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.

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

Tri-domain Bifunctional Inhibitor of Metallocarboxypeptidases A and Serine Proteases Isolated from Marine Annelid Sabellastarte magnifica*

Science.gov (United States)

Alonso-del-Rivero, Maday; Trejo, Sebastian A.; Reytor, Mey L.; Rodriguez-de-la-Vega, Monica; Delfin, Julieta; Diaz, Joaquin; González-González, Yamile; Canals, Francesc; Chavez, Maria Angeles; Aviles, Francesc X.

2012-01-01

This study describes a novel bifunctional metallocarboxypeptidase and serine protease inhibitor (SmCI) isolated from the tentacle crown of the annelid Sabellastarte magnifica. SmCI is a 165-residue glycoprotein with a molecular mass of 19.69 kDa (mass spectrometry) and 18 cysteine residues forming nine disulfide bonds. Its cDNA was cloned and sequenced by RT-PCR and nested PCR using degenerated oligonucleotides. Employing this information along with data derived from automatic Edman degradation of peptide fragments, the SmCI sequence was fully characterized, indicating the presence of three bovine pancreatic trypsin inhibitor/Kunitz domains and its high homology with other Kunitz serine protease inhibitors. Enzyme kinetics and structural analyses revealed SmCI to be an inhibitor of human and bovine pancreatic metallocarboxypeptidases of the A-type (but not B-type), with nanomolar Ki values. SmCI is also capable of inhibiting bovine pancreatic trypsin, chymotrypsin, and porcine pancreatic elastase in varying measures. When the inhibitor and its nonglycosylated form (SmCI N23A mutant) were overproduced recombinantly in a Pichia pastoris system, they displayed the dual inhibitory properties of the natural form. Similarly, two bi-domain forms of the inhibitor (recombinant rSmCI D1-D2 and rSmCI D2-D3) as well as its C-terminal domain (rSmCI-D3) were also overproduced. Of these fragments, only the rSmCI D1-D2 bi-domain retained inhibition of metallocarboxypeptidase A but only partially, indicating that the whole tri-domain structure is required for such capability in full. SmCI is the first proteinaceous inhibitor of metallocarboxypeptidases able to act as well on another mechanistic class of proteases (serine-type) and is the first of this kind identified in nature. PMID:22411994

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

Science.gov (United States)

Davis, R.; Tebo, B. M.

2013-12-01

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

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.

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; Saenz-Agudelo, Pablo; Scott, Anna; Berumen, Michael L.

2016-01-01

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.

Inhibitory effect of self-generated extracellular dissolved organic carbon on carbon dioxide fixation in sulfur-oxidizing bacteria during a chemoautotrophic cultivation process and its elimination.

Science.gov (United States)

Wang, Ya-Nan; Tsang, Yiu Fai; Wang, Lei; Fu, Xiaohua; Hu, Jiajun; Li, Huan; Le, Yiquan

2018-03-01

The features of extracellular dissolved organic carbon (EDOC) generation in two typical aerobic sulfur-oxidizing bacteria (Thiobacillus thioparus DSM 505 and Halothiobacillus neapolitanus DSM 15147) and its impact on CO 2 fixation during chemoautotrophic cultivation process were investigated. The results showed that EDOC accumulated in both strains during CO 2 fixation process. Large molecular weight (MW) EDOC derived from cell lysis and decay was dominant during the entire process in DSM 505, whereas small MW EDOC accounted for a large proportion during initial and middle stages of DSM 15147 as its cytoskeleton synthesis rate did not keep up with CO 2 assimilation rate. The self-generated EDOC feedback repressed cbb gene transcription and thus decreased total bacterial cell number and CO 2 fixation yield in both strains, but DSM 505 was more sensitive to this inhibition effect. Moreover, the membrane bioreactor effectively decreased the EDOC/TOC ratio and improved carbon fixation yield of DSM 505. Copyright © 2017 Elsevier Ltd. All rights reserved.

Heavy metal bioaccumulation in the organisms at hydrothermal fields of the Mid-Atlantic Ridge and East-Pacific Rise

International Nuclear Information System (INIS)

Demina, L.L.; Galkin, S.V.

2008-01-01

The influence of geochemical environment as well as biological parameters on the heavy metal bioaccumulation in the hydrothermal fauna at certain fields of the Mid-Atlantic ridge (MAR) and East Pacific Rise (EPR) are studied. The highest concentration of Fe, Zn, Cu, Mn, Ni, Cr, Co, Pb, Cd, Ag, Se, Sb, As, and Hg were detected in the tubes of the most thermophilic organism Alvinella caudata inhabited sulfide chimneys at 9 0 50 ' N EPR, i.e. at place where the influence of hydrothermal fluids was the maximal. Elevated heavy metals levels were typical for organs associated with the endo symbiotic bacteria activity, such as gills of specialized mussels Bathymodiolus, clams Archivestica gigas (Calyptogena magnifica), trophosome of vestimentifera Riftia, maxillipeds of shrimps Rimicaris exoculata. Inter-site (Broken Spur vs. Rainbow) comparison of the partitioning of metals within soft tissues has revealed that metal concentrations in the fauna habitats is an important albeit not the single factor that controls the metal content in the interior organs of the taxa. The external parts of mussels, such as shells, demonstrate patterns of bioaccumulation reflecting the metal concentrations in the micro-habitats. In spite of the minimal metal content was found in the mussel shells, they serve as a great reservoirs for heavy metal deposition and storage at the hydrothermal regions. For some elements a trend of heavy metal transferring through the food chains was revealed. There were no clear dependence between age of mussels and metal content (except Hg) in the soft tissues

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

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

Distribution Modeling of three screwworm species in the ecologically diverse landscape of North West Pakistan.

Science.gov (United States)

Zaidi, Farrah; Fatima, Syeda Hira; Khisroon, Muhammad; Gul, Ayesha

2016-10-01

North West Pakistan (NWP) is characterized by four eco-zones: Northern Montane Region, North Western Hills, Submontane Region and Indus Plains. Present study identified 1037 cases of traumatic myiasis in the region during 2012-2015. Screw worm larvae were classified as 12 species: Chrysomya bezziana (Villeneuve), Chryomya megacephala (Fabricius), Chrysomya rufifacies (Macquart), Lucilia cuprina (Wiedemann), Lucilia sericata (Meigen), Lucilia illustris (Meigen), Lucilia porphyrina (Walker), Hemipyrellia ligguriens (Wiedemann), Calliphora vicina (Robineau-Desvoidy), Wohlfahrtia magnifica (Schiner), Sarcophaga crassipalpalis (Macquart), Sarchophaga species. Among these C. bezziana, L. cuprina and W. magnifica with approximately 882 case reports were the principal agents of traumatic myiasis. The species W. magnifica is a first report from Pakistan. In order to investigate spatial distribution of these dominant species we used MaxEnt niche model. Our results revealed a well-established occurrence of C. bezziana and L. cuprina in the four eco-regions while W. magnifica is currently contained in the Submontane Region. Several hot spot areas of infestation were detected all characterized by high human population density showing synanthropic nature of these species. Wohlfahrtia magnifica was excluded from Northern Montane Region with severe winters and Southern Indus Plains with harsh summers revealing that invasive species are initially sensitive to extreme of temperatures. Presence of L. cuprina in the wet areas of North Humid Belt (Maximum annual precipitation: 1641mm) depicted a moisture preference of the species. In perspective of changing climate and future predictions of severe events such as droughts and flooding in NWP, W. magnifica can potentially alter the species composition. Considering these findings in an eco-geographically dynamic region of Pakistan we predict that two factors (1) Growing human population (2) Climatic conditions, equally contribute to range

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

THE FLABELLATE-LEAVED SPECIES OF SALACCA (PALMAE

Directory of Open Access Journals (Sweden)

JOHANIS P. MOGEA

1980-03-01

Full Text Available Salacca dransfieldiana Mogea, S. magnifica Mogea and S. sarawak-ensis Mogea are proposed as new species of flabellate-leaved Salacca.A key to the four recognized species, descriptions and illustrations arepresented.

Antifungal potential of marine sponge extract against plant and fish pathogenic fungi

Digital Repository Service at National Institute of Oceanography (India)

PrabhaDevi; Ravichandran, S.; Ribeiro, M.; Ciavatta, M.L.

scope for rediscovering compounds with antimicrobial activity. This study screens extracts (Diethyl Ether and Butanol) of a marine red-Sea sponge Negombata magnifica for invitro fungicidal activity against 10 plant and 3 fish pathogens. Fungicidal...

Comparative Study of Three Achillea Essential Oils from Eastern Part of Turkey and their Biological Activities

Directory of Open Access Journals (Sweden)

Betül Demirci

2018-03-01

Full Text Available Essential oils obtained by hydrodistillation were analyzed both by gas chromatography (GC and gas chromatography-mass spectrometry (GC-MS.The main constituents found in Achillea oil were as follows: A. filipendulina Lam.: 43.8% santolina alcohol, 14.5% 1,8-cineole and 12.5% cis-chrysanthenyl acetate; A. magnifica Hiemerl ex Hub.-Mor.: 27.5% linalool, 5.8% spathulenol, 5.5% terpinen-4-ol, 4.7% α-terpineol and 4.7% β-eudesmol; A. tenuifolia Lam.: 12.4% artemisia ketone, 9.9% p-cymene, 7.1% camphor, 5.9% terpinen-4-ol, 4.7% caryophyllene oxide and 4.5% α-pinene. Furthermore, the Achillea essential oils were evaluated for antimalarial and antimicrobial activities. A. magnifica and A. filipendulina oils showed strong antimalarial activity against both chloroquine sensitive D6 (IC 50= 1.2 and 0.68 m g/mL and chloroquine resistant W2 (IC 50= 1.1 and 0.9 m g/mL strains of Plasmodium falciparum without any cytotoxicity to mammalian cells up to IC 50=47.6 m g/mL against Vero cells. whereas A. tenuifolia oil showed no antimalarial activity up to a concentration of 20 mg/mL. All three Achillea oils showed no antibacterial activity against human pathogenic bacteria up to a concentration of 200 m g/mL. A. tenuifolia and A. magnifica oils demonstrated mild antifungal activity against Cryptococcus neoformans (IC 50= 45, 20 and 15 m g/mL, respectively.

The response of microalgal biomass and community composition to ...

African Journals Online (AJOL)

2011-06-06

Jun 6, 2011 ... Estuary (33º 43' S; 25º 51' E), and is permanently open to the sea (Fig. 1). .... visualised using the Imaplan V 2.06 image analysis programme. (IMATEC ... using the Zeiss IM 35 inverted microscope at 630x magnifica- tion.

Fir dwarf mistletoe (FIDL).

Science.gov (United States)

Gregory M. Filip; Jerome S. Beatty; Robert L. Mathiasen

2000-01-01

Fir dwarf mistletoe (Arceuthobium abietinum Engelmann ex Munz) is a common and damaging parasite of white fir (Abies concolor (Gord. & Glend.) Lindl. ex Hildebr.), grand fir (Abies grandis (Dougl. ex D. Don) Lindl.), and California red fir (A. magnifica A. Murr.) in the western...

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...

Mortality and growth of dwarf mistletoe-infected red and white fir and the efficacy of thinning for reducing associated losses

Science.gov (United States)

H. K. Mehl; S. R. Mori; S. J. Frankel; D. M. Rizzo

2013-01-01

In managed forests dominated by true fir (Abies) species, stands are often restocked using understory trees retained during timber harvest, making the effects of dwarf mistletoe (Arceuthobium spp.) infestation on small true fir a concern. This study examined the response of small red (A. magnifica) and...

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...

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...

Impact of metabolism and growth phase on the hydrogen isotopic composition of microbial fatty acids

Science.gov (United States)

Heinzelmann, Sandra M.; Villanueva, Laura; Sinke-Schoen, Danielle; Sinninghe Damsté, Jaap S.; Schouten, Stefan; van der Meer, Marcel T. J.

2015-01-01

Microorganisms are involved in all elemental cycles and therefore it is important to study their metabolism in the natural environment. A recent technique to investigate this is the hydrogen isotopic composition of microbial fatty acids, i.e., heterotrophic microorganisms produce fatty acids enriched in deuterium (D) while photoautotrophic and chemoautotrophic microorganisms produce fatty acids depleted in D compared to the water in the culture medium (growth water). However, the impact of factors other than metabolism have not been investigated. Here, we evaluate the impact of growth phase compared to metabolism on the hydrogen isotopic composition of fatty acids of different environmentally relevant microorganisms with heterotrophic, photoautotrophic and chemoautotrophic metabolisms. Fatty acids produced by heterotrophs are enriched in D compared to growth water with εlipid/water between 82 and 359‰ when grown on glucose or acetate, respectively. Photoautotrophs (εlipid/water between −149 and −264‰) and chemoautotrophs (εlipid/water between −217 and −275‰) produce fatty acids depleted in D. Fatty acids become, in general, enriched by between 4 and 46‰ with growth phase which is minor compared to the influence of metabolisms. Therefore, the D/H ratio of fatty acids is a promising tool to investigate community metabolisms in nature. PMID:26005437

Dwarf mistletoe in red and white firs in California–23 to 28 years after inoculation

Science.gov (United States)

John R. Parmeter Jr.; Robert F. Scharpf

1989-01-01

Spread and buildup of dwarf mistletoe, Arceuthobium abietinum, was studied on inoculated white fir, Abies concolor, and red fir, A. magnifica, in northern California for 23 to 28 years. At the end of these studies (1986), and in the absence of overstory infection, 13 of 23 trees had dwarf mistletoe populations...

Nest trees of northern flying squirrels in the Sierra Nevada

Science.gov (United States)

Marc D. Meyer; Douglas A. Kelt; Malcolm P. North

2005-01-01

We examined the nest-tree preferences of northern flying squirrels (Glaucomys sabrinus) in an old-growth, mixed-conifer and red fir (Abies magnifica) forest of the southern Sierra Nevada of California. We tracked 27 individuals to 122 nest trees during 3 summers. Flying squirrels selected nest trees that were larger in diameter and...

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

Czech Academy of Sciences Publication Activity Database

Kollár, P.; Šmejkal, K.; Salmonová, H.; Vlková, E.; Lepšová-Skácelová, O.; Balounová, Z.; Rajchard, J.; Cvačka, Josef; Jaša, Libor; Babica, Pavel; Pazourek, J.

2016-01-01

Roč. 21, č. 11 (2016), č. článku 1476. ISSN 1420-3049 Institutional support: RVO:61388963 ; RVO:67985939 Keywords : Aeromonas * antimicrobial activity * bacteria * Bryozoa * cyanobacteria * invasive species Subject RIV: EH - Ecology, Behaviour Impact factor: 2.861, year: 2016 http://www.mdpi.com/1420-3049/21/11/1476/htm

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

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.

Dietary carbon sources of mussels and tubeworms from Galapagos hydrothermal vents determined from tissue adC activity

Energy Technology Data Exchange (ETDEWEB)

Williams, P M; Smith, K L; Druffel, E M; Linick, T W

1981-07-30

The large quantities of reduced carbon that are required to support the filter-feeding mytilid mussels (Mytilus sp.), vesicomyid clams (Clayptogena sp.) and various other animals in the Galapagos hydrothermal vent systems are thought to be derived from either the in situ synthesis of particulate organic matter by chemoautotrophic, sulfide-oxidizing bacteria or by the advection of sedimentary organic carbon into the vent environment from surrounding areas. In contrast, the dense populations of vestimentiferan tubeworms (Riftia pachyptila), which lack mouth organs and digestive tracts, apparently utilize organic carbon synthesized by symbiotic chemoautotrophs. We present evidence here, based on adC activities and acC/abC ratios, that the principal source of dietary carbon for mussels and tubeworms is derived from the dissolved inorganic carbon (DIOC) in the vent effluent waters.

