organisms (Anoxium) evolved in an anoxic ocean prior to 3.9 × 109 yr ago at Archean analogs of modern oceanic hydrothermal vents. At this time geothermal energy was more readily available to organisms than photic energy, given atmospheric conditions at the surface similar to Venus, where intensity is low and only middle and red visible wavelengths penetrate the cloudy CO2-rich atmosphere. Competition for the reduced sulfur developed due to oxidation and loss of sulfur to sediments. Consequently, evolutionary advantage shifted to Anoxium isolates that could use alternate energy sources such as light to supplement the diminished supplies of reduced sulfur. Initially, photo-sulfur organisms evolved similar to modern purple bacteria that absorb in the red visible spectra. Subsequent carbon fixing and oxidation improved both the quantity and range of light reaching the ocean surface. This permitted absorption in the blue visible range so that water splitting was now feasible, releasing free oxygen and accelerating oxidation. Eventually, reducing environments became restricted, completing the shift in the principal marine carbon-fixing activity from anoxic chemoautotrophic to aerobic photosynthetic organisms.

  8. Major contribution of autotrophy to microbial carbon cycling in the deep North Atlantic’s interior

    Science.gov (United States)

    Reinthaler, Thomas; van Aken, Hendrik M.; Herndl, Gerhard J.

    2010-08-01

    Current estimates point to a mismatch of particulate organic carbon supply derived from the surface ocean and the microbial organic carbon demand in the meso- and bathypelagic realm. Based on recent findings that chemoautotrophic Crenarchaeota are abundant in the mesopelagic zone, we quantified dissolved inorganic carbon (DIC) fixation in the meso- and bathypelagic North Atlantic and compared it with heterotrophic microbial activity. Measuring 14C-bicarbonate fixation and 3H-leucine incorporation revealed that microbial DIC fixation is substantial in the mesopelagic water masses, ranging from 0.1 to 56.7 μmol C m -3 d -1, and is within the same order of magnitude as heterotrophic microbial activity. Integrated over the dark ocean's water column, DIC fixation ranged from 1-2.5 mmol C m -2 d -1, indicating that chemoautotrophy in the dark ocean represents a significant source of autochthonously produced 'new organic carbon' in the ocean's interior amounting to about 15-53% of the phytoplankton export production. Hence, chemoautotrophic DIC fixation in the oxygenated meso- and bathypelagic water column of the North Atlantic might substantially contribute to the organic carbon demand of the deep-water microbial food web.

  9. A New Deep-Sea Hydrothermal Vent Species of Ostracoda (Crustacea) from the Western Pacific: Implications for Adaptation, Endemism, and Dispersal of Ostracodes in Chemosynthetic Systems.

    Science.gov (United States)

    Tanaka, Hayato; Yasuhara, Moriaki

    2016-10-01

    Deep-sea hydrothermal vent fields are among the most extreme habitats on Earth. Major research interests in these ecosystems have focused on the anomalous macrofauna, which are nourished by chemoautotrophic bacterial endosymbionts. In contrast, the meiofauna is largely overlooked in this chemosynthetic environment. The present study describes a new species, Thomontocypris shimanagai sp. nov. (Crustacea: Ostracoda), which was collected from the surface of colonies of neoverrucid barnacles and paralvinellid worms on the chimneys at the Myojin-sho submarine caldera. This is the first discovery of an ostracode from deep-sea hydrothermal vent environments in the western Pacific region. In addition to the species description, we discuss three aspects: 1) adaptation, 2) endemism, and 3) dispersal strategy of the hydrothermal vent ostracodes. Regarding these aspects, we conclude the following: 1) the new species may feed on sloughed-off tissues, mucus secretions, or fecal pellets of sessile organisms, rather than depend on chemoautotrophic bacteria as symbionts for energy; 2) as has been pointed out by other studies, Thomontocypris does not likely represent a vent-specific genus; however, this new species is considered to be endemic at the species level, as it has not been found outside of the type locality; and 3) this new species may have migrated from adjacent deep-sea chemosynthesis-based habitats, such as hydrothermal vents, with wood falls potentially having acted as stepping stones.

  10. Physiological ecology of microorganisms in Subglacial Lake Whillans

    Directory of Open Access Journals (Sweden)

    Trista J Vick-Majors

    2016-10-01

    Full Text Available Subglacial microbial habitats are widespread in glaciated regions of our planet. Some of these environments have been isolated from the atmosphere and from sunlight for many thousands of years. Consequently, ecosystem processes must rely on energy gained from the oxidation of inorganic substrates or detrital organic matter. Subglacial Lake Whillans (SLW is one of more than 400 subglacial lakes known to exist under the Antarctic ice sheet; however, little is known about microbial physiology and energetics in these systems. When it was sampled through its 800 m thick ice cover in 2013, the SLW water column was shallow (~2 m deep, oxygenated, and possessed sufficient concentrations of C, N, and P substrates to support microbial growth. Here, we use a combination of physiological assays and models to assess the energetics of microbial life in SLW. In general, SLW microorganisms grew slowly in this energy-limited environment. Heterotrophic cellular carbon turnover times, calculated from 3H-thymidine and 3H-leucine incorporation rates, were long (60 to 500 days while cellular doubling times averaged 196 days. Inferred growth rates (average ~0.006 d-1 obtained from the same incubations were at least an order of magnitude lower than those measured in Antarctic surface lakes and oligotrophic areas of the ocean. Low growth efficiency (8% indicated that heterotrophic populations in SLW partition a majority of their carbon demand to cellular maintenance rather than growth. Chemoautotrophic CO2-fixation exceeded heterotrophic organic C-demand by a factor of ~1.5. Aerobic respiratory activity associated with heterotrophic and chemoautotrophic metabolism surpassed the estimated supply of oxygen to SLW, implying that microbial activity could deplete the oxygenated waters, resulting in anoxia. We used thermodynamic calculations to examine the biogeochemical and energetic consequences of environmentally imposed switching between aerobic and anaerobic metabolisms

  11. Physiological Ecology of Microorganisms in Subglacial Lake Whillans

    Science.gov (United States)

    Vick-Majors, Trista J.; Mitchell, Andrew C.; Achberger, Amanda M.; Christner, Brent C.; Dore, John E.; Michaud, Alexander B.; Mikucki, Jill A.; Purcell, Alicia M.; Skidmore, Mark L.; Priscu, John C.

    2016-01-01

    Subglacial microbial habitats are widespread in glaciated regions of our planet. Some of these environments have been isolated from the atmosphere and from sunlight for many thousands of years. Consequently, ecosystem processes must rely on energy gained from the oxidation of inorganic substrates or detrital organic matter. Subglacial Lake Whillans (SLW) is one of more than 400 subglacial lakes known to exist under the Antarctic ice sheet; however, little is known about microbial physiology and energetics in these systems. When it was sampled through its 800 m thick ice cover in 2013, the SLW water column was shallow (~2 m deep), oxygenated, and possessed sufficient concentrations of C, N, and P substrates to support microbial growth. Here, we use a combination of physiological assays and models to assess the energetics of microbial life in SLW. In general, SLW microorganisms grew slowly in this energy-limited environment. Heterotrophic cellular carbon turnover times, calculated from 3H-thymidine and 3H-leucine incorporation rates, were long (60 to 500 days) while cellular doubling times averaged 196 days. Inferred growth rates (average ~0.006 d−1) obtained from the same incubations were at least an order of magnitude lower than those measured in Antarctic surface lakes and oligotrophic areas of the ocean. Low growth efficiency (8%) indicated that heterotrophic populations in SLW partition a majority of their carbon demand to cellular maintenance rather than growth. Chemoautotrophic CO2-fixation exceeded heterotrophic organic C-demand by a factor of ~1.5. Aerobic respiratory activity associated with heterotrophic and chemoautotrophic metabolism surpassed the estimated supply of oxygen to SLW, implying that microbial activity could deplete the oxygenated waters, resulting in anoxia. We used thermodynamic calculations to examine the biogeochemical and energetic consequences of environmentally imposed switching between aerobic and anaerobic metabolisms in the SLW

  12. Importance of copper for nitrification in biological rapid sand filters for drinking water production

    DEFF Research Database (Denmark)

    Wagner, Florian Benedikt

    , the reaction rate is sometimes not high enough. This results in incomplete nitrification, with residual ammonium and nitrite concentrations in the finished water, which are problematic for the biological stability of the drinking water. In Denmark, 11 % of the larger water works (>350,000 m3/year) fail......When anoxic groundwater is treated to produce drinking water, ammonium is commonly removed through nitrification in rapid sand filters. Nitrification is a biological process, and is mediated by chemoautotrophic microorganisms. Ammonia oxidizing bacteria (AOB) and archaea (AOA) oxidize ammonium...... were the main active ammonium oxidizers during the dosing. This PhD project revealed that copper is of vital importance for efficient nitrification in biological rapid sand filters for drinking water production. The results of this study have important practical implications for biofilters currently...

  13. Evidence for microbial carbon and sulfur cycling in deeply buried ridge flank basalt

    Science.gov (United States)

    Lever, Mark A.; Rouxel, Olivier; Alt, Jeffrey C.; Shimizu, Nobumichi; Ono, Shuhei; Coggon, Rosalind M.; Shanks, Wayne C.; Lapham, Laura; Elvert, Marcus; Prieto-Mollar, Xavier; Hinrichs, Kai-Uwe; Inagaki, Fumio; Teske, Andreas

    2013-01-01

    Sediment-covered basalt on the flanks of mid-ocean ridges constitutes most of Earth's oceanic crust, but the composition and metabolic function of its microbial ecosystem are largely unknown. By drilling into 3.5-million-year-old subseafloor basalt, we demonstrated the presence of methane- and sulfur-cycling microbes on the eastern flank of the Juan de Fuca Ridge. Depth horizons with functional genes indicative of methane-cycling and sulfate-reducing microorganisms are enriched in solid-phase sulfur and total organic carbon, host δ13C- and δ34S-isotopic values with a biological imprint, and show clear signs of microbial activity when incubated in the laboratory. Downcore changes in carbon and sulfur cycling show discrete geochemical intervals with chemoautotrophic δ13C signatures locally attenuated by heterotrophic metabolism.

  14. The giant ciliate Zoothamnium niveum and its thiotrophic epibiont Candidatus Thiobios zoothamnicoli: a model system to study interspecies cooperation

    Directory of Open Access Journals (Sweden)

    Monika eBright

    2014-04-01

    Full Text Available Symbioses between chemoautotrophic sulfur-oxidizing (thiotrophic bacteria and protists or animals are among the most diverse and prevalent in the ocean. They are extremely difficult to maintain in aquaria and no thiotrophic symbiosis involving an animal host has ever been successfully cultivated. In contrast, we have cultivated the giant ciliate Zoothamnium niveum and its obligate ectosymbiont Cand. Thiobios zoothamnicoli in small flow-through aquaria. This review provides an overview of the host and the symbiont and their phylogenetic relationships. We summarize our knowledge on the ecology, geographic distribution and life cycle of the host, on the vertical transmission of the symbiont, and on the cultivation of this symbiosis. We then discuss the benefits and costs involved in this cooperation compared with other thiotrophic symbioses and outline our view on the evolution and persistence of this byproduct mutualism.

  15. Microbial Fossils from Terrestrial Subsurface Hydrothermal Environments: Examples and Implications for Mars

    Science.gov (United States)

    Hofmann, Beda A.; Farmer, Jack; Chang, Sherwood (Technical Monitor)

    1997-01-01

    The recognition of biological signatures in ancient epithermal deposits has special relevance for studies of early blaspheme evolution and in exploring for past life on Mars. Recently, proposals for the existence of an extensive subsurface blaspheme on Earth, dominated by chemoautotrophic microbial life, has gained prominence. However, reports of fossilized microbial remains, or biosedimentary structures (e.g. stromatolites) from the deposits of ancient subsurface systems, are rare. Microbial preservation is favoured where high population densities co-exist with rapid mineral precipitation. Near-surface epithetical systems with strong gradients in temperature and redox are good candidates for the abundant growth and fossilization of microorganisms, and are also favorable environments for the precipitation of ore minerals. Therefore, we might expect microbial remain, to be particularly well preserved in various kinds of hydrothermal and diagenetic mineral precipitates that formed below the upper temperature limit for life (approx. 120 C).

  16. Sequence homologs of the carboxysomal polypeptide CsoS1 of the thiobacilli are present in cyanobacteria and enteric bacteria that form carboxysomes- polyhedral bodies

    Energy Technology Data Exchange (ETDEWEB)

    Shively, J. M.; Bradburne, C. E.; Mehlman, J. L.; Jin, S.; Baker, S. H. [Clemson Univ., Dept. of Microbiology and Cell Science, Clemson, SC (United States); Aldrich, H. C.; Bobik, T. A. [Florida Univ., Dept. of Microbiology and Cell Science, Gainesville, FL (United States)

    1998-06-01

    Carboxysomes containing the Calvin cycle enzyme ribulose-1,5-biphosphate carboxylase-oxygenase have been demonstrated in a variety of chemoautotrophic prokaryotes and cyanobacteria. Probing Southern blots of Escherichia coli genomic DNA with csoS1A showed positive hybridization indicating the presence of a csoS1-like gene. Growing Salmonella enterica and Klebsiella oxytoca with proponediol, and E. coli, with ethanolamine as the energy source, under anaerobic conditions resulted in the formation of polyhedral bodies in these bacteria. The DNA-deduced amino acid sequence of three additional CsoS1 polypeptides in Thiobacillus sp. was determined. The polypeptides determined exhibited greater than 67 per cent sequence identity. Identity and similarity comparisons and phylogenetic analysis of known polyhedral body CsoS1-like polypeptides indicate a close structural relationship between polyhedral bodies of potentially very different function. 32 refs., 7 figs.

  17. Autotrophic microbial arsenotrophy in arsenic-rich soda lakes

    Science.gov (United States)

    Oremland, Ronald S.; Saltikov, Chad W.; Stolz, John F.; Hollibaugh, James T.

    2017-01-01

    A number of prokaryotes are capable of employing arsenic oxy-anions as either electron acceptors [arsenate; As(V)] or electron donors [arsenite; As(III)] to sustain arsenic-dependent growth (‘arsenotrophy’). A subset of these microorganisms function as either chemoautotrophs or photoautotrophs, whereby they gain sufficient energy from their redox metabolism of arsenic to completely satisfy their carbon needs for growth by autotrophy, that is the fixation of inorganic carbon (e.g. HCO3−) into their biomass. Here we review what has been learned of these processes by investigations we have undertaken in three soda lakes of the western USA and from the physiological characterizations of the relevant bacteria, which include the critical genes involved, such as respiratory arsenate reductase (arrA) and the discovery of its arsenite-oxidizing counterpart (arxA). When possible, we refer to instances of similar process occurring in other, less extreme ecosystems and by microbes other than haloalkaliphiles.

  18. Effect of zinc and benzalkonium chloride on Nitrosomonas communis and potential nitrification in soil.

    Science.gov (United States)

    Frühling, W; Rönnpagel, K; Ahlf, W

    2001-10-01

    A bacterial contact assay is described which uses a chemoautotrophic microorganism, Nitrosomonas communis (strain Nm2) to evaluate the biological effect of contaminated soils. The effects of two toxicants on the ammonium oxidation activity of the autochthonous microbial population in the soil are compared with inhibition of the same biological response in the new monospecies bioassay. Experiments were performed using soil samples dosed with organic and inorganic contaminants (benzalkonium chloride and zinc) to demonstrate the mode of operation and the sensitivity of the bioassay. The EC50 values of zinc and benzalkonium chloride were calculated to be 171 and 221 mg kg-1 soil, respectively. The toxic response provided by the bioassay can thus predict the effect of soil pollutants on the autochthonous nitrifying bacteria.

  19. 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.

  20. Earth analogs for Martian life - Microbes in evaporites, a new model system for life on Mars

    Science.gov (United States)

    Rothschild, Lynn J.

    1990-01-01

    It is suggested that 'oases' in which life forms may persist on Mars could occur, by analogy with terrestrial cases, in (1) rocks, as known in endolithic microorganisms, (2) polar ice caps, as seen in snow and ice algae, and (3) volcanic regions, as witnessed in the chemoautotrophs which live in ocean-floor hydrothermal vents. Microorganisms, moreover, have been known to survive in salt crystals, and it has even been shown that organisms can metabolize while encrusted in evaporites. Evaporites which may occur on Mars would be able to attenuate UV light, while remaining more transparent to the 400-700 nm radiation useful in photosynthesis. Suggestions are made for the selection of Martian exobiological investigation sites.

  1. 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.

  2. Catalysis in the Primordial World

    Directory of Open Access Journals (Sweden)

    Nenad Raos

    2017-11-01

    Full Text Available Catalysis provides orderly prebiotic synthesis and eventually its evolution into autocatalytic (self-reproduction systems. Research on homogeneous catalysis is concerned mostly with random peptide synthesis and the chances to produce catalytic peptide oligomers. Synthesis of ribose via formose reaction was found to be catalysed by B(OH4−, presumably released by weathering of borate minerals. Oxide and clay mineral surfaces provide catalytic sites for the synthesis of oligopeptides and oligonucleotides. Chemoautotrophic or iron-sulphur-world theory assumes that the first (pioneer organisms developed by catalytic processes on (Fe/NiS particles formed near/close hydrothermal vents. The review provides an overlay of possible catalytic reactions in prebiotic environment, discussing their selectivity (regioselectivity, stereoselectivity as well as geological availability of catalytic minerals and geochemical conditions enabling catalytic reactions on early Earth.

  3. 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..

  4. The history of aerobic ammonia oxidizers: from the first discoveries to today.

    Science.gov (United States)

    Monteiro, Maria; Séneca, Joana; Magalhães, Catarina

    2014-07-01

    Nitrification, the oxidation of ammonia to nitrite and nitrate, has long been considered a central biological process in the global nitrogen cycle, with its first description dated 133 years ago. Until 2005, bacteria were considered the only organisms capable of nitrification. However, the recent discovery of a chemoautotrophic ammonia-oxidizing archaeon, Nitrosopumilus maritimus, changed our concept of the range of organisms involved in nitrification, highlighting the importance of ammonia-oxidizing archaea (AOA) as potential players in global biogeochemical nitrogen transformations. The uniqueness of these archaea justified the creation of a novel archaeal phylum, Thaumarchaeota. These recent discoveries increased the global scientific interest within the microbial ecology society and have triggered an analysis of the importance of bacterial vs archaeal ammonia oxidation in a wide range of natural ecosystems. In this mini review we provide a chronological perspective of the current knowledge on the ammonia oxidation pathway of nitrification, based on the main physiological, ecological and genomic discoveries.

  5. The Geological Structure and Prospect of Gas Hydrate over the Dongsha Slope, South China Sea

    Directory of Open Access Journals (Sweden)

    Pin Yan

    2006-01-01

    Full Text Available The area around the Dongsha Island in the northeastern South China Sea was generally known for the occurrence of gas hydrate related features, like BSR, cold seep carbonates and chemoautotrophic bacteria. To precisely evaluate the potential of gas hydrate occurrence in the NE South China Sea, marine geology of the large Dongsha slope region is studied based on more geophysical and geological data including multiple-channel seismic and high resolution sub-bottom topographic images. The east Dongsha slope area represents the largest slumping zone in the northern slope of the South China Sea, and might exhibit the highest potential of gas hydrate occurrences. The central Dongsha slope area, with very thin Cenozoic sediments, was tectonically disturbed by the latest Cenozoic uplifting and magmatism events, therefore is unfavorable for gas hydrate occurrence. The west Dongsha slope area with the deepest Cenozoic depression and moderate to minor slumping bodies might be favorable for gas hydrate occurrence.

  6. Modeling the mutualistic interactions between tubeworms and microbial consortia.

    Directory of Open Access Journals (Sweden)

    Erik E Cordes

    2005-03-01

    Full Text Available The deep-sea vestimentiferan tubeworm Lamellibrachia luymesi forms large aggregations at hydrocarbon seeps in the Gulf of Mexico that may persist for over 250 y. Here, we present the results of a diagenetic model in which tubeworm aggregation persistence is achieved through augmentation of the supply of sulfate to hydrocarbon seep sediments. In the model, L. luymesi releases the sulfate generated by its internal, chemoautotrophic, sulfide-oxidizing symbionts through posterior root-like extensions of its body. The sulfate fuels sulfate reduction, commonly coupled to anaerobic methane oxidation and hydrocarbon degradation by bacterial-archaeal consortia. If sulfate is released by the tubeworms, sulfide generation mainly by hydrocarbon degradation is sufficient to support moderate-sized aggregations of L. luymesi for hundreds of years. The results of this model expand our concept of the potential benefits derived from complex interspecific relationships, in this case involving members of all three domains of life.

  7. Nitrogen removal and electricity production at a double-chamber microbial fuel cell with cathode nitrite denitrification.

    Science.gov (United States)

    Yu, Yangyang; Zhao, Jianqiang; Wang, Sha; Zhao, Huimin; Ding, Xiaoqian; Gao, Kun

    2017-12-01

    Double-chamber microbial fuel cell was applied to investigate the performance of the electricity production and nitrite denitrification through feeding nitrite into the cathode. Factors influencing denitrification performance and power production, such as external resistance, influent nitrite concentration and Nitrite Oxygen Bacteria inhibitors, were studied. The results show that when the concentration of nitrite nitrogen and external resistance were 100 mg L -1 and 10 Ω, respectively, the nitrite denitrification reached the best state. The NaN 3 can inhibit nitrite oxidation effectively; meanwhile, the nitrite denitrification with N 2 O as the final products was largely improved. The [Formula: see text] was reduced to [Formula: see text], causing the cathode denitrification coulombic efficiency to exceed 100%. In chemoautotrophic bio-nitrification, microorganisms may utilize H 2 O to oxidize nitrite under anaerobic conditions. Proteobacteria might play a major role in the process of denitrification in MFC.

  8. Metagenome of a versatile chemolithoautotroph from expanding oceanic dead zones.

    Science.gov (United States)

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

    2009-10-23

    Oxygen minimum zones, also known as oceanic "dead zones," are widespread oceanographic features currently expanding because of global warming. Although inhospitable to metazoan life, they support a cryptic microbiota whose metabolic activities affect nutrient and trace gas cycling within the global ocean. Here, we report metagenomic analyses of a ubiquitous and abundant but uncultivated oxygen minimum zone microbe (SUP05) 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. Our analysis provides a genomic foundation for understanding the ecological and biogeochemical role of pelagic SUP05 in oxygen-deficient oceanic waters and its potential sensitivity to environmental changes.

  9. Growth of non-phototrophic microorganisms using solar energy through mineral photocatalysis.

    Science.gov (United States)

    Lu, Anhuai; Li, Yan; Jin, Song; Wang, Xin; Wu, Xiao-Lei; Zeng, Cuiping; Li, Yan; Ding, Hongrui; Hao, Ruixia; Lv, Ming; Wang, Changqiu; Tang, Yueqin; Dong, Hailiang

    2012-04-03

    Phototrophy and chemotrophy are two dominant modes of microbial metabolism. To date, non-phototrophic microorganisms have been excluded from the solar light-centered phototrophic metabolism. Here we report a pathway that demonstrates a role of light in non-phototrophic microbial activity. In lab simulations, visible light-excited photoelectrons from metal oxide, metal sulfide, and iron oxide stimulated the growth of chemoautotrophic and heterotrophic bacteria. The measured bacterial growth was dependent on light wavelength and intensity, and the growth pattern matched the light absorption spectra of the minerals. The photon-to-biomass conversion efficiency was in the range of 0.13-1.90‰. Similar observations were obtained in a natural soil sample containing both bacteria and semiconducting minerals. Results from this study provide evidence for a newly identified, but possibly long-existing pathway, in which the metabolisms and growth of non-phototrophic bacteria can be stimulated by solar light through photocatalysis of semiconducting minerals.

  10. Predicting yields for autotrophic and cometabolic processes

    Energy Technology Data Exchange (ETDEWEB)

    Andrews, G. [Idaho National Engineering Lab., Idaho Falls, ID (United States)

    1995-12-31

    The goal of bioprocess engineering is to state how the optimum design and control strategy for a bioprocess follow from the metabolism of the particular microorganism. A necessary step toward this goal is to show how the parameters used in quantitative descriptions of a process (e.g., yield and maintenance coefficients) are related to those describing the metabolism [e.g., Y{sub ATP}, (P/O)]. The {open_quotes}yield equation{close_quotes} approach to this problem involves dividing metabolism into the separate pathways for catabolism, anabolism, respiration, and product formation and balancing the production and consumption of reducing equivalents and ATP. The general approach, demonstrated previously for heterotrophic cell growth and products of fermentation, is illustrated by three new examples: the cell yield for chemoautotrophic iron-oxidizing bacteria, the cometabolic degradation of chloroform by methanotrophic bacteria, and the theoretical yield of succinic acid from glucose.

  11. 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.

  12. From Mantle to Microbe to Mollusc: How Animal-Microbial Symbioses Influence Carbon and Sulfur Cycling in Hydrothermal Vent Flows.

    Science.gov (United States)

    Girguis, P. R.; Beinart, R.

    2014-12-01

    Symbioses between animals and chemoautotrophic bacteria dominate many hydrothermal vents. In these associations, symbiotic bacteria harness energy and "fix" carbon from the oxidation of reduced chemicals such as sulfide, methane, and hydrogen that are found in venting fluids. At vents along the Eastern Lau Spreading Center (ELSC) in the South Pacific, snails and mussels with chemoautotrophic symbionts have been shown to harness energy via the oxidation of sulfide. However, partially oxidized sulfur species such as thiosulfate and polysulfides have also been detected in abundance in their habitats. No studies to date have established whether thiosulfate or other partially oxidized sulfur compounds are used by these symbiotic associations, nor have studies constrained the potential role that symbioses might play in sulfur biogeochemical cycles at diffuse vent flows. To address these questions, we used high-pressure, flow through incubations to study three symbiotic molluscs from the ELSC - the snails Alviniconcha and Ifremeria nautilei and the mussel Bathymodiolus brevior - at conditions mimicking those in situ. Via the use of isotopically labeled inorganic carbon, shipboard mass spectrometry and voltammetric microelectrodes, we quantified the production and consumption of different sulfur compounds by each of these symbioses. We established that the uptake and oxidation of either sulfide or thiosulfate could -to varying degrees- support carbon fixation in all three species. Notably, we also observed that some symbioses excreted thiosulfate and polysulfides under sulfidic conditions, suggesting that these symbioses are a source of partially oxidized sulfur species in the environment. We further observed spatial disparity in the carbon fixation rates among the individuals in our incubations that have implications for the variability of productivity in situ.Collectively, these data reveal that thiosulfate can support net autotrophy, and may be an ecologically important

  13. Cold seep epifaunal communities on the Hikurangi margin, New Zealand: composition, succession, and vulnerability to human activities.

    Directory of Open Access Journals (Sweden)

    David A Bowden

    Full Text Available Cold seep communities with distinctive chemoautotrophic fauna occur where hydrocarbon-rich fluids escape from the seabed. We describe community composition, population densities, spatial extent, and within-region variability of epifaunal communities at methane-rich cold seep sites on the Hikurangi Margin, New Zealand. Using data from towed camera transects, we match observations to information about the probable life-history characteristics of the principal fauna to develop a hypothetical succession sequence for the Hikurangi seep communities, from the onset of fluid flux to senescence. New Zealand seep communities exhibit taxa characteristic of seeps in other regions, including predominance of large siboglinid tubeworms, vesicomyid clams, and bathymodiolin mussels. Some aspects appear to be novel; however, particularly the association of dense populations of ampharetid polychaetes with high-sulphide, high-methane flux, soft-sediment microhabitats. The common occurrence of these ampharetids suggests they play a role in conditioning sulphide-rich sediments at the sediment-water interface, thus facilitating settlement of clam and tubeworm taxa which dominate space during later successional stages. The seep sites are subject to disturbance from bottom trawling at present and potentially from gas hydrate extraction in future. The likely life-history characteristics of the dominant megafauna suggest that while ampharetids, clams, and mussels exploit ephemeral resources through rapid growth and reproduction, lamellibrachid tubeworm populations may persist potentially for centuries. The potential consequences of gas hydrate extraction cannot be fully assessed until extraction methods and target localities are defined but any long-term modification of fluid flow to seep sites would have consequences for all chemoautotrophic fauna.

  14. 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

  15. 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. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Can the hemoglobin characteristics of vesicomyid clam species influence their distribution in deep-sea sulfide-rich sediments? A case study in the Angola Basin

    Science.gov (United States)

    Decker, C.; Zorn, N.; Le Bruchec, J.; Caprais, J. C.; Potier, N.; Leize-Wagner, E.; Lallier, F. H.; Olu, K.; Andersen, A. C.

    2017-08-01

    Vesicomyids live in endosymbiosis with sulfur-oxidizing bacteria and therefore need hydrogen sulfide to survive. They can nevertheless live in a wide range of sulfide and oxygen levels and depths, which may explain the exceptional diversity of this clam family in deep-sea habitats. In the Gulf of Guinea, nine species of vesicomyid clams are known to live in cold-seep areas with pockmarks from 600 to 3200 m deep, as well as in the organic-rich sediments of the Congo deep-sea fan at 5000 m deep. Our previous study showed that two species living in a giant pockmark have different oxygen carriers, suggesting different adaptations to hypoxia. Here, we studied the hemoglobin structure and oxygen affinity in three other species, Calyptogena valdiviae, Elenaconcha guiness and Abyssogena southwardae to determine whether the characteristics of their oxygen carriers contribute to their distribution in sulfide-rich sediments at a regional scale. Documenting pairwise species associations in various proportions, we give a semi-quantitative account of their local distribution and oxygen and sulfide measurements at seven sites. Mass spectrometry showed that each vesicomyid species has four intracellular monomeric hemoglobin molecules of 15-16 kDa, all differing in their molecular mass. As expected, the monomers showed no cooperativity in oxygen binding. Their oxygen affinities were very high (below 1 Torr), but differed significantly. C. valdiviae had the highest affinity and was dominant in the Harp pockmark, the site with the lowest oxygen content (half the value of fully oxygenated water). A. southwardae dominated in the Congo Lobe area, the site with the deepest sulfides. We discuss how hemoglobin may favor an active, vertical distribution of vesicomyids in sulfide-rich sediments.

  17. 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.

  18. Parasitic diseases of camels in Iran (1931-2017) - a literature review.

    Science.gov (United States)

    Sazmand, Alireza; Joachim, Anja

    2017-01-01

    Parasitic diseases of camels are major causes of impaired milk and meat production, decreases in performance or even death. Some camel parasites also represent a threat to human health. About 171,500 one-humped camels (Camelus dromedarius) and 100-300 two-humped camels (Camelus bactrianus) live in Iran. Knowledge of the biodiversity of their parasites is still limited. The present review covers all information about camel parasitic diseases in Iran published as dissertations and in both Iranian and international journals from 1931 to February 2017. Ten genera of Protozoa (Trypanosoma, Eimeria, Cryptosporidium, Toxoplasma, Neospora, Sarcocystis, Besnoitia, Theileria, Babesia and Balantidium), 48 helminth species detected in the digestive system, including three species of Trematoda, four species of Cestoda, and 41 species of Nematoda, as well as helminths from other organs - Echinococcus spp., Dictyocaulus filaria, Thelazia leesei, Dipetalonema evansi and Onchocerca fasciata - have so far been described in Iranian camels. Furthermore, 13 species of hard ticks, mange mites, the myiasis flies Cephalopina titillator and Wohlfahrtia magnifica, and immature stages of the Pentastomida Linguatula serrata have also been reported from camels of Iran. Camel parasitic diseases are a major issue in Iran in terms of economics and public health. The present review offers information for an integrated control programme against economically relevant parasites of camels. © A. Sazmand & A. Joachim, published by EDP Sciences, 2017.

  19. Scanning electron microscopy of conidia of Trichoderma stromaticum, a biocontrol agent of witches' broom disease of cocoa Microscopia eletrônica de varredura de conídios de Trichoderma stromaticum, um agente de biocontrole da vassoura-de-bruxa do cacaueiro

    Directory of Open Access Journals (Sweden)

    Itamar Soares de Melo

    2004-12-01

    Full Text Available A field emission electron microscope (SEM was used to study the conidia surface of Trichoderma stromaticum, a biocontrol of witches broom disease of cocoa. Surface features of conidia were difficult distinguish by light microscope. Conidia appeared to be verrugose and minutely roughened, but the nature of the roughening was not easy to discern. It was common to observe sheath-like structures that completely covered groups of conidia, and also details of wide cells that form the pustules.Estudos morfológicos de conídios de Trichoderma harzianun, um agente de biocontrole da vassoura-de-bruxa do cacaueiro, foram feitos sob microscopia eletrônica de varredura com emissão de campo. Características da superfície de conídios do fungo mostraram ser rugosas quando observadas em alta magnificação; fato esse impossível de ser visualizado por microscopia ótica. Também foram observados, com freqüência, massas de conídios completamente envolvidos por material mucilaginoso e detalhes de células ramificadas dicotomicamente que formam as pústulas.

  20. The Lepidoptera associated with forestry crop species in Brazil: a historical approach.

    Science.gov (United States)

    Kowalczuck, Manoela; Carneiro, E; Casagrande, M M; Mielke, O H H

    2012-10-01

    Despite the long history of forestry activity in Brazil and its importance to the national economy, there is still much disorder in the information regarding pests of forestry species. Considering the importance of the entomological knowledge for the viability of silvicultural management, this work aimed to gather information on the species of Lepidoptera associated with forestry crops within Brazil using a historical approach. Through a literature review, all registered species of Lepidoptera related to forestry crops in Brazil from 1896 to 2010 were identified. The historical evaluation was based on the comparison of the number of published articles, species richness, and community similarities of the Lepidoptera and their associated forest crops, grouped in 10-year samples. A total of 417 occurrences of Lepidoptera associated with forestry species were recorded, from which 84 species are related with 40 different forestry crops. The nocturnal Lepidoptera were dominant on the records, with Eacles imperialis magnifica Walker as the most frequent pest species cited. Myrtaceae was the most frequent plant family, with Cedrela fissilis as the most cited forestry crop species. A successional change in both Lepidoptera species and their host plants was observed over the decades. The richness of lepidopteran pest species increased over the years, unlike the richness of forestry crop species. This increase could be related to the inefficient enforcement of sanitary barriers, to the increase of monoculture areas, and to the adaptability of native pests to exotic forestry species used in monoculture stands.

  1. Parasitic diseases of camels in Iran (1931–2017 – a literature review

    Directory of Open Access Journals (Sweden)

    Sazmand Alireza

    2017-01-01

    Full Text Available Parasitic diseases of camels are major causes of impaired milk and meat production, decreases in performance or even death. Some camel parasites also represent a threat to human health. About 171,500 one-humped camels (Camelus dromedarius and 100–300 two-humped camels (Camelus bactrianus live in Iran. Knowledge of the biodiversity of their parasites is still limited. The present review covers all information about camel parasitic diseases in Iran published as dissertations and in both Iranian and international journals from 1931 to February 2017. Ten genera of Protozoa (Trypanosoma, Eimeria, Cryptosporidium, Toxoplasma, Neospora, Sarcocystis, Besnoitia, Theileria, Babesia and Balantidium, 48 helminth species detected in the digestive system, including three species of Trematoda, four species of Cestoda, and 41 species of Nematoda, as well as helminths from other organs – Echinococcus spp., Dictyocaulus filaria, Thelazia leesei, Dipetalonema evansi and Onchocerca fasciata – have so far been described in Iranian camels. Furthermore, 13 species of hard ticks, mange mites, the myiasis flies Cephalopina titillator and Wohlfahrtia magnifica, and immature stages of the Pentastomida Linguatula serrata have also been reported from camels of Iran. Camel parasitic diseases are a major issue in Iran in terms of economics and public health. The present review offers information for an integrated control programme against economically relevant parasites of camels.

  2. Parasitic diseases of camels in Iran (1931–2017) – a literature review

    Science.gov (United States)

    Sazmand, Alireza; Joachim, Anja

    2017-01-01

    Parasitic diseases of camels are major causes of impaired milk and meat production, decreases in performance or even death. Some camel parasites also represent a threat to human health. About 171,500 one-humped camels (Camelus dromedarius) and 100–300 two-humped camels (Camelus bactrianus) live in Iran. Knowledge of the biodiversity of their parasites is still limited. The present review covers all information about camel parasitic diseases in Iran published as dissertations and in both Iranian and international journals from 1931 to February 2017. Ten genera of Protozoa (Trypanosoma, Eimeria, Cryptosporidium, Toxoplasma, Neospora, Sarcocystis, Besnoitia, Theileria, Babesia and Balantidium), 48 helminth species detected in the digestive system, including three species of Trematoda, four species of Cestoda, and 41 species of Nematoda, as well as helminths from other organs – Echinococcus spp., Dictyocaulus filaria, Thelazia leesei, Dipetalonema evansi and Onchocerca fasciata – have so far been described in Iranian camels. Furthermore, 13 species of hard ticks, mange mites, the myiasis flies Cephalopina titillator and Wohlfahrtia magnifica, and immature stages of the Pentastomida Linguatula serrata have also been reported from camels of Iran. Camel parasitic diseases are a major issue in Iran in terms of economics and public health. The present review offers information for an integrated control programme against economically relevant parasites of camels. PMID:28617666

  3. Nutrient distribution in flowering stems, nutrient removal and fertilization of three proteaceae cultivars

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    M.M. Hernández

    2014-06-01

    Full Text Available Several parameters of flowering stems of two cultivars of protea Leucospermum cordifolium (Knight Fourc (‘Succession II’ and ‘Tango’ and one of protea Protea L. (Protea susannae x magnifica ‘Susara’ were studied in different commercial plantations. These included length and weight measures, nutrient concentrations of detached parts (flower heads, leaves and stems, and removal of nutrients of harvested flowers. A base for fertilization was also calculated. Harvested flowers of ‘Susara’ removed more P, K and Cu than ‘Succession II’ and ‘Tango’, and more Ca and Fe than ‘Tango’. ‘Succession II’ showed the highest Zn removal. The P and Cu removal by the crop of ‘Susara’ were significantly higher than those of both Leucospermum cultivars, while K, Ca, and Fe outputs of ‘Susara’ exceeded only those of ‘Tango’. The nutrient top removals amounted to 4.55 g m-2 of N, 0.48 g m-2 of P, and 5.26 g m-2 of K. Data as a base to supply fertilizer to each cultivar are given, with N:P:K ratios of 1:0.08:0.87 for ‘Succession II’, 1:0.08:0.83 for ‘Tango’ and 1:0.10:1.27 for ‘Susara’.

  4. Generalized magnification in visual optics. Part 2: Magnification as affine transformation

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    W. F. Harris

    2010-12-01

    Full Text Available In astigmatic systems magnification may be different in different directions.  It may also be accompanied by rotation or reflection.  These changes from object to image are examples of generalized magnification.  They are represented by  2 2×  matrices.  Because they are linear transformations they can be called linear magnifications.  Linear magnifications account for a change in appearance without regard to position.  Mathematical structure suggests a natural further generalization to a magnification that is complete in the sense that it accountsfor change in appearance and position.  It is represented by a  3 3×  matrix with a dummy third row. The transformation is called affine in linear algebra which suggests that these generalized magnifica-tions be called affine magnifications.  The purpose of the paper is to define affine magnification in the context of astigmatic optics.  Several examples are presented and illustrated graphically. (S Afr Optom 2010 69(4 166-172

  5. INVENTARISASI KEANEKARAGAMAN MAKROZOOBENTOS DI DAERAH ALIRAN SUNGAI BRANTAS KECAMATAN NGORO MOJOKERTO SEBAGAI SUMBER BELAJAR BIOLOGI SMA KELAS X

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    Iin Ratih

    2015-07-01

    Full Text Available Jenis penelitian ini adalah deskriptif yang dilakukan untuk memperoleh fakta atau data tentang keanekaragaman jenis Makrozoobentos di DAS Brantas Kecamatan Ngoro Mojokerto. Pengambilan sampel dilakukan tiga stasiun dengan tiga kali ulangan untuk masing-masing stasiun. Parameter fisika yang diamati adalah kedalaman, kecerahan air, suhu air dan kecepatan arus. Parameter kimia yang diamati adalah pH, DO, BOD5, dan COD. Sedangkan parameter biologi yang diamati adalah kepadatan (D, kepadatan relatif (RD, kelimpahan (K, kelimpahan relatif (KR dan indeks keanekaragaman (H’. Keanekaragaman makrozoobentos yang ditemukan di daerah aliran sungai Brantas terdiri dari Terdapat 11 spesies yakni Anentome Helena, Hydrophilus ovatus, Berosus sp, Lumbricus sp, Macromia magnifica , Sulcospira schmidti, Parathelphusa convexa, Melanoides torulosa, Melanoides tuberculata, Corbicula fluminea, Corbicula largillierti. Indeks keanekaragaman tertinggi adalah Melanoides torulosa dan terendah adalah Berosus sp. Famili Buccinidae dengan kedalaman memiliki hubungan yang sangat kuat. Sedangkan famili Macromiidae dengan DO memiliki hubungan lemah. Hasil penelitian ini digunakan sebagai sumber belajar berupa handout materi invertebrata pada kelas X SMA IPA. Materi tersebut sesuai dengan penelitian yang memanfaatkan keanekaragaman invertebrata air di DAS Brantas untuk diidentifikasi dan dianalisis kegunaannya.

  6. Differential susceptibilities of human lung, breast and skin cancer cell lines to killing by five sea anemone venoms

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    M Ramezanpour

    2012-01-01

    Full Text Available Although sea anemones are well known for being rich sources of toxins, including cytolysins and neurotoxins, their venoms and toxins have been poorly studied. In the present study, the venoms from five sea anemones (Heteractis crispa, Heteractis magnifica, Heteractis malu, Cryptodendrum adhaesivum and Entacmaea quadricolor were obtained by the milking technique, and the potential of these venoms to kill cancer cells was tested on three cell lines (A549 lung cancer, T47D breast cancer and A431 skin cancer. The total protein level in the crude extract was determined by the bicinchoninic acid (BCA protein assay. The cytotoxicity on different cell lines was assayed using the 3-(4, 5-dimethylthiazol-2yl-2, 5-diphenyltetrazolium bromide (MTT assay which measures survival based on the detection of mitochondrial activity and by the crystal violet assay, which measures survival based on the ability of cells to remain adherent to microplates. The results indicate that the sea anemone venom is cytotoxic to human cancer cells. The A549 cell line was the most sensitive of the cell lines tested with a significant reduction in viability observed at 40 µg/mL. H. malu, C. adhaesivum and E. quadricolor had a significant inhibitory effect on A431 cells. Furthermore, H. malu and C. adhaesivum had a significant inhibitory effect on T47D cell line at 40 µg/mL. In conclusion, the sea anemone venoms tested have the potential to be developed as anticancer agents.

  7. 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. © 2016 The Author(s).

  8. Canine Myiasis and Its Causal Agents in Northeastern Iran

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    Ali MOSHAVERINIA

    2016-03-01

    Full Text Available Background: Myiasis is defined as the infestation of live human and vertebrate animals with dipterous larvae for a certain period. There are reports indicating that dogs are the most common species affected by myiasis. This study was conducted to identify myiasis-causing flies in owned and stray dogs in Mashhad (Northeastern Iran. Methods: A total of 435 owned dogs and 800 stray dogs were examined for myia­sis. Myiasis cases were cured and fly larvae were identified by microscopy using the relevant standard identification keys.Results: Ten out of 435 owned dogs (2.29 % and 18 out of 800 stray dogs (2.25 % had myiasis. The causative agents of myiasis in dogs based on their fre­quencies were as follows: Wohlfahrtia magnifica (50%, Lucilia sericata (28.57% and Chrysomya albiceps (21.42%.Conclusion: W. magnifica was the most important myiasis-causing fly among the dogs sampled here, sometimes causing very serious damages. However, when treatment was given early enough, the larvae removed and the wound disinfected, the animals usually made a full recovery.

  9. 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

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    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.

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

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    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. Nectar Meals of a Mosquito-Specialist Spider

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    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.

  12. Bark Thickness Equations for Mixed-Conifer Forest Type in Klamath and Sierra Nevada Mountains of California

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    Nickolas E. Zeibig-Kichas

    2016-01-01

    Full Text Available We studied bark thickness in the mixed-conifer forest type throughout California. Sampling included eight conifer species and covered latitude and elevation gradients. The thickness of tree bark at 1.37 m correlated with diameter at breast height (DBH and varied among species. Trees exhibiting more rapid growth had slightly thinner bark for a given DBH. Variability in bark thickness obscured differences between sample locations. Model predictions for 50 cm DBH trees of each species indicated that bark thickness was ranked Calocedrus decurrens > Pinus jeffreyi > Pinus lambertiana > Abies concolor > Pseudotsuga menziesii > Abies magnifica > Pinus monticola > Pinus contorta. We failed to find reasonable agreement between our bark thickness data and existing bark thickness regressions used in models predicting fire-induced mortality in the mixed-conifer forest type in California. The fire effects software systems generally underpredicted bark thickness for most species, which could lead to an overprediction in fire-caused tree mortality in California. A model for conifers in Oregon predicted that bark was 49% thinner in Abies concolor and 37% thicker in Pseudotsuga menziesii than our samples from across California, suggesting that more data are needed to validate and refine bark thickness equations within existing fire effects models.

  13. Biosygnatures on olivines in search of past life on Mars

    Science.gov (United States)

    Jakus, Natalia; Manecki, Maciej; Faehnrich, Karol; Młynarska, Maria; Słupski, Paweł

    2017-04-01

    Biosignatures indicate past and present activity of living organisms. Only inorganic biosignatures, e.g. results of interactions between the minerals and the microorganisms in Martian soils could resist harsh environmental conditions on Mars. However, it may be difficult to distinguish the traces of the organism activities from the effects of "natural" chemical and physical processes. In this study, an acidiophilic, chemoautotrophic, iron-oxidizing bacteria Acidithiobacillus ferrooxidans were incubated with magnesium-iron silicate (olivine) crystals to identify the potential development of biogenic textures on the surface. The Mg-rich olivines were separated from the gabbro rock (Trodos, Cyprus). The isometric crystals were up to 2 mm in size. All the grains were cleaned in ultrasonic bath and fixed on the epoxy stubs. This enabled the observation of the very same surfaces before and after the experiments allowing inspection of natural etch pits and weathering patterns present before inoculation as well as the forms resulting from the experiments. The stubs with the olivines were sterilized with ethanol prior to the experiments. Bacteria were isolated from old pyrite mine in Klucze near Olkusz (Southern Poland). A liquid media K9 was used through the experiments (Silverman and Ludgren, 1959). The experiments were run in triplicates. Olivine grains were placed in the inoculated medium and incubated for 7 days at 28 C. An abiotic experiment was run as control. Additionally, the experiments in modified (iron deficient) medium were designed to stimulate potential active scavenging for Fe by bacteria-mediated dissolution. In the Fe-deficient medium, the negligible amount of iron was present only to initiate the bacteria growth: the only source of Fe was the olivine grain throughout the experiment. After 7 days of incubation the olivine grains were removed and air-dried. The alterations of the crystals by both, purely inorganic and biologically mediated dissolution were

  14. 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 (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 Alicyclobacillus-like Firmicutes) were isolated as pure

  15. Functions and Unique Diversity of Genes and Microorganisms Involved in Arsenite Oxidation from the Tailings of a Realgar Mine.

    Science.gov (United States)

    Zeng, Xian-Chun; E, Guoji; Wang, Jianing; Wang, Nian; Chen, Xiaoming; Mu, Yao; Li, Hao; Yang, Ye; Liu, Yichen; Wang, Yanxin

    2016-12-15

    The tailings of the Shimen realgar mine have unique geochemical features. Arsenite oxidation is one of the major biogeochemical processes that occurs in the tailings. However, little is known about the functional and molecular aspects of the microbial community involved in arsenite oxidation. Here, we fully explored the functional and molecular features of the microbial communities from the tailings of the Shimen realgar mine. We collected six samples of tailings from sites A, B, C, D, E, and F. Microcosm assays indicated that all of the six sites contain both chemoautotrophic and heterotrophic arsenite-oxidizing microorganisms; their activities differed considerably from each other. The microbial arsenite-oxidizing activities show a positive correlation with soluble arsenic concentrations. The microbial communities of the six sites contain 40 phyla of bacteria and 2 phyla of archaea that show extremely high diversity. Soluble arsenic, sulfate, pH, and total organic carbon (TOC) are the key environmental factors that shape the microbial communities. We further identified 114 unique arsenite oxidase genes from the samples; all of them code for new or new-type arsenite oxidases. We also isolated 10 novel arsenite oxidizers from the samples, of which 4 are chemoautotrophic and 6 are heterotrophic. These data highlight the unique diversities of the arsenite-oxidizing microorganisms and their oxidase genes from the tailings of the Shimen realgar mine. To the best of our knowledge, this is the first report describing the functional and molecular features of microbial communities from the tailings of a realgar mine. This study focused on the functional and molecular characterizations of microbial communities from the tailings of the Shimen realgar mine. We fully explored, for the first time, the arsenite-oxidizing activities and the functional gene diversities of microorganisms from the tailings, as well as the correlation of the microbial activities/diversities with

  16. Microbial community structure and productivity in the oxygen minimum zone of the eastern tropical North Pacific

    Science.gov (United States)

    Podlaska, Agnieszka; Wakeham, Stuart G.; Fanning, Kent A.; Taylor, Gordon T.