Paracatenula, an ancient symbiosis between thiotrophic Alphaproteobacteria and catenulid flatworms

Science.gov (United States)

Gruber-Vodicka, Harald Ronald; Dirks, Ulrich; Leisch, Nikolaus; Stoecker, Kilian; Bulgheresi, Silvia; Heindl, Niels Robert; Horn, Matthias; Lott, Christian; Loy, Alexander; Wagner, Michael; Ott, Jörg

2011-01-01

Harnessing chemosynthetic symbionts is a recurring evolutionary strategy. Eukaryotes from six phyla as well as one archaeon have acquired chemoautotrophic sulfur-oxidizing bacteria. In contrast to this broad host diversity, known bacterial partners apparently belong to two classes of bacteria—the Gamma- and Epsilonproteobacteria. Here, we characterize the intracellular endosymbionts of the mouthless catenulid flatworm genus Paracatenula as chemoautotrophic sulfur-oxidizing Alphaproteobacteria. The symbionts of Paracatenula galateia are provisionally classified as “Candidatus Riegeria galateiae” based on 16S ribosomal RNA sequencing confirmed by fluorescence in situ hybridization together with functional gene and sulfur metabolite evidence. 16S rRNA gene phylogenetic analysis shows that all 16 Paracatenula species examined harbor host species-specific intracellular Candidatus Riegeria bacteria that form a monophyletic group within the order Rhodospirillales. Comparing host and symbiont phylogenies reveals strict cocladogenesis and points to vertical transmission of the symbionts. Between 33% and 50% of the body volume of the various worm species is composed of bacterial symbionts, by far the highest proportion among all known endosymbiotic associations between bacteria and metazoans. This symbiosis, which likely originated more than 500 Mya during the early evolution of flatworms, is the oldest known animal–chemoautotrophic bacteria association. The distant phylogenetic position of the symbionts compared with other mutualistic or parasitic Alphaproteobacteria promises to illuminate the common genetic predispositions that have allowed several members of this class to successfully colonize eukaryote cells. PMID:21709249

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

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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.

Bacterial chemoautotrophy in coastal sediments

NARCIS (Netherlands)

Vasquez Cardenas, D.

2016-01-01

A key process in the biogeochemistry of coastal sediments is the reoxidation of reduced intermediates formed during anaerobic mineralization which in part is performed by chemoautotrophic bacteria. These bacteria fix inorganic carbon using the energy derived from reoxidation reactions. However the

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

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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

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

Science.gov (United States)

Cavanaugh, C M; Abbott, M S; Veenhuis, M

1988-10-01

The distribution of the Calvin cycle enzyme ribulose-1,5-bisphosphate carboxylase (RbuP(2)Case; EC 4.1.1.39) was examined by using two immunological methods in tissues of Solemya velum, an Atlantic coast bivalve containing putative chemoautotrophic symbionts. Antibodies elicited by the purified large subunit of RbuP(2)Case from tobacco (Nicotiana tabacum) cross-reacted on immunoblots with a protein of similar molecular mass occurring in extracts of the symbiont-containing gill tissue of S. velum. No cross-reactivity was detected in symbiont-free tissue extracts. The antiserum also cross-reacted in immunoblots with proteins of Thiobacillus neapolitanus, a free-living sulfuroxidizing chemoautotroph whose RbuP(2)Case has been well characterized. In protein A-gold immunoelectron microscopy studies, this antiserum consistently labeled the symbionts but not surrounding host gill tissue, indicating that the symbionts are responsible for the RbuP(2)Case activity.

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

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

DEFF Research Database (Denmark)

Dehant, Veronique; Banerdt, Bruce; Lognonné, Philippe

2012-01-01

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

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

NARCIS (Netherlands)

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

1988-01-01

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

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

Science.gov (United States)

Nakajima, Ryota; Yamamoto, Hiroyuki; Kawagucci, Shinsuke; Takaya, Yutaro; Nozaki, Tatsuo; Chen, Chong; Fujikura, Katsunori; Miwa, Tetsuya; Takai, Ken

2015-01-01

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 ecosystem in the area has

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.

Mediterranean climate effects. II. Conifer growth phenology across a Sierra Nevada ecotone.

Science.gov (United States)

Royce, E B; Barbour, M G

2001-05-01

Growth and xylem water potential of the lower elevation conifers Pinus jeffreyi and Abies concolor and the higher elevation Pinus monticola and Abies magnifica were monitored in their montane Mediterranean habitat of the southernmost Sierra Nevada mountains of California. Measurements were made across the ecotone between the midmontane and upper montane forests and through light and heavy snowfall years.Radial stem growth, averaging ∼1.5 mm/yr, started 2 wk after snow melt, providing that maximum air temperatures had reached 21°C, and ended when predawn water potentials fell rapidly at the onset of the summer drought. Leader growth started on or after a fixed date, providing that minimum air temperatures were above -4°C for Pinus species or +2.5°C for Abies species. The cue for leader growth was inferred to be photoperiodic. Leader growth ended when either a determinate internode length of ∼1 mm was reached or predawn water potentials fell rapidly. Abies magnifica grew more rapidly than the low-elevation species, but had a shorter growth period; its annual leader growth, as a consequence, was only 35 mm/yr vs. 50 mm/yr for the low-elevation species. Needle growth was similarly determinate in the absence of early drought. This growth phenology contributes to determining species distribution across the ecotone.

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.

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

Science.gov (United States)

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. PMID:16346347

Climate and Anthropogenic Change in Aquatic Environments: A Cross Ecosystem Perspective

Science.gov (United States)

2010-01-01

contrac- tions of species habitat ranges and alter physiological processes, both of which can translate to significant disrup- tions in the ecological ...threatened by rising tempera- tures and ocean acidification. Among the threatened organisms are the planktonic larvae of many ecologically and economically...habitats, from the rocky mid-ocean ridges, submarine canyons, trenches, and seamounts , to the island-like chemoautotrophic cold seeps, hydrothermal

Comparison of the radiosensitivity of dry dormant eggs, gemmules, and statoblasts of three invertebrate forms

International Nuclear Information System (INIS)

Shimada, Atsuko; Egami, Nobuo

1985-01-01

Radiosensitivities of the special structures (reproductive organs) of various invertebrate animals were examined. The doses of 50 % hatch were about 5 kR for staboblasts of the bryozoa, Pectinatella magnifica; 70 kR for gemmules of the freshwater sponge, Eunapius fragilis; 130 kR for gemmuls of the freshwater sponge, Ephydatia fluviatilis; 180 kR for dry eggs of the rotifer, Brachionus plicatilis, and 350 kR for dry eggs of Artemia salina. The results showed that Artemia eggs were the most radioresistant reproductive organ among the materials examined. (author)

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...

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.

Transcriptional Response of the Archaeal Ammonia Oxidizer Nitrosopumilus maritimus to Low and Environmentally Relevant Ammonia Concentrations

OpenAIRE

Nakagawa, Tatsunori; Stahl, David A.

2013-01-01

The ability of chemoautotrophic ammonia-oxidizing archaea to compete for ammonia among marine microorganisms at low ambient concentrations has been in part attributed to their extremely high affinity for ammonia, but as yet there is no mechanistic understanding of supporting metabolism. We examined transcription of selected genes for anabolic functions (CO2 fixation, ammonia transport, and cell wall synthesis) and a central catabolic function (ammonia oxidation) in the thaumarchaeon Nitrosopu...

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.

Tubeworm May Live Longer by Cycling Its Sulfur Downward

OpenAIRE

Cordes, Erik E; Arthur, Michael A; Shea, Katriona; Arvidson, Rolf S; Fisher, Charles R

2005-01-01

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 extens...

The globally widespread genus Sulfurimonas: versatile energy metabolisms and adaptations to redox clines

OpenAIRE

Han, Yuchen; Perner, Mirjam

2015-01-01

Sulfurimonas species are commonly isolated from sulfidic habitats and numerous 16S rRNA sequences related to Sulfurimonas species have been identified in chemically distinct environments, such as hydrothermal deep-sea vents, marine sediments, the ocean’s water column, and terrestrial habitats. In some of these habitats, Sulfurimonas have been demonstrated to play an important role in chemoautotrophic processes. Sulfurimonas species can grow with a variety of electron donors and acceptors, whi...

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

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

Biosphere in 3.5 Ga submarine hydrothermal system

Energy Technology Data Exchange (ETDEWEB)

Ueno, Yuichiro [Tokyo Univ. (Japan). Dept. of Earth Science and Astronomy

2003-04-01

Abundant organic matter (kerogen) was identified in {approx}3.5 Ga hydrothermal silica dikes from the North Pole area in the Pilbara craton, Western Australia. The silica dikes developed in the uppermost 1000 m of the ancient oceanic crust. Thus, they would have been deposited in the 3.5 Ga sub-seafloor hydrothermal system. The carbon and nitrogen isotopic compositions of the kerogen were analyzed in this study. Their highly {sup 13}C-depleted isotopic compositions ({delta}{sup 13}C = -38 to -33 per mille) strongly suggest that they are originally derived from biologically produced organic matter. The remarkable similarity of the {delta}{sup 13}C values between the kerogen and modern hydrothermal vent organisms may suggest that the kerogen was derived from chemoautotrophic organisms. This idea is also consistent with their nitrogen isotopic compositions ({delta}{sup 15}N = -4 to +4 per mille). The silica dikes consist mainly of fine-grained silica with minor pyrite and sphalerite. These mineral assemblages indicate that the silica dike was deposited from relatively low-temperature (probably less than 150degC) reducing hydrothermal fluid. Thus, anaerobic thermophilic/hyperthermophilic organisms could have survived in the hydrothermal fluid, which formed the silica dikes. Therefore, it is plausible that a chemoautotrophic-based biosphere (possibly methanogenesis) probably existed in the Early Archean sub-seafloor hydrothermal system. (author)

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

Mars Analog Research and Technology Experiment (MARTE): A Simulated Mars Drilling Mission to Search for Subsurface Life at the Rio Tinto, Spain

Science.gov (United States)

Stoker, Carol; Lemke, Larry; Mandell, Humboldt; McKay, David; George, Jeffrey; Gomez-Alvera, Javier; Amils, Ricardo; Stevens, Todd; Miller, David

2003-01-01

The MARTE (Mars Astrobiology Research and Technology Experiment) project was selected by the new NASA ASTEP program, which supports field experiments having an equal emphasis on Astrobiology science and technology development relevant to future Astrobiology missions. MARTE will search for a hypothesized subsurface anaerobic chemoautotrophic biosphere in the region of the Tinto River in southwestern Spain while also demonstrating technology needed to search for a subsurface biosphere on Mars. The experiment is informed by the strategy for searching for life on Mars.

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

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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.

Arsenic, Anaerobes, and Autotrophy.

Science.gov (United States)

Oremland, R. S.

2008-12-01

That microbes have resistance to the toxic arsenic oxyanions arsenite [As(III)] and arsenate [As(V)] has been recognized for some time. More recently it was shown that certain prokaryotes can demonstrate As- dependent growth by conserving the energy gained from the aerobic oxidation of As(III) to As(V), or from the reduction of As(V) to As(III) under anaerobic conditions. During the course of our field studies of two alkaline, hypersaline soda lakes (Mono Lake and Searles Lake, CA) we have discovered several new anaerobic chemo- and photo-autotrophic bacteria that can center their energy gain around the redox reactions between As(III) and As(V). Alkalilimnicola ehrlichii, isolated from the water column of Mono Lake is a nitrate-respiring, As(III)-oxidizing chemoautotroph of the gamma-proteobacteria that has a highly flexible metabolism. It can function either as a facultative anaerobe or as a chemo-autotroph, or as a heterotroph (Hoeft et al., 2007). In contrast, strain MLMS-1 of the delta-proteobacteria was also isolated from Mono Lake, but to date is the first example of an obligate As(V)-respirer that is also an obligate chemo-autotroph, gaining its energy via the oxidation of sulfide to sulfate (Hoeft et al., 2004). Strain SLAS-1, isolated from salt-saturated Searles Lake is a member of the Halananerobiales, and can either grow as a heterotroph (lactate e-donor) or chemo- autotroph (sulfide e-donor) while respiring As(V). The fact that it can achieve this feat at salt-saturation (~ 340 g/L) makes it a true extremophile (Oremland et. al., 2005). Finally, strain PHS-1 isolated from a hot spring on Paoha island in Mono Lake is the first example of a photosynthetic bacterium of the gamma- proteobacteria able to link its growth to As(III)-dependent anoxygenic photosynthesis (Kulp et al., 2008). These novel microbes give us new insights into the evolution of arsenic-based metabolism and their role in the biogeochemical cycling of this toxic element. Hoeft, S.E., et

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

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......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...

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

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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.

Acquisition of a Novel Sulfur-Oxidizing Symbiont in the Gutless Marine Worm Inanidrilus exumae

Science.gov (United States)

2018-01-01

ABSTRACT Gutless phallodrilines are marine annelid worms without a mouth or gut, which live in an obligate association with multiple bacterial endosymbionts that supply them with nutrition. In this study, we discovered an unusual symbiont community in the gutless phallodriline Inanidrilus exumae that differs markedly from the microbiomes of all 22 of the other host species examined. Comparative 16S rRNA gene sequence analysis and fluorescence in situ hybridization revealed that I. exumae harbors cooccurring gamma-, alpha-, and deltaproteobacterial symbionts, while all other known host species harbor gamma- and either alpha- or deltaproteobacterial symbionts. Surprisingly, the primary chemoautotrophic sulfur oxidizer “Candidatus Thiosymbion” that occurs in all other gutless phallodriline hosts does not appear to be present in I. exumae. Instead, I. exumae harbors a bacterial endosymbiont that resembles “Ca. Thiosymbion” morphologically and metabolically but originates from a novel lineage within the class Gammaproteobacteria. This endosymbiont, named Gamma 4 symbiont here, had a 16S rRNA gene sequence that differed by at least 7% from those of other free-living and symbiotic bacteria and by 10% from that of “Ca. Thiosymbion.” Sulfur globules in the Gamma 4 symbiont cells, as well as the presence of genes characteristic for autotrophy (cbbL) and sulfur oxidation (aprA), indicate that this symbiont is a chemoautotrophic sulfur oxidizer. Our results suggest that a novel lineage of free-living bacteria was able to establish a stable and specific association with I. exumae and appears to have displaced the “Ca. Thiosymbion” symbionts originally associated with these hosts. IMPORTANCE All 22 gutless marine phallodriline species examined to date live in a highly specific association with endosymbiotic, chemoautotrophic sulfur oxidizers called “Ca. Thiosymbion.” These symbionts evolved from a single common ancestor and represent the ancestral trait for

Evaluation of nutrient and energy sources of the deepest known serpentinite-hosted ecosystem using stable carbon, nitrogen, and sulfur isotopes.