    2012-08-01

    Microbial abundances and activities (heterotrophic and chemoautotrophic) were profiled in the fall of 2007 along a transect of four stations in the upwelling region between the Tehuantepec Bowl, off the coast of southern Mexico, and the Costa Rica Dome. Heterotrophic potential varied with depth exhibiting relatively low maximum values of 4-8 nM leucine d-1, but varied among stations by a factor of 2. Generally, heterotrophic potential varied inversely with nitrate implying NO3- draw down by nitrate-reducing chemoorganotrophs. Dark dissolved inorganic carbon assimilation (≈chemoautotrophy) was also highly variable with depth and reached a maximum value of 6.4 μM C d-1 at one station, but only attained maxima of 0.02 and 0.2 μM C d-1 at other stations. Elevated values of chemoautotrophy corresponded with enrichments in nitrite concentrations suggesting nitrification as well as with depletions in nitrite and ammonium concentrations suggesting anammox processes. Additions of 30 μM NH4+ at selected depths stimulated chemoautotrophic activity up to 33-fold. Fluorescence in situ hybridization (FISH) analyses revealed elevated abundances of Crenarchaeota and β-proteobacteria (up to 1.0×107 and 10.0×107 cells L-1, respectively) associated with NH4+ minima and NO3- maxima. Nitrifying β-proteobacteria were most abundant in the upper oxycline (1.1-1.8×107 cells L-1) at three stations and exhibited a secondary peak of 0.3×107 cells L-1 in the lower oxycline at one station. Anammox bacterial (Planctomycetes) abundances were as high as 2.1×106 cells L-1, but accounted for less than 1% of total DAPI counts. The concentration of diploptene (a hopanoid biomarker found in bacteria) varied from 2 to 15 pg L-1 in the upper oxycline and from 51 to 160 pg L-1 in the lower oxycline. Delta 13C values of particulate organic carbon (POC) varied from -30 to -21‰ in the water column (avg. -25‰). Distributions of isotopically light POC coincided with enrichments in diploptene

  17. Minimal Influence of [NiFe] Hydrogenase on Hydrogen Isotope Fractionation in H2-Oxidizing Cupriavidus necator

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    Brian J. Campbell

    2017-10-01

    Full Text Available Fatty acids produced by H2-metabolizing bacteria are sometimes observed to be more D-depleted than those of photoautotrophic organisms, a trait that has been suggested as diagnostic for chemoautotrophic bacteria. The biochemical reasons for such a depletion are not known, but are often assumed to involve the strong D-depletion of H2. Here, we cultivated the bacterium Cupriavidus necator H16 (formerly Ralstonia eutropha H16 under aerobic, H2-consuming, chemoautotrophic conditions and measured the isotopic compositions of its fatty acids. In parallel with the wild type, two mutants of this strain, each lacking one of two key hydrogenase enzymes, were also grown and measured. In all three strains, fractionations between fatty acids and water ranged from -173‰ to -235‰, and averaged -217‰, -196‰, and -226‰, respectively, for the wild type, SH- mutant, and MBH- mutant. There was a modest increase in δD as a result of loss of the soluble hydrogenase enzyme. Fractionation curves for all three strains were constructed by growing parallel cultures in waters with δDwater values of approximately -25‰, 520‰, and 1100‰. These curves indicate that at least 90% of the hydrogen in fatty acids is derived from water, not H2. Published details of the biochemistry of the soluble and membrane-bound hydrogenases confirm that these enzymes transfer electrons rather than intact hydride (H- ions, providing no direct mechanism to connect the isotopic composition of H2 to that of lipids. Multiple lines of evidence thus agree that in this organism, and presumably others like it, environmental H2 plays little or no direct role in controlling lipid δD values. The observed fractionations must instead result from isotope effects in the reduction of NAD(PH by reductases with flavin prosthetic groups, which transfer two electrons and acquire H+ (or D+ from solution. Parallels to NADPH reduction in photosynthesis may explain why D/H fractionations in C. necator

  18. Investigation of Metal Bioavailability and Microbial Metal Utilization in Methane Seep Ecosystems through Integration of Geochemical and Biological Datasets

    Science.gov (United States)

    Glass, J. B.; Gadh, V.; Steele, J. A.; Adkins, J. F.; Orphan, V. J.

    2012-12-01

    Methane hydrate seeps are important sources of greenhouse gases and host unique microbial communities that couple anaerobic oxidation of methane and sulfate reduction. Microbial enzymes that catalyze the reactions driving these anaerobic metabolisms require transition metals such as Fe, Ni, Co, Zn, and Mo as essential cofactors. These metals are expected to be drawn down to low concentrations by precipitation as sulfide phases in the highly sulfidic porewaters at methane seep ecosystems. However, in situ concentrations of biologically-important metals in sulfidic methane seep pore fluids and the relative importance of different metals for anaerobic methanotrophic archaea (ANME) vs. sulfate reducing bacteria (SRB) are unknown. We are integrating geochemical and metagenomic datasets with nano-scale maps of cellular metal distributions to gain insights into metal bioavailability and utilization in methane seep ecosystems. We have measured porewater profiles of dissolved metals (V, Ni, Cu, Co, Fe, Mn, Zn, Mo and W) from three habitat types at Hydrate Ridge, offshore Oregon: Calyptogena clam beds, microbial mats and sites with low methane flux. Highly sulfidic sediment porewaters beneath microbial mats contained the lowest metal concentrations, suggesting that microbes inhabiting these environments may be limited by metal scarcity. Cobalt occurred at particularly low abundances (≤5 nM in all cores and frequently at sub-nanomolar levels). We also analyzed the taxonomic distribution of ABC (ATP-binding cassette) metal transporters in metagenomes from environmentally-enriched consortia of ANME-2 and SRB from Eel River Basin methane seeps. Our findings suggest that both ANME and SRB possess genes encoding ABC transporters with high affinity for Fe, Ni, Co, Zn and Mo. Combined with our geochemical data, these results imply that ANME-SRB consortia in highly sulfidic environments have specialized mechanisms that allow them to acquire metal micronutrients, although it is

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

    Science.gov (United States)

    Li, Chia-Chin; Chung, Hsiao-Ping; Wen, Hsiao-Wei; Chang, Ching-Tu; Wang, Ya-Ting; Chou, Fong-In

    2015-08-01

    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 (60)Co 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 10(5) 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 (60)Co biosorption efficiency of 99.7 ± 0.1% and 98.3 ± 0.2%, respectively in (60)Co aqueous solution (700 Bq/mL), and the (60)Co 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 (60)Co and Co (II) from contaminated aqueous solution, on the other hand, but may have the

  20. Submeter Mapping Of Methane Seeps By ROV Observations And Measurements At The Hikurangi Margin, New Zeeland

    Science.gov (United States)

    Naudts, L.; Greinert, J.; Poort, J.; Belza, J.; Vangampelaere, E.; Boone, D.; Linke, P.; Henriet, J.; de Batist, M.

    2008-12-01

    During R.V. Sonne cruise SO191-3, part of the "New (Zealand Cold) Vents" expedition, RCMG deployed their CHEROKEE ROV "Genesis" on the Hikurangi Margin. This accretionary margin, on the east coast of New Zealand, is related to the subduction of the Pacific Plate under the Australian Plate. Several cold seep locations as well as an extensive BSR, indicating the presence of gas hydrates, have been found at this margin. The aims of the ROV-work were to precisely localize active methane seeps, to conduct detailed visual observations of the seep structures and activity, and to perform measurements of physical properties and collect samples at and around the seep locations. The ROV allowed first ever visual observations of bubble- releasing seeps at the Hikurangi Margin. Seeps were observed at Faure Site and LM-3 in the Rock Garden area, at a flat to moderately undulating sea floor where soft sediments alternate with carbonate platforms. Bubble-releasing activity was very variable in time, with periods of almost non-activity (5 bubbles/second) alternating with periods of violent outbursts (190 bubbles/second). Bubbles sizes ranged from less than 5 mm to more than 20 mm. At Faure Site, bubble release was monitored over a period of 20 minutes, resulting in the observation of 6 outbursts, each lasting 1 minute at a 3 minute interval. These violent outbursts were accompanied by the displacement and resuspension of sediment grains and the formation of small depressions showing what is possibly an initial stage of pockmark formation. At the LM-3 site only some small bubbling seeps were observed near a large carbonate platform covered by Bathymodiolus mussels, Calyptogena shells and tube worms. Sediment-temperature measurements, in both areas, were largely comparable with the bottom-water temperature except at LM-3, at a site densely populated by polychaetes, where anomalous low sediment-temperature was measured. Overall, both seep areas are very confined in space and bottom

  1. La Gazeta de Madrid y la Guerra de Sucesión

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    María Rosa CAL MARTÍNEZ

    2009-11-01

    Full Text Available RESUMEN: El artículo estudia el papel que desempeñó la Gazeta de Madrid durante la Guerra de Sucesión en España, tema inédito. Desde el siglo XVII las Cortes europeas disponían de publicaciones periódicas que amparaban o subvencionaban a cambio de controlar los contenidos y de que en ellas apareciesen todas las noticias que favoreciesen a las diversas Coronas. En España la primera Gazeta a favor de la monarquía surgió también en el siglo XVII fue una concesión del rey Felipe IV a su hijo bastardo Juan José de Austria. Es esta misma Gazeta (tras pasar por diferentes vicisitudes, la que recoge los acontecimientos de 1701 a 1714. Como vamos a comprobar, la publicación silencia las derrotas y los desastres, y magnifica las victorias y los éxitos de las tropas reales; y deja muy claro quiénes eran los amigos del monarca.ABSTRACT: This article studies the role that la Gazeta de Madrid had during the Spanish Succession War, a subject that has not been investigated before. Since the XVII century, European Courts had periodical publications that were supported or funded to control the information. Therefore, these publications only printed news approved by the Spanish Royalty and that favoured the different Crowns. In Spain, this first royalist Gazette in favour of monarchy also began in the XVII century and was a concession of Felipe IV to his bastard son, Juan José de Austria. This is also the Gazette, after different problems were overcome, that published information about the 1701-14 events. As we can see, the gazette remains silent about the defeats and magnifies the triumphs and successes of the royal troops, and gives a clear idea of who were the monarch’s friends.

  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. 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.

  5. Brazilian Atlantic Forest lato sensu: the most ancient Brazilian forest, and a biodiversity hotspot, is highly threatened by climate change

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    AF. Colombo

    Full Text Available After 500 years of exploitation and destruction, the Brazilian Atlantic Forest has been reduced to less the 8% of its original cover, and climate change may pose a new threat to the remnants of this biodiversity hotspot. In this study we used modelling techniques to determine present and future geographical distribution of 38 species of trees that are typical of the Brazilian Atlantic Forest (Mata Atlântica, considering two global warming scenarios. The optimistic scenario, based in a 0.5% increase in the concentration of CO2 in the atmosphere, predicts an increase of up to 2 °C in the Earth's average temperature; in the pessimistic scenario, based on a 1% increase in the concentration of CO2 in the atmosphere, temperature increase may reach 4 °C. Using these parameters, the occurrence points of the studied species registered in literature, the Genetic Algorithm for Rule-set Predictions/GARP and Maximum entropy modeling of species geographic distributions/MaxEnt we developed models of present and future possible occurrence of each species, considering Earth's mean temperature by 2050 with the optimistic and the pessimistic scenarios of CO2 emission. The results obtained show an alarming reduction in the area of possible occurrence of the species studied, as well as a shift towards southern areas of Brazil. Using GARP, on average, in the optimistic scenario this reduction is of 25% while in the pessimistic scenario it reaches 50%, and the species that will suffer the worst reduction in their possible area of occurrence are: Euterpe edulis, Mollinedia schottiana, Virola bicuhyba, Inga sessilis and Vochysia magnifica. Using MaxEnt, on average, in the optimistic scenario the reduction will be of 20% while in the pessimistic scenario it reaches 30%, and the species that will suffer the worst reduction are: Hyeronima alchorneoides, Schefflera angustissima, Andira fraxinifolia and the species of Myrtaceae studied.

  6. Brazilian Atlantic Forest lato sensu: the most ancient Brazilian forest, and a biodiversity hotspot, is highly threatened by climate change.

    Science.gov (United States)

    Colombo, A F; Joly, C A

    2010-10-01

    After 500 years of exploitation and destruction, the Brazilian Atlantic Forest has been reduced to less the 8% of its original cover, and climate change may pose a new threat to the remnants of this biodiversity hotspot. In this study we used modelling techniques to determine present and future geographical distribution of 38 species of trees that are typical of the Brazilian Atlantic Forest (Mata Atlântica), considering two global warming scenarios. The optimistic scenario, based in a 0.5% increase in the concentration of CO2 in the atmosphere, predicts an increase of up to 2 °C in the Earth's average temperature; in the pessimistic scenario, based on a 1% increase in the concentration of CO2 in the atmosphere, temperature increase may reach 4 °C. Using these parameters, the occurrence points of the studied species registered in literature, the Genetic Algorithm for Rule-set Predictions/GARP and Maximum entropy modeling of species geographic distributions/MaxEnt we developed models of present and future possible occurrence of each species, considering Earth's mean temperature by 2050 with the optimistic and the pessimistic scenarios of CO2 emission. The results obtained show an alarming reduction in the area of possible occurrence of the species studied, as well as a shift towards southern areas of Brazil. Using GARP, on average, in the optimistic scenario this reduction is of 25% while in the pessimistic scenario it reaches 50%, and the species that will suffer the worst reduction in their possible area of occurrence are: Euterpe edulis, Mollinedia schottiana, Virola bicuhyba, Inga sessilis and Vochysia magnifica. Using MaxEnt, on average, in the optimistic scenario the reduction will be of 20% while in the pessimistic scenario it reaches 30%, and the species that will suffer the worst reduction are: Hyeronima alchorneoides, Schefflera angustissima, Andira fraxinifolia and the species of Myrtaceae studied.

  7. 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

    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.

  8. Análise do número de foraminas apicais nas raízes mésio-vestibulares dos primeiros molares superiores

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    Gabriela Mignoni

    2015-11-01

    Full Text Available O conhecimento da morfologia radicular interna tem sido um assunto complexo e extremamente importante, considerando o planejamento e execução da terapia endodôntica. As inúmeras variações anatômicas que existem no sistema de canais radiculares contribuem para as falhas de tratamentos. O forame fisiológico e a constrição apical são considerados o término da preparo do canal radicular. O propósito desta pesquisa foi investigar em raízes mésio-vestibulares dos primeiros molares superiores o número de foraminas apicais e o diâmetro médio da foramina maior. Foram analisados 78 primeiros molares superiores humanos permanentes extraídos, tingidos com azul de metileno na porção apical. Após o preparo das amostras, os dentes foram submetidos à análise apical em um microscópio clínico operatório com magnificação de 40X. Os resultados obtidos em relação ao número de foraminas observadas foram: ausência de foraminas 2,6%, uma foramina 26,9%, duas foraminas 34,6%, três foraminas 21,8%, quatro foraminas 11,5% e cinco foraminas 2,6%, sendo que o diâmetro médio da foramina maior foi de 0,34 mm. A incidência de três ou mais foraminas e o diâmetro médio da foramina maior alerta para a complexidade anatômica e a necessidade de se encontrar meios adequados para a limpeza do sistema de canais radiculares.

  9. Retricciones del canal de comunicación efectos psicosociales en entornos educativos

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    Jorge Ricardo Vivas

    Full Text Available Uno de los fenómenos más notables en el campo de la educación y la capacitación ha sido el creciente interés por el aprendizaje abierto y a distancia mediado por nuevas tecnologías. Si bien resulta innegable una ganancia en cuanto a la accesibilidad de los actores al liberarlos de las limitaciones de tiempo y espacio en la interacción electrónicamente mediada, no resultan tan bien conocidas las consecuencias emergentes de las restricciones en la presencia social. En este trabajo se sugiere que como producto de propiedades intrínsecas del medio de comunicación queda afectado el acceso y distribución de la participación de los actores. Se reportan los resultados de una observación de grupos de alumnos trabajando en forma presencial y mediada por computadora en una tarea de toma de decisión denominada Moon Survival. Utilizando análisis de redes sociales se pudo establecer diferencias significativas en el nivel de actividad, la participación y la cohesión de las redes de comunicación para cada medio. La distribución de la participación de los agentes en comunicación mediada por computadora pone de manifiesto que este medio replica y magnifica las desigualdades en la utilización del recurso por parte de los diferentes actores implicados en la tarea.

  10. 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.

  11. Estudo epidemiológico do tracoma em comunidade da Chapada do Araripe - Pernambuco - Brasil

    Directory of Open Access Journals (Sweden)

    Lucena Abrahão da Rocha

    2004-01-01

    Full Text Available OBJETIVOS: Fazer estudo epidemiológico do tracoma no povoado de Serrolândia, município de Ipubi, na chapada do Araripe, sertão de Pernambuco, região historicamente conhecida como bolsão. MÉTODOS: Em outubro e novembro de 2002 foi realizado trabalho de campo prospectivo, no qual se examinaram 1.239 indivíduos. A idade dos indivíduos variou de 1 a 93 anos (média de 25,3 anos. O exame foi realizado com lupa binocular de 2,5 vezes de magnificação e obedeceu-se a classificação clínica de tracoma preconizada pela OMS. RESULTADOS: O tracoma foi diagnosticado clinicamente em 250 (20,5% indivíduos, com predileção pelo sexo masculino. A média de idade dos indivíduos com tracoma folicular (TF foi 13 anos e com tracoma cicatricial (TS 49 anos. Observaram-se as seguintes gradações do tracoma: 107 (8,6% casos de TF, 2 (0,2% de TI (tracoma inflamatório, 139 (11,2% de TS, 1 (0,1% de TT (triquíase tracomatosa e nenhum caso de CO (opacificação corneana. CONCLUSÕES: Pode-se considerar que o tracoma na comunidade de Serrolândia, Ipubi-PE, apresenta baixa endemicidade (8,8% TF / TI, apesar de localizar-se em região de baixo nível socio-econômico da chapada do Araripe, conhecida como bolsão de tracoma. Não é, portanto, um grave problema de saúde pública nessa comunidade.

  12. Contribuição ao estudo anatômico da inervação sensitiva do punho

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    Edie Benedito Caetano

    2009-11-01

    Full Text Available Objetivo: descrever a inervação sensitiva do punho cujo conhecimento é de fundamental importância para a exploração cirúrgica da região. Métodos: foi realizada dissecação macroscópica de 15 membros superiores de cadáveres no Laboratório de Anatomia da Faculdade de Medicina da PUC-SP utilizando lupa cirúrgica (2,5 x 340 mm como meio de magnificação. Resultados: as dissecações realizadas mostraram que os seguintes nervos contribuem para a inervação sensitiva do punho: nervos interósseo anterior e cutâneo palmar (ramos do nervo mediano, ramo cutâneo dorsal do nervo ulnar, ramo superficial do nervo radial e nervo interósseo posterior (originados do nervo radial. Não registramos a inervação do punho pelos nervos cutâneo medial (ramo do nervo ulnar e cutâneo lateral do antebraço (ramo do nervo musculocutâneo. Conclusões: os nervos interósseo posterior e interósseo anterior são os principais responsáveis pela inervação da articulação do punho. Os nervos ramo superficial do nervo radial, ramo cutâneo dorsal do nervo ulnar também contribuem com frequência para inervar a articulação do punho. O ramo profundo do nervo ulnar e o nervo mediano contribuem, porém de maneira pouco frequente e inconstante para a inervação dessa articulação.

  13. Onset of the aerobic nitrogen cycle during the Great Oxidation Event.

    Science.gov (United States)

    Zerkle, Aubrey L; Poulton, Simon W; Newton, Robert J; Mettam, Colin; Claire, Mark W; Bekker, Andrey; Junium, Christopher K

    2017-02-23

    The rise of oxygen on the early Earth (about 2.4 billion years ago) caused a reorganization of marine nutrient cycles, including that of nitrogen, which is important for controlling global primary productivity. However, current geochemical records lack the temporal resolution to address the nature and timing of the biogeochemical response to oxygenation directly. Here we couple records of ocean redox chemistry with nitrogen isotope (15N/14N) values from approximately 2.31-billion-year-old shales of the Rooihoogte and Timeball Hill formations in South Africa, deposited during the early stages of the first rise in atmospheric oxygen on the Earth (the Great Oxidation Event). Our data fill a gap of about 400 million years in the temporal 15N/14N record and provide evidence for the emergence of a pervasive aerobic marine nitrogen cycle. The interpretation of our nitrogen isotope data in the context of iron speciation and carbon isotope data suggests biogeochemical cycling across a dynamic redox boundary, with primary productivity fuelled by chemoautotrophic production and a nitrogen cycle dominated by nitrogen loss processes using newly available marine oxidants. This chemostratigraphic trend constrains the onset of widespread nitrate availability associated with ocean oxygenation. The rise of marine nitrate could have allowed for the rapid diversification and proliferation of nitrate-using cyanobacteria and, potentially, eukaryotic phytoplankton.

  14. 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.

  15. Onset of the aerobic nitrogen cycle during the Great Oxidation Event

    Science.gov (United States)

    Zerkle, Aubrey L.; Poulton, Simon W.; Newton, Robert J.; Mettam, Colin; Claire, Mark W.; Bekker, Andrey; Junium, Christopher K.

    2017-02-01

    The rise of oxygen on the early Earth (about 2.4 billion years ago) caused a reorganization of marine nutrient cycles, including that of nitrogen, which is important for controlling global primary productivity. However, current geochemical records lack the temporal resolution to address the nature and timing of the biogeochemical response to oxygenation directly. Here we couple records of ocean redox chemistry with nitrogen isotope (15N/14N) values from approximately 2.31-billion-year-old shales of the Rooihoogte and Timeball Hill formations in South Africa, deposited during the early stages of the first rise in atmospheric oxygen on the Earth (the Great Oxidation Event). Our data fill a gap of about 400 million years in the temporal 15N/14N record and provide evidence for the emergence of a pervasive aerobic marine nitrogen cycle. The interpretation of our nitrogen isotope data in the context of iron speciation and carbon isotope data suggests biogeochemical cycling across a dynamic redox boundary, with primary productivity fuelled by chemoautotrophic production and a nitrogen cycle dominated by nitrogen loss processes using newly available marine oxidants. This chemostratigraphic trend constrains the onset of widespread nitrate availability associated with ocean oxygenation. The rise of marine nitrate could have allowed for the rapid diversification and proliferation of nitrate-using cyanobacteria and, potentially, eukaryotic phytoplankton.

  16. Heterotrophic bicarbonate assimilation is the main process of de novo organic carbon synthesis in hadal zone of the Hellenic Trench, the deepest part of Mediterranean Sea.

    Science.gov (United States)

    Yakimov, Michail M; La Cono, Violetta; Smedile, Francesco; Crisafi, Francesca; Arcadi, Erika; Leonardi, Marcella; Decembrini, Franco; Catalfamo, Maurizio; Bargiela, Rafael; Ferrer, Manuel; Golyshin, Peter N; Giuliano, Laura

    2014-12-01

    Ammonium-oxidizing chemoautotrophic members of Thaumarchaea are proposed to be the key players in the assimilation of bicarbonate in the dark (ABD). However, this process may also involve heterotrophic metabolic pathways, such as fixation of carbon dioxide (CO2) via various anaplerotic reactions. We collected samples from the depth of 4900 m at the Matapan-Vavilov Deep (MVD) station (Hellenic Trench, Eastern Mediterranean) and used the multiphasic approach to study the ABD mediators in this deep-sea ecosystem. At this depth, our analysis indicated the occurrence of actively CO2-fixing heterotrophic microbial assemblages dominated by Gammaproteobacteria with virtually no Thaumarchaea present. [14C]-bicarbonate incorporation experiments combined with shotgun [14C]-proteomic analysis identified a series of proteins of gammaproteobacterial origin. More than quarter of them were closely related with Alteromonas macleodii ‘deep ecotype’ AltDE, the predominant organism in the microbial community of MVD. The present study demonstrated that in the aphotic/hadal zone of the Mediterranean Sea, the assimilation of bicarbonate is associated with both chemolithoauto- and heterotrophic ABD. In some deep-sea areas, the latter may predominantly contribute to the de novo synthesis of organic carbon which points at the important and yet underestimated role heterotrophic bacterial populations can play the in global carbon cycle/sink in the ocean interior.

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

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    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.

  18. 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.

  19. Acquisition of epibiotic bacteria along the life cycle of the hydrothermal shrimp Rimicaris exoculata.

    Science.gov (United States)

    Guri, Mathieu; Durand, Lucile; Cueff-Gauchard, Valérie; Zbinden, Magali; Crassous, Philippe; Shillito, Bruce; Cambon-Bonavita, Marie-Anne

    2012-03-01

    The caridean shrimp Rimicaris exoculata dominates the fauna at several Mid-Atlantic Ridge hydrothermal vent sites. This shrimp has an enlarged gill chamber, harboring a dense ectosymbiotic community of chemoautotrophic bacteria associated with mineral oxide deposits. Until now, their acquisition is not fully understood. At three hydrothermal vent sites, we analyzed the epibionts diversity at different moult stages and also in the first stages of the shrimp life (eggs, hatched eggs (with larvae) and juveniles). Hatched eggs associated with young larvae were collected for the first time directly from gravid females at the Logachev vent site during the Serpentine cruise. An approach using 16S rRNA clone libraries, scanning and transmission electron microscopy, and fluorescent in situ hybridization was used. Molecular results and microscope observations indicated a switch in the composition of the bacterial community between early R. exoculata life cycle stage (egg libraries dominated by the Gammaproteobacteria) and later stages (juvenile/adult libraries dominated by the Epsilonproteobacteria). We hypothesized that the epibiotic phylotype composition could vary according to the life stage of the shrimp. Our results confirmed the occurrence of a symbiosis with Gammaproteobacteria and Epsilonproteobacteria, but more complex than previously assumed. We revealed the presence of active type-I methanotrophic bacteria colonizing the cephalothorax of shrimps from the Rainbow site. They were also present on the eggs from the Logachev site. This could be the first 'epibiotic' association between methanotrophic bacteria and hydrothermal vent crustacean. We discuss possible transmission pathways for epibionts linked to the shrimp life cycle.

  20. The origin of life and its methodological challenge.

    Science.gov (United States)

    Wächtershäuser, G

    1997-08-21

    The problem of the origin of life is discussed from a methodological point of view as an encounter between the teleological thinking of the historian and the mechanistic thinking of the chemist; and as the Kantian task of replacing teleology by mechanism. It is shown how the Popperian situational logic of historic understanding and the Popperian principle of explanatory power of scientific theories, when jointly applied to biochemistry, lead to a methodology of biochemical retrodiction, whereby common precursor functions are constructed for disparate successor functions. This methodology is exemplified by central tenets of the theory of the chemo-autotrophic origin of life: the proposal of a surface metabolism with a two-dimensional order; the basic polarity of life with negatively charged constituents on positively charged mineral surfaces; the surface-metabolic origin of phosphorylated sugar metabolism and nucleic acids; the origin of membrane lipids and of chemi-osmosis on pyrite surfaces; and the principles of the origin of the genetic machinery. The theory presents the early evolution of life as a process that begins with chemical necessity and winds up in genetic chance.

  1. The stepwise evolution of early life driven by energy conservation.

    Science.gov (United States)

    Ferry, James G; House, Christopher H

    2006-06-01

    Two main theories have emerged for the origin and early evolution of life based on heterotrophic versus chemoautotrophic metabolisms. With the exception of a role for CO, the theories have little common ground. Here we propose an alternative theory for the early evolution of the cell which combines principal features of the widely disparate theories. The theory is based on the extant pathway for conversion of CO to methane and acetate, largely deduced from the genomic analysis of the archaeon Methanosarcina acetivorans. In contrast to current paradigms, we propose that an energy-conservation pathway was the major force which powered and directed the early evolution of the cell. We envision the proposed primitive energy-conservation pathway to have developed sometime after a period of chemical evolution but prior to the establishment of diverse protein-based anaerobic metabolisms. We further propose that energy conservation played the predominant role in the later evolution of anaerobic metabolisms which explains the origin and evolution of extant methanogenic pathways.

  2. Measurement of organic carbon quantity at chemoautorophic bacterium; Kagaku dokuritsu eiyo saikin ni okeru yuki tansoryo no sokutei ni tsuite

    Energy Technology Data Exchange (ETDEWEB)

    Tsuda, I.; Kato, K.; Nozaki, K. [Electrotechnical Laboratory, Tsukuba (Japan); Kurokawa, K. [Tokyo University of Agriculture and Technology, Tokyo (Japan)

    1996-10-27

    Described herein is the method for analyzing quantity of organic carbon synthesized by chemoautotrophic bacterium. It is based on the combustion-infrared spectroscopy, which is normally adopted for quantitative analysis of organic carbon. The problems involved in the measurement of organic compounds synthesized by iron-oxidizing bacteria are noise by culture medium components, aging of gas analyzer and contamination with organic compounds from a silicon plug. The measures taken in this study against these problems include comparison of the results with a medium containing iron-oxidizing bacteria with those with a medium free of these bacteria, calibration with the standard solution for each measurement, and replacement of a silicone plug by a silicon cap. Organic carbon is measured by a TOC-5000 analyzer equipped with an automatic sample feeder ASI-5000. Biomass density is determined by the MPN method. It is confirmed that organic carbon quantity is almost in proportion to biomass density, a phenomenon which can be used to determine organic carbon quantity. 7 refs., 6 figs., 1 tab.

  3. 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.

  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

    2008-11-01

    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, CO(2) 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% CH(4)) 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.

  5. Dynamics of bacterial communities in rice field soils as affected by different long-term fertilization practices.

    Science.gov (United States)

    Ahn, Jae-Hyung; Lee, Shin Ae; Kim, Jeong Myeong; Kim, Myung-Sook; Song, Jaekyeong; Weon, Hang-Yeon

    2016-11-01

    Fertilization and the response of the soil microbial community to the process significantly affect crop yield and the environment. In this study, the seasonal variation in the bacterial communities in rice field soil subjected to different fertilization treatments for more than 50 years was investigated using 16S rRNA sequencing. The simultaneous application of inorganic fertilizers and rice straw compost (CAPK) maintained the species richness of the bacterial communities at levels higher than that in the case of non-fertilization (NF) and application of inorganic fertilizers only (APK) in the initial period of rice growth. The seasonal variation in the bacterial community structure in the NF and APK plots showed cyclic behavior, suggesting that the effect of season was important; however, no such trend was observed in the CAPK plot. In the CAPK plot, the relative abundances of putative copiotrophs such as Bacteroidetes, Firmicutes, and Proteobacteria were higher and those of putative oligotrophs such as Acidobacteria and Plactomycetes were lower than those in the other plots. The relative abundances of organotrophs with respiratory metabolism, such as Actinobacteria, were lower and those of chemoautotrophs that oxidize reduced iron and sulfur compounds were higher in the CAPK plot, suggesting greater carbon storage in this plot. Increased methane emission and nitrogen deficiency, which were inferred from the higher abundances of Methylocystis and Bradyrhizobium in the CAPK plot, may be a negative effect of rice straw application; thus, a solution for these should be considered to increase the use of renewable resources in agricultural lands.

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

    Science.gov (United States)

    Corbari, L.; Cambon-Bonavita, M.-A.; Long, G. J.; Grandjean, F.; Zbinden, M.; Gaill, F.; Compère, P.

    2008-04-01

    The Rimicaris exoculata shrimp is considered 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 minerals associated with these bacteria have been investigated by using X-ray microanalyses, light microscopy, and transmission, environmental scanning and scanning transmission electron microscopy. The nature of the iron oxides in shrimps obtained from the Rainbow vent field at 36°14.0' N, has also been determined by Mössbauer spectroscopy. This multidisciplinary approach has revealed that the three step-levels of mineral crust found in the Rimicaris exoculata shrimps consist of heavy concretions formed by nanoparticles of two-line ferrihydrite intermixed with minor inorganic SiO2, (Ca,Mg)SO4, and (Ca,Mg)3(PO4)2 minerals that may stabilise the ferrihydrite form of iron oxides. Morphological observations on the bacteria have revealed their close interactions with these minerals and, thus, indicate the biogenic origin of the iron oxide deposits. The evolution of the bacterial density in the three mineral crust levels is related to the amount of the iron deposits and it is proposed that the lower crust level is the most likely region for the location of the iron-oxidizing bacteria.

  7. Panspermia-Nature's Exercise in Microbial Cultivation on a Vast Scale

    Science.gov (United States)

    Wainwright, Milton; Aharbi, Sulamain; Alabri, Khalid

    2011-10-01

    Although the idea that life on Earth originated from space has a long history, the modern version of the theory was developed by Hoyle and Wickramasinghe as their cometary theory of panspermia. This theory is discussed here from a microbiologist's point of view, i.e. the prebiotic Earth is seen as a vast culture vessel containing both Earth and space-derived nutrients. This vast culture medium was then, we suggest, naturally inoculated by microbes from space. Life may have arrived as a single organism, but more likely it did so in the form of a mixed "inoculum". Once established in the Earth's culture medium the incoming organisms would have replicated rapidly to from a huge biomass made up of a "mixed culture" of microorganisms representing all of the major metabolic strategies, such as heterotrophs (including oligotrophs), chemoautotrophs and phototrophs. The dominant organisms would arise sequentially depending upon the prevailing physical conditions and to the existence of inter-microbe competition. The incoming mixed inoculum is considered to have originated form comets which, as suggested by Hoyle and Wickramasinghe, provide vast incubators, collectors and deliverers of this inoculum to Earth and the wider cosmos.

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

    Directory of Open Access Journals (Sweden)

    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.

  9. Fungi associated with chimney and sulfide samples from a South Mid-Atlantic Ridge hydrothermal site: Distribution, diversity and abundance

    Science.gov (United States)

    Xu, Wei; Guo, Shuangshuang; Pang, Ka-Lai; Luo, Zhu-Hua

    2017-05-01

    Deep-sea hydrothermal vent ecosystems are known to support remarkably diverse microbial communities, ranging from chemoautotrophic prokaryotes to heterotrophic prokaryotes and microeukaryotes. While fungi have generally been identified as an important component of various microbial communities in the environment, little is known about the species richness and abundance of such microorganisms in deep-sea hydrothermal vent ecosystems. In this study, a combined culture-dependent and culture-independent sequence-based approach was used to investigate fungal distribution and diversity at a deep-sea hydrothermal vent site located at the Mid-Atlantic Ridge of the South Atlantic Ocean. Sequence analyses showed that the fungal community was dominated by members of the Ascomycota and the Basidiomycota. Several new phylotypes (28 of 65 total fungal OTUs and 2 of 19 culturable fungal phylotypes) were identified, contributing to the literally unknown diversity of fungi in this understudied habitat. The fungal community structures in the chimney samples were distinct from those in three sulfide samples. The qPCR results revealed that fungal LSU rRNA gene copy numbers ranged from 5.88×105 to 6.77×106 copies/gram rock (wet weight), and the Ascomycota was significantly more abundant 2-3 orders) than the Basidiomycota. Our findings provide new insights into the diversity and abundance of fungi in deep-sea hydrothermal vent ecosystems, which increases our knowledge and understanding of the fungal diversity in deep-sea environments.

  10. Cold-seep ostracods from the western Svalbard margin: direct palaeo-indicator for methane seepage?

    Science.gov (United States)

    Yasuhara, Moriaki; Sztybor, Kamila; Rasmussen, Tine L.; Okahashi, Hisayo; Sato, Runa; Tanaka, Hayato

    2018-01-01

    Despite their high abundance and diversity, microfossil taxa adapted to a particular chemosynthetic environment have rarely been studied and are therefore poorly known. Here we report on an ostracod species, Rosaliella svalbardensis gen. et sp. nov., from a cold methane seep site at the western Svalbard margin, Fram Strait. The new species shows a distinct morphology, different from other eucytherurine ostracod genera. It has a marked similarity to Xylocythere, an ostracod genus known from chemosynthetic environments of wood falls and hydrothermal vents. Rosaliella svalbardensis is probably an endemic species or genus linked to methane seeps. We speculate that the surface ornamentation of pore clusters, secondary reticulation, and pit clusters may be related to ectosymbiosis with chemoautotrophic bacteria. This new discovery of specialized microfossil taxa is important because they can be used as an indicator species for past and present seep environments (http://zoobank.org/urn:lsid:zoobank.org:pub:6075FF30-29D5-4DAB-9141-AE722CD3A69B" target="_blank">http://zoobank.org/urn:lsid:zoobank.org:pub:6075FF30-29D5-4DAB-9141-AE722CD3A69B).

  11. Beyond the vent: New perspectives on hydrothermal plumes and pelagic biology

    Science.gov (United States)

    Phillips, Brennan T.

    2017-03-01

    Submarine hydrothermal vent fields introduce buoyant plumes of chemically altered seawater to the deep-sea water column. Chemoautotrophic microbes exploit this energy source, facilitating seafloor-based primary production that evidence suggests may transfer to pelagic consumers. While most hydrothermal plumes have relatively small volumes, there are recent examples of large-scale plume events associated with periods of eruptive activity, which have had a pronounced effect on water-column biology. This correlation suggests that hydrothermal plumes may have influenced basin-scale ocean chemistry during periods of increased submarine volcanism during the Phanerozoic eon. This paper synthesizes a growing body of scientific evidence supporting the hypothesis that hydrothermal plumes are the energetic basis of unique deep-sea pelagic food webs. While many important questions remain concerning the biology of hydrothermal plumes, this discussion is not present in ongoing management efforts related to seafloor massive sulfide (SMS) mining. Increased research efforts, focused on high-resolution surveys of midwater biology relative to plume structures, are recommended to establish baseline conditions and monitor the impact of future mining-based disturbances to the pelagic biosphere.

  12. Organic matter along longitudinal and vertical gradients in the Black Sea

    Science.gov (United States)

    Kaiser, David; Konovalov, Sergey; Schulz-Bull, Detlef E.; Waniek, Joanna J.

    2017-11-01

    We studied organic matter in the central Black Sea and its northeastern and northwestern shelf break within three weeks in November 2013 to test the hypothesis that in situ production could explain lateral and vertical variability in its composition and distribution. The wide spatial coverage over a short period of time achieved during this study revealed longitudinal variability in organic matter characteristics reflecting productivity at the Black Sea surface. Particulate organic matter was dominantly autochthonous in the central Black Sea. Allochthonous influence of river discharge was only traced on the northwestern shelf by high concentrations but low freshness of particulate organic matter. Compared to the NW shelf break and central Black Sea, primary production was high near the NE shelf break, likely fueled by input from the Azov Sea. Vertical patterns were similar throughout the deep Black Sea and appeared to also be governed by in situ processes rather than reflect variability in the surface water. As concentrations of organic matter decreased with depth, its elemental and isotopic composition indicated chemoautotrophic production at the oxic-anoxic interface and organic matter degradation in the benthic boundary layer. Though profiles of dissolved organic carbon indicated a minor source in anoxic deep water, likely linked to chemosynthesis and reflux from sediments, a negative deviation of concentrations from a conservative mixing line between two endmembers suggested net removal of labile dissolved organic carbon.

  13. Electrochemically active microorganisms from an acid mine drainage-affected site promote cathode oxidation in microbial fuel cells.

    Science.gov (United States)

    Rojas, Claudia; Vargas, Ignacio T; Bruns, Mary Ann; Regan, John M

    2017-12-01

    The limited database of acidophilic or acidotolerant electrochemically active microorganisms prevents advancements on microbial fuel cells (MFCs) operated under low pH. In this study, three MFCs were used to enrich cathodic biofilms using acid mine drainage (AMD) sediments as inoculum. Linear sweep voltammetry showed cathodic current plateaus of 5.5 (±0.7) mA at about -170mV vs Ag/AgCl and 8.5 (±0.9) mA between -500mV to -450mV vs Ag/AgCl for biofilms developed on small graphite fiber brushes. After gamma irradiation, biocathodes exhibited a decrease in current density approaching that of abiotic controls. Electrochemical impedance spectroscopy showed six-fold lower charge transfer resistance with viable biofilm. Pyrosequencing data showed that Proteobacteria and Firmicutes dominated the biofilms. Acidithiobacillus representatives were enriched in some biocathodes, supporting the potential importance of these known iron and sulfur oxidizers as cathodic biocatalysts. Other acidophilic chemolithoautotrophs identified included Sulfobacillus and Leptospirillum species. The presence of chemoautotrophs was consistent with functional capabilities predicted by PICRUSt related to carbon fixation pathways in prokaryotic microorganisms. Acidophilic or acidotolerant heterotrophs were also abundant; however, their contribution to cathodic performance is unknown. This study directs subsequent research efforts to particular groups of AMD-associated bacteria that are electrochemically active on cathodes. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Carbon isotopes in biological carbonates: Respiration and photosynthesis

    Science.gov (United States)

    McConnaughey, Ted A.; Burdett, Jim; Whelan, Joseph F.; Paull, Charles K.

    1997-02-01

    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 CO 2/O 2 ratios appear to be the major controlling variable. Atmospheric CO 2/O 2 ratios are about thirty times lower than in most natural waters, hence air breathing animals absorb less environmental CO 2 in the course of obtaining 0 2. Tissue CO 2 therefore, does not isotopically equilibrate with environmental CO 2 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 CO 2 in their tissues. Photosynthetic corals calcify mainly during the daytime when photosynthetic CO 2 uptake is several times faster than respiratory CO 2 release. Photosynthesis, therefore, affects skeletal δ13C 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.

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

    Directory of Open Access Journals (Sweden)

    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.

  16. 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

  17. Comparison of the effect of salinity on the D/H ratio of fatty acids of heterotrophic and photoautotrophic microorganisms.

    Science.gov (United States)

    Heinzelmann, Sandra M; Chivall, David; M'Boule, Daniela; Sinke-Schoen, Danielle; Villanueva, Laura; Damsté, Jaap S Sinninghe; Schouten, Stefan; van der Meer, Marcel T J

    2015-05-01

    The core metabolism of microorganisms has a major influence on the hydrogen isotopic composition of their fatty acids. Heterotrophic microorganisms produce fatty acids with a deuterium to hydrogen (D/H) ratio either slightly depleted or enriched in D compared to the growth water, while photo- and chemoautotrophic microorganisms produce fatty acids which are heavily depleted in D. However, besides metabolism other biochemical and environmental factors (i.e. biosynthetic pathways, growth phase and temperature) have been shown to affect the D/H ratio of fatty acids, and it is necessary to evaluate the magnitude of these effects compared to that of metabolism. Here, we show that the effect of salinity on the D/H ratio of fatty acids depends on the core metabolism of the microorganism. While fatty acids of the photoautotroph Isochrysis galbana become more enriched in D with increasing salinity (enrichment of 30-40‰ over a range of 25 salinity units), no effect of salinity on the D/H ratio of fatty acids of the heterotrophic Pseudomonas str. LFY10 was observed ((ε)lipid/water of the C16:0 fatty acid of ~120‰ over a range of 10 salinity units). This can likely be explained by the relative contributions of different H and nicotinamide adenine dinucleotide phosphate sources during fatty acid biosynthesis. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  18. Not Just a Poison: Microbes That Derive Energy From Arsenic and Their Linkages to the C, N, and S Cycles.

    Science.gov (United States)

    Falkowski, P. G.; Follows, M.; Fennel, K.; Oremland, R. S.

    2003-12-01

    Elements that are abundant in the Earth's crust and the microbes that derive energy from them have been the focus of much research in geomicrobiology. However, some trace elements also have significant biogeochemical cycles that are mediated by microorganisms, but the wider implications of these phenomena have generally been overlooked. This has been the case for arsenic. Arsenic is a toxicant owing to its action as an analog of its Group VB neighbor phosphorous. However, a surprising finding was that a wide diversity of anaerobic prokaryotes gain energy for growth by using arsenate as their electron acceptor, and that they are broadly distributed in nature. They carry out the dissimilatory reduction of arsenate to arsenite while oxidizing organic matter (or hydrogen). Since the electrochemical potential of the arsenate/arsenite couple is 60 mV, it acts as an oxidant of more reduced species like sulfide (- 220 mV). Some arsenate respirers oxidize sulfide, and in doing so fix CO2 into cellular material. Arsenite can be oxidized back to arsenate by aerobic chemoautotrophic microorganisms, or by anaerobes that use nitrate (440 mv). In addition, heterotrophic arsenate-respirers can carry out the reverse reaction, especially in arsenic rich environments like Mono Lake. The possible evolutionary significance of these phenomena and speculation about their occurrence elsewhere in the Solar System will be discussed.

  19. Automatic content-based analysis of georeferenced image data: Detection of Beggiatoa mats in seafloor video mosaics from the HÅkon Mosby Mud Volcano

    Science.gov (United States)

    Jerosch, K.; Lüdtke, A.; Schlüter, M.; Ioannidis, G. T.

    2007-02-01

    The combination of new underwater technology as remotely operating vehicles (ROVs), high-resolution video imagery, and software to compute georeferenced mosaics of the seafloor provides new opportunities for marine geological or biological studies and applications in offshore industry. Even during single surveys by ROVs or towed systems large amounts of images are compiled. While these underwater techniques are now well-engineered, there is still a lack of methods for the automatic analysis of the acquired image data. During ROV dives more than 4200 georeferenced video mosaics were compiled for the HÅkon Mosby Mud Volcano (HMMV). Mud volcanoes as HMMV are considered as significant source locations for methane characterised by unique chemoautotrophic communities as Beggiatoa mats. For the detection and quantification of the spatial distribution of Beggiatoa mats an automated image analysis technique was developed, which applies watershed transformation and relaxation-based labelling of pre-segmented regions. Comparison of the data derived by visual inspection of 2840 video images with the automated image analysis revealed similarities with a precision better than 90%. We consider this as a step towards a time-efficient and accurate analysis of seafloor images for computation of geochemical budgets and identification of habitats at the seafloor.

  20. 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.

  1. Microbial diversity in nonsulfur, sulfur and iron geothermal steam vents.

    Science.gov (United States)

    Benson, Courtney A; Bizzoco, Richard W; Lipson, David A; Kelley, Scott T

    2011-04-01

    Fumaroles, commonly called steam vents, are ubiquitous features of geothermal habitats. Recent studies have discovered microorganisms in condensed fumarole steam, but fumarole deposits have proven refractory to DNA isolation. In this study, we report the development of novel DNA isolation approaches for fumarole deposit microbial community analysis. Deposit samples were collected from steam vents and caves in Hawaii Volcanoes National Park, Yellowstone National Park and Lassen Volcanic National Park. Samples were analyzed by X-ray microanalysis and classified as nonsulfur, sulfur or iron-dominated steam deposits. We experienced considerable difficulty in obtaining high-yield, high-quality DNA for cloning: only half of all the samples ultimately yielded sequences. Analysis of archaeal 16S rRNA gene sequences showed that sulfur steam deposits were dominated by Sulfolobus and Acidianus, while nonsulfur deposits contained mainly unknown Crenarchaeota. Several of these novel Crenarchaeota lineages were related to chemoautotrophic ammonia oxidizers, indicating that fumaroles represent a putative habitat for ammonia-oxidizing Archaea. We also generated archaeal and bacterial enrichment cultures from the majority of the deposits and isolated members of the Sulfolobales. Our results provide the first evidence of Archaea in geothermal steam deposits and show that fumaroles harbor diverse and novel microbial lineages. © 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  2. Linking hydrothermal geochemistry to organismal physiology: physiological versatility in Riftia pachyptila from sedimented and basalt-hosted vents.

    Directory of Open Access Journals (Sweden)

    Julie C Robidart

    Full Text Available Much of what is known regarding Riftia pachyptila physiology is based on the wealth of studies of tubeworms living at diffuse flows along the fast-spreading, basalt-hosted East Pacific Rise (EPR. These studies have collectively suggested that Riftia pachyptila and its chemoautotrophic symbionts are physiologically specialized, highly productive associations relying on hydrogen sulfide and oxygen to generate energy for carbon fixation, and the symbiont's nitrate reduction to ammonia for energy and biosynthesis. However, Riftia also flourish in sediment-hosted vents, which are markedly different in geochemistry than basalt-hosted systems. Here we present data from shipboard physiological studies and global quantitative proteomic analyses of Riftia pachyptila trophosome tissue recovered from tubeworms residing in the EPR and the Guaymas basin, a sedimented, hydrothermal vent field. We observed marked differences in symbiont nitrogen metabolism in both the respirometric and proteomic data. The proteomic data further suggest that Riftia associations in Guaymas may utilize different sulfur compounds for energy generation, may have an increased capacity for energy storage, and may play a role in degrading exogenous organic carbon. Together these data reveal that Riftia symbionts are far more physiologically plastic than previously considered, and that--contrary to previous assertions--Riftia do assimilate reduced nitrogen in some habitats. These observations raise new hypotheses regarding adaptations to the geochemical diversity of habitats occupied by Riftia, and the degree to which the environment influences symbiont physiology and evolution.