Science.gov (United States)

Onishi, Yuji; Yamanaka, Toshiro; Okumura, Tomoyo; Kawagucci, Shinsuke; Watanabe, Hiromi Kayama; Ohara, Yasuhiko

2018-01-01

The Shinkai Seep Field (SSF) in the southern Mariana forearc discovered in 2010 is the deepest (~5,700 m in depth) known serpentinite-hosted ecosystem dominated by a vesicomyid clam, Calyptogena (Abyssogena) mariana. The pioneering study presumed that the animal communities are primary sustained by reducing fluid originated from the serpentinization of mantle peridotite. For understanding the nutrient and energy sources for the SSF community, this study conducted four expeditions to the SSF and collected additional animal samples such as polychaetes and crustaceans as well as sediments, fragments of chimneys developing on fissures of serpentinized peridotite, seeping fluid on the chimneys, and pore water within the chimneys. Geochemical analyses of seeping fluids on the chimneys and pore water of the chimneys revealed significantly high pH (~10) that suggest subseafloor serpentinization controlling fluid chemistry. Stable isotope systematics (carbon, nitrogen, and sulfur) among animals, inorganic molecules, and environmental organic matter suggest that the SSF animal community mostly relies on the chemosynthetic production while some organisms appear to partly benefit from photosynthetic production despite the great depth of SSF.

Isolation and identification of aromatic hydrocarbon degrading yeasts present in gasoline tanks of urbans vehicles

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Nathalia Catalina Delgadillo-Ordoñez

2017-07-01

Full Text Available Yeast isolates were obtained from fuel tanks of vehicles in order to assess their potential use in the degradation of aromatic hydrocarbons. Growth assays were performed in minimum mineral medium using different aromatic hydrocarbons (benzene, toluene, naphthalene, phenanthrene, and pyrene as the sole carbon source. Isolates that showed growth in any of the tested polycyclic aromatic hydrocarbons were identified by Sanger sequencing of the ITS1 and ITS2 rDNA molecular markers. A total of 16 yeasts strains were isolated, and three showed remarkable growth in media with aromatic hydrocarbons as the sole carbon source. These strains belong to the genus Rhodotorula, and correspond to the species Rhodotorula calyptogenae (99,8% identity and Rhodotorula dairenensis (99,8% identity.  These strains grew in benzene, toluene, naphthalene, phenanthrene and pyrene. This study demonstrates for the first time that yeasts of the genus Rhodotorula inhabit pipelines and fuel tanks of vehicles and that remove   aromatic hydrocarbons that are environmental pollutants. Our results suggest that these yeasts are potential candidates for aromatic hydrocarbon degradation as part of bioremediation strategies.

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.

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.

City sewer collectors biocorrosion

Science.gov (United States)

Ksiażek, Mariusz

2014-12-01

This paper presents the biocorrosion of city sewer collectors impregnated with special polymer sulphur binders, polymerized sulphur, which is applied as the industrial waste material. The city sewer collectors are settled with a colony of soil bacteria which have corrosive effects on its structure. Chemoautotrophic nitrifying bacteria utilize the residues of halites (carbamide) which migrate in the city sewer collectors, due to the damaged dampproofing of the roadway and produce nitrogen salts. Chemoorganotrophic bacteria utilize the traces of organic substrates and produce a number of organic acids (formic, acetic, propionic, citric, oxalic and other). The activity of microorganisms so enables the origination of primary and secondary salts which affect physical properties of concretes in city sewer collectors unfavourably.

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.

Surfing the vegetal pole in a small population: extracellular vertical transmission of an 'intracellular' deep-sea clam symbiont.

Science.gov (United States)

Ikuta, Tetsuro; Igawa, Kanae; Tame, Akihiro; Kuroiwa, Tsuneyoshi; Kuroiwa, Haruko; Aoki, Yui; Takaki, Yoshihiro; Nagai, Yukiko; Ozawa, Genki; Yamamoto, Masahiro; Deguchi, Ryusaku; Fujikura, Katsunori; Maruyama, Tadashi; Yoshida, Takao

2016-05-01

Symbiont transmission is a key event for understanding the processes underlying symbiotic associations and their evolution. However, our understanding of the mechanisms of symbiont transmission remains still fragmentary. The deep-sea clam Calyptogena okutanii harbours obligate sulfur-oxidizing intracellular symbiotic bacteria in the gill epithelial cells. In this study, we determined the localization of their symbiont associating with the spawned eggs, and the population size of the symbiont transmitted via the eggs. We show that the symbionts are located on the outer surface of the egg plasma membrane at the vegetal pole, and that each egg carries approximately 400 symbiont cells, each of which contains close to 10 genomic copies. The very small population size of the symbiont transmitted via the eggs might narrow the bottleneck and increase genetic drift, while polyploidy and its transient extracellular lifestyle might slow the rate of genome reduction. Additionally, the extracellular localization of the symbiont on the egg surface may increase the chance of symbiont exchange. This new type of extracellular transovarial transmission provides insights into complex interactions between the host and symbiont, development of both host and symbiont, as well as the population dynamics underlying genetic drift and genome evolution in microorganisms.

Extraction of extracellular lipids from chemoautotrophic bacteria Serratia sp. ISTD04 for production of biodiesel.

Science.gov (United States)

Bharti, Randhir K; Srivastava, Shaili; Thakur, Indu Shekhar

2014-08-01

A CO2 sequestering bacterial strain, Serratia sp. ISTD04, that produces a significant amount of extracellular lipids was isolated from marble mine rocks. (14)C labeling analysis revealed that the rate of assimilation of CO2 by the strain is 0.756×10(-9)μmolCO2fixedcell(-1)h(-1). It was found to produce 466mg/l of extracellular lipid which was characterized using (1)H NMR. After transesterification of lipids, the total saturated and unsaturated FAME was found to be 51% and 49% respectively. The major FAME contained in the biodiesel were palmitic acid methyl ester (C16:0), oleic acid methyl ester (C18:1) and 10-nonadecenoic acid methyl ester (C19:1). Biodiesel produced by Serratia sp. ISTD04 is balanced in terms of FAME composition of good quality. It also contained higher proportion of oleic acid (35%) which makes it suitable for utilization in existing engines. Thus, the strain can be harnessed commercially to sequester CO2 into biodiesel. Copyright © 2014 Elsevier Ltd. All rights reserved.

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.

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

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

International Nuclear Information System (INIS)

Distel, D.L.

1987-01-01

Low magnification electron microscopy and light microscopy were performed on plastic embedded and fresh samples of bacteriocyte tissues from L. annulata, L. aequizonata and L. floridana. Serial sectioning was used to determine the three dimensional relationship between host tissues, symbiont cells, and the external environment. Possible effects of structure on the exchange of metabolites and inorganic molecules are discussed. Density gradient centrifugation was used to purify symbiotic bacteria from homogenates of host bacteriocyte tissue. The results demonstrate that bacteria can be recovered intact, biologically active and nearly free of contaminants from host tissue. Incorporation of H 14 CO 3 - into acid soluble metabolic intermediates by either whole gills, isolated bacteria or bacteria isolated from gills previously exposed to label was examined in L. aequizonata. HPLC, paper chromatography and enzymatic techniques were used to identify and quantify labeled products. The initial fixation product in whole gills is malate. In the symbionts aspartate and 3-phosphoglycerate are the major labeled compounds. Possible pathways of carbon exchange between hosts and symbionts are discussed

Identification of anaerobic arsenite-oxidizing and arsenate-reducing bacteria associated with an alkaline saline lake in Khovsgol, Mongolia.

Science.gov (United States)

Hamamura, Natsuko; Itai, Takaaki; Liu, Yitai; Reysenbach, Anna-Louise; Damdinsuren, Narantuya; Inskeep, William P

2014-10-01

Microbial arsenic transformation pathways associated with a saline lake located in northern Mongolia were examined using molecular biological and culturing approaches. Bacterial 16S rRNA gene sequences recovered from saline lake sediments and soils were affiliated with haloalkaliphiles, including Bacillus and Halomonas spp. Diverse sequences of arsenate respiratory reductase (arrA) and a new group of arsenite oxidase (arxA) genes were also identified. Pure cultures of arsenate-reducing Nitrincola strain and anaerobic arsenite-oxidizing Halomonas strain were isolated. The chemoorganotrophic Halomonas strain contains arxA gene similar to that of a chemoautotrophic arsenite-oxidizing Alkalilimnicola ehrlichii strain MLHE-1. These results revealed the diversity of arsenic transformation pathways associated with a geographically distinct saline system and the potential contribution of arx-dependent arsenite oxidation by heterotrophic bacteria.

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

DEFF Research Database (Denmark)

Wagner, Florian Benedikt

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...... to remove ammonium to below the national drinking water quality standard of 0.05 mg NH4+/L. A better process understanding of nitrifying biofilters is needed to optimize treatment performance, remediate existing filters, and to prevent future nitrification problems. The frequent incidents of insufficient...... in the oxidation of ammonia to hydroxylamine. Thus, slow and incomplete nitrification could be caused by a lack of sufficient amounts of copper. The overall aim of this PhD project was therefore to determine whether copper supplementation could enhance nitrification in rapid sand filters with incomplete...

Catalysis in the Primordial World

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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.

Nitrogenase genes in non-cyanobacterial plankton: prevalence, diversity, and regulation in marine waters

DEFF Research Database (Denmark)

Riemann, Lasse; Farnelid, H.; Steward, G.F.

2010-01-01

Marine waters are generally considered to be nitrogen (N) limited and are therefore favourable environments for diazotrophs, i.e. organisms converting atmospheric N2 into ammonium or nitrogen oxides available for growth. In some regions, this import of N supports up to half of the primary...... productivity. Diazotrophic Cyanobacteria appear to be the major contributors to marine N2 fixation in surface waters, whereas the contribution of heterotrophic or chemoautotrophic diazotrophs to this process is usually regarded inconsequential. Culture-independent studies reveal that non......-cyanobacterial diazotrophs are diverse, widely distributed, and actively expressing the nitrogenase gene in marine and estuarine environments. The detection of nifH genes and nifH transcripts, even in N-replete marine waters, suggests that N2 fixation is an ecologically important process throughout the oceans. Because...

Relatos clínicos de contaminación y peligro. Cocreando desde dentro el estigma social en la gestante seropositiva

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José Manuel Hernández Garre

2015-12-01

Full Text Available El objetivo del artículo ha sido explorar las principales representaciones de los sanitarios respecto a las parturientas VIH positivo, y sus posibles repercusiones en el proceso de creación/destrucción de su identidad en clave de estigma social. La metodología elegida ha sido la realización de una serie de entrevistas semiestructuradas, cuyos resultados muestran ciertos miedos e inseguridades que afloran en los sanitarios como consecuencia de la sensación de vulnerabilidad, miedos que se acrecientan en el parto, donde la posibilidad de infección se magnifica al tener contacto con fluidos corporales potencialmente contaminantes. La conclusión final es que la corporalidad de la gestante seropositiva se construye en los medios clínicos en clave negativa, apareciendo en los relatos dos tipos de estigma, el «determinante», asociado al peligro de contagio en sí mismo, y el «simbólico», derivado de las conductas socialmente desacreditadas que se relacionan popularmente a la enfermedad.

Mineralogy of Surface Serpentinite Outcrops in the Coast Range Ophiolite: Implications for the Deep Biosphere and Astrobiology

Science.gov (United States)

Mccann, A. R.; Cardace, D.; Carnevale, D.; Ehlmann, B. L.

2011-12-01

California contains a number of ultramafic (Fe- and Mg rich) rock bodies, including the Coast Range Ophiolite, a block of oceanic crust and upper mantle tectonically emplaced onto land. These ultramafic rocks are primarily composed of olivine and pyroxene, both of which are stable at the high temperatures and pressures in the deep subsurface where they crystallize but become unstable at low temperature and low pressure conditions near the surface. They are highly reduced rocks, creating chemical disequilibria, which can theoretically provide energy to chemoautotrophic organisms. Serpentinization (serpentine-forming) reactions between the rocks and water produce hydrogen molecules, which can be metabolized by diverse organisms. Earth and Mars have shown evidence of similar early geologic histories, possibly with widespread reducing habitable environments (Schulte et al., 2006). Recent data from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) have shown serpentine-bearing outcrops near Nili Fossae (21 N, 282 W) and elsewhere in Mars' cratered highlands. Serpentine-bearing outcrops are rare, but their presence confirms that such systems involving the aqueous alteration of ultramafic rocks were active in the past (specifically during the Noachian epoch (older than ~3.7 billion years), possibly producing aqueous habitats suitable for chemoautotrophic life (Ehlmann et al., 2010). Remotely sensed data cannot confirm whether there is active serpentinization on Mars, however exposed, presently serpentinizing ultramafics in terrestrial ophiolites such as those of the California Coast Range provide points of comparison for similar Martian rocks. Volume expansion during serpentinization fractures the host rock, exposing new reaction surfaces, allowing further serpentinization. If subsurface liquid water is present on Mars, serpentinization may still be occurring. We will provide x-ray diffraction and petrographic data for surface serpentinites from the Coast

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

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

International Nuclear Information System (INIS)

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

1991-01-01

Carbon isotopic compositions of autotrophic organisms can be predicted based on recently established relationships between [CO 2 (aq)] and var-epsilon p , the isotopic fractionation accompanying carbon fixation. In both the Black Sea and the Cariaco Trench, where [CO 2 (aq)] values are known and δ values for hydrocarbons were recently determined, predicted biomass δ values can be compared to those of biomarkers extracted from POM and sediment samples. The agreement is good, although a 5 per-thousand range in δ values is observed for the lipids, which may be due to ecological factors or to contributions from organisms that assimilate HCO 3 -. Lycopane and pentamethyleicosane apparently derive from planktonic organisms. Diploptene in the Black Sea apparently is derived from chemoautotrophic bacteria living at the oxic/anoxic interface. Some odd-C, long-chain n-alkanes have planktonic δ values, and the authors suggest they are not strict terrestrial indicators

Metagenome of a Versatile Chemolithoautotroph from Expanding Oceanic Dead Zones

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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.

Advances in metabolic engineering in the microbial production of fuels and chemicals from C1 gas.

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Humphreys, Christopher M; Minton, Nigel P

2018-04-01

The future sustainable production of chemicals and fuels from non-petrochemical sources, while at the same time reducing greenhouse gas (GHG) emissions, represent two of society's greatest challenges. Microbial chassis able to grow on waste carbon monoxide (CO) and carbon dioxide (CO 2 ) can provide solutions to both. Ranging from the anaerobic acetogens, through the aerobic chemoautotrophs to the photoautotrophic cyanobacteria, they are able to convert C1 gases into a range of chemicals and fuels which may be enhanced and extended through appropriate metabolic engineering. The necessary improvements will be facilitated by the increasingly sophisticated gene tools that are beginning to emerge as part of the Synthetic Biology revolution. These tools, in combination with more accurate metabolic and genome scale models, will enable C1 chassis to deliver their full potential. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

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

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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.

Rediscovered and new perisphaerine cockroaches from SW China with a review of subfamilial diagnosis (Blattodea: Blaberidae).