  3. Genomic and metabolic diversity of Marine Group I Thaumarchaeota in the mesopelagic of two subtropical gyres.

    Directory of Open Access Journals (Sweden)

    Brandon K Swan

    Full Text Available Marine Group I (MGI Thaumarchaeota are one of the most abundant and cosmopolitan chemoautotrophs within the global dark ocean. To date, no representatives of this archaeal group retrieved from the dark ocean have been successfully cultured. We used single cell genomics to investigate the genomic and metabolic diversity of thaumarchaea within the mesopelagic of the subtropical North Pacific and South Atlantic Ocean. Phylogenetic and metagenomic recruitment analysis revealed that MGI single amplified genomes (SAGs are genetically and biogeographically distinct from existing thaumarchaea cultures obtained from surface waters. Confirming prior studies, we found genes encoding proteins for aerobic ammonia oxidation and the hydrolysis of urea, which may be used for energy production, as well as genes involved in 3-hydroxypropionate/4-hydroxybutyrate and oxidative tricarboxylic acid pathways. A large proportion of protein sequences identified in MGI SAGs were absent in the marine cultures Cenarchaeum symbiosum and Nitrosopumilus maritimus, thus expanding the predicted protein space for this archaeal group. Identifiable genes located on genomic islands with low metagenome recruitment capacity were enriched in cellular defense functions, likely in response to viral infections or grazing. We show that MGI Thaumarchaeota in the dark ocean may have more flexibility in potential energy sources and adaptations to biotic interactions than the existing, surface-ocean cultures.

  4. Potential for biogeochemical cycling of sulfur, iron and carbon within massive sulfide deposits below the seafloor.

    Science.gov (United States)

    Kato, Shingo; Ikehata, Kei; Shibuya, Takazo; Urabe, Tetsuro; Ohkuma, Moriya; Yamagishi, Akihiko

    2015-05-01

    Seafloor massive sulfides are a potential energy source for the support of chemosynthetic ecosystems in dark, deep-sea environments; however, little is known about microbial communities in these ecosystems, especially below the seafloor. In the present study, we performed culture-independent molecular analyses of sub-seafloor sulfide samples collected in the Southern Mariana Trough by drilling. The depth for the samples ranged from 0.52 m to 2.67 m below the seafloor. A combination of 16S rRNA and functional gene analyses suggested the presence of chemoautotrophs, sulfur-oxidizers, sulfate-reducers, iron-oxidizers and iron-reducers. In addition, mineralogical and thermodynamic analyses are consistent with chemosynthetic microbial communities sustained by sulfide minerals below the seafloor. Although distinct bacterial community compositions were found among the sub-seafloor sulfide samples and hydrothermally inactive sulfide chimneys on the seafloor collected from various areas, we also found common bacterial members at species level including the sulfur-oxidizers and sulfate-reducers, suggesting that the common members are widely distributed within massive sulfide deposits on and below the seafloor and play a key role in the ecosystem function. © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd.

  5. 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.

  6. Electrochemically active microorganisms from an acid mine drainage-affected site promote cathode oxidation in microbial fuel cells

    KAUST Repository

    Rojas, Claudia

    2017-08-03

    The limited database of acidophilic or acidotolerant electrochemically active microorganisms prevents advancements on microbial fuel cells (MFCs) operated under low pH. In this study, three MFCs were used to enrich cathodic biofilms using acid mine drainage (AMD) sediments as inoculum. Linear sweep voltammetry showed cathodic current plateaus of 5.5 (± 0.7) mA at about − 170 mV vs Ag/AgCl and 8.5 (± 0.9) mA between − 500 mV to − 450 mV vs Ag/AgCl for biofilms developed on small graphite fiber brushes. After gamma irradiation, biocathodes exhibited a decrease in current density approaching that of abiotic controls. Electrochemical impedance spectroscopy showed six-fold lower charge transfer resistance with viable biofilm. Pyrosequencing data showed that Proteobacteria and Firmicutes dominated the biofilms. Acidithiobacillus representatives were enriched in some biocathodes, supporting the potential importance of these known iron and sulfur oxidizers as cathodic biocatalysts. Other acidophilic chemolithoautotrophs identified included Sulfobacillus and Leptospirillum species. The presence of chemoautotrophs was consistent with functional capabilities predicted by PICRUSt related to carbon fixation pathways in prokaryotic microorganisms. Acidophilic or acidotolerant heterotrophs were also abundant; however, their contribution to cathodic performance is unknown. This study directs subsequent research efforts to particular groups of AMD-associated bacteria that are electrochemically active on cathodes.

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

    Directory of Open Access Journals (Sweden)

    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.

  8. A Search for Life in the Subsurface At Rio Tinto Spain, An Analog To Searching For Life On Mars.

    Science.gov (United States)

    Stoker, C. R.

    2003-12-01

    Most familiar life forms on Earth live in the surface biosphere where liquid water, sunlight, and the essential chemical elements for life are abundant. However, such environments are not found on Mars or anywhere else in the solar system. On Mars, the surface environmental conditions of pressure and temperature prevent formation of liquid water. Furthermore, conditions at the Martian surface are unfavorable to life due to intense ultraviolet radiation and strong oxidizing compounds that destroy organic compounds. However, subsurface liquid water on Mars has been predicted on theoretical grounds. The recent discovery of near surface ground ice by the Mars Odyssey mission, and the abundant evidence for recent Gully features observed by the Mars Global Surveyor mission strengthen the case for subsurface liquid water on Mars. Thus, the strategy for searching for life on Mars points to drilling to the depth of liquid water, bringing samples to the surface and analyzing them with instrumentation to detect in situ organisms and biomarker compounds. The MARTE (Mars Astrobiology Research and Technology Experiment) project is a field experiment focused on searching for a hypothesized subsurface anaerobic chemoautotrophic biosphere in the region of the Rio Tinto, a river in southwestern Spain while also demonstrating technology relevant to searching for a subsurface biosphere on Mars. The Tinto river is located in the Iberian Pyrite belt, one of the largest deposits of sulfide minerals in the world. The surface (river) system is an acidic extreme environment produced and maintained by microbes that metabolize sulfide minerals and produce sulfuric acid as a byproduct. Evidence suggests that the river is a surface manifestation of an underground biochemical reactor. Organisms found in the river are capable of chemoautotrophic metabolism using sulfide and ferric iron mineral substrates, suggesting these organisms could thrive in groundwater which is the source of the Rio Tinto

  9. 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.

  10. 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

  11. Myiasis in a dog shelter in Greece: epidemiological and clinical features and therapeutic considerations.

    Science.gov (United States)

    Orfanou, D C; Papadopoulos, E; Cripps, P J; Athanasiou, L V; Fthenakis, G C

    2011-09-27

    The paper describes features of myiasis in a cohort of 163 dogs in an animal shelter, monitored over 3.5 years (4 fly activity seasons). Seven dogs (4 males, 3 females) were presented with myiasis; two dogs were presented twice with infestation in different areas of their body. The overall incidence rate (IR) of myiasis was 5.8 cases per 10(3) animal-months at risk, or else 0.0058 case per animal-month at risk. Six cases occurred from May to July and three from August to October, giving IRs of 7.7 per 10(3) animal-months and 3.9 per 10(3) animal-months, respectively, and an IR ratio of 1.97 (P=0.35). Five cases occurred in males and four in females, giving IRs of 7.8 per 10(3) animal months and 4.3 per 10(3) animal-months, respectively, and an incidence rate ratio of 1.78 (P=0.41). Three cases were diagnosed as cutaneous myiasis of the thigh, 2 cases as myiasis of the ear canal, 2 as myiasis of the prepuce, 1 as myiasis of the toes and 1 case as myiasis of the vagina. Median time from entrance into the shelter to infestation was 5 months; it was 1m in three dogs which were injured at entrance of animal into the shelter, but longer (5-15m) in the other four dogs. Larvae were identified as 2nd or 3rd stage instars of Wohlfahrtia magnifica. Signs characteristic of local inflammation, in the affected area of the body, were recorded. Treatment included mechanical removal of larvae, cleansing of the area, administration of injectable moxidectin and a broad-spectrum antimicrobial agent. Complete recovery was achieved within 1.5 months, bar that of preputial infestations which required 2.5 months. Copyright © 2011 Elsevier B.V. All rights reserved.

  12. Livestock ectoparasites: integrated management in a changing climate.

    Science.gov (United States)

    Wall, Richard; Rose, Hannah; Ellse, Lauren; Morgan, Eric

    2011-08-04

    The prevalence of livestock ectoparasites is the result of a complex interaction of factors such as parasite and host abundance, host susceptibility, climate and, critically, farmer husbandry and intervention strategies, all of which change seasonally in space and time. Given the complexity of the interacting factors, the effects of any climate change on disease incidence are hard to predict, as accordingly are the optimal husbandry responses required to ameliorate any effects. Here cutaneous myiasis in sheep, by the blowfly Lucilia sericata in the United Kingdom, is used to highlight the impact of a range of such issues. Cutaneous myiasis would be expected to be highly sensitive to even small changes in climate and therefore provides a good model to illustrate the problems inherent in attempting to predict the effect of climate change on livestock disease incidence. Both simulation and spatial species distribution models, show that the range of elevated temperatures predicted by current climate change scenarios are likely to result in an elongated blowfly season with earlier spring emergence and a higher cumulative incidence of strike. Strike incidence would be expected to increase, particularly for ewes in early summer. However, under higher IPCC emissions senarios (+3 °C), parts of central and southern England may become too hot and dry for strike by L. sericata to persist in mid-summer. Under these conditions, it is possible that other, more pathogenic Mediterranean agents of myiasis, such as Wohlfahrtia magnifica could replace L. sericata. Nevertheless, the models suggest that simple changes in some husbandry practices, such as shearing or trap use, could have an important effect in reducing early season ewe strike incidences by L. sericata. The work reviewed here, suggests that climate warming is likely to increase the risk of fly strike incidence, with consequent animal welfare and economic problems. However, practical measures exist which, with modest

  13. Modelling the impact of climate change on spatial patterns of disease risk: sheep blowfly strike by Lucilia sericata in Great Britain.

    Science.gov (United States)

    Rose, Hannah; Wall, Richard

    2011-06-01

    Understanding the spatial scale and temporal pattern of disease incidence is a fundamental prerequisite for the development of appropriate management and intervention strategies. It is particularly critical, given the need to understand the elevated risks linked to climate change, to allow the most likely changes in the distribution of parasites and disease vectors to be predicted under a range of climate change scenarios. Using statistical models, the spatial distribution and climatic correlates of a range of parasites and diseases have been mapped previously, but their development into dynamic, predictive tools is less common. The aim of the work described here, was to use a species distribution model to characterise the environmental determinants of the monthly occurrence of ovine cutaneous myiasis (blowfly strike) by Lucilia sericata, the most frequent primary agent of northern European myiasis, and to then use this model to describe the potential spatial changes that might be expected in response to predicted climate change in Great Britain. The model predicts that the range of elevated temperatures predicted by current climate change scenarios will result in an increase in the risk of strike and an elongated blowfly season. However, even for the most rapid warming scenario predictions over the next 70 years, strike is not predicted to occur throughout the winter. Nevertheless, in this latter case, parts of central and southern England are likely to become too hot and dry for strike by L. sericata, to persist in mid-summer. Under these conditions, it is possible that other, more pathogenic Mediterranean agents of myiasis, such as Wolfhartia magnifica, could potentially replace L. sericata. Where the phenology of strike is altered by climate change, as predicted here, significant changes to the timing and frequency of parasite treatments and husbandry practices, such as shearing, will be required to manage the problem. The results suggest that the modelling

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

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    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

  15. Propiedades y aplicaciones de los cementos alcalinos Properties and uses of alkali cements

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    Ana Fernández-Jiménez

    2009-12-01

    Full Text Available En este trabajo se presentan algunas de las propiedades tecnológicas de los materiales cementantes elaborados por activación alcalina de aluminosilicatos. Más específicamente sobre las propiedades de morteros y hormigones elaborados con cenizas volantes activadas alcalinamente (sin cemento Portland. Así en función del tipo de activador alcalino empleado y tras un curado térmico previo, el material resultante presentará una interesante lista de propiedades y características que incluyen: elevadas resistencias mecánicas iniciales (a flexión y a compresión, baja retracción al secado, y una muy buena adherencia matriz-acero, así como una excelente resistencia al ataque ácido y un excelente comportamiento frente al fuego. Es por ello que estos nuevos cementos debido a sus magnificas características tecnológicas y durables, así como a la facilidad de adecuarlos a las instalaciones existentes en la industria de los prefabricados, pueden ser fácilmente utilizados en diversas aplicaciones como por ejemplo: elaboración de durmientes para el ferrocarril, bloques para edificación o pavimentación, etc.In this paper are presented some of the technologic properties of cementitious material elaborated by alkali activation of aluminosilicates are presented. More specifically it is about the properties of alkali activated fly ash concrete and mortar (without Portland cement. So depending on the type of alkali activator that is used and after a previous thermal curing, the resulting material will show an interesting list of properties and features that includes: high initial mechanical strengths (under flexure and compression, low drying shrinkage, and a very good matrix-steel bonding, as well as an excellent strength to acid attack and an excellent behaviour when is exposed to fire. That is the reason why these new cements, due to their magnificent and durable technologic features as well as its easy adaptability to the existing

  16. Reforma y modernización del Hotel Alfonso XIII de Sevilla, España

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    Castellón, Carlos Ricardo

    1979-11-01

    Full Text Available This article describes the careful remodeling work of this hotel — a part of the city's history since it was opened in 1926 — a general improvement aimed at making this facility a model in its class, a beautiful building fitted with all the amenities becoming its high luxury classification, a category shared with very few hotels in the country. Special attention has been given to the repair of roofs and walls, renewal of exterior fenestration, grills, artistic glazed tiling, dadoes, coffered ceilings, lamps, floor construction in the banquet hall, plumbing, electric system, air conditioned and providing adequate services. A new magnificent, roomy suite has been incorporated, as well as new classy bathrooms, gardens, roofed car park, and 800 m3 water tank, a bar, a breakfast coffee room, a restaurant in the half-basement with accesses from the inside and the outside, fountains, etc. The refined taste of the architect, the highly specialized work of the contractor and the participation of the qualified Sevillian craftsmen, have all contributed to the neat detailing of the facility and to the highly successful final result.

    Se describe en el articulo la cuidadosa reforma de este Hotel —parte de la Historia de la ciudad, desde su inauguración, en 1926— con la consiguiente modernización general, al objeto de convertirlo en una instalación ejemplar, de gran belleza y dotada de todo el confort que requiere su categoría de gran lujo, condición que comparte con muy pocos hoteles del País. Se ha dedicado especial atención a la consolidación de la cubierta y tabiquería; renovación de la carpintería exterior, verjas, azulejos, zócalos, artesonados, lámparas, forjado del comedor de banquetes, instalaciones de fontanería, electricidad y aire acondicionado; servicios adecuados, etcétera. Se han creado: una magnifica y espaciosa suite, baños de categoría, jardinería, estacionamientos cubiertos, un aljibe de

  17. Ecogenomic characterization of a marine microorganism belonging to a Firmicutes lineage that is widespread in both terrestrial and oceanic subsurface environments

    Science.gov (United States)

    Jungbluth, S.; Glavina del Rio, T.; Tringe, S. G.; Stepanauskas, R.; Rappe, M. S.

    2015-12-01

    Large-volumes of basalt-hosted fluids from the sediment-covered subseafloor were collected in July 2011 from a horizon extending 29-117 meters below the sediment-rock interface at borehole 1362B, as well as from a deep horizon extending 193-292 meters below the sediment-rock interface at borehole 1362A, which are two of the latest generation of borehole observatories on the Juan de Fuca Ridge flank in the Northeast Pacific Ocean. Environmental DNA was sequenced from one fluid sample collected from each borehole, and a genomic bin related to the terrestrial Candidatus Desulforudis audaxviator lineage within the Firmicutes phylum of bacteria was identified. The near-complete bacterial genome, herein named Candidatus Desulfopertinax inferamarinus, is composed of six scaffolds totaling 1.78 Mbp in length. Despite vast differences in geography and environment of origin, phylogenomic analysis indicate that D. inferamarinus and D. audaxviator form a monophyletic clade to the exclusion of all other sequenced genomes. Similar to its terrestrial relative, the draft genome of the marine D. inferamarinus revealed a motile, sporulating, sulfate-reducing, chemoautotrophic thermophile that is capable of synthesizing all amino acids and fixing inorganic carbon via the Wood-Ljungdahl pathway. Unlike the terrestrial clade, relatively few integrases and transposases were identified. The marine genome described here provides evidence that a life-style adapted to the isolated deep subsurface environment is a general feature of the broader, globally-distributed Desulforudis/Desulfopertinax lineage and provides insight into the adaptations required for microbial life in the marine versus terrestrial deep biospheres.

  18. [Abundance and activity of microorganisms at the water-sediment interface and their effect on the carbon isotopic composition of suspended organic matter and sediments of the Kara Sea].

    Science.gov (United States)

    Ivanov, M V; Lein, A Iu; Savvichev, A S; Rusanov, I I; Veslopolova, E F; Zakharova, E E; Prusakova, T S

    2013-01-01

    At ten stations of the meridian profile in the eastern Kara Sea from the Yenisei estuary through the shallow shelf and further through the St. Anna trough, total microbial numbers (TMN) determined by direct counting, total activity of the microbial community determined by dark CO2 assimilation (DCA), and the carbon isotopic composition of organic matter in suspension and upper sediment horizons (δ13C, per thousand) were investigated. Three horizons were studied in detail: (1) the near-bottom water layer (20-30 cm above the sediment); (2) the uppermost, strongly hydrated sediment horizon, further termed warp (5-10 mm); and (3) the upper sediment horizon (1-5 cm). Due to decrease in the amount of isotopically light carbon of terrigenous origin with increasing distance from the Yenisei estuary, the TMN and DCA values decreased, and the δ13C changed gradually from -29.7 to -23.9 per thousand. At most stations, a noticeable decrease in TMN and DCA values with depth was observed in the water column, while the carbon isotopic composition of suspended organic matter did not change significantly. Considerable changes of all parameters were detected in the interface zone: TMN and DCA increased in the sediments compared to their values in near-bottom water, while the 13C content increased significantly, with δ13C of organic matter in the sediments being at some stations 3.5- 4.0 per thousand higher than in the near-bottom water. Due to insufficient illumination in the near-bottom zone, newly formed isotopically heavy organic matter (δ13C(-) -20 per thousand) could not be formed by photosynthesis, active growth of chemoautotrophic microorganisms in this zone is suggested, which may use reduced sulfur, nitrogen, and carbon compounds diffusing from anaerobic sediments. High DCA values for the interface zone samples confirm this hypothesis. Moreover, neutrophilic sulfur-oxidizing bacteria were retrieved from the samples of this zone.

  19. Microbial sulfur transformations in sediments from Subglacial Lake Whillans

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    Alicia M Purcell

    2014-11-01

    Full Text Available Diverse microbial assemblages inhabit subglacial aquatic environments. While few of these environments have been sampled, data reveal that subglacial organisms gain energy for growth from reduced minerals containing nitrogen, iron, and sulfur. Here we investigate the role of microbially mediated sulfur transformations in sediments from Subglacial Lake Whillans (SLW, Antarctica, by examining key genes involved in dissimilatory sulfur oxidation and reduction. The presence of sulfur transformation genes throughout the top 34 cm of SLW sediments changes with depth. SLW surficial sediments were dominated by genes related to known sulfur-oxidizing chemoautotrophs. Sequences encoding the adenosine-5’-phosphosulfate (APS reductase gene, involved in both dissimilatory sulfate reduction and sulfur oxidation, were present in all samples and clustered into 16 distinct OTUs. The majority of APS reductase sequences (74% clustered with known sulfur oxidizers including those within the Sideroxydans and Thiobacillus genera. Reverse-acting dissimilatory sulfite reductase (rDSR and 16S rRNA gene sequences further support dominance of Sideroxydans and Thiobacillus phylotypes in the top 2 cm of SLW sediments. The SLW microbial community has the genetic potential for sulfate reduction which is supported by experimentally measured low rates (1.4 pmol cm-3d-1 of biologically mediated sulfate reduction and the presence of APS reductase and DSR gene sequences related to Desulfobacteraceae and Desulfotomaculum. Our results also infer the presence of sulfur oxidation, which can be a significant energetic pathway for chemosynthetic biosynthesis in SLW sediments. The water in SLW ultimately flows into the Ross Sea where intermediates from subglacial sulfur transformations can influence the flux of solutes to the Southern Ocean.

  20. Characterization of a Planctomycetal Organelle: a Novel Bacterial Microcompartment for the Aerobic Degradation of Plant Saccharides

    Science.gov (United States)

    Erbilgin, Onur; McDonald, Kent L.

    2014-01-01

    Bacterial microcompartments (BMCs) are organelles that encapsulate functionally linked enzymes within a proteinaceous shell. The prototypical example is the carboxysome, which functions in carbon fixation in cyanobacteria and some chemoautotrophs. It is increasingly apparent that diverse heterotrophic bacteria contain BMCs that are involved in catabolic reactions, and many of the BMCs are predicted to have novel functions. However, most of these putative organelles have not been experimentally characterized. In this study, we sought to discover the function of a conserved BMC gene cluster encoded in the majority of the sequenced planctomycete genomes. This BMC is especially notable for its relatively simple genetic composition, its remote phylogenetic position relative to characterized BMCs, and its apparent exclusivity to the enigmatic Verrucomicrobia and Planctomycetes. Members of the phylum Planctomycetes are known for their morphological dissimilarity to the rest of the bacterial domain: internal membranes, reproduction by budding, and lack of peptidoglycan. As a result, they are ripe for many discoveries, but currently the tools for genetic studies are very limited. We expanded the genetic toolbox for the planctomycetes and generated directed gene knockouts of BMC-related genes in Planctomyces limnophilus. A metabolic activity screen revealed that BMC gene products are involved in the degradation of a number of plant and algal cell wall sugars. Among these sugars, we confirmed that BMCs are formed and required for growth on l-fucose and l-rhamnose. Our results shed light on the functional diversity of BMCs as well as their ecological role in the planctomycetes, which are commonly associated with algae. PMID:24487526

  1. Microbial communities in dark oligotrophic volcanic ice cave ecosystems of Mt. Erebus, Antarctica.

    Science.gov (United States)

    Tebo, Bradley M; Davis, Richard E; Anitori, Roberto P; Connell, Laurie B; Schiffman, Peter; Staudigel, Hubert

    2015-01-01

    The Earth's crust hosts a subsurface, dark, and oligotrophic biosphere that is poorly understood in terms of the energy supporting its biomass production and impact on food webs at the Earth's surface. Dark oligotrophic volcanic ecosystems (DOVEs) are good environments for investigations of life in the absence of sunlight as they are poor in organics, rich in chemical reactants and well known for chemical exchange with Earth's surface systems. Ice caves near the summit of Mt. Erebus (Antarctica) offer DOVEs in a polar alpine environment that is starved in organics and with oxygenated hydrothermal circulation in highly reducing host rock. We surveyed the microbial communities using PCR, cloning, sequencing and analysis of the small subunit (16S) ribosomal and Ribulose-1,5-bisphosphate Carboxylase/Oxygenase (RubisCO) genes in sediment samples from three different caves, two that are completely dark and one that receives snow-filtered sunlight seasonally. The microbial communities in all three caves are composed primarily of Bacteria and fungi; Archaea were not detected. The bacterial communities from these ice caves display low phylogenetic diversity, but with a remarkable diversity of RubisCO genes including new deeply branching Form I clades, implicating the Calvin-Benson-Bassham (CBB) cycle as a pathway of CO2 fixation. The microbial communities in one of the dark caves, Warren Cave, which has a remarkably low phylogenetic diversity, were analyzed in more detail to gain a possible perspective on the energetic basis of the microbial ecosystem in the cave. Atmospheric carbon (CO2 and CO), including from volcanic emissions, likely supplies carbon and/or some of the energy requirements of chemoautotrophic microbial communities in Warren Cave and probably other Mt. Erebus ice caves. Our work casts a first glimpse at Mt. Erebus ice caves as natural laboratories for exploring carbon, energy and nutrient sources in the subsurface biosphere and the nutritional limits on

  2. The Diverse AAA+ Machines that Repair Inhibited Rubisco Active Sites

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    Oliver Mueller-Cajar

    2017-05-01

    Full Text Available Gaseous carbon dioxide enters the biosphere almost exclusively via the active site of the enzyme ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco. This highly conserved catalyst has an almost universal propensity to non-productively interact with its substrate ribulose 1,5-bisphosphate, leading to the formation of dead-end inhibited complexes. In diverse autotrophic organisms this tendency has been counteracted by the recruitment of dedicated AAA+ (ATPases associated with various cellular activities proteins that all use the energy of ATP hydrolysis to remodel inhibited Rubisco active sites leading to release of the inhibitor. Three evolutionarily distinct classes of these Rubisco activases (Rcas have been discovered so far. Green and red-type Rca are mostly found in photosynthetic eukaryotes of the green and red plastid lineage respectively, whereas CbbQO is associated with chemoautotrophic bacteria. Ongoing mechanistic studies are elucidating how the various motors are utilizing both similar and contrasting strategies to ultimately perform their common function of cracking the inhibited Rubisco active site. The best studied mechanism utilized by red-type Rca appears to involve transient threading of the Rubisco large subunit C-terminal peptide, reminiscent of the action performed by Clp proteases. As well as providing a fascinating example of convergent molecular evolution, Rca proteins can be considered promising crop-improvement targets. Approaches aiming to replace Rubisco in plants with improved enzymes will need to ensure the presence of a compatible Rca protein. The thermolability of the Rca protein found in crop plants provides an opportunity to fortify photosynthesis against high temperature stress. Photosynthesis also appears to be limited by Rca when light conditions are fluctuating. Synthetic biology strategies aiming to enhance the autotrophic CO2 fixation machinery will need to take into consideration the requirement for

  3. Microbial diversity and iron oxidation at Okuoku-hachikurou Onsen, a Japanese hot spring analog of Precambrian iron formations.

    Science.gov (United States)

    Ward, L M; Idei, A; Terajima, S; Kakegawa, T; Fischer, W W; McGlynn, S E

    2017-11-01

    Banded iron formations (BIFs) are rock deposits common in the Archean and Paleoproterozoic (and regionally Neoproterozoic) sedimentary successions. Multiple hypotheses for their deposition exist, principally invoking the precipitation of iron via the metabolic activities of oxygenic, photoferrotrophic, and/or aerobic iron-oxidizing bacteria. Some isolated environments support chemistry and mineralogy analogous to processes involved in BIF deposition, and their study can aid in untangling the factors that lead to iron precipitation. One such process analog system occurs at Okuoku-hachikurou (OHK) Onsen in Akita Prefecture, Japan. OHK is an iron- and CO2 -rich, circumneutral hot spring that produces a range of precipitated mineral textures containing fine laminae of aragonite and iron oxides that resemble BIF fabrics. Here, we have performed 16S rRNA gene amplicon sequencing of microbial communities across the range of microenvironments in OHK to describe the microbial diversity present and to gain insight into the cycling of iron, oxygen, and carbon in this ecosystem. These analyses suggest that productivity at OHK is based on aerobic iron-oxidizing Gallionellaceae. In contrast to other BIF analog sites, Cyanobacteria, anoxygenic phototrophs, and iron-reducing micro-organisms are present at only low abundances. These observations support a hypothesis where low growth yields and the high stoichiometry of iron oxidized per carbon fixed by aerobic iron-oxidizing chemoautotrophs like Gallionellaceae result in accumulation of iron oxide phases without stoichiometric buildup of organic matter. This system supports little dissimilatory iron reduction, further setting OHK apart from other process analog sites where iron oxidation is primarily driven by phototrophic organisms. This positions OHK as a study area where the controls on primary productivity in iron-rich environments can be further elucidated. When compared with geological data, the metabolisms and mineralogy at

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

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    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.

  5. Inorganic carbon fixation by chemosynthetic ectosymbionts and nutritional transfers to the hydrothermal vent host-shrimp Rimicaris exoculata.

    Science.gov (United States)

    Ponsard, Julie; Cambon-Bonavita, Marie-Anne; Zbinden, Magali; Lepoint, Gilles; Joassin, André; Corbari, Laure; Shillito, Bruce; Durand, Lucile; Cueff-Gauchard, Valérie; Compère, Philippe

    2013-01-01

    The shrimp Rimicaris exoculata dominates several hydrothermal vent ecosystems of the Mid-Atlantic Ridge and is thought to be a primary consumer harbouring a chemoautotrophic bacterial community in its gill chamber. The aim of the present study was to test current hypotheses concerning the epibiont's chemoautotrophy, and the mutualistic character of this association. In-vivo experiments were carried out in a pressurised aquarium with isotope-labelled inorganic carbon (NaH(13)CO(3) and NaH(14)CO(3)) in the presence of two different electron donors (Na(2)S(2)O(3) and Fe(2+)) and with radiolabelled organic compounds ((14)C-acetate and (3)H-lysine) chosen as potential bacterial substrates and/or metabolic by-products in experiments mimicking transfer of small biomolecules from epibionts to host. The bacterial epibionts were found to assimilate inorganic carbon by chemoautotrophy, but many of them (thick filaments of epsilonproteobacteria) appeared versatile and able to switch between electron donors, including organic compounds (heterotrophic acetate and lysine uptake). At least some of them (thin filamentous gammaproteobacteria) also seem capable of internal energy storage that could supply chemosynthetic metabolism for hours under conditions of electron donor deprivation. As direct nutritional transfer from bacteria to host was detected, the association appears as true mutualism. Import of soluble bacterial products occurs by permeation across the gill chamber integument, rather than via the digestive tract. This first demonstration of such capabilities in a decapod crustacean supports the previously discarded hypothesis of transtegumental absorption of dissolved organic matter or carbon as a common nutritional pathway.

  6. Methane-carbon flow into the benthic food web at cold seeps--a case study from the Costa Rica subduction zone.

    Science.gov (United States)

    Niemann, Helge; Linke, Peter; Knittel, Katrin; MacPherson, Enrique; Boetius, Antje; Brückmann, Warner; Larvik, Gaute; Wallmann, Klaus; Schacht, Ulrike; Omoregie, Enoma; Hilton, David; Brown, Kevin; Rehder, Gregor

    2013-01-01

    Cold seep ecosystems can support enormous biomasses of free-living and symbiotic chemoautotrophic organisms that get their energy from the oxidation of methane or sulfide. Most of this biomass derives from animals that are associated with bacterial symbionts, which are able to metabolize the chemical resources provided by the seeping fluids. Often these systems also harbor dense accumulations of non-symbiotic megafauna, which can be relevant in exporting chemosynthetically fixed carbon from seeps to the surrounding deep sea. Here we investigated the carbon sources of lithodid crabs (Paralomis sp.) feeding on thiotrophic bacterial mats at an active mud volcano at the Costa Rica subduction zone. To evaluate the dietary carbon source of the crabs, we compared the microbial community in stomach contents with surface sediments covered by microbial mats. The stomach content analyses revealed a dominance of epsilonproteobacterial 16S rRNA gene sequences related to the free-living and epibiotic sulfur oxidiser Sulfurovum sp. We also found Sulfurovum sp. as well as members of the genera Arcobacter and Sulfurimonas in mat-covered surface sediments where Epsilonproteobacteria were highly abundant constituting 10% of total cells. Furthermore, we detected substantial amounts of bacterial fatty acids such as i-C15∶0 and C17∶1ω6c with stable carbon isotope compositions as low as -53‰ in the stomach and muscle tissue. These results indicate that the white microbial mats at Mound 12 are comprised of Epsilonproteobacteria and that microbial mat-derived carbon provides an important contribution to the crab's nutrition. In addition, our lipid analyses also suggest that the crabs feed on other (13)C-depleted organic matter sources, possibly symbiotic megafauna as well as on photosynthetic carbon sources such as sedimentary detritus.

  7. A mimicking-of-DNA-methylation-patterns pipeline for overcoming the restriction barrier of bacteria.

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    Guoqiang Zhang

    2012-09-01

    Full Text Available Genetic transformation of bacteria harboring multiple Restriction-Modification (R-M systems is often difficult using conventional methods. Here, we describe a mimicking-of-DNA-methylation-patterns (MoDMP pipeline to address this problem in three difficult-to-transform bacterial strains. Twenty-four putative DNA methyltransferases (MTases from these difficult-to-transform strains were cloned and expressed in an Escherichia coli strain lacking all of the known R-M systems and orphan MTases. Thirteen of these MTases exhibited DNA modification activity in Southwestern dot blot or Liquid Chromatography-Mass Spectrometry (LC-MS assays. The active MTase genes were assembled into three operons using the Saccharomyces cerevisiae DNA assembler and were co-expressed in the E. coli strain lacking known R-M systems and orphan MTases. Thereafter, results from the dot blot and restriction enzyme digestion assays indicated that the DNA methylation patterns of the difficult-to-transform strains are mimicked in these E. coli hosts. The transformation of the Gram-positive Bacillus amyloliquefaciens TA208 and B. cereus ATCC 10987 strains with the shuttle plasmids prepared from MoDMP hosts showed increased efficiencies (up to four orders of magnitude compared to those using the plasmids prepared from the E. coli strain lacking known R-M systems and orphan MTases or its parental strain. Additionally, the gene coding for uracil phosphoribosyltransferase (upp was directly inactivated using non-replicative plasmids prepared from the MoDMP host in B. amyloliquefaciens TA208. Moreover, the Gram-negative chemoautotrophic Nitrobacter hamburgensis strain X14 was transformed and expressed Green Fluorescent Protein (GFP. Finally, the sequence specificities of active MTases were identified by restriction enzyme digestion, making the MoDMP system potentially useful for other strains. The effectiveness of the MoDMP pipeline in different bacterial groups suggests a universal

  8. A Mimicking-of-DNA-Methylation-Patterns Pipeline for Overcoming the Restriction Barrier of Bacteria

    Science.gov (United States)

    Zhang, Guoqiang; Wang, Wenzhao; Deng, Aihua; Sun, Zhaopeng; Zhang, Yun; Liang, Yong; Che, Yongsheng; Wen, Tingyi

    2012-01-01

    Genetic transformation of bacteria harboring multiple Restriction-Modification (R-M) systems is often difficult using conventional methods. Here, we describe a mimicking-of-DNA-methylation-patterns (MoDMP) pipeline to address this problem in three difficult-to-transform bacterial strains. Twenty-four putative DNA methyltransferases (MTases) from these difficult-to-transform strains were cloned and expressed in an Escherichia coli strain lacking all of the known R-M systems and orphan MTases. Thirteen of these MTases exhibited DNA modification activity in Southwestern dot blot or Liquid Chromatography–Mass Spectrometry (LC–MS) assays. The active MTase genes were assembled into three operons using the Saccharomyces cerevisiae DNA assembler and were co-expressed in the E. coli strain lacking known R-M systems and orphan MTases. Thereafter, results from the dot blot and restriction enzyme digestion assays indicated that the DNA methylation patterns of the difficult-to-transform strains are mimicked in these E. coli hosts. The transformation of the Gram-positive Bacillus amyloliquefaciens TA208 and B. cereus ATCC 10987 strains with the shuttle plasmids prepared from MoDMP hosts showed increased efficiencies (up to four orders of magnitude) compared to those using the plasmids prepared from the E. coli strain lacking known R-M systems and orphan MTases or its parental strain. Additionally, the gene coding for uracil phosphoribosyltransferase (upp) was directly inactivated using non-replicative plasmids prepared from the MoDMP host in B. amyloliquefaciens TA208. Moreover, the Gram-negative chemoautotrophic Nitrobacter hamburgensis strain X14 was transformed and expressed Green Fluorescent Protein (GFP). Finally, the sequence specificities of active MTases were identified by restriction enzyme digestion, making the MoDMP system potentially useful for other strains. The effectiveness of the MoDMP pipeline in different bacterial groups suggests a universal potential

  9. Microbial communities in dark oligotrophic volcanic ice cave ecosystems of Mt. Erebus, Antarctica

    Science.gov (United States)

    Tebo, Bradley M.; Davis, Richard E.; Anitori, Roberto P.; Connell, Laurie B.; Schiffman, Peter; Staudigel, Hubert

    2015-01-01

    The Earth's crust hosts a subsurface, dark, and oligotrophic biosphere that is poorly understood in terms of the energy supporting its biomass production and impact on food webs at the Earth's surface. Dark oligotrophic volcanic ecosystems (DOVEs) are good environments for investigations of life in the absence of sunlight as they are poor in organics, rich in chemical reactants and well known for chemical exchange with Earth's surface systems. Ice caves near the summit of Mt. Erebus (Antarctica) offer DOVEs in a polar alpine environment that is starved in organics and with oxygenated hydrothermal circulation in highly reducing host rock. We surveyed the microbial communities using PCR, cloning, sequencing and analysis of the small subunit (16S) ribosomal and Ribulose-1,5-bisphosphate Carboxylase/Oxygenase (RubisCO) genes in sediment samples from three different caves, two that are completely dark and one that receives snow-filtered sunlight seasonally. The microbial communities in all three caves are composed primarily of Bacteria and fungi; Archaea were not detected. The bacterial communities from these ice caves display low phylogenetic diversity, but with a remarkable diversity of RubisCO genes including new deeply branching Form I clades, implicating the Calvin-Benson-Bassham (CBB) cycle as a pathway of CO2 fixation. The microbial communities in one of the dark caves, Warren Cave, which has a remarkably low phylogenetic diversity, were analyzed in more detail to gain a possible perspective on the energetic basis of the microbial ecosystem in the cave. Atmospheric carbon (CO2 and CO), including from volcanic emissions, likely supplies carbon and/or some of the energy requirements of chemoautotrophic microbial communities in Warren Cave and probably other Mt. Erebus ice caves. Our work casts a first glimpse at Mt. Erebus ice caves as natural laboratories for exploring carbon, energy and nutrient sources in the subsurface biosphere and the nutritional limits on

  10. Parallels between two geographically and ecologically disparate cave invasions by the same species, Asellus aquaticus (Isopoda, Crustacea).

    Science.gov (United States)

    Konec, M; Prevorčnik, S; Sarbu, S M; Verovnik, R; Trontelj, P

    2015-04-01

    Caves are long-known examples of evolutionary replications where similar morphologies (troglomorphies) evolve independently as the result of strong natural selection of the extreme environment. Recently, this paradigm has been challenged based on observations that troglomorphies are inconsistent across taxa and different subterranean habitats. We investigated the degree of replicated phenotypic change in two independent cave invasions by the freshwater isopod Asellus aquaticus; the first in a sulphidic aquifer in Romania, the second in a sinking river in the Dinaric Karst in Slovenia. Both ancestral surface populations still live alongside the subterranean ones. Phylogenetic analyses show independence of the two colonization events, and microsatellite analysis shows no evidence of ongoing genetic exchange between surface and subterranean ecomorphs. The overall morphology has changed dramatically at both sites (50 of 62 morphometric traits). The amount of phenotypic change did not reflect differences in genetic diversity between the two ancestral populations. Multivariate analyses revealed divergent evolution in caves, not parallel or convergent as predicted by the current paradigm. Still, 18 traits changed in a parallel fashion, including eye and pigment loss and antennal elongation. These changes might be a consequence of darkness as the only common ecological feature, because Romanian caves are chemoautotrophic and rich in food, whereas Slovenian caves are not. Overall, these results show that morphologically alike surface populations can diverge after invading different subterranean habitats, and that only about one-third of all changing traits behave as troglomorphies in the traditional sense. © 2015 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2015 European Society For Evolutionary Biology.

  11. Drastic environmental change and its effects on a planetary biosphere

    Science.gov (United States)

    Schulze-Makuch, Dirk; Irwin, Louis N.; Fairén, Alberto G.

    2013-07-01

    Environmental conditions can change drastically and rapidly during the natural history of a planetary body. These changes affect the biosphere and can spur evolution via the mechanism of directional selection leading to the innovation of new processes and forms of life, or alternatively leading to the extinction of certain life forms. Based on the natural history of Earth, the effect on a planet's biosphere depends on three factors: (1) the nature and time scale of change, (2) the composition of the biosphere prior to change, and (3) the nature of the environment following the change. Though Earth has undergone various periods of drastic environmental change, life has shown an enormous resiliency and became more diverse and complex as a consequence of these events. Mars and Venus have undergone even larger environmental changes, both from habitable conditions under which the origin of life (or transfer of life from Earth) seem plausible, to a dry and cold planet punctuated by wetter conditions, and a hyperthermic greenhouse, respectively. Given its planetary history, life on Mars could have retreated to a psychrophilic lifestyle in the deep subsurface or to environmental near-surface niches, such as hydrothermal regions and caves. Further, strong directional selection could have pushed putative martian life to evolve alternating cycles between active and dormant forms, as well as the innovation of new traits adapted to challenging near-surface conditions. Life in the subsurface or on the surface of Venus seems impossible today, but microorganisms may have adapted to thrive in the lower cloud layer, possibly using a biochemical strategy analogous to Photosystem I and chemoautotrophic sulfur metabolism, and employing cycloocta sulfur for UV protection.

  12. Physical Conditions and Exobiology Potential of Icy Satellites of the Giant Planets

    Science.gov (United States)

    Simakov, M. B.

    2017-05-01

    All giant planets of the Solar system have a big number of satellites. A small part of them consist very large bodies, quite comparable to planets of terrestrial type, but including very significant share of water ice. Galileo spacecraft has given indications, primarily from magnetometer and gravity data, of the possibility that three of Jupiter's four large moons, Europa, Ganymede and Callisto have internal oceans. Formation of such satellites is a natural phenomenon, and satellite systems definitely should exist at extrasolar planets. The most recent models of the icy satellites interior lead to the conclusion that a substantial liquid layer exists today under relatively thin ice cover inside. The putative internal water ocean provide some exobiological niches on these bodies. We can see all conditions needed for origin and evolution of biosphere - liquid water, complex organic chemistry and energy sources for support of biological processes - are on the moons. The existing of liquid water ocean within icy world can be consequences of the physical properties of water ice, and they neither require the addition of antifreeze substances nor any other special conditions. On Earth life exists in all niches where water exists in liquid form for at least a portion of the year. Possible metabolic processes, such as nitrate/nitrite reduction, sulfate reduction and methanogenesis could be suggested for internal oceans of Titan and Jovanian satellites. Excreted products of the primary chemoautotrophic organisms could serve as a source for other types of microorganisms (heterotrophes). Subglacial life may be widespread among such planetary bodies as satellites of extrasolar giant planets, detected in our Galaxy.

  13. 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.

  14. Stability of Hydrothermal Vent Communities on the Eastern Lau Spreading Center

    Science.gov (United States)

    Fisher, C. R.; Du Preez, C.; Ferrini, V. L.; Beinart, R.; Seewald, J.; Hoer, D.; Girguis, P. R.

    2016-12-01

    With polymetalic sulfide deposit mining imminent in the Western Pacific, understanding the pace and patterns of natural change in the hydrothermal vent communities of the region is critical to the design of pre-mining surveys and post-exploitation monitoring that should accompany responsible resource extraction. The overarching goals of our April 2016 expedition to the Eastern Lau Spreading Center (ELSC) with the RV Falkor, were therefore to significantly increase our understanding of the natural patterns of change in the vent geology, chemistry, and biology along the ELSC, and the processes that govern these changes. During the expedition we were able to revisit 17 community study sites in four vent fields, which were established during the NSF Ridge 2000 program. In each vent field, we acquired high resolution multibeam and spatially explicit chemical data and imagery for photo mosaics of seven chimney, six diffuse flow, and four peripheral vent faunal communities to compare with similar data collected in 2005, 2006 and 2009. Advances in chemical sensor and imaging technology not only facilitate comparisons to the pre-existing data sets, but also provide new insights to the physiological ecology of the fauna and the factors contributing to their realized distribution. Notably, our preliminary analyses have found no evidence of significant volcanic or tectonic activity at any of the sites since 2005. The most surprising observation, however, was the remarkable stability in the community structure and faunal distribution at most of the chimney, diffuse flow, and peripheral community study sites at three of the major vent fields, which showed little evidence of change over the decade that they have been monitored. While the discovery of fauna with chemoautotrophic symbionts at the southern-most vent field visited, Mariner, suggests significant changes in the chemistry of the diffuse flow in this vent field since 2009, the apparent geological and ecological stability

  15. 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.

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

    Directory of Open Access Journals (Sweden)

    N. Lampadariou

    2013-08-01

    Full Text Available 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.

  17. Cold seep communities in the deep eastern Mediterranean Sea: composition, symbiosis and spatial distribution on mud volcanoes

    Science.gov (United States)

    Olu-Le Roy, Karine; Sibuet, Myriam; Fiala-Médioni, Aline; Gofas, Serge; Salas, Carmen; Mariotti, André; Foucher, Jean-Paul; Woodside, John

    2004-12-01

    Two mud volcano fields were explored during the French-Dutch MEDINAUT cruise (1998) with the submersible NAUTILE, one south of Crete along the Mediteranean Ridge at about 2000 m depth (Olimpi mud field) and the other south of Turkey between 1700 and 2000 m depth (Anaximander mud field) where high methane concentrations were measured. Chemosynthetic communities were observed and sampled on six mud volcanoes and along a fault scarp. The communities were dominated by bivalves of particularly small size, belonging to families commonly found at seeps (Mytilidae, Vesicomyidae, Thyasiridae) and to Lucinidae mostly encountered in littoral sulfide-rich sediments and at the shallowest seeps. Siboglinid polychaetes including a large vestimentiferan Lamellibrachia sp. were also associated. At least four bivalve species and one siboglinid are associated with symbiotic chemoautotrophic bacteria, as evidenced by Transmission Electronic Microscopy and isotopic ratio measurements. Among the bivalves, a mytilid harbors both methanotrophic and sulfide-oxidizing bacteria. Video spatial analysis of the community distribution on three volcanoes shows that dense bivalve shell accumulations (mainly lucinids) spread over large areas, from 10% to 38% of the explored areas (2500-15000 m 2) on the different volcanoes. Lamellibrachia sp. had different spatial distribution and variable density in the two mud volcano fields, apparently related with higher methane fluxes in the Anaximander volcanoes and maybe with the instability due to brines in the Olimpi area. The abundance and richness of the observed chemosynthetic fauna and the size of some of the species contrast with the poverty of the deep eastern Mediterranean. The presence of a specialized fauna, with some mollusk genera and species shared with other reduced environments of the Mediterranean, but not dominated by the large bivalves usually found at seeps, is discussed.

  18. Combined genomic and structural analyses of a cultured magnetotactic bacterium reveals its niche adaptation to a dynamic environment

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    Ana Carolina Vieira Araujo

    2016-10-01

    Full Text Available Abstract Background Magnetotactic bacteria (MTB are a unique group of prokaryotes that have a potentially high impact on global geochemical cycling of significant primary elements because of their metabolic plasticity and the ability to biomineralize iron-rich magnetic particles called magnetosomes. Understanding the genetic composition of the few cultivated MTB along with the unique morphological features of this group of bacteria may provide an important framework for discerning their potential biogeochemical roles in natural environments. Results Genomic and ultrastructural analyses were combined to characterize the cultivated magnetotactic coccus Magnetofaba australis strain IT-1. Cells of this species synthesize a single chain of elongated, cuboctahedral magnetite (Fe3O4 magnetosomes that cause them to align along magnetic field lines while they swim being propelled by two bundles of flagella at velocities up to 300 μm s−1. High-speed microscopy imaging showed the cells move in a straight line rather than in the helical trajectory described for other magnetotactic cocci. Specific genes within the genome of Mf. australis strain IT-1 suggest the strain is capable of nitrogen fixation, sulfur reduction and oxidation, synthesis of intracellular polyphosphate granules and transporting iron with low and high affinity. Mf. australis strain IT-1 and Magnetococcus marinus strain MC-1 are closely related phylogenetically although similarity values between their homologous proteins are not very high. Conclusion Mf. australis strain IT-1 inhabits a constantly changing environment and its complete genome sequence reveals a great metabolic plasticity to deal with these changes. Aside from its chemoautotrophic and chemoheterotrophic metabolism, genomic data indicate the cells are capable of nitrogen fixation, possess high and low affinity iron transporters, and might be capable of reducing and oxidizing a number of sulfur compounds. The relatively

  19. Bacterial sulfite dehydrogenases in organotrophic metabolism: separation and identification in Cupriavidus necator H16 and in Delftia acidovorans SPH-1.