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Li, Xin-Ran; Wang, Li-Li; Wang, Zong-Qing

2018-04-17

The taxonomic records of Chinese perisphaerine cockroaches were scattered in literature, and therefore a dedicated study is desired to update our knowledge. This paper reviews the subfamilial diagnosis and Chinese species, mostly from southwestern China. We provide high-definition habitus photos and drawings, the latter emphasizes the genitalia of both sexes, which are generalized with diagrams, abstracted from specimens examined. A total of 18 species are recorded in four genera, including Perisphaerus, or pill cockroach, the type genus of the subfamily. Two new genera and three new species are proposed: Achatiblatta achates gen. sp. nov., Frumentiforma frumentiformis gen. sp. nov., and Pseudoglomeris montana sp. nov.. Pseudoglomeris has five new junior synonyms: Corydidarum, Trichoblatta, Kurokia, Glomerexis, and Glomeriblatta; the following combinations are thus revived or new: Ps. aerea comb. nov., Ps. angustifolia comb. nov., Ps. beybienkoi comb. nov., Ps. fallax comb. nov., Ps. magnifica comb. rev., Ps. montshadskii comb. nov., Ps. nigra comb. nov., Ps. sculpta comb. nov., Ps. semisulcata comb. rev., Ps. tibetana comb. nov., and Ps. valida moderata comb. nov.. The following species are revalidated and combinations revived: Pe. pygmaeus comb. rev., Ps. dubia comb. sp. rev., and Ps. planiuscla comb. sp. rev.

Carboxysomal carbonic anhydrases: Structure and role in microbial CO2 fixation

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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.

High potential for temperate viruses to drive carbon cycling in chemoautotrophy-dominated shallow-water hydrothermal vents.

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Rastelli, Eugenio; Corinaldesi, Cinzia; Dell'Anno, Antonio; Tangherlini, Michael; Martorelli, Eleonora; Ingrassia, Michela; Chiocci, Francesco L; Lo Martire, Marco; Danovaro, Roberto

2017-11-01

Viruses are the most abundant life forms in the world's oceans and they are key drivers of biogeochemical cycles, but their impact on the microbial assemblages inhabiting hydrothermal vent ecosystems is still largely unknown. Here, we analysed the viral life strategies and virus-host interactions in the sediments of a newly discovered shallow-water hydrothermal field of the Mediterranean Sea. Our study reveals that temperate viruses, once experimentally induced to replicate, can cause large mortality of vent microbes, significantly reducing the chemoautotrophic carbon production, while enhancing the metabolism of microbial heterotrophs and the re-cycling of the organic matter. These results provide new insights on the factors controlling primary and secondary production processes in hydrothermal vents, suggesting that the inducible provirus-host interactions occurring in these systems can profoundly influence the functioning of the microbial food web and the efficiency in the energy transfer to the higher trophic levels. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

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

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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.

Metabolic profiles of prokaryotic and eukaryotic communities in deep-sea sponge Neamphius huxleyi indicated by metagenomics

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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 Neamphius huxleyi at the whole community level. Metagenomic data showed phylogenetically diverse prokaryotes and eukaryotes in Neamphius huxleyi. 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 Neamphius huxleyi. PMID:24463735

Metabolic profiles of prokaryotic and eukaryotic communities in deep-sea sponge Neamphius huxleyi [corrected]. indicated by metagenomics.

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

2014-01-27

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 Neamphius huxleyi [corrected] . at the whole community level. Metagenomic data showed phylogenetically diverse prokaryotes and eukaryotes in Neamphius huxleyi [corrected]. 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 Neamphius huxleyi [corrected].

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..

Modeling the mutualistic interactions between tubeworms and microbial consortia.

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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.

Enrichment of marine anammox bacteria from seawater-related samples and bacterial community study.

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Kawagoshi, Y; Nakamura, Y; Kawashima, H; Fujisaki, K; Furukawa, K; Fujimoto, A

2010-01-01

Anaerobic ammonium oxidation (anammox) is a novel nitrogen pathway catalyzed by anammox bacteria which are obligate anaerobic chemoautotrophs. In this study, enrichment culture of marine anammox bacteria (MAAOB) from the samples related to seawater was conducted. Simultaneous removal of ammonium and nitrite was confirmed in continuous culture inoculated with sediment of a sea-based waste disposal site within 50 days. However, no simultaneous nitrogen removal was observed in cultures inoculated with seawater-acclimated denitrifying sludge or with muddy sediment of tideland even during 200 days. Nitrogen removal rate of 0.13 kg/m(3)/day was achieved at nitrogen loading rate of 0.16 kg/m(3)/day after 320th days in the culture inoculated with the sediment of waste disposal site. The nitrogen removal ratio between ammonium nitrogen and nitrite nitrogen was 1:1.07. Denaturing gradient gel electrophoresis (DGGE) analysis indicated that an abundance of the bacteria close to MAAOB and coexistence of ammonium oxidizing bacteria and denitrifying bacteria in the culture.

High-Elevation Sierra Nevada Conifers Reveal Increasing Reliance on Snow Water with Changing Climate

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Lepley, K. S.; Meko, D. M.; Touchan, R.; Shamir, E.; Graham, R.

2017-12-01

Snowpack in the Sierra Nevada Mountains accounts for around one third of California's water supply. Melting snow can provide water into dry summer months characteristic of the region's Mediterranean climate. As climate changes, understanding patterns of snowpack, snowmelt, and biological response are critical in this region of agricultural, recreational, and ecological value. Tree rings can act as proxy records to inform scientists and resource managers of past climate variability where instrumental data is unavailable. Here we investigate relationships between tree rings of high-elevation, snow-adapted conifer trees (Tsuga mertensiana, Abies magnifica) and April 1st snow-water equivalent (SWE) in the northern Sierra Nevada Mountains. The 1st principal component of 29 highly correlated regional SWE time series was modeled using multiple linear regression of four tree-ring chronologies including two lagged chronologies. Split-period verification analysis of this model revealed poor predictive skill in the early half (1929 - 1966) of the calibration period (1929 - 2003). Further analysis revealed a significant (p time. Snow water is becoming a more limiting resource to tree growth as average temperatures rise and the hydrologic regime shifts. These results highlight the need for resource managers and policy makers to consider that biological response to climate is not static.

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.

Sequestration and utilization of carbon dioxide by chemical and biological methods for biofuels and biomaterials by chemoautotrophs: Opportunities and challenges.

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Thakur, Indu Shekhar; Kumar, Manish; Varjani, Sunita J; Wu, Yonghong; Gnansounou, Edgard; Ravindran, Sindhu

2018-05-01

To meet the CO 2 emission reduction targets, carbon dioxide capture and utilization (CCU) comes as an evolve technology. CCU concept is turning into a feedstock and technologies have been developed for transformation of CO 2 into useful organic products. At industrial scale, utilization of CO 2 as raw material is not much significant as compare to its abundance. Mechanisms in nature have evolved for carbon concentration, fixation and utilization. Assimilation and subsequent conversion of CO 2 into complex molecules are performed by the photosynthetic and chemolithotrophic organisms. In the last three decades, substantial research is carry out to discover chemical and biological conversion of CO 2 in various synthetic and biological materials, such as carboxylic acids, esters, lactones, polymer biodiesel, bio-plastics, bio-alcohols, exopolysaccharides. This review presents an over view of catalytic transformation of CO 2 into biofuels and biomaterials by chemical and biological methods. Copyright © 2018 Elsevier Ltd. All rights reserved.

Metatranscriptomics reveal differences in in situ energy and nitrogen metabolism among hydrothermal vent snail symbionts.

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Sanders, J G; Beinart, R A; Stewart, F J; Delong, E F; Girguis, P R

2013-08-01

Despite the ubiquity of chemoautotrophic symbioses at hydrothermal vents, our understanding of the influence of environmental chemistry on symbiont metabolism is limited. Transcriptomic analyses are useful for linking physiological poise to environmental conditions, but recovering samples from the deep sea is challenging, as the long recovery times can change expression profiles before preservation. Here, we present a novel, in situ RNA sampling and preservation device, which we used to compare the symbiont metatranscriptomes associated with Alviniconcha, a genus of vent snail, in which specific host-symbiont combinations are predictably distributed across a regional geochemical gradient. Metatranscriptomes of these symbionts reveal key differences in energy and nitrogen metabolism relating to both environmental chemistry (that is, the relative expression of genes) and symbiont phylogeny (that is, the specific pathways employed). Unexpectedly, dramatic differences in expression of transposases and flagellar genes suggest that different symbiont types may also have distinct life histories. These data further our understanding of these symbionts' metabolic capabilities and their expression in situ, and suggest an important role for symbionts in mediating their hosts' interaction with regional-scale differences in geochemistry.

The origin of life and its methodological challenge.

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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.

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

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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.

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.

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

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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.

Public health importance of non-biting cyclorrhaphan flies.

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Fetene, Teshome; Worku, Netsanet

2009-02-01

This study was carried out to determine the role of non-biting cyclorrhaphan flies as carriers of human intestinal parasites at Woreta, northwestern Ethiopia. In total, 6530 flies were collected from four breeding sites and then examined for human intestinal parasites, mainly using the formol-ether concentration method. Fly species identified were Musca domestica (32.9%), Chrysomya rufifacies (32.6%), Musca sorbens (23%), Lucina cuprina (4.7%), Calliphora vicina (2.8%), Chrysomya bezziana (2.3%) and Wohlfahrtia magnifica (1.7%). Intestinal parasites such as Ascaris lumbricoides (36.9%), Trichuris trichiura (38.8%), hookworm (13.0%), Hymenolepis nana (0.6%), Taenia spp. (8.4%), Strongyloides stercoralis (1.7%), Entamoeba histolytica/dispar (48.1%), Entamoeba coli (24.7%), Cryptosporidium spp. (16.7%) and Giardia lamblia (10.4%) were isolated from both external and gut contents of the flies. Trichuris trichiura and A. lumbricoides among the helminths and E. histolytica/dispar and E. coli among the protozoans were the dominant parasites identified. It was observed that more parasites were isolated from gut contents than the external surfaces of the flies examined (PChrysomya rufifacies were found to carry more helminths than M. sorbens and M. domestica. Musca sorbens were the highest carriers of protozoan parasites followed by M. domestica and C. rufifacies. The significance of filth flies as carriers of human intestinal parasites has been highlighted.

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

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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.

TWO FUNDAMENTAL ECOLOGICAL RELATIONSHIPS THAT DEEPEN THE SENSE OF SOCIAL, ECONOMICAL AND ETHICAL VALUES OF MENTAL REPRESENTATIONS

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ALFREDO O. LÓPEZ ALONSO

2010-01-01

Full Text Available A partir de dos relaciones ecológicas básicas, ferocidad / depredación y angelicalidad / protección, se ensayan diferentes progresiones biológico- sociales y culturales. La primera relación está directamente referida a las figuras presa y depredador en cadenas tróficas y ecosistemas de competitividad y convivencia. La segunda magnifica el valor y significado del cuidado y supervivencia del recién nacido. Se revisa el origen evolutivo, ecológico y etológico de ambas relaciones como balance conductual entre situaciones extremas de cada individuo y especie, abrien do un nuevo insight sobre viejos problemas de la Biología, la Sociología, la Etica y la Economía. La clave es lo que relaciona a estas dos relaciones con valores materiales-tangibles y valores in materialesintangibles, respectivamente. Resulta directo asociar la primera relación con la satisfacción inmediata de necesidades básicas, juzgadas como materiales y tan gibles. En contraste, la segunda relación viene como un complemento que genera nuevos significados y riqueza de sentidos ecológico- etológicos de toda forma de vida. Los valores se estiman como un sistema abierto y creciente. A más valores intangibles, mayor es el avance en representaciones significantes.

Anemone bleaching increases the metabolic demands of symbiont anemonefish.

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Norin, Tommy; Mills, Suzanne C; Crespel, Amélie; Cortese, Daphne; Killen, Shaun S; Beldade, Ricardo

2018-04-11

Increased ocean temperatures are causing mass bleaching of anemones and corals in the tropics worldwide. While such heat-induced loss of algal symbionts (zooxanthellae) directly affects anemones and corals physiologically, this damage may also cascade on to other animal symbionts. Metabolic rate is an integrative physiological trait shown to relate to various aspects of organismal performance, behaviour and locomotor capacity, and also shows plasticity during exposure to acute and chronic stressors. As climate warming is expected to affect the physiology, behaviour and life history of animals, including ectotherms such as fish, we measured if residing in bleached versus unbleached sea anemones ( Heteractis magnifica ) affected the standard (i.e. baseline) metabolic rate and behaviour (activity) of juvenile orange-fin anemonefish ( Amphiprion chrysopterus ) . Metabolic rate was estimated from rates of oxygen uptake [Formula: see text], and the standard metabolic rate [Formula: see text] of anemonefish from bleached anemones was significantly higher by 8.2% compared with that of fish residing in unbleached anemones, possibly due to increased stress levels. Activity levels did not differ between fish from bleached and unbleached anemones. As [Formula: see text] reflects the minimum cost of living, the increased metabolic demands may contribute to the negative impacts of bleaching on important anemonefish life history and fitness traits observed previously (e.g. reduced spawning frequency and lower fecundity). © 2018 The Author(s).

Lipids of Prokaryotic Origin at the Base of Marine Food Webs

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Maria José Caramujo

2012-11-01

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

Comparative genomics of vesicomyid clam (Bivalvia: Mollusca chemosynthetic symbionts

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Girguis Peter R

2008-12-01

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

An ArsR/SmtB family member is involved in the regulation by arsenic of the arsenite oxidase operon in Thiomonas arsenitoxydans.

Science.gov (United States)

Moinier, Danielle; Slyemi, Djamila; Byrne, Deborah; Lignon, Sabrina; Lebrun, Régine; Talla, Emmanuel; Bonnefoy, Violaine

2014-10-01

The genetic organization of the aioBA operon, encoding the arsenite oxidase of the moderately acidophilic and facultative chemoautotrophic bacterium Thiomonas arsenitoxydans, is different from that of the aioBA operon in the other arsenite oxidizers, in that it encodes AioF, a metalloprotein belonging to the ArsR/SmtB family. AioF is stabilized by arsenite, arsenate, or antimonite but not molybdate. Arsenic is tightly attached to AioF, likely by cysteine residues. When loaded with arsenite or arsenate, AioF is able to bind specifically to the regulatory region of the aio operon at two distinct positions. In Thiomonas arsenitoxydans, the promoters of aioX and aioB are convergent, suggesting that transcriptional interference occurs. These results indicate that the regulation of the aioBA operon is more complex in Thiomonas arsenitoxydans than in the other aioBA containing arsenite oxidizers and that the arsenic binding protein AioF is involved in this regulation. On the basis of these data, a model to explain the tight control of aioBA expression by arsenic in Thiomonas arsenitoxydans is proposed. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Transcriptional Response of the Archaeal Ammonia Oxidizer Nitrosopumilus maritimus to Low and Environmentally Relevant Ammonia Concentrations

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Stahl, David A.

2013-01-01

The ability of chemoautotrophic ammonia-oxidizing archaea to compete for ammonia among marine microorganisms at low ambient concentrations has been in part attributed to their extremely high affinity for ammonia, but as yet there is no mechanistic understanding of supporting metabolism. We examined transcription of selected genes for anabolic functions (CO2 fixation, ammonia transport, and cell wall synthesis) and a central catabolic function (ammonia oxidation) in the thaumarchaeon Nitrosopumilus maritimus SCM1 growing at two ammonia concentrations, as measured by combined ammonia and ammonium, one well above the Km for ammonia oxidation (∼500 μM) and the other well below the Km (ammonia-replete to ammonia-limiting conditions. Transcript levels for ammonia oxidation, CO2 fixation, and one of the ammonia transport genes were approximately the same at high and low ammonia availability. Transcripts for all analyzed genes decreased with time in the complete absence of ammonia, but with various rates of decay. The new steady-state mRNA levels established are presumably more reflective of the natural physiological state of ammonia-oxidizing archaea and offer a reference for interpreting message abundance patterns in the natural environment. PMID:23995944

Deep-biosphere consortium of fungi and prokaryotes in Eocene subseafloor basalts.

Science.gov (United States)

Bengtson, S; Ivarsson, M; Astolfo, A; Belivanova, V; Broman, C; Marone, F; Stampanoni, M

2014-11-01

The deep biosphere of the subseafloor crust is believed to contain a significant part of Earth's biomass, but because of the difficulties of directly observing the living organisms, its composition and ecology are poorly known. We report here a consortium of fossilized prokaryotic and eukaryotic micro-organisms, occupying cavities in deep-drilled vesicular basalt from the Emperor Seamounts, Pacific Ocean, 67.5 m below seafloor (mbsf). Fungal hyphae provide the framework on which prokaryote-like organisms are suspended like cobwebs and iron-oxidizing bacteria form microstromatolites (Frutexites). The spatial inter-relationships show that the organisms were living at the same time in an integrated fashion, suggesting symbiotic interdependence. The community is contemporaneous with secondary mineralizations of calcite partly filling the cavities. The fungal hyphae frequently extend into the calcite, indicating that they were able to bore into the substrate through mineral dissolution. A symbiotic relationship with chemoautotrophs, as inferred for the observed consortium, may be a pre-requisite for the eukaryotic colonization of crustal rocks. Fossils thus open a window to the extant as well as the ancient deep biosphere. © 2014 The Authors. Geobiology Published by John Wiley & Sons Ltd.

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.

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

OpenAIRE

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

2013-01-01

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

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

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

2013-06-01

Recently, evidence suggests that dark CO2 fixation in the pelagic realm of the ocean does not only occur in the suboxic and anoxic water bodies but also in the oxygenated meso- and bathypelagic waters of the North Atlantic. To elucidate the significance and phylogeny of the key organisms mediating dark CO2 fixation in the tropical Atlantic, we quantified functional genes indicative for CO2 fixation. We used a Q-PCR-based assay targeting the bifunctional acetyl-CoA/propionyl-CoA carboxylase (accA subunit), a key enzyme powering inter alia the 3-hydroxypropionate/4-hydroxybutyrate cycle (HP/HB) and the archaeal ammonia monooxygenase (amoA). Quantification of accA-like genes revealed a consistent depth profile in the upper mesopelagial with increasing gene abundances from subsurface layers towards the oxygen minimum zone (OMZ), coinciding with an increase in archaeal amoA gene abundance. Gene abundance profiles of metabolic marker genes (accA, amoA) were correlated with thaumarchaeal 16S rRNA gene abundances as well as CO2 fixation rates to link the genetic potential to actual rate measurements. AccA gene abundances correlated with archaeal amoA gene abundance throughout the water column (r(2)  = 0.309, P < 0.0001). Overall, a substantial genetic predisposition of CO2 fixation was present in the dark realm of the tropical Atlantic in both Archaea and Bacteria. Hence, dark ocean CO2 fixation might be more widespread among prokaryotes inhabiting the oxygenated water column of the ocean's interior than hitherto assumed. © 2013 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

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

NARCIS (Netherlands)

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

2013-01-01

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

Carbon isotopes in biological carbonates: Respiration and photosynthesis

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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.

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.

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

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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.

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

2012-05-01

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.

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

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

2011-04-01

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

Comparative metagenomic analysis of the microbial communities in the surroundings of Iheya north and Iheya ridge hydrothermal fields reveals insights into the survival strategy of microorganisms in deep-sea environments

Science.gov (United States)

Wang, Hai-liang; Sun, Li

2018-04-01

In this study, metagenomic analysis was performed to investigate the taxonomic compositions and metabolic profiles of the microbial communities inhabiting the sediments in the surroundings of Iheya North and Iheya Ridge hydrothermal fields. The microbial communities in four different samples were found to be dominated by bacteria and, to a much lesser extent, archaea belonging to the phyla Proteobacteria, Actinobacteria, Planctomycetes, Firmicutes, Deinococcus-Thermus, and Nitrospirae, which play important roles in the cycling of carbon, nitrogen, and sulfur. All four microbial communities (i) contained chemoautotrophs and heterotrophs, the former probably fixed CO2 via various carbon fixation pathways, and the latter may degrade organic matters using nitrate and sulfate as electron acceptors, (ii) exhibited an abundance of DNA repair genes and bacterial sulfur oxidation mediated by reverse sulfate reduction, and (iii) harbored bacteria and archaea involved in anaerobic methane oxidation via intra-aerobic denitrification and reverse methanogenesis, which were found for the first time in hydrothermal areas. Furthermore, genes involved in DNA repair, reductive acetyl-CoA pathway, and ammonia metabolism were possibly affected by distance to the vent fields. These findings facilitate our understanding of the strategies of the microbial communities to adapt to the environments in deep sea areas associated with hydrothermal vents.

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

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.

Phylogenetic inference of calyptrates, with the first mitogenomes for Gasterophilinae (Diptera: Oestridae) and Paramacronychiinae (Diptera: Sarcophagidae)

Science.gov (United States)

Zhang, Dong; Yan, Liping; Zhang, Ming; Chu, Hongjun; Cao, Jie; Li, Kai; Hu, Defu; Pape, Thomas

2016-01-01

The complete mitogenome of the horse stomach bot fly Gasterophilus pecorum (Fabricius) and a near-complete mitogenome of Wohlfahrt's wound myiasis fly Wohlfahrtia magnifica (Schiner) were sequenced. The mitogenomes contain the typical 37 mitogenes found in metazoans, organized in the same order and orientation as in other cyclorrhaphan Diptera. Phylogenetic analyses of mitogenomes from 38 calyptrate taxa with and without two non-calyptrate outgroups were performed using Bayesian Inference and Maximum Likelihood. Three sub-analyses were performed on the concatenated data: (1) not partitioned; (2) partitioned by gene; (3) 3rd codon positions of protein-coding genes omitted. We estimated the contribution of each of the mitochondrial genes for phylogenetic analysis, as well as the effect of some popular methodologies on calyptrate phylogeny reconstruction. In the favoured trees, the Oestroidea are nested within the muscoid grade. Relationships at the family level within Oestroidea are (remaining Calliphoridae (Sarcophagidae (Oestridae, Pollenia + Tachinidae))). Our mito-phylogenetic reconstruction of the Calyptratae presents the most extensive taxon coverage so far, and the risk of long-branch attraction is reduced by an appropriate selection of outgroups. We find that in the Calyptratae the ND2, ND5, ND1, COIII, and COI genes are more phylogenetically informative compared with other mitochondrial protein-coding genes. Our study provides evidence that data partitioning and the inclusion of conserved tRNA genes have little influence on calyptrate phylogeny reconstruction, and that the 3rd codon positions of protein-coding genes are not saturated and therefore should be included. PMID:27019632

Development of a broad-host synthetic biology toolbox for Ralstonia eutropha and its application to engineering hydrocarbon biofuel production.

Science.gov (United States)

Bi, Changhao; Su, Peter; Müller, Jana; Yeh, Yi-Chun; Chhabra, Swapnil R; Beller, Harry R; Singer, Steven W; Hillson, Nathan J

2013-11-13

The chemoautotrophic bacterium Ralstonia eutropha can utilize H2/CO2 for growth under aerobic conditions. While this microbial host has great potential to be engineered to produce desired compounds (beyond polyhydroxybutyrate) directly from CO2, little work has been done to develop genetic part libraries to enable such endeavors. We report the development of a toolbox for the metabolic engineering of Ralstonia eutropha H16. We have constructed a set of broad-host-range plasmids bearing a variety of origins of replication, promoters, 5' mRNA stem-loop structures, and ribosomal binding sites. Specifically, we analyzed the origins of replication pCM62 (IncP), pBBR1, pKT (IncQ), and their variants. We tested the promoters P(BAD), T7, P(xyls/PM), P(lacUV5), and variants thereof for inducible expression. We also evaluated a T7 mRNA stem-loop structure sequence and compared a set of ribosomal binding site (RBS) sequences derived from Escherichia coli, R. eutropha, and a computational RBS design tool. Finally, we employed the toolbox to optimize hydrocarbon production in R. eutropha and demonstrated a 6-fold titer improvement using the appropriate combination of parts. We constructed and evaluated a versatile synthetic biology toolbox for Ralstonia eutropha metabolic engineering that could apply to other microbial hosts as well.

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 ( 15 N/ 14 N) 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 15 N/ 14 N 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.

Isotopic investigations of the waters from the Movile Cave - Mangalia area

International Nuclear Information System (INIS)

Feurdean, Lucia; Feurdean, Victor

2001-01-01

As a conservative tracer in carbonate rocks deuterium was used to determine the unelucidated problems of water origin in the Movile Cave-Mangalia, which is the unique ecosystem from the world based on chemoautotrophic conditions. According to the δD values the water from Movile Cave is meteoric in origin but can not originate from local site. The groundwater from neighboring area of cave has their recharge area at high altitude and considerable distance. δD values of water samples present time variations with a distinct seasonal effect. The seasonal δD values are shifted with a half meteoric cycle vs. normal succession of seasonal maximum and minimum values. Water seems to be originated from the Prebalkan Plateau situated in the south of Dobrogea. The study indicates that the intrusion of water in the karst occurs by conduit flow and hydrostatic pressure. The geometry of conduit controls the movement of the water. The cave and the Karaoban Lake is the discharge area of two main components of groundwater: the first is coming from southwest and has isotope characteristic similar to lower altitude water (500 m) and the second is moving from southeast and has the isotope composition similar to high altitude water (>1000 m). The Movile Cave and Karaoban Lake are connected and the cave water is discharged by overflow mechanism isolating the cave from atmosphere. (authors)

[Effects of short-term elevated CO2 concentration and drought stress on the rhizosphere effects of soil carbon, nitrogen and microbes of Bothriochloa ischaemum.

Science.gov (United States)

Xiao, Lie; Liu, Guo Bin; Li, Peng; Xue, Sha

2017-10-01

A water control pot experiment was conducted in climate controlled chambers to study soil carbon, nitrogen and microbial community structure and their rhizosphere effects in the rhizosphere and non rhizosphere soil of Bothriochloa ischaemum at elevated CO2 concentrations (800 μmol·mol -1 ) under three water regimes, i.e., well watered (75%-80% of field capacity, FC), moderate drought stress (55%-60% of FC), and severe drought stress (35%-40% of FC). The results showed that elevated CO2 concentration and drought stress did not have significant impacts on the content of soil organic carbon, total nitrogen or dissolved organic carbon (DOC) in the rhizosphere and bulk soils or their rhizosphere effects. Elevated CO2 concentration significantly decreased dissolved organic nitrogen (DON) content in the rhizosphere soil under moderate drought stress, increased DOC/DON, and significantly increased the negative rhizosphere effect of DON and positive rhizosphere effect of DOC/DON. Drought stress and elevated CO2 concentration did not have significant impacts on the rhizosphere effect of total and bacterial phospholipid fatty acids (PLFA). Drought stress under elevated CO2 concentration significantly increased the G + /G - PLFA in the rhizosphere soil and decreased the G + /G - PLFA in the bulk soil, so its rhizosphere effect significantly increased, indicating that the soil microbial community changed from chemoautotroph microbes to heterotrophic microbes.

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

KAUST Repository

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

2017-01-01

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 − 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.

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.

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

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Maura Manganelli

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

Novel archaeal tetraether lipids with a cyclohexyl ring identified in Fayetteville Green Lake, NY, and other sulfidic lacustrine settings.

Science.gov (United States)

Liu, Xiao-Lei; De Santiago Torio, Ana; Bosak, Tanja; Summons, Roger Everett

2016-05-30

The meromictic Fayetteville Green Lake (FGL) is of significant geobiological interest because of microbial cycling of sulfur within and below the permanent chemocline and in the euxinic deep waters. Studies of glycerol dibiphytanyl glycerol tetraethers (GDGTs) may help shed light on understanding the activity of archaeal communities in these habitats. Normal-phase and reversed-phase liquid chromatography/mass spectrometry (LC/MS) analysis on total lipid extracts of environmental samples revealed series of GDGTs with different biphytane structures. Comparison of the mass spectrum of biphytane obtained from separated novel GDGTs with that of a synthetic C 40 biphytane confirms our structural assignments. A unique cyclohexyl ring configured in the middle of a C 40 biphytane chain was identified in these novel GDGTs. We suggest the trivial name S-GDGTs for these compounds, where 'S' stands for 'sulfidic' and 'six-membered ring'. S-GDGT derivatives composed of biphytanes modified with double bonds and cyclopentane rings were also detected in the samples we analyzed. Intact polar lipid precursors of S-GDGT include compounds with mono- and diglycosyl head groups. The carbon isotopic composition of S-GDGTs and their occurrence in FGL, Messel Shale as well as Salt Pond and salt marshes on Cape Cod suggest that S-GDGTs may be produced by chemoautotrophic archaea that prefer sulfidic conditions. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

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.

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.

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.

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.

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

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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.

Food-web structure of seep sediment macrobenthos from the Gulf of Mexico

Science.gov (United States)

Demopoulos, Amanda W.J.; Gualtieri, Daniel; Kovacs, Kaitlin

2010-01-01

The slope environment of the Gulf of Mexico (GOM) supports dense communities of seep megafaunal invertebrates that rely on endosymbiotic bacteria for nutrition. Seep sediments also contain smaller macrofaunal invertebrates whose nutritional pathways are not well understood. Using stable-isotope analysis, we investigate the utilization of chemosynthetically fixed and methane-derived organic matter by macrofauna. Biological sampling was conducted in three lower-slope GOM seep environs: Green Canyon (GC852, 1428 m), Atwater Valley (AT340, 2230 m), and Alaminos Canyon (AC601, 2384 m). Infaunal delta13C and delta15N exhibited a broad range of values; most infauna appeared to be heterotrophic, although several taxa had very light delta15N and delta13C values, indicating possible reliance on chemoautotrophic symbioses. The lightest delta13C and delta15N values were observed in nematodes (delta13C=-54.6 + or - 0.1 per mil, delta15N=-6.1 + or - 0.2 per mil) and one gastropod (delta13C=-54.1 per mil, delta15N=-1.1 per mil) from Green Canyon. Mixing-model results indicated that sulfur-oxidizing Beggiatoa may be an important food source for seep infauna; the rate of utilization ranged from 60% to 100% at Green Canyon and Atwater Valley. The overall range in isotope values was similar across the three sites, suggesting that biogeochemical processes may be very similar in these geographically distinct areas.

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

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P. Compère

2008-09-01

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

A paradox resolved: Sulfide acquisition by roots of seep tubeworms sustains net chemoautotrophy

Science.gov (United States)

Freytag, John K.; Girguis, Peter R.; Bergquist, Derk C.; Andras, Jason P.; Childress, James J.; Fisher, Charles R.

2001-01-01

Vestimentiferan tubeworms, symbiotic with sulfur-oxidizing chemoautotrophic bacteria, dominate many cold-seep sites in the Gulf of Mexico. The most abundant vestimentiferan species at these sites, Lamellibrachia cf. luymesi, grows quite slowly to lengths exceeding 2 meters and lives in excess of 170–250 years. L. cf. luymesi can grow a posterior extension of its tube and tissue, termed a “root,” down into sulfidic sediments below its point of original attachment. This extension can be longer than the anterior portion of the animal. Here we show, using methods optimized for detection of hydrogen sulfide down to 0.1 μM in seawater, that hydrogen sulfide was never detected around the plumes of large cold-seep vestimentiferans and rarely detectable only around the bases of mature aggregations. Respiration experiments, which exposed the root portions of L. cf. luymesi to sulfide concentrations between 51–561 μM, demonstrate that L. cf. luymesi use their roots as a respiratory surface to acquire sulfide at an average rate of 4.1 μmol⋅g−1⋅h−1. Net dissolved inorganic carbon uptake across the plume of the tubeworms was shown to occur in response to exposure of the posterior (root) portion of the worms to sulfide, demonstrating that sulfide acquisition by roots of the seep vestimentiferan L. cf. luymesi can be sufficient to fuel net autotrophic total dissolved inorganic carbon uptake. PMID:11687647

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

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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.

Ammonia oxidizing bacteria community dynamics in a pilot-scale wastewater treatment plant.

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Xiaohui Wang

Full Text Available BACKGROUND: Chemoautotrophic ammonia oxidizing bacteria (AOB have the metabolic ability to oxidize ammonia to nitrite aerobically. This metabolic feature has been widely used, in combination with denitrification, to remove nitrogen from wastewater in wastewater treatment plants (WWTPs. However, the relative influence of specific deterministic environmental factors to AOB community dynamics in WWTP is uncertain. The ecological principles underlying AOB community dynamics and nitrification stability and how they are related are also poorly understood. METHODOLOGY/PRINCIPAL FINDINGS: The community dynamics of ammonia oxidizing bacteria (AOB in a pilot-scale WWTP were monitored over a one-year period by Terminal Restriction Fragment Length Polymorphism (T-RFLP. During the study period, the effluent ammonia concentrations were almost below 2 mg/L, except for the first 60 days, indicting stable nitrification. T-RFLP results showed that, during the test period with stable nitrification, the AOB community structures were not stable, and the average change rate (every 15 days of AOB community structures was 10% ± 8%. The correlations between T-RFLP profiles and 10 operational and environmental parameters were tested by Canonical Correlation Analysis (CCA and Mantel test. The results indicated that the dynamics of AOB community correlated most strongly with Dissolved Oxygen (DO, effluent ammonia, effluent Biochemical Oxygen Demand (BOD and temperature. CONCLUSIONS/SIGNIFICANCE: This study suggests that nitrification stability is not necessarily accompanied by a stable AOB community, and provides insight into parameters controlling the AOB community dynamics within bioreactors with stable nitrification.

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.

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.

Reconstructing the muscular ground pattern of phylactolaemate bryozoans: first data from gelatinous representatives.

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Gawin, Natalie; Wanninger, Andreas; Schwaha, Thomas

2017-11-07

Phylactolaemata is commonly regarded the earliest branch within Bryozoa and thus the sister group to the other bryozoan taxa, Cyclostomata and Gymnolaemata. Therefore, the taxon is important for the reconstruction of the bryozoan morphological ground pattern. In this study the myoanatomy of Pectinatella magnifica, Cristatella mucedo and Hyalinella punctata was analysed by means of histology, f-actin staining and confocal laser-scanning microscopy in order to fill gaps in knowledge concerning the myoanatomy of Phylactolaemata. The retractor muscles and muscles of the aperture, gut, body wall, tentacle sheath, lophophore constitute the most prominent muscular subsets in these species. The lophophore shows longitudinal muscle bands in the tentacles, lophophoral arm muscles, epistome musculature and hitherto undescribed muscles of the ring canal. In general the muscular system of the three species is very similar with differences mainly in the body wall, tentacle sheath and epistome. The body wall contains an orthogonal grid of musculature. The epistome exhibits either a muscular meshwork in the epistomal wall or muscle fibers traversing the epistomal cavity. The whole tentacle sheath possesses a regular mesh of muscles in Pectinatella and Cristatella, whereas circular muscles are limited to the tentacle sheath base in Hyalinella. This study is the first to describe muscles of the ring canal and contributes to reconstructing muscular features for the last common ancestor of all bryozoans. The data available suggest that two longitudinal muscle bands in the tentacles, as well as retractor muscles and longitudinal and circular muscles in the tentacle sheath, were present in the last common bryozoan ancestor. Comparisons among bryozoans shows that several apomorphies are present in the myoanatomy of each class- level taxon such as the epistomal musculature and musculature of the lophophoral arms in phylactolaemates, annular muscles in cyclostomes and parietal muscles in

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

Energy Technology Data Exchange (ETDEWEB)

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

2013-01-01

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

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.

A Novel Bioreactor for High Density Cultivation of Diverse Microbial Communities.

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Price, Jacob R; Shieh, Wen K; Sales, Christopher M

2015-12-25

A novel reactor design, coined a high density bioreactor (HDBR), is presented for the cultivation and study of high density microbial communities. Past studies have evaluated the performance of the reactor for the removal of COD(1) and nitrogen species(2-4) by heterotrophic and chemoautotrophic bacteria, respectively. The HDBR design eliminates the requirement for external flocculation/sedimentation processes while still yielding effluent containing low suspended solids. In this study, the HDBR is applied as a photobioreactor (PBR) in order to characterize the nitrogen removal characteristics of an algae-based photosynthetic microbial community. As previously reported for this HDBR design, a stable biomass zone was established with a clear delineation between the biologically active portion of the reactor and the recycling reactor fluid, which resulted in a low suspended solid effluent. The algal community in the HDBR was observed to remove 18.4% of total nitrogen species in the influent. Varying NH4(+) and NO3(-) concentrations in the feed did not have an effect on NH4(+) removal (n=44, p=0.993 and n=44, p=0.610 respectively) while NH4(+) feed concentration was found to be negatively related with NO3(-) removal (n=44, p=0.000) and NO3(-) feed concentration was found to be positively correlated with NO3(-) removal (n=44, p=0.000). Consistent removal of NH4(+), combined with the accumulation of oxidized nitrogen species at high NH4(+) fluxes indicates the presence of ammonia- and nitrite-oxidizing bacteria within the microbial community.

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

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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.

High bicarbonate assimilation in the dark by Arctic bacteria.

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Alonso-Sáez, Laura; Galand, Pierre E; Casamayor, Emilio O; Pedrós-Alió, Carlos; Bertilsson, Stefan

2010-12-01

Although both autotrophic and heterotrophic microorganisms incorporate CO₂ in the dark through different metabolic pathways, this process has usually been disregarded in oxic marine environments. We studied the significance and mediators of dark bicarbonate assimilation in dilution cultures inoculated with winter Arctic seawater. At stationary phase, bicarbonate incorporation rates were high (0.5-2.5 μg C L⁻¹ d⁻¹) and correlated with rates of bacterial heterotrophic production, suggesting that most of the incorporation was due to heterotrophs. Accordingly, very few typically chemoautotrophic bacteria were detected by 16S rRNA gene cloning. The genetic analysis of the biotin carboxylase gene accC putatively involved in archaeal CO₂ fixation did not yield any archaeal sequence, but amplified a variety of bacterial carboxylases involved in fatty acids biosynthesis, anaplerotic pathways and leucine catabolism. Gammaproteobacteria dominated the seawater cultures (40-70% of cell counts), followed by Betaproteobacteria and Flavobacteria as shown by catalyzed reporter deposition fluorescence in situ hybridization (CARDFISH). Both Beta- and Gammaproteobacteria were active in leucine and bicarbonate uptake, while Flavobacteria did not take up bicarbonate, as measured by microautoradiography combined with CARDFISH. Within Gammaproteobacteria, Pseudoalteromonas-Colwellia and Oleispira were very active in bicarbonate uptake (ca. 30 and 70% of active cells, respectively), while the group Arctic96B-16 did not take up bicarbonate. Our results suggest that, potentially, the incorporation of CO₂ can be relevant for the metabolism of specific Arctic heterotrophic phylotypes, promoting the maintenance of their cell activity and/or longer survival under resource depleted conditions.

Cancer and Toxicology Section

International Nuclear Information System (INIS)

Anon.

1980-01-01

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

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

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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

The uptake and excretion of partially oxidized sulfur expands the repertoire of energy resources metabolized by hydrothermal vent symbioses.

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Beinart, R A; Gartman, A; Sanders, J G; Luther, G W; Girguis, P R

2015-05-07

Symbiotic associations between animals and chemoautotrophic bacteria crowd around hydrothermal vents. In these associations, symbiotic bacteria use chemical reductants from venting fluid for the energy to support autotrophy, providing primary nutrition for the host. At vents along the Eastern Lau Spreading Center, the partially oxidized sulfur compounds (POSCs) thiosulfate and polysulfide have been detected in and around animal communities but away from venting fluid. The use of POSCs for autotrophy, as an alternative to the chemical substrates in venting fluid, could mitigate competition in these communities. To determine whether ESLC symbioses could use thiosulfate to support carbon fixation or produce POSCs during sulfide oxidation, we used high-pressure, flow-through incubations to assess the productivity of three symbiotic mollusc genera-the snails Alviniconcha spp. and Ifremeria nautilei, and the mussel Bathymodiolus brevior-when oxidizing sulfide and thiosulfate. Via the incorporation of isotopically labelled inorganic carbon, we found that the symbionts of all three genera supported autotrophy while oxidizing both sulfide and thiosulfate, though at different rates. Additionally, by concurrently measuring their effect on sulfur compounds in the aquaria with voltammetric microelectrodes, we showed that these symbioses excreted POSCs under highly sulfidic conditions, illustrating that these symbioses could represent a source for POSCs in their habitat. Furthermore, we revealed spatial disparity in the rates of carbon fixation among the animals in our incubations, which might have implications for the variability of productivity in situ. Together, these results re-shape our thinking about sulfur cycling and productivity by vent symbioses, demonstrating that thiosulfate may be an ecologically important energy source for vent symbioses and that they also likely impact the local geochemical regime through the excretion of POSCs.

The importance of methane and thiosulfate in the metabolism of the bacterial symbionts of two deep-sea mussels

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Fisher, C.R.; Childress, J.J.; Oremland, R.S.; Bidigare, R.R.

1987-01-01

Undescribed hydrocarbon-seep mussels were collected from the Louisiana Slope, Gulf of Mexico, during March 1986, and the ultrastructure of their gills was examined and compared to Bathymodiolus thermophilus, a mussel collected from the deep-sea hydrothermal vents on the Gala??pagos Rift in March 1985. These closely related mytilids both contain abundant symbiotic bacteria in their gills. However, the bacteria from the two species are distinctly different in both morphology and biochemistry, and are housed differently within the gills of the two mussels. The symbionts from the seep mussel are larger than the symbionts from B. thermophilus and, unlike the latter, contain stacked intracytoplasmic membranes. In the seep mussel three or fewer symbionts appear to be contained in each host-cell vacuole, while in B. thermophilus there are often more than twenty bacteria visible in a single section through a vacuole. The methanotrophic nature of the seep-mussel symbionts was confirmed in 14C-methane uptake experiments by the appearance of label in both CO2 and acid-stable, non-volatile, organic compounds after a 3 h incubation of isolated gill tissue. Furthermore, methane consumption was correlated with methanol dehydrogenase activity in isolated gill tissue. Activity of ribulose-1,5-biphosphate (RuBP) carboxylase and 14CO2 assimilation studies indicate the presence of either a second type of symbiont or contaminating bacteria on the gills of freshly captured seep mussels. A reevaluation of the nutrition of the symbionts in B. thermophilus indicates that while the major symbiont is not a methanotroph, its status as a sulfur-oxidizing chemoautotroph, as has been suggested previously, is far from proven. ?? 1987 Springer-Verlag.

Assessment of biotechnological strategies for the valorization of metal bearing wastes

International Nuclear Information System (INIS)

Beolchini, Francesca; Fonti, Viviana; Dell’Anno, Antonio; Rocchetti, Laura; Vegliò, Francesco

2012-01-01

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

Comparative Genomics Unravels the Functional Roles of Co-occurring Acidophilic Bacteria in Bioleaching Heaps

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Zhang, Xian; Liu, Xueduan; Liang, Yili; Xiao, Yunhua; Ma, Liyuan; Guo, Xue; Miao, Bo; Liu, Hongwei; Peng, Deliang; Huang, Wenkun; Yin, Huaqun

2017-01-01

The spatial-temporal distribution of populations in various econiches is thought to be potentially related to individual differences in the utilization of nutrients or other resources, but their functional roles in the microbial communities remain elusive. We compared differentiation in gene repertoire and metabolic profiles, with a focus on the potential functional traits of three commonly recognized members (Acidithiobacillus caldus, Leptospirillum ferriphilum, and Sulfobacillus thermosulfidooxidans) in bioleaching heaps. Comparative genomics revealed that intra-species divergence might be driven by horizontal gene transfer. These co-occurring bacteria shared a few homologous genes, which significantly suggested the genomic differences between these organisms. Notably, relatively more genes assigned to the Clusters of Orthologous Groups category [G] (carbohydrate transport and metabolism) were identified in Sulfobacillus thermosulfidooxidans compared to the two other species, which probably indicated their mixotrophic capabilities that assimilate both organic and inorganic forms of carbon. Further inspection revealed distinctive metabolic capabilities involving carbon assimilation, nitrogen uptake, and iron-sulfur cycling, providing robust evidence for functional differences with respect to nutrient utilization. Therefore, we proposed that the mutual compensation of functionalities among these co-occurring organisms might provide a selective advantage for efficiently utilizing the limited resources in their habitats. Furthermore, it might be favorable to chemoautotrophs' lifestyles to form mutualistic interactions with these heterotrophic and/or mixotrophic acidophiles, whereby the latter could degrade organic compounds to effectively detoxify the environments. Collectively, the findings shed light on the genetic traits and potential metabolic activities of these organisms, and enable us to make some inferences about genomic and functional differences that might

Comparative Genomics Unravels the Functional Roles of Co-occurring Acidophilic Bacteria in Bioleaching Heaps

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Xian Zhang

2017-05-01

Full Text Available The spatial-temporal distribution of populations in various econiches is thought to be potentially related to individual differences in the utilization of nutrients or other resources, but their functional roles in the microbial communities remain elusive. We compared differentiation in gene repertoire and metabolic profiles, with a focus on the potential functional traits of three commonly recognized members (Acidithiobacillus caldus, Leptospirillum ferriphilum, and Sulfobacillus thermosulfidooxidans in bioleaching heaps. Comparative genomics revealed that intra-species divergence might be driven by horizontal gene transfer. These co-occurring bacteria shared a few homologous genes, which significantly suggested the genomic differences between these organisms. Notably, relatively more genes assigned to the Clusters of Orthologous Groups category [G] (carbohydrate transport and metabolism were identified in Sulfobacillus thermosulfidooxidans compared to the two other species, which probably indicated their mixotrophic capabilities that assimilate both organic and inorganic forms of carbon. Further inspection revealed distinctive metabolic capabilities involving carbon assimilation, nitrogen uptake, and iron-sulfur cycling, providing robust evidence for functional differences with respect to nutrient utilization. Therefore, we proposed that the mutual compensation of functionalities among these co-occurring organisms might provide a selective advantage for efficiently utilizing the limited resources in their habitats. Furthermore, it might be favorable to chemoautotrophs' lifestyles to form mutualistic interactions with these heterotrophic and/or mixotrophic acidophiles, whereby the latter could degrade organic compounds to effectively detoxify the environments. Collectively, the findings shed light on the genetic traits and potential metabolic activities of these organisms, and enable us to make some inferences about genomic and functional

Highly similar prokaryotic communities of sunken wood at shallow and deep-sea sites across the oceans.

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Palacios, Carmen; Zbinden, Magali; Pailleret, Marie; Gaill, Françoise; Lebaron, Philippe

2009-11-01

With an increased appreciation of the frequency of their occurrence, large organic falls such as sunken wood and whale carcasses have become important to consider in the ecology of the oceans. Organic-rich deep-sea falls may play a major role in the dispersal and evolution of chemoautotrophic communities at the ocean floor, and chemosynthetic symbiotic, free-living, and attached microorganisms may drive the primary production at these communities. However, little is known about the microbiota thriving in and around organic falls. Our aim was to investigate and compare free-living and attached communities of bacteria and archaea from artificially immersed and naturally sunken wood logs with varying characteristics at several sites in the deep sea and in shallow water to address basic questions on the microbial ecology of sunken wood. Multivariate indirect ordination analyses of capillary electrophoresis single-stranded conformation polymorphisms (CE-SSCP) fingerprinting profiles demonstrated high similarity of bacterial and archaeal assemblages present in timbers and logs situated at geographically distant sites and at different depths of immersion. This similarity implies that wood falls harbor a specialized microbiota as observed in other ecosystems when the same environmental conditions reoccur. Scanning and transmission electron microscopy observations combined with multivariate direct gradient analysis of Bacteria CE-SSCP profiles demonstrate that type of wood (hard vs. softwood), and time of immersion are important in structuring sunken wood bacterial communities. Archaeal populations were present only in samples with substantial signs of decay, which were also more similar in their bacterial assemblages, providing indirect evidence of temporal succession in the microbial communities that develop in and around wood falls.

Drastic environmental change and its effects on a planetary biosphere

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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.

MICROTOMOGRAFIA DE ALTA RESOLUÇÃO NO SETOR MINERAL

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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.

Spatial elements of mortality risk in old-growth forests

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Das, Adrian; Battles, John; van Mantgem, Phillip J.; Stephenson, Nathan L.

2008-01-01

For many species of long-lived organisms, such as trees, survival appears to be the most critical vital rate affecting population persistence. However, methods commonly used to quantify tree death, such as relating tree mortality risk solely to diameter growth, almost certainly do not account for important spatial processes. Our goal in this study was to detect and, if present, to quantify the relevance of such processes. For this purpose, we examined purely spatial aspects of mortality for four species, Abies concolor, Abies magnifica, Calocedrus decurrens, and Pinus lambertiana, in an old-growth conifer forest in the Sierra Nevada of California, USA. The analysis was performed using data from nine fully mapped long-term monitoring plots.In three cases, the results unequivocally supported the inclusion of spatial information in models used to predict mortality. For Abies concolor, our results suggested that growth rate may not always adequately capture increased mortality risk due to competition. We also found evidence of a facilitative effect for this species, with mortality risk decreasing with proximity to conspecific neighbors. For Pinus lambertiana, mortality risk increased with density of conspecific neighbors, in keeping with a mechanism of increased pathogen or insect pressure (i.e., a Janzen-Connell type effect). Finally, we found that models estimating risk of being crushed were strongly improved by the inclusion of a simple index of spatial proximity.Not only did spatial indices improve models, those improvements were relevant for mortality prediction. For P. lambertiana, spatial factors were important for estimation of mortality risk regardless of growth rate. For A. concolor, although most of the population fell within spatial conditions in which mortality risk was well described by growth, trees that died occurred outside those conditions in a disproportionate fashion. Furthermore, as stands of A. concolor become increasingly dense, such spatial

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.

Classification of sea-floor features associated with methane seeps along the Gulf of Cádiz continental margin

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León, Ricardo; Somoza, Luis; Medialdea, Teresa; Maestro, Adolfo; Díaz-del-Río, Victor; Fernández-Puga, María del Carmen

2006-06-01

Based on recently gathered swath-bathymetry, high- to ultra-high-resolution seismic, and underwater camera data, along with dredging and coring samples, this paper examines the relationship between sea-floor features and the nature of hydrocarbon-enriched fluid and gas leaks from degassing of deeply buried sediments along the continental margin of the Gulf of Cádiz (eastern Central Atlantic). A classification into three main groups is proposed on the basis of the morphology and nature of deposits: (1) mud volcanoes, (2) methane-derived authigenic carbonates (MDAC) mounds, and (3) crater-like pockmarks. Mud volcanoes are, topographically, cone-shaped sea-floor edifices, built up from catastrophic mud and fluid degassing, intercalated with periods of inactivity. So far more than 25 mud volcanoes have been discovered in the Gulf of Cádiz, named in memory of deceased colleagues (e.g., Ginsburg and Baraza), or researchers' birth places (e.g. Faro, Cibeles, Almazán, San Petersburgh, Yuma, Rabat, Bonjardim, Coruña, Gades). These structures range from 800 to 2500 m in diameter and tower 150-300 m above the seabed. The volcanoes consistently feature a well-defined outer ring or circular terrace and an inner dome. All mud volcanoes are built up of episodes of mud-breccia flows, intercalated with deep-current deposits, with evident indications of gas saturation: degassing structures, a strong H 2S smell, and chemosynthetic fauna (such as Pogonophora sp. tube worms and Calyptogena sp.). Commonly observed carbonate crusts and slabs overlying some mud volcanoes are thought to have been formed by slow, diffuse venting during periods of inactivity or slower rates of fluid venting following the ejection of mud. A "fermentation" process, the result of microbial-mediated oxidation of hydrocarbon-enriched fluids, seems to play an important role in the growth of large deep-water carbonate mounds and chimneys during periods of low methane-seep fluid pressure. More than 400 crater

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

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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

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

Science.gov (United States)

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

2014-12-01

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

Chemical and isotopic signature of bulk organic matter and hydrocarbon biomarkers within mid-slope accretionary sediments of the northern Cascadia margin gas hydrate system

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Kaneko, Masanori; Shingai, Hiroshi; Pohlman, John W.; Naraoka, Hiroshi

2010-01-01

The chemical and isotopic compositions of sedimentary organic matter (SOM) from two mid-slope sites of the northern Cascadia margin were investigated during Integrated Ocean Drilling Program (IODP) Expedition 311 to elucidate the organic matter origins and identify potential microbial contributions to SOM. Gas hydrate is present at both locations (IODP Sites U1327 and U1328), with distinct patterns of near-seafloor structural accumulations at the cold seep Site U1328 and deeper stratigraphic accumulations at the slope-basin Site U1327. Source characterization and evidence that some components of the organic matter have been diagenetically altered are determined from the concentrations and isotopic compositions of hydrocarbon biomarkers, total organic carbon (TOC), total nitrogen (TN) and total sulfur (TS). The carbon isotopic compositions of TOC (δ13CTOC = −26 to −22‰) and long-chain n-alkanes (C27, C29 and C31, δ13C = −34 to − 29‰) suggest the organic matter at both sites is a mixture of 1) terrestrial plants that employ the C3 photosynthetic pathway and 2) marine algae. In contrast, the δ15NTN values of the bulk sediment (+ 4 to + 8‰) are consistent with a predominantly marine source, but these values most likely have been modified during microbial organic matter degradation. The δ13C values of archaeal biomarker pentamethylicosane (PMI) (− 46.4‰) and bacterial-sourced hopenes, diploptene and hop-21-ene (− 40.9 to − 34.7‰) indicate a partial contribution from methane carbon or a chemoautotrophic pathway. Our multi-isotope and biomarker-based conclusions are consistent with previous studies, based only on the elemental composition of bulk sediments, that suggested a mixed marine-terrestrial organic matter origin for these mid-slope sites of the northern Cascadia margin.

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

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Karina van der Heijden

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

Population genomic analysis of strain variation in Leptospirillum group II bacteria involved in acid mine drainage formation.

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Simmons, Sheri L; Dibartolo, Genevieve; Denef, Vincent J; Goltsman, Daniela S Aliaga; Thelen, Michael P; Banfield, Jillian F

2008-07-22

Deeply sampled community genomic (metagenomic) datasets enable comprehensive analysis of heterogeneity in natural microbial populations. In this study, we used sequence data obtained from the dominant member of a low-diversity natural chemoautotrophic microbial community to determine how coexisting closely related individuals differ from each other in terms of gene sequence and gene content, and to uncover evidence of evolutionary processes that occur over short timescales. DNA sequence obtained from an acid mine drainage biofilm was reconstructed, taking into account the effects of strain variation, to generate a nearly complete genome tiling path for a Leptospirillum group II species closely related to L. ferriphilum (sampling depth approximately 20x). The population is dominated by one sequence type, yet we detected evidence for relatively abundant variants (>99.5% sequence identity to the dominant type) at multiple loci, and a few rare variants. Blocks of other Leptospirillum group II types ( approximately 94% sequence identity) have recombined into one or more variants. Variant blocks of both types are more numerous near the origin of replication. Heterogeneity in genetic potential within the population arises from localized variation in gene content, typically focused in integrated plasmid/phage-like regions. Some laterally transferred gene blocks encode physiologically important genes, including quorum-sensing genes of the LuxIR system. Overall, results suggest inter- and intrapopulation genetic exchange involving distinct parental genome types and implicate gain and loss of phage and plasmid genes in recent evolution of this Leptospirillum group II population. Population genetic analyses of single nucleotide polymorphisms indicate variation between closely related strains is not maintained by positive selection, suggesting that these regions do not represent adaptive differences between strains. Thus, the most likely explanation for the observed patterns of

Population genomic analysis of strain variation in Leptospirillum group II bacteria involved in acid mine drainage formation.

Directory of Open Access Journals (Sweden)

Sheri L Simmons

2008-07-01

Full Text Available Deeply sampled community genomic (metagenomic datasets enable comprehensive analysis of heterogeneity in natural microbial populations. In this study, we used sequence data obtained from the dominant member of a low-diversity natural chemoautotrophic microbial community to determine how coexisting closely related individuals differ from each other in terms of gene sequence and gene content, and to uncover evidence of evolutionary processes that occur over short timescales. DNA sequence obtained from an acid mine drainage biofilm was reconstructed, taking into account the effects of strain variation, to generate a nearly complete genome tiling path for a Leptospirillum group II species closely related to L. ferriphilum (sampling depth approximately 20x. The population is dominated by one sequence type, yet we detected evidence for relatively abundant variants (>99.5% sequence identity to the dominant type at multiple loci, and a few rare variants. Blocks of other Leptospirillum group II types ( approximately 94% sequence identity have recombined into one or more variants. Variant blocks of both types are more numerous near the origin of replication. Heterogeneity in genetic potential within the population arises from localized variation in gene content, typically focused in integrated plasmid/phage-like regions. Some laterally transferred gene blocks encode physiologically important genes, including quorum-sensing genes of the LuxIR system. Overall, results suggest inter- and intrapopulation genetic exchange involving distinct parental genome types and implicate gain and loss of phage and plasmid genes in recent evolution of this Leptospirillum group II population. Population genetic analyses of single nucleotide polymorphisms indicate variation between closely related strains is not maintained by positive selection, suggesting that these regions do not represent adaptive differences between strains. Thus, the most likely explanation for the

Ferrous iron- and ammonium-rich diffuse vents support habitat-specific communities in a shallow hydrothermal field off the Basiluzzo Islet (Aeolian Volcanic Archipelago).

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Bortoluzzi, G; Romeo, T; La Cono, V; La Spada, G; Smedile, F; Esposito, V; Sabatino, G; Di Bella, M; Canese, S; Scotti, G; Bo, M; Giuliano, L; Jones, D; Golyshin, P N; Yakimov, M M; Andaloro, F

2017-09-01

Ammonium- and Fe(II)-rich fluid flows, known from deep-sea hydrothermal systems, have been extensively studied in the last decades and are considered as sites with high microbial diversity and activity. Their shallow-submarine counterparts, despite their easier accessibility, have so far been under-investigated, and as a consequence, much less is known about microbial communities inhabiting these ecosystems. A field of shallow expulsion of hydrothermal fluids has been discovered at depths of 170-400 meters off the base of the Basiluzzo Islet (Aeolian Volcanic Archipelago, Southern Tyrrhenian Sea). This area consists predominantly of both actively diffusing and inactive 1-3 meters-high structures in the form of vertical pinnacles, steeples and mounds covered by a thick orange to brown crust deposits hosting rich benthic fauna. Integrated morphological, mineralogical, and geochemical analyses revealed that, above all, these crusts are formed by ferrihydrite-type Fe 3+ oxyhydroxides. Two cruises in 2013 allowed us to monitor and sampled this novel ecosystem, certainly interesting in terms of shallow-water iron-rich site. The main objective of this work was to characterize the composition of extant communities of iron microbial mats in relation to the environmental setting and the observed patterns of macrofaunal colonization. We demonstrated that iron-rich deposits contain complex and stratified microbial communities with a high proportion of prokaryotes akin to ammonium- and iron-oxidizing chemoautotrophs, belonging to Thaumarchaeota, Nitrospira, and Zetaproteobacteria. Colonizers of iron-rich mounds, while composed of the common macrobenthic grazers, predators, filter-feeders, and tube-dwellers with no representatives of vent endemic fauna, differed from the surrounding populations. Thus, it is very likely that reduced electron donors (Fe 2+ and NH 4 + ) are important energy sources in supporting primary production in microbial mats, which form a habitat

CONVENTIONAL VIDEOENDOSCOPY CAN IDENTIFY HELICOBACTER PYLORI GASTRITIS?

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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

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

Twentieth-century decline of large-diameter trees in Yosemite National Park, California, USA

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Lutz, J.A.; van Wagtendonk, J.W.; Franklin, J.F.

2009-01-01

Studies of forest change in western North America often focus on increased densities of small-diameter trees rather than on changes in the large tree component. Large trees generally have lower rates of mortality than small trees and are more resilient to climate change, but these assumptions have rarely been examined in long-term studies. We combined data from 655 historical (1932-1936) and 210 modern (1988-1999) vegetation plots to examine changes in density of large-diameter trees in Yosemite National Park (3027 km2). We tested the assumption of stability for large-diameter trees, as both individual species and communities of large-diameter trees. Between the 1930s and 1990s, large-diameter tree density in Yosemite declined 24%. Although the decrease was apparent in all forest types, declines were greatest in subalpine and upper montane forests (57.0% of park area), and least in lower montane forests (15.3% of park area). Large-diameter tree densities of 11 species declined while only 3 species increased. Four general patterns emerged: (1) Pinus albicaulis, Quercus chrysolepis, and Quercus kelloggii had increases in density of large-diameter trees occur throughout their ranges; (2) Pinus jeffreyi, Pinus lambertiana, and Pinus ponderosa, had disproportionately larger decreases in large-diameter tree densities in lower-elevation portions of their ranges; (3) Abies concolor and Pinus contorta, had approximately uniform decreases in large-diameter trees throughout their elevational ranges; and (4) Abies magnifica, Calocedrus decurrens, Juniperus occidentalis, Pinus monticola, Pseudotsuga menziesii, and Tsuga mertensiana displayed little or no change in large-diameter tree densities. In Pinus ponderosa-Calocedrus decurrens forests, modern large-diameter tree densities were equivalent whether or not plots had burned since 1936. However, in unburned plots, the large-diameter trees were predominantly A. concolor, C. decurrens, and Q. chrysolepis, whereas P. ponderosa

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

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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

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

Relative Importance of Chemoautotrophy for Primary Production in a Light Exposed Marine Shallow Hydrothermal System

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Gonzalo V. Gomez-Saez

2017-04-01

Full Text Available The unique geochemistry of marine shallow-water hydrothermal systems promotes the establishment of diverse microbial communities with a range of metabolic pathways. In contrast to deep-sea vents, shallow-water vents not only support chemosynthesis, but also phototrophic primary production due to the availability of light. However, comprehensive studies targeting the predominant biogeochemical processes are rare, and consequently a holistic understanding of the functioning of these ecosystems is currently lacking. To this end, we combined stable isotope probing of lipid biomarkers with an analysis of the bacterial communities to investigate if chemoautotrophy, in parallel to photoautotrophy, plays an important role in autotrophic carbon fixation and to identify the key players. The study was carried out at a marine shallow-water hydrothermal system located at 5 m water depth off Dominica Island (Lesser Antilles, characterized by up to 55°C warm hydrothermal fluids that contain high amounts of dissolved Fe2+. Analysis of the bacterial diversity revealed Anaerolineae of the Chloroflexi as the most abundant bacterial class. Furthermore, the presence of key players involved in iron cycling generally known from deep-sea hydrothermal vents (e.g., Zetaproteobacteria and Geothermobacter, supported the importance of iron-driven redox processes in this hydrothermal system. Uptake of 13C-bicarbonate into bacterial fatty acids under light and dark conditions revealed active photo- and chemoautotrophic communities, with chemoautotrophy accounting for up to 65% of the observed autotrophic carbon fixation. Relatively increased 13C-incorporation in the dark allowed the classification of aiC15:0, C15:0, and iC16:0 as potential lipid biomarkers for bacterial chemoautotrophy in this ecosystem. Highest total 13C-incorporation into fatty acids took place at the sediment surface, but chemosynthesis was found to be active down to 8 cm sediment depth. In conclusion

Uranium nanoparticle synthesis from leaching solution

International Nuclear Information System (INIS)

Sadowski, Z.; Sklodowska, A.

2014-01-01

The removal of uranium from leaching and bioleaching solutions is of great significance for an environment protection. In comparison with conventional separation techniques, synthesis of uranium nanoparticles has a number of benefits. It has been demonstrated that the uranium nanoparticles show high catalytic activity. In the present studies a variety of synthesis systems have been used for reduction of uranium from bioleaching solution. Among various catalytical templates the hematite Fe_2O_3 nanoparticles are most interest It was presented the report on development of synthesis method to produce nano structured Fe_2O_3 particles. The efficiency of hematite nanoparticles for adsorption of uranium ions from bioleaching solutions was investigated. Bacterial leaching is alternate technique used to extract uranium from mining wastes. The bioleaching process is environment friendly and gives the extraction yield of over 90%. The bioleaching solutions were obtained from bioleaching experiments using waste materials from different places at Lower Silesia (Kowary, Grzmiaca, Kopaniec, Radoniow). Chemoautotrophic bacteria were used for bioleaching tests. The significant adsorption capacity of U(VI) onto iron oxide and hydroxides (goethite, hematite, and magnetite) was observed. The sorption of U(VI) onto the hematite surface was connected with the chemical reduction of U(VI) to U(IV) by Fe"2"+ ions. The initial reaction system contained excess of Fe"2"+ ions which were used to reduce of U(VI). The reduction of U(VI) occurred at pH at the vicinity of pH=2.4. The colloid particles of hematite with UO_2 nanoparticles were obtained. The results of zeta potential measurements of hematite nanoparticles showed that at the ionic strength equals 10"-"3M NaCl, the average zeta potential was +32.4±3.5 mV at pH = 2.6. The interaction of hematite nanoparticles with the bioleaching solutions led to decrease of positive zeta potential to the value of 6.4± 2.7 mV. (author)

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

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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

Hot spring microbial community composition, morphology, and carbon fixation: implications for interpreting the ancient rock record

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Schuler, Caleb G.; Havig, Jeff R.; Hamilton, Trinity L.

2017-11-01

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. Our data highlight

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

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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

Aseptically Sampled Organics in Subsurface Rocks From the Mars Analog Rio Tinto Experiment: An Analog For The Search for Deep Subsurface Life on Mars.}

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Bonaccorsi, R.; Stoker, C. R.

2005-12-01

The subsurface is the key environment for searching for life on planets lacking surface life. Subsurface ecosystems are of great relevance to astrobiology including the search for past/present life on Mars. The surface of Mars has conditions preventing current life but the subsurface might preserve organics and even host some life [1]. The Mars-Analog-Rio-Tinto-Experiment (MARTE) is performing a simulation of a Mars drilling experiment. This comprises conventional and robotic drilling of cores in a volcanically-hosted-massive-pyrite deposit [2] from the Iberian Pyritic Belt (IBP) and life detection experiments applying anti-contamination protocols (e.g., ATP Luminometry assay). The RT is considered an important analog of the Sinus Meridiani site on Mars and an ideal model analog for a deep subsurface Martian environment. Former results from MARTE suggest the existence of a relatively complex subsurface life including aerobic and anaerobic chemoautotrophs and strict anaerobic methanogens sustained by Fe and S minerals in anoxic conditions. A key requirement for the analysis of a subsurface sample on Mars is a set of simple tests that can help determine if the sample contains organic material of biological origin, and its potential for retaining definitive biosignatures. We report here on the presence of bulk organic matter Corg (0.03-0.05 Wt%), and Ntot (0.01-0.04 Wt%) and amount of measured ATP (Lightning MVP, Biocontrol) in weathered rocks (tuffs, gossan, pyrite stockwork from Borehole #8; >166m). This provides key insight on the type of trophic system sustaining the subsurface biosphere (i.e., heterotrophs vs. autotrophs) at RT. ATP data (Relative-Luminosity-Units, RLU) provide information on possible contamination and distribution of viable biomass with core depth (BH#8, and BH#7, ~3m). Avg. 153 RLU, i.e., surface vs. center of core, suggest that cleaness/sterility can be maintained when using a simple sterile protocol under field conditions. Results from this

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

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

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Dehant, Veronique; Banerdt, Bruce; Lognonné, Philippe; Grott, Matthias; Asmar, Sami; Biele, Jens; Breuer, Doris; Forget, François; Jaumann, Ralf; Johnson, Catherine; Knapmeyer, Martin; Langlais, Benoit; Le Feuvre, Mathieu; Mimoun, David; Mocquet, Antoine; Read, Peter; Rivoldini, Attilio; Romberg, Oliver; Schubert, Gerald; Smrekar, Sue; Spohn, Tilman; Tortora, Paolo; Ulamec, Stephan; Vennerstrøm, Susanne

2012-08-01

helping to understand the planet's climate evolution, and by providing a limit for the energy available to the chemoautotrophic biosphere through a measurement of the surface heat flow. The landers of the mission will also provide meteorological stations to monitor the climate and obtain new measurements in the atmospheric boundary layer.

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.

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

International Nuclear Information System (INIS)

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

2015-01-01

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 impact on

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

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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

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

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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

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

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

2007-09-24

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 gamma-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. 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. Quantitative PCR analyses were congruent with our libraries

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

Arsenic, Anaerobes, and Astrobiology

Science.gov (United States)

Stolz, J. F.; Oremland, R. S.; Switzer Blum, J.; Hoeft, S. E.; Baesman, S. M.; Bennett, S.; Miller, L. G.; Kulp, T. R.; Saltikov, C.

2013-12-01

Arsenic is an element best known for its highly poisonous nature, so it is not something one would associate with being a well-spring for life. Yet discoveries made over the past two decades have delineated that not only are some microbes resistant to arsenic, but that this element's primary redox states can be exploited to conserve energy and support prokaryotic growth ('arsenotrophy') in the absence of oxygen. Hence, arsenite [As(III)] can serve as an electron donor for chemo- or photo-autotrophy while arsenate [As(V)] will serve as an electron acceptor for chemo-heterotrophs and chemo-autotrophs. The phylogenetic diversity of these microbes is broad, encompassing many individual species from diverse taxonomic groups in the Domain Bacteria, with fewer representatives in the Domain Archaea. Speculation with regard to the evolutionary origins of the key functional genes in anaerobic arsenic transformations (arrA and arxA) and aerobic oxidation (aioB) has led to a disputation as to which gene and function is the most ancient and whether arsenic metabolism extended back into the Archaean. Regardless of its origin, robust arsenic metabolism has been documented in extreme environments that are rich in their arsenic content, such as hot springs and especially hypersaline soda lakes associated with volcanic regions. Searles Lake, CA is an extreme, salt-saturated end member where vigorous arsenic metabolism occurs, but there is no detectable sulfate-reduction or methanogenesis. The latter processes are too weak bio-energetically to survive as compared with arsenotrophy, and are also highly sensitive to the abundance of borate ions present in these locales. These observations have implications with respect to the search for microbial life elsewhere in the Solar System where volcanic-like processes have been operative. Hence, because of the likelihood of encountering dense brines in the regolith of Mars (formed by evapo-concentration) or beneath the ice layers of Europa

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

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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

Faunal and stable isotopic analyses of benthic foraminifera from the Southeast Seep on Kimki Ridge offshore southern California, USA

Science.gov (United States)

McGann, Mary; Conrad, James E.

2018-01-01

We investigated the benthic foraminiferal faunal and stable carbon and oxygen isotopic composition of a 15-cm push core (NA075-092b) obtained on a Telepresence-Enabled cruise to the Southeast Seep on Kimki Ridge offshore southern California. The seep core was taken at a depth of 973 m in the vicinity of a Beggiatoa bacterial mat and vesicomyid clams (Calyptogena) and compared to previously published data of living assemblages from ~ 714 m, four reference cores obtained at ~ 1030 m, and another one at 739 m. All of the reference sites are also from the Inner Continental Borderland but with no evidence of methane seepage.No endemic species were found at the seep site and most of the taxa recovered there have been reported previously from other seep or low oxygen environments. Q- and R-mode cluster analyses clearly illustrated differences in the faunal assemblages of the seep and non-seep sites. The living assemblage at Southeast Seep was characterized by abundant Takayanagia delicata, Cassidulina translucens, and Spiroplectammina biformis, whereas the non-seep San Pedro Basin reference assemblage was comprised primarily of Chilostomella oolina and Globobulimina pacifica. Density and species richness were lower at the seep site compared to the non-seep site, reflecting the harsher living conditions there. The dead assemblage at the seep site was dominated by Gyroidina turgida compared to Cassidulina translucens at the ~ 1030 m non-seep site and Cassidulina translucens, Pseudoparrella pacifica, and Takayanagia delicata at the 739 m non-seep site. Density was three times lower at Southeast Seep than at the non-seep sites of comparable water depth but species richness was ~ 30% higher. Stable carbon isotopic values were considerably depleted in the seep samples compared to the non-seep samples, with a progression from lightest to heaviest average δ13C values evident at the seep site reflecting microhabitat preference and vital effect: the

Enabling technologies to improve area-wide integrated pest management programmes for the control of screwworms.

Science.gov (United States)

Robinson, A S; Vreysen, M J B; Hendrichs, J; Feldmann, U

2009-06-01

. Wohlfahrtia magnifica (Schiner) (Diptera: Sarcophagidae) is a screwworm of temperate regions, which, although of limited agricultural importance, has invaded several new locations in the past few years. This special issue reports on the results of a 6-year project funded by the Joint Food and Agriculture Organization of the United Nations/International Atomic Energy Agency (FAO/IAEA) Programme of Nuclear Techniques in Food and Agriculture entitled 'Enabling Technologies for the Expansion of the SIT for Old and New World Screwworm'. A major goal of the project was to better understand population genetic variation in screwworms as an aid to the identification of isolated populations. The project also addressed issues related to genetic sexing, cuticular hydrocarbons, population dynamics, genetic transformation and chromosome analysis.

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

Science.gov (United States)

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

2004-12-01

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

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

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.

Carbon sequestration in soybean crop soils: the role of hydrogen-coupled CO2 fixation

Science.gov (United States)

Graham, A.; Layzell, D. B.; Scott, N. A.; Cen, Y.; Kyser, T. K.

2011-12-01

Conversion of native vegetation to agricultural land in order to support the world's growing population is a key factor contributing to global climate change. However, the extent to which agricultural activities contribute to greenhouse gas emissions compared to carbon storage is difficult to ascertain, especially for legume crops, such as soybeans. Soybean establishment often leads to an increase in N2O emissions because N-fixation leads to increased soil available N during decomposition of the low C:N legume biomass. However, soybean establishment may also reduce net greenhouse gas emissions by increasing soil fertility, plant growth, and soil carbon storage. The mechanism behind increased carbon storage, however, remains unclear. One explanation points to hydrogen coupled CO2 fixation; the process by which nitrogen fixation releases H2 into the soil system, thereby promoting chemoautotrophic carbon fixation by soil microbes. We used 13CO2 as a tracer to track the amount and fate of carbon fixed by hydrogen coupled CO2 fixation during one-year field and laboratory incubations. The objectives of the research are to 1) quantify rates of 13CO2 fixation in soil collected from a field used for long-term soybean production 2) examine the impact of H2 gas concentration on rates of 13CO2 fixation, and 3) measure changes in δ13C signature over time in 3 soil fractions: microbial biomass, light fraction, and acid stable fraction. If this newly-fixed carbon is incorporated into the acid-stable soil C fraction, it has a good chance of contributing to long-term soil C sequestration under soybean production. Soil was collected in the field both adjacent to root nodules (nodule soil) and >3cm away (root soil) and labelled with 13CO2 (1% v/v) in the presence and absence of H2 gas. After a two week labelling period, δ13C signatures already revealed differences in the four treatments of bulk soil: -17.1 for root, -17.6 for nodule, -14.2 for root + H2, and -6.1 for nodule + H2

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

Science.gov (United States)

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

2012-12-01

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

Precipitation of hydrated Mg carbonate with the aid of carbonic anhydrase for CO2 sequestration

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Power, I. M.; Harrison, A. L.; Dipple, G. M.

2011-12-01

Strategies for sequestering CO2 directly from the atmosphere are likely required to achieve the desired reduction in CO2 concentration and avoid the most damaging effects of climate change [1]. Numerous studies have demonstrated the accelerated precipitation of calcium carbonate minerals with the aid of carbonic anhydrase (CA) as a means of sequestering CO2 in solid carbonate form; however, no study has examined precipitation of magnesium carbonate minerals using CA. Precipitation of magnesite (MgCO3) is kinetically inhibited [2]; therefore, Mg2+ must be precipitated as hydrated carbonate minerals. In laboratory experiments, the uptake of atmospheric CO2 into brine solutions (0.1 M Mg) was rate-limiting for the precipitation of dypingite [Mg5(CO3)4(OH)2-5H2O] with initial precipitation