    Science.gov (United States)

    Denger, Karin; Weinitschke, Sonja; Smits, Theo H M; Schleheck, David; Cook, Alasdair M

    2008-01-01

    The utilization of organosulfonates as carbon sources by aerobic or nitrate-reducing bacteria usually involves a measurable, uncharacterized sulfite dehydrogenase. This is tacitly assumed to be sulfite : ferricytochrome-c oxidoreductase [EC 1.8.2.1], despite negligible interaction with (eukaryotic) cytochrome c: the enzyme is assayed at high specific activity with ferricyanide as electron acceptor. Purified periplasmic sulfite dehydrogenases (SorAB, SoxCD) are known from chemoautotrophic growth and are termed 'sulfite oxidases' by bioinformatic services. The catalytic unit (SorA, SoxC; termed 'sulfite oxidases' cd02114 and cd02113, respectively) binds a molybdenum-cofactor (Moco), and involves a cytochrome c (SorB, SoxD) as electron acceptor. The genomes of several bacteria that express a sulfite dehydrogenase during heterotrophic growth contain neither sorAB nor soxCD genes; others contain at least four paralogues, for example Cupriavidus necator H16, which is known to express an inducible sulfite dehydrogenase during growth with taurine (2-aminoethanesulfonate). This soluble enzyme was enriched 320-fold in four steps. The 40 kDa protein (denatured) had an N-terminal amino acid sequence which started at position 42 of the deduced sequence of H16_B0860 (termed 'sulfite oxidase' cd02114), which we named SorA. The neighbouring gene is an orthologue of sorB, and the sorAB genes were co-transcribed. Cell fractionation showed SorA to be periplasmic. The corresponding enzyme in Delftia acidovorans SPH-1 was enriched 270-fold, identified as Daci_0055 (termed 'sulfite oxidase' cd02110) and has a cytochrome c encoded downstream. We presume, from genomic data for bacteria and archaea, that there are several subgroups of sulfite dehydrogenases, which all contain a Moco, and transfer electrons to a specific cytochrome c.

  20. Methane fates in the benthos and water column at cold seep sites along the continental margin of Central and North America

    Science.gov (United States)

    Hansman, Roberta L.; Thurber, Andrew R.; Levin, Lisa A.; Aluwihare, Lihini I.

    2017-02-01

    The potential influence of methane seeps on carbon cycling is a key question for global assessments, but the study of carbon cycling in surface sediments and the water column of cold seep environments is complicated by the high temporal and spatial variability of fluid and gas fluxes at these sites. In this study we directly examined carbon sources supporting benthic and planktonic food webs at venting methane seeps using isotopic and molecular approaches that integrate this variability. At four seep environments located along North and Central America, microorganisms from two size fractions were collected over several days from 2800 to 9050 l of seawater to provide a time-integrated measure of key microbial groups and the carbon sources supporting the overall planktonic microbial community. In addition to water column measurements, the extent of seafloor methane release was estimated at two of the sites by examining the stable carbon isotopic signature (δ13C) of benthic metazoan infauna. This signature reveals carbon sources fueling the base of the food chain and thus provides a metric that represents a time-integrated view of the dominant microbial processes within the sediment. The stable carbon isotopic composition of microbial DNA (δ13C-DNA), which had values between -17.0 and -19.5‰, indicated that bulk planktonic microbial production was not ultimately linked to methane or other 13C-depleted seep-derived carbon sources. Instead these data support the importance of organic carbon derived from either photo- or chemoautotrophic CO2 fixation to the planktonic food web. Results of qPCR of microbial DNA sequences coding for a subunit of the particulate methane monooxygenase gene (pmoA) showed that only a small percentage of the planktonic microbial community were potential methane oxidizers possessing pmoA (planktonic microbial community.

  1. Geochemical Energy for Catabolism and Anabolism in Hydrothermal Systems

    Science.gov (United States)

    Amend, J. P.; McCollom, T. M.; Bach, W.

    2008-12-01

    Chemically reduced deep-sea vent fluids mixed with oxidized seawater can generate redox disequilibria that serve as energy sources for chemolithoautotrophic (catabolism) and biomass synthesis (anabolism) reactions. Numerical models can be used to evaluate Gibbs energies of such processes on the early Earth and in present-day systems. Here, geochemical data from compositionally diverse vent fluids (Lost City, Rainbow, Logatchev, TAG, 21 °N EPR) are combined with several seawater chemistries to yield a wide range of mixed hydrothermal solutions; this is the starting point for our thermodynamic calculations. In ultramafic-hosted hydrothermal systems, such as Rainbow or Lost City, aerobic chemolithotrophic catabolisms (oxidation of H2, FeII, CH4) are the most energy-yielding at low temperatures (<25 °C); at elevated temperatures, the anaerobic counterparts (e.g., sulfate reduction, methanogenesis) dominate. In basalt-hosed systems, such as TAG and 21 °N EPR, aerobic sulfide oxidation appears to dominate over much of the microbially-relevant temperature range. Such catabolic reaction energetics can then be used to put constraints on the amount of primary biomass production. Under putative early Earth conditions, for example, the net chemoautotrophic synthesis of cellular building blocks is thermodynamically most favorable at moderate temperatures (~50°C), where the energy contributions from HCO3- and H+ in cool seawater coupled to the reducing power in hot vent fluid are optimized. At these conditions, and counter to conventional wisdom, the synthesis of amino acids may even yield small amounts of energy.

  2. Caribbean Spiny Lobster Fishery Is Underpinned by Trophic Subsidies from Chemosynthetic Primary Production.

    Science.gov (United States)

    Higgs, Nicholas D; Newton, Jason; Attrill, Martin J

    2016-12-19

    The Caribbean spiny lobster, Panulirus argus, is one of the most valuable fisheries commodities in the Central American region, directly employing 50,000 people and generating >US$450 million per year [1]. This industry is particularly important to small island states such as The Bahamas, which exports more lobster than any other country in the region [1]. Several factors contribute to this disproportionally high productivity, principally the extensive shallow-water banks covered in seagrass meadows [2], where fishermen deploy artificial shelters for the lobsters to supplement scarce reef habitat [3]. The surrounding seabed communities are dominated by lucinid bivalve mollusks that live among the seagrass root system [4, 5]. These clams host chemoautotrophic bacterial symbionts in their gills that synthesize organic matter using reduced sulfur compounds, providing nutrition to their hosts [6]. Recent studies have highlighted the important role of the lucinid clam symbiosis in maintaining the health and productivity of seagrass ecosystems [7, 8], but their biomass also represents a potentially abundant, but as yet unquantified, food source to benthic predators [9]. Here we undertake the first analysis of Caribbean spiny lobster diet using a stable isotope approach (carbon, nitrogen, and sulfur) and show that a significant portion of their food (∼20% on average) is obtained from chemosynthetic primary production in the form of lucinid clams. This nutritional pathway was previously unrecognized in the spiny lobster's diet, and these results are the first empirical evidence that chemosynthetic primary production contributes to the productivity of commercial fisheries stocks. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  3. 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 LG; Woyke, Tanja; Wu, Dongying; Lang, Jenna; Eisen, Jonathan A.; Cavanaugh, Colleen M.

    2014-01-01

    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

  4. Genomic signatures of fifth autotrophic carbon assimilation pathway in bathypelagic Crenarchaeota.

    Science.gov (United States)

    La Cono, Violetta; Smedile, Francesco; Ferrer, Manuel; Golyshin, Peter N; Giuliano, Laura; Yakimov, Michail M

    2010-09-01

    Marine Crenarchaeota, ubiquitous and abundant organisms in the oceans worldwide, remain metabolically uncharacterized, largely due to their low cultivability. Identification of candidate genes for bicarbonate fixation pathway in the Cenarchaeum symbiosum A was an initial step in understanding the physiology and ecology of marine Crenarchaeota. Recent cultivation and genome sequencing of obligate chemoautotrophic Nitrosopumilus maritimus SCM1 were a major breakthrough towards understanding of their functioning and provide a valuable model for experimental validation of genomic data. Here we present the identification of multiple key components of 3-hydroxipropionate/4-hydroxybutyrate cycle, the fifth pathway in carbon fixation, found in data sets of environmental sequences representing uncultivated superficial and bathypelagic Crenarchaeota from Sargasso sea (GOS data set) and KM3 (Mediterranean Sea) and ALOHA (Atlantic ocean) stations. These organisms are likely to use acetyl-CoA/propionyl-CoA carboxylase(s) as CO₂-fixing enzyme(s) to form succinyl-CoA, from which one molecule of acetyl-CoA is regenerated via 4-hydroxybutyrate cleavage and another acetyl-CoA to be the pathway product. The genetic distinctiveness and matching sympatric abundance imply that marine crenarchaeal genotypes from the three different geographic sites share similar ecophysiological properties, and therefore may represent fundamental units of marine ecosystem functioning. To couple results of sequence comparison with the dark ocean primary production, dissolved inorganic carbon fixation rates were measured at KM3 Station (3000 m depth, Eastern Mediterranean Sea), i.e. at the same site and depth used for metagenomic library construction. © 2010 The Authors. Journal compilation © 2010 Society for Applied Microbiology and Blackwell Publishing Ltd.

  5. Microbial communities in dark oligotrophic volcanic ice cave ecosystems of Mt. Erebus, Antarctica

    Directory of Open Access Journals (Sweden)

    Bradley M. Tebo

    2015-03-01

    Full Text Available The Earth’s crust hosts a subsurface, dark, and oligotrophic biosphere that is poorly understood in terms of the energy supporting its biomass production and impact on food webs at the Earth’s surface. Dark oligotrophic volcanic ecosystems (DOVEs are good environments for investigations of life in the absence of sunlight as they are poor in organics, rich in chemical reactants and well known for chemical exchange with Earth’s surface systems. Ice caves near the summit of Mt. Erebus (Antarctica offer DOVEs in a polar alpine environment that is starved in organics and with oxygenated hydrothermal circulation in highly reducing host rock. We surveyed the microbial communities using PCR, cloning, sequencing and analysis of the small subunit (16S ribosomal and Ribulose-1,5-bisphosphate Carboxylase/Oxygenase (RubisCO genes in sediment samples from three different caves, two that are completely dark and one that receives snow-filtered sunlight seasonally. The microbial communities in all three caves are composed primarily of Bacteria and fungi; Archaea were not detected. The bacterial communities from these ice caves display low phylogenetic diversity, but with a remarkable diversity of RubisCO genes including new deeply branching Form I clades, implicating the Calvin-Benson-Bassham cycle as a pathway of CO2 fixation. The microbial communities in one of the dark caves, Warren Cave, which has a remarkably low phylogenetic diversity, were analyzed in more detail to gain a possible perspective on the energetic basis of the microbial ecosystem in the cave. Atmospheric carbon (CO2 and CO, including from volcanic emissions, likely supplies carbon and/or some of the energy requirements of chemoautotrophic microbial communities in Warren Cave and probably other Mt. Erebus ice caves. Our work casts a first glimpse at Mt. Erebus ice caves as natural laboratories for exploring carbon, energy and nutrient sources in the subsurface biosphere and the

  6. Dissection of Microbial Community Functions during a Cyanobacterial Bloom in the Baltic Sea via Metatranscriptomics

    Directory of Open Access Journals (Sweden)

    Carlo Berg

    2018-02-01

    Full Text Available Marine and brackish surface waters are highly dynamic habitats that undergo repeated seasonal variations in microbial community composition and function throughout time. While succession of the various microbial groups has been well investigated, little is known about the underlying gene-expression of the microbial community. We investigated microbial interactions via metatranscriptomics over a spring to fall seasonal cycle in the brackish Baltic Sea surface waters, a temperate brackish water ecosystem periodically promoting massive cyanobacterial blooms, which have implications for primary production, nutrient cycling, and expansion of hypoxic zones. Network analysis of the gene expression of all microbes from 0.22 to 200 μm in size and of the major taxonomic groups dissected the seasonal cycle into four components that comprised genes peaking during different periods of the bloom. Photoautotrophic nitrogen-fixing Cyanobacteria displayed the highest connectivity among the microbes, in contrast to chemoautotrophic ammonia-oxidizing Thaumarchaeota, while heterotrophs dominated connectivity among pre- and post-bloom peaking genes. The network was also composed of distinct functional connectivities, with an early season balance between carbon metabolism and ATP synthesis shifting to a dominance of ATP synthesis during the bloom, while carbon degradation, specifically through the glyoxylate shunt, characterized the post-bloom period, driven by Alphaproteobacteria as well as by Gammaproteobacteria of the SAR86 and SAR92 clusters. Our study stresses the exceptionally strong biotic driving force executed by cyanobacterial blooms on associated microbial communities in the Baltic Sea and highlights the impact cyanobacterial blooms have on functional microbial community composition.

  7. High resolution shallow imaging of the mega-splay fault in the central Nankai Trough off Kumano

    Science.gov (United States)

    Ashi, J.

    2012-12-01

    fault plane itself is not recognized, displacements of sedimentary layers are observed along the fault up to 30 meter below the seafloor. Landward dip of the fault is estimated to be 30 degrees. Displacements of strata are about 3 m near the surface and about 5 m at 7 m below the seafloor suggesting accumulation of fault displacement. The structure more than 30 m below the seafloor is obscure due to decrease of acoustic signal. Active cold seep is expected in this site by high heat flow (Yamano et al., 2012) and many trails of Calyptogena detected by seafloor observations. These results are consistent with the shallow structures reveled by our subbottom profiling survey. References Sakaguchi, A. et al., Geology 39, 919-922, 2011. Yamano, M. et al., JpGU Meeting abstract, SSS38-P23, 2012

  8. 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

  9. 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

  10. CONVENTIONAL VIDEOENDOSCOPY CAN IDENTIFY HELICOBACTER PYLORI GASTRITIS?

    Science.gov (United States)

    Gomes, Alexandre; Skare, Thelma Larocca; Prestes, Manoel Alberto; Costa, Maiza da Silva; Petisco, Roberta Dombroski; Ramos, Gabriela Piovezani

    2016-01-01

    are suggestive but not specific to the infection. The other forms were not conclusive of the presence of HP. Estudos com tecnologias mais recentes como endoscopia com magnificação e cromoscopia mostraram que vários aspectos endoscópicos estão claramente associados à infecção por Helicobacter pylori. A descrição de padrões diferenciados de enantema no corpo gástrico através da magnificação de imagens reavivou o interesse na identificação desses padrões pela endoscopia convencional. Validar os padrões morfológicos de mucosa gástrica usando videogastroendoscopia convencional relacionados à gastrite por infecção por Helicobacter pylori, permitindo previsibilidade do seu diagnóstico e o direcionamento de biópsias. Estudo prospectivo de 339 pacientes consecutivos com análise das imagens de videogastroendoscopia obtidas, gravadas e armazenadas em banco de dados. Estas imagens foram estudadas com relação à presença ou não do Helicobacter pylori diagnosticado por teste rápido de urease e/ou por pesquisa direta por estudo anatomopatológico. Foram estudados: a) aspecto normal da mucosa; b) nodularidade da mucosa; c) enantema inespecífico difuso de antro e corpo; d) enantema em mosaico ou salpicado; e) enantema em estrias ou faixas; f) erosões elevadas; g) erosões planas; h) pólipos de glândulas fúndicas. Os principais critérios de exclusão foram o uso de medicamentos, tratamento prévio de HP e outras entidades que pudessem interferir nos resultados. Aplicando os critérios de exclusão, incluíram-se 170 dos 339 pacientes sendo 52 (30,58%) positivos para Helicobacter pylori e 118 negativos. No grupo positivo os achados que mais se associaram com a infecção foram: nodularidade no antro (26,92%); presença de erosões elevadas (15,38%) e mucosa em mosaico no corpo (21,15%). No grupo negativo o aspecto normal da mucosa foi de 66,94%; enantema em estrias ou faixas em 9,32%; erosões planas em 11,86%; e pólipos de glândulas fúndicas 11

  11. Colonoscopia de alta resolução com cromoscopia no diagnóstico diferencial dos pólipos neoplásicos e não-neoplásicos High resolution chromoendoscopy in the differential diagnosis of neoplastic and non-neoplastic polyps

    Directory of Open Access Journals (Sweden)

    Marcelo Averbach

    2003-06-01

    Full Text Available RACIONAL: Com o advento da colonoscopia com magnificação de imagem, tem se mostrado possível a identificação da natureza histopatológica das lesões colorretais através de suas características da forma que as glândulas se abrem na superfície da mucosa (PITS. Apesar de ser método com alto índice de acurácia para o diagnóstico diferencial entre lesões neoplásicas e não-neoplásicas, trata-se de equipamento especializado, de custos elevados, não disponível na grande maioria dos centros médicos. Diante dessa realidade, a colonoscopia convencional com cromoscopia vem adquirindo espaço, pois acredita-se que pode reproduzir grande parte das informações obtidas até então pela colonoscopia com magnificação de imagem. OBJETIVO: Determinar o papel da colonoscopia de alta resolução com cromoscopia no diagnóstico diferencial entre pólipos neoplásicos e não-neoplásicos através dos seguintes índices estatísticos: acurácia, sensibilidade, especificidade, valores preditivos positivo e negativo. PACIENTES E MÉTODO: Realizou-se estudo prospectivo, onde foram avaliadas 74 lesões polipóides colorretais em 54 pacientes. Foi utilizado o colonoscópio Olympus Exera CFQ 160L de alta resolução. Após identificadas, as lesões foram coradas com índigo carmim 0,2% e analisadas conforme classificação descrita por Kudo, por um único examinador. Após ressecados, os pólipos foram encaminhados para estudo anatomopatológico. RESULTADOS: Os achados endoscópicos foram comparados com os resultados histopatológicos. A acurácia do método foi de 79,7%, sensibilidade de 88,8%, especificidade de 55%, valor preditivo positivo de 84,2% e valor preditivo negativo de 64,7%. CONCLUSÃO: Pode-se concluir que se deve ter cautela na aplicação clínica da colonoscopia de alta resolução com cromoscopia, pois lesões adenomatosas podem ser interpretadas como não-neoplásicas.BACKGROUND: Magnifying colonoscopy brought the possibility of

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

    Science.gov (United States)

    Sanchez, Sophie; Hourdez, Stéphane; Lallier, François H

    2007-01-01

    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 analyses were

  13. 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=handling and environmental dust loadings on cleaned/sterilized control surfaces (e.g., 6,782-36,243RLU/cm2). Cleanliness/sterility can be maintained by applying a simple sterile protocol under field conditions. Science results from this research will support future Astrobiology driven drilling mission planned on Mars. Specifically, ground truth offers relevant insights to assess strengths

  14. Clusters of orthologous genes for 41 archaeal genomes and implications for evolutionary genomics of archaea

    Science.gov (United States)

    Makarova, Kira S; Sorokin, Alexander V; Novichkov, Pavel S; Wolf, Yuri I; Koonin, Eugene V

    2007-01-01

    Background An evolutionary classification of genes from sequenced genomes that distinguishes between orthologs and paralogs is indispensable for genome annotation and evolutionary reconstruction. Shortly after multiple genome sequences of bacteria, archaea, and unicellular eukaryotes became available, an attempt on such a classification was implemented in Clusters of Orthologous Groups of proteins (COGs). Rapid accumulation of genome sequences creates opportunities for refining COGs but also represents a challenge because of error amplification. One of the practical strategies involves construction of refined COGs for phylogenetically compact subsets of genomes. Results New Archaeal Clusters of Orthologous Genes (arCOGs) were constructed for 41 archaeal genomes (13 Crenarchaeota, 27 Euryarchaeota and one Nanoarchaeon) using an improved procedure that employs a similarity tree between smaller, group-specific clusters, semi-automatically partitions orthology domains in multidomain proteins, and uses profile searches for identification of remote orthologs. The annotation of arCOGs is a consensus between three assignments based on the COGs, the CDD database, and the annotations of homologs in the NR database. The 7538 arCOGs, on average, cover ~88% of the genes in a genome compared to a ~76% coverage in COGs. The finer granularity of ortholog identification in the arCOGs is apparent from the fact that 4538 arCOGs correspond to 2362 COGs; ~40% of the arCOGs are new. The archaeal gene core (protein-coding genes found in all 41 genome) consists of 166 arCOGs. The arCOGs were used to reconstruct gene loss and gene gain events during archaeal evolution and gene sets of ancestral forms. The Last Archaeal Common Ancestor (LACA) is conservatively estimated to possess 996 genes compared to 1245 and 1335 genes for the last common ancestors of Crenarchaeota and Euryarchaeota, respectively. It is inferred that LACA was a chemoautotrophic hyperthermophile that, in addition to the

  15. Clusters of orthologous genes for 41 archaeal genomes and implications for evolutionary genomics of archaea

    Directory of Open Access Journals (Sweden)

    Wolf Yuri I

    2007-11-01

    Full Text Available Abstract Background An evolutionary classification of genes from sequenced genomes that distinguishes between orthologs and paralogs is indispensable for genome annotation and evolutionary reconstruction. Shortly after multiple genome sequences of bacteria, archaea, and unicellular eukaryotes became available, an attempt on such a classification was implemented in Clusters of Orthologous Groups of proteins (COGs. Rapid accumulation of genome sequences creates opportunities for refining COGs but also represents a challenge because of error amplification. One of the practical strategies involves construction of refined COGs for phylogenetically compact subsets of genomes. Results New Archaeal Clusters of Orthologous Genes (arCOGs were constructed for 41 archaeal genomes (13 Crenarchaeota, 27 Euryarchaeota and one Nanoarchaeon using an improved procedure that employs a similarity tree between smaller, group-specific clusters, semi-automatically partitions orthology domains in multidomain proteins, and uses profile searches for identification of remote orthologs. The annotation of arCOGs is a consensus between three assignments based on the COGs, the CDD database, and the annotations of homologs in the NR database. The 7538 arCOGs, on average, cover ~88% of the genes in a genome compared to a ~76% coverage in COGs. The finer granularity of ortholog identification in the arCOGs is apparent from the fact that 4538 arCOGs correspond to 2362 COGs; ~40% of the arCOGs are new. The archaeal gene core (protein-coding genes found in all 41 genome consists of 166 arCOGs. The arCOGs were used to reconstruct gene loss and gene gain events during archaeal evolution and gene sets of ancestral forms. The Last Archaeal Common Ancestor (LACA is conservatively estimated to possess 996 genes compared to 1245 and 1335 genes for the last common ancestors of Crenarchaeota and Euryarchaeota, respectively. It is inferred that LACA was a chemoautotrophic hyperthermophile

  16. Energetic and hydrogen limitations of thermophilic and hyperthermophilic methanogens

    Science.gov (United States)

    Stewart, L. C.; Holden, J. F.

    2013-12-01

    Deep-sea hydrothermal vents are a unique ecosystem, based ultimately not on photosynthesis but chemosynthetic primary production. This makes them an excellent analog environment for the early Earth, and for potential extraterrestrial habitable environments, such as those on Mars and Europa. The habitability of given vent systems for chemoautotrophic prokaryotes can be modeled energetically by estimating the available Gibbs energy for specific modes of chemoautotrophy, using geochemical data and mixing models for hydrothermal fluids and seawater (McCollom and Shock, 1997). However, modeling to date has largely not taken into account variation in organisms' energy demands in these environments. Controls on maintenance energies are widely assumed to be temperature-dependent, rising with increasing temperature optima (Tijhuis et al., 1993), and species-independent. The impacts of other environmental stressors and particular energy-gathering strategies on maintenance energies have not been investigated. We have undertaken culture-based studies of growth and maintenance energies in thermophilic and hyperthermophilic methanogenic (hydrogenotrophic) archaea from deep-sea hydrothermal vents to investigate potential controls on energy demands in hydrothermal vent microbes, and to quantify their growth and maintenance energies for future bioenergetic modeling. We have investigated trends in their growth energies over their full temperature range and a range of nitrogen concentrations, and in their maintenance energies at different hydrogen concentrations. Growth energies in these organisms appear to rise with temperature, but do not vary between hyperthermophilic and thermophilic methanogens. Nitrogen availability at tested levels (40μM - 9.4 mM) does not appear to affect growth energies in all but one tested organism. In continuous chemostat culture, specific methane production varied with hydrogen availability but was similar between a thermophilic and a hyperthermophilic

  17. Thermal intensification of microbial Fe(II)/Fe(III) redox cycling in a pristine shallow sand aquifer on the Canadian Shield.

    Science.gov (United States)

    Shirokova, V L; Enright, A M L; Kennedy, C B; Ferris, F G

    2016-12-01

    This investigation evaluates spatial relationships between summer (July) groundwater temperatures and Fe(II)/Fe(III) biogeochemical cycling over a five year period in a shallow pristine sand aquifer at Meilleurs Bay near Deep River, Ontario, Canada. A warm subsurface thermal island of 12.5-16.1 °C, compared to background conditions of 10-11 °C, was manifest in contour maps of average groundwater temperature over the study period. The warm zone coincided with an area of convergent groundwater flow, implicating horizontal heat transfer by advective convection as the reason for elevated temperatures. Additionally, high concentrations of dissolved Fe(II) and Fe(III) overlapped the warm thermal island, indicative of increased rates of bacterial Fe(II)-oxidation and Fe(III)-reduction. A depletion in the modal abundance of Fe(II)-bearing minerals, notably amphibole and biotite, inside the area of the warm thermal island was also observed, suggesting enhanced mineral dissolution owing to chemoautotrophic Fe(II)-oxidation coupled to the reduction and fixation of dissolved inorganic carbon as biomass. Throughout the aquifer, redox conditions were poised in terms of Eh and pH close to equilibrium with respect to the Fe(II)/Fe(OH)3 couple, feasibly enabling simultaneous bacterial Fe(II)-oxidation and Fe(III)-reduction with an adequate supply of electron acceptors and donors, respectively. The significance of higher groundwater temperature as a determinant of elevated dissolved Fe(II) and Fe(III) concentrations induced by thermal intensification of microbial biogeochemical activities yielded Pearson product-moment correlations in which temperature alone, as a single independent variable, explains almost 30 to nearly 60 percent of the variation in the measured dissolved Fe(II) and Fe(III) concentrations in the groundwater. These results emphasize the important influence of thermal conditions on biogeochemical processes in aquifers coupled to the development of steep

  18. 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

  19. Hot Spring Microbial Community Composition, Morphology, and Carbon Fixation: Implications for Interpreting the Ancient Rock Record

    Directory of Open Access Journals (Sweden)

    Caleb G. Schuler

    2017-11-01

    Full Text Available Microbial communities in hydrothermal systems exist in a range of macroscopic morphologies including stromatolites, mats, and filaments. The architects of these structures are typically autotrophic, serving as primary producers. Structures attributed to microbial life have been documented in the rock record dating back to the Archean including recent reports of microbially-related structures in terrestrial hot springs that date back as far as 3.5 Ga. Microbial structures exhibit a range of complexity from filaments to more complex mats and stromatolites and the complexity impacts preservation potential. As a result, interpretation of these structures in the rock record relies on isotopic signatures in combination with overall morphology and paleoenvironmental setting. However, the relationships between morphology, microbial community composition, and primary productivity remain poorly constrained. To begin to address this gap, we examined community composition and carbon fixation in filaments, mats, and stromatolites from the Greater Obsidian Pool Area (GOPA of the Mud Volcano Area, Yellowstone National Park, WY. We targeted morphologies dominated by bacterial phototrophs located in close proximity within the same pool which are exposed to similar geochemistry as well as bacterial mat, algal filament and chemotrophic filaments from nearby springs. Our results indicate (i natural abundance δ13C values of biomass from these features (−11.0 to −24.3‰ are similar to those found in the rock record; (ii carbon uptake rates of photoautotrophic communities is greater than chemoautotrophic; (iii oxygenic photosynthesis, anoxygenic photosynthesis, and chemoautotrophy often contribute to carbon fixation within the same morphology; and (iv increasing phototrophic biofilm complexity corresponds to a significant decrease in rates of carbon fixation—filaments had the highest uptake rates whereas carbon fixation by stromatolites was significantly lower

  20. 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.

  1. 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

  2. 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

  3. The Microbiome and Occurrence of Methanotrophy in Carnivorous Sponges

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    Jon Thomassen Hestetun

    2016-11-01

    Full Text Available As shown by recent studies, filter-feeding sponges are known to host a wide variety of microorganisms. However, the microbial community of the non-filtering carnivorous sponges (Porifera, Cladorhizidae has been the subject of less scrutiny. Here, we present the results from a comparative study of the methanotrophic carnivorous sponge Cladorhiza methanophila from a mud volcano-rich area at the Barbados Accretionary Prism (BAP, and five carnivorous species from the Jan Mayen Vent Field (JMVF at the Arctic Mid-Ocean Ridge. Results from 16S rRNA microbiome data indicate the presence of a diverse assemblage of associated microorganisms in carnivorous sponges mainly from the Gamma- and Alphaproteobacteria, Flavobacteriaceae and Thaumarchaeota. While the abundance of particular groups varied throughout the dataset, we found interesting similarities to previous microbiome results from non-carnivorous deep sea sponges, suggesting that the carnivorous sponges share characteristics of a previously hypothesized putative deep-sea sponge microbial community. Chemolithoautotrophic symbiosis was confirmed for C. methanophila through a microbial community with a high abundance of Methylococcales and very light isotopic δ13C and δ15N ratios (-60 to -66‰/3.5 to 5.2‰ compared to the other cladorhizid species (-22 to -24‰/8.5-10.5‰. We provide evidence for the presence of putative sulfur-oxidizing Gammaproteobacteria in the arctic cladorhizids; however, δ13C and δ15N signatures did not provide evidence for significant chemoautotrophic symbiosis in this case, and the slightly higher abundance of cladorhizids at the JMVF site compared to the nearby deep sea likely stem from an increased abundance of prey rather than a more direct vent association. The phylogenetic position of C. methanophila in relation to other carnivorous sponges was established using a three-gene phylogenetic analysis, and it was found to be closely related to other non

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

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    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

  5. 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

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

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    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. Using metatranscriptomics to understand the roles of Fe(II)-oxidizing microbes in marine hydrothermal vents

    Science.gov (United States)

    Glazer, B. T.; Mcallister, S.; Polson, S. W.; Chan, C. S. Y.

    2015-12-01

    Fe(II)-oxidizing microbes (FeOM) are thought to be key players in marine Fe cycling, particularly at hydrothermal vents. However, we do not have tools to track their activity, largely because we do not know the genes involved in neutrophilic chemolithotrophic Fe oxidation. Researchers have used gene homology between FeOM isolates to suggest several genes that may be involved in Fe(II) oxidation, including the Fe oxidase cyc2 found in the Zetaproteobacteria type strain Mariprofundus ferrooxydans, as well as all other known neutrophilic microaerophilic FeOM. Although many Zetaproteobacteria are found within natural Fe mats, close relatives of Fe(II)-oxidizing isolates are rarely present. Therefore, one goal of this study was to determine the activity of putative Fe(II) oxidation genes in dominant OTUs found in natural environments. We collected Fe mats from hydrothermal vents at Loihi Seamount, Hawaii, preserving RNA in situ. By analyzing metatranscriptomes of different Fe mat niches, we were able to determine the OTUs involved and the gene expression patterns associated with Fe(II) oxidation in the marine environment. Analysis of metatranscriptomic data confirms that the Zetaproteobacteria express the various genes necessary to support the Fe mat community through chemoautotrophic growth. Globally ubiquitous and even some rare species of the Zetaproteobacteria were active, with different relative abundances depending on Fe mat niches defined by fluid flow and geochemistry. Initial results show that genes thought to be involved in the electron transport pathway from Fe(II) to O2, including cyc2, are some of the most highly expressed genes in marine Fe microbial mats. Species-specific variants of these genes suggest that many of the Zetaproteobacteria species, spanning the breadth of the diversity of the class, are expressing genes necessary for Fe(II) oxidation within natural Fe mat niches. Understanding the differential expression of these genes in different niches

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

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    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

  9. Racionalidad del terror

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    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.

  10. Superposição automatizada de modelos tomográficos tridimensionais em cirurgia ortognática Superimposition of 3D cone-beam CT models in orthognathic surgery

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    Alexandre Trindade Simões da Motta

    2010-04-01

    Full Text Available INTRODUÇÃO: as limitações na avaliação quantitativa e qualitativa de deslocamentos cirúrgicos pelos métodos bidimensionais podem ser superadas através de tomografias volumétricas e ferramentas de imagens tridimensionais. OBJETIVOS: a metodologia descrita neste trabalho permite avaliar as mudanças nas posições de côndilos, ramos, mento, maxila e da dentição após a cirurgia ortognática através de tomografias computadorizadas de feixe cônico (Cone Beam Computed Tomography, CBCT antes e após o procedimento cirúrgico. MÉTODOS: são construídos modelos 3D que possibilitam superposições tendo a base do crânio pré-cirúrgica como referência, utilizando-se um método automático que identifica e compara a escala de cinza dos voxels de duas estruturas tridimensionais, eliminando a necessidade do operador marcar os pontos anatômicos. Então, as distâncias entre as superfícies anatômicas são computadas, no mesmo indivíduo, entre as duas fases. A avaliação das direções de deslocamento das estruturas é determinada visualmente pelos métodos de mapas coloridos e de semitransparências. CONCLUSÕES: conclui-se que a metodologia apresentada, que utiliza softwares de domínio público, mostra vantagens na avaliação longitudinal de pacientes ortocirúrgicos, quando comparada aos métodos radiográficos convencionais, uma vez que as imagens geradas não apresentam magnificações ou sobreposições de estruturas e a maioria dos passos são automatizados, o que torna os procedimentos de mensuração mais precisos, além de disponibilizar uma maior quantidade de informações ao clínico ou pesquisador.INTRODUCTION: Limitations of 2D quantitative and qualitative evaluation of surgical displacements can be overcome by CBCT and three-dimensional imaging tools. OBJECTIVES: The method described in this study allows the assessment of changes in the condyles, rami, chin, maxilla and dentition by the comparison of CBCT scans before

  11. Efeitos do raloxifeno sobre a angiogênese do carcinoma de mama de mulheres menopausadas Effects of raloxifene on angiogenesis of the breast carcinoma of menopausal women

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    Pedro Vitor Lopes-Costa

    2007-07-01

    Full Text Available OBJETIVO: avaliar o efeito do raloxifeno sobre a angiogênese do carcinoma de mama em mulheres menopausadas. MÉTODOS: dezesseis pacientes menopausadas com carcinoma de mama operável, estádio II (diâmetro >3 cm, positivo para receptor de estrógeno, foram incluídas no estudo. Após confirmação do diagnóstico por biópsia incisional, as pacientes receberam 60 mg de raloxifeno diariamente por 28 dias, previamente à cirurgia definitiva. Exame imunohistoquímico foi realizado nas amostras tumorais, obtidas por ocasião da biópsia para diagnóstico e avaliação do status do receptor de estrógeno e da cirurgia definitiva. O anticorpo monoclonal anti-CD34 foi usado como marcador das células endoteliais. A unidade vascular considerada foi qualquer célula ou grupo de células endoteliais coradas, nitidamente separadas de microvasos adjacentes, células tumorais ou tecido conjuntivo, formando ou não lúmen. A contagem de microvasos antes e após tratamento com raloxifeno foi realizada em dez campos aleatórios, usando microscópio acoplado a sistema de captura e análise de imagem (Imagelab® com magnificação de 400X. O teste t de Student para duas amostras pareadas foi usado para análise estatística dos dados (pPURPOSE: to evaluate the effect of raloxifene on breast cancer angiogenesis of menopausal women. METHODS: sixteen menopausal women with stage II (>3 cm estrogen receptor positive operable breast cancer were enrolled in this study. Following confirmation of the diagnosis by incisional biopsy, the patients received 60 mg raloxifene daily for 28 days prior to the definitive surgery. Immunohistochemical study was performed on the sample tumors obtained during the biopsy for the diagnosis and evaluation of the status of estrogen receptor and during the definitive surgery. The anti-CD34 monoclonal antibody was used as a marker for endothelial cells. The vascular unit was considered as any endothelial cell or group of cells of a

  12. Videocolonoscopia convencional e cromoscopia com índigo carmim no diagnóstico de pólipos colônicos Colonic polyps diagnosis by conventional video colonoscopes and chromoscopy with indigo carmine dye solution

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    Frank Shigueo NAKAO

    2002-04-01

    Full Text Available Racional - Colonoscópios com magnificação e cromoscopia com índigo carmim vêm sendo utilizados na diferenciação de pólipos colônicos neoplásicos (adenomatosos e adenocarcinomas dos não-neoplásicos (hiperplásicos, inflamatórios, juvenis, in loco, antes da realização do estudo histológico. Por outro lado, ainda foi pouco estudado o uso de colonoscópios convencionais e cromoscopia na predição da histologia destas lesões. Objetivo - Avaliar o desempenho de videocolonoscópios convencionais com cromoscopia com índigo carmim no diagnóstico diferencial de pólipos colônicos. Métodos - Previamente à polipectomia de pólipos detectados durante exames diagnósticos de rotina, foi realizada cromoscopia com índigo carmim. Se fossem observados sulcos na superfície da lesão a mesma era classificada como neoplásica. Na ausência deste aspecto, a mesma era classificada como não-neoplásica. Estas observações foram comparadas com as conclusões do estudo histológico. Resultados - No período de estudo (18 meses, foram detectados 133 pólipos em 53 pacientes. A cromoendoscopia apresentou, em 126 lesões, sensibilidade de 56,4%, especificidade de 79,2%, valor preditivo positivo de 81,5%, valor preditivo negativo de 52,8% e acurácia de 65,1% no diagnóstico de lesões neoplásicas. Conclusão - Os dados desta série permitem concluir que a cromoscopia com índigo carmim durante a colonoscopia convencional não é método confiável no diagnóstico diferencial in loco do tipo histológico dos pólipos colônicos.Background - Magnification colonoscopy and contrast chromoscopy with indigo carmine dye solution have been used to differentiate neoplastic polyps (adenomas and adenocarcinomas from non-neoplastic (hyperplastic, inflammatory, juvenile in an attempt to obviate endoscopic polypectomy. On the other hand, little published information exists concerning conventional video colonoscopes and chromoscopy for polyp histology

  13. 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

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    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.

  14. 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

  15. 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

  16. Harpacticoid copepods-their symbiotic associations and biogenic substrata: a review.

    Science.gov (United States)

    Huys, Rony

    2016-10-11

    Amenophia Boeck, 1865. Idomene australis Brady, 1910, I. pusilla Brady, 1910, Dactylopusia ferrieri T. Scott, 1912 and I. kabylica Monard, 1936 are ranked species incertae sedis in the Pseudotachidiidae. Dactylopus bahamensis Edwards, 1891 is tentatively considered as species incertae sedis in the Dactylopusiidae. Canuellina onchophora Por, 1967 and C. nicobaris Wells & Rao, 1987 are transferred to the genus Ellucana Coull, 1971b while Ellucana secunda Coull, 1971b is assigned to the genus Canuellina Gurney, 1927. Xylora calyptogenae Willen, 2006 is sunk as a junior subjective synonym of X. bathyalis Hicks, 1988a. The incorrect original spellings of Parathalestris pacificus Chislenko, 1971, P. infestus Ho & Hong, 1988, Tripartisoma ovalis Avdeev, 1983, T. trapezoidalis Avdeev, 1983, Amplipedicola pectinatus Avdeev, 2010 and Sunaristes japonicus Ho, 1986a are amended to reflect agreement in gender with their respective generic names.

  17. 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

  18. Vertical profile and components of marine planktonic archaea in the Pacific sector of the Arctic Oceean

    Science.gov (United States)

    Akiyama, S.; Amano (Sato), C.; Uchida, M.; Utsumi, M.

    2011-12-01

    Archaea had been considered as extremophiles, which thrive exclusively in extreme environments. However, developing with molecular biological techniques like detecting the sequence of 16S rRNA gene, it was found that Group I Crenarchaeota, and group II, III and IV Euryarchaeota, which are affiliated with Archaea, exist in the worldwide oceans. Besides, quantification of these marine planktonic archaea using fluorescence in situ hybridization (FISH) revealed that they are distributed ubiquitously and abundantly in the ocean. Isotopic studies using lipid biomarkers and microautoradiographic analyses, and isolation of Nitrosopumilus maritimus, which was first cultivated Group I Crenarchaeota, showed that some Group I Crenarchaeota lives by chemoautotrophically oxidizing ammonium to nitrite. Therefore, the archaea would be expected that they are one of the most important key players to drive carbon cycle under the euphotic zone in the ocean. On the other hand, some marine planktonic archaea are heterotrophic or mixotrophic, because a large fraction of them have been shown to assimilate amino acid. Thus, it is necessary to investigate which groups of marine planktonic archaea exist and are dominant in the ocean so as to estimate carbon flux drived by marine planktonic archaea. The Arctic Ocean is known as one of the coldest sea water areas. Since absorbing anthropogenic carbon dioxide into the Arctic Ocean probably impacts on carbon cycle and ecosystem, it is necessary to understand detailed carbon cycle in this ocean. Consequently, it needs to identify distribution of marine planktonic archaea in the Arctic Ocean. Several studies of the marine planktonic archaea in the Arctic Ocean were conducted in the central Arctic Ocean, Beaufort Sea and Canada Basin, but not in the Pacific sector of the Arctic Ocean. Based on this point, we investigated distribution of marine planktonic archaea in the Pacific sector of the Arctic Ocean. Sampling in the Pacific sector of the Arctic

  19. 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

  20. Worldwide Eutrophication of Water Bodies: Causes, Concerns, Controls

    Science.gov (United States)

    Prepas, E. E.; Charette, T.

    2003-12-01

    cyanobacteria, heterotrophic, and chemoautotrophic bacteria) can use nitrogen gas directly and incorporate it into organic compounds through a process called nitrogen fixation. Nitrogen fixation is an enzyme-catalyzed process that reduces nitrogen gas (N2) to ammonia (NH3). Nitrogen-fixing cyanobacteria make up less than 1% of the total biomass of phytoplankton in estuaries of the Atlantic coast of North America, whereas in lakes they often make up more than 50% of phytoplankton biomass (reviewed in Howarth, 1988). An increase in water clarity can also spur the growth of aquatic vegetation in systems where the clarity of water is poor from high concentrations of suspended particles.The biodiversity of most aquatic systems decreases with eutrophication (Figure 1). Phytoplankton species diversity is reduced in highly productive systems. Cyanobacteria are usually dominant in eutrophic systems because these organisms are better adapted to conditions of high nutrients (Smith, 1986; Trimbee and Prepas, 1987; Watson et al., 1997). In addition, fish and macro-invertebrate species diversity can decrease with eutrophication. Depletion of dissolved oxygen in deep water is associated with eutrophication and can lead to a loss or displacement of species intolerant of such conditions ( Ludsin et al., 2001). In eutrophic lakes of North America, characteristic fish types are surface-dwelling, warm water fishes such as pike, perch, and bass, as compared to deep-dwelling, cold-water fishes like salmon, trout, and cisco ( Ryding and Rast, 1989). (9K)Figure 1. Suggested changes in various characteristics of lakes with eutrophication (reproduced by permission of Cambridge University Press from Welch, E. B., Ecological Effects of Waste Water, 1980, p. 273).

  1. Cinder Pool's Sulfur Chemistry: Implications for the Origin of Life in Hydrothermal Environments

    Science.gov (United States)

    Sydow, L.; Bennett, P.; Nordstrom, D.

    2012-12-01

    One theory of the origin of life posits the abiotic formation of alkyl thiols as an initial step to forming biomolecules and eventually a simple chemoautotrophic cell. The premise of this theory is that a recurring reaction on the charged surfaces of pyrite served as a primordial metabolism analogous to the Acetyl-CoA pathway (Wächtershäuser 1988) and was later enveloped by a primitive cellular membrane. However, alkyl thiols have not previously been identified in terrestrial hot springs as unequivocally abiogenic. We have identified methanethiol (CH3SH), the simplest of the alkyl thiols, as well as dimethyl sulfide and dimethyldisulfide, in Cinder Pool, an acid-sulfate-chloride hot spring in the One Hundred Spring Plain of Norris Geyser Basin, Yellowstone National Park. It is unusual in that it contains a molten sulfur layer on the bottom (~20 m depth) and thousands of iron-sulfur-spherules floating on the surface (the iconic "cinders" the pool is named for), created by gas bubbling through the molten basement of the spring. These unique features make it a good candidate for abiotically generated CH3SH. Gas samples were collected from Cinder pool as well as an adjacent hydrothermal feature in the autumn of 2011 using the bubble strip method modified for use with hydrothermal waters. Several samples contained measurable quantities of methanethiol and other organic sulfur gases, with concentrations increasing with depth in the pool. Laboratory microcosm experiments were conducted to investigate the geochemical conditions required to abiotically form CH3SH. Sterile, artificial Cinder Pool water was injected into sterilized 60 mL serum bottles containing different iron-sulfur compounds, including cinders collected from the pool itself, as catalytic surfaces for the methanethiol-generating reaction. The bottles were then charged with hydrogen and carbon dioxide as reaction gases and incubated for a week at temperatures between 60 and 120oC. Bottles using FeS as a

  2. 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

  3. Quantifying microbial activity in deep subsurface sediments using a tritium based hydrognease enzyme assay

    Science.gov (United States)

    Adhikari, R.; Nickel, J.; Kallmeyer, J.

    2012-12-01

    Microbial life is widespread in Earth's subsurface and estimated to represent a significant fraction of Earth's total living biomass. However, very little is known about subsurface microbial activity and its fundamental role in biogeochemical cycles of carbon and other biologically important elements. Hydrogen is one of the most important elements in subsurface anaerobic microbial metabolism. Heterotrophic and chemoautotrophic microorganisms use hydrogen in their metabolic pathways. They either consume or produce protons for ATP synthesis. Hydrogenase (H2ase) is a ubiquitous intracellular enzyme that catalyzes the interconversion of molecular hydrogen and/or water into protons and electrons. The protons are used for the synthesis of ATP, thereby coupling energy generating metabolic processes to electron acceptors such as CO2 or sulfate. H2ase enzyme targets a key metabolic compound in cellular metabolism therefore the assay can be used as a measure for total microbial activity without the need to identify any specific metabolic process. Using the highly sensitive tritium assay we measured H2ase enzyme activity in the organic-rich sediments of Lake Van, a saline, alkaline lake in eastern Turkey, in marine sediments of the Barents Sea and in deep subseafloor sediments from the Nankai Trough. H2ase activity could be quantified at all depths of all sites but the activity distribution varied widely with depth and between sites. At the Lake Van sites H2ase activity ranged from ca. 20 mmol H2 cm-3d-1 close to the sediment-water interface to 0.5 mmol H2 cm-3d-1 at a depth of 0.8 m. In samples from the Barents Sea H2ase activity ranged between 0.1 to 2.5 mmol H2 cm-3d-1 down to a depth of 1.60 m. At all sites the sulfate reduction rate profile followed the upper part of the H2ase activity profile until sulfate reduction reached the minimum detection limit (ca. 10 pmol cm-3d-1). H2ase activity could still be quantified after the decline of sulfate reduction, indicating that

  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. Aspectos Históricos de la deficiencia de Yodo en América

    Directory of Open Access Journals (Sweden)

    Mario Paredes Suárez

    2001-08-01

    , originario de hace 1500 años A. C., habla de las primeras operaciones de bocio y de la administración de sal yodada como una adecuada estrategia de profilaxis.

    La presencia de algunos aspectos de la deficiencia crónica de yodo en América, particularmente del bocio, se ha hecho evidente a través de los estudios e investigaciones de un gran numero de autores. Luis A. León en 1959 (2, en su magnifica publicación “Folklore e Historia del Bocio Endémico en la República del Ecuador”, expresa: “… En la literatura medica y social del país durante la dominación española, no se encuentra mayor información acerca de la endemia bociógena; sólo en las postrimerías de dicho periodo se comienza a hablar del coto como entidad nosológica que existe en nuestra patología…”. Por otro lado en sus varias publicaciones, Greenwald (3, 4, 5, 6, 7, 8, manifiesta que el bocio no existió en América antes de la llegada de los españoles, y que se hace presente a partir del siglo XVIII. Otros autores como McClendon, tienen una similar opinión al respecto.

    Es interesante anotar la observación de que muchos investigadores como Cieza de León (9, Jorge Juan de Santasilla (10 y Antonio de Ulloa (11, La Condamine (12, el Padre Juan de Velasco (13 y Eugenio Espejo (14 no mencionen, en su extensa producción, esta entidad nosológica.

    Pero ya León en Ecuador, Lastres en Perú (15, 16 y posteriormente Rodrigo Fierro (17 enfatizan la palabra coto, sobre la base de toponimias quichuas, como manifestación de la presencia de esta enfermedad; el último autor tiene la opinión de que el bocio, si bien existió en el pre-incario, no tuvo caracteres endémicos sino a partir de la época hispánica en América.

    Sin embargo se considera que la frecuencia del bocio en las poblaciones indígenas de varios países latinoamericanos se ha evidenciado por la presencia y permanencia del término “cotto” o “coto”, para denominar por toponimia al abultamiento de

  6. 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

  7. 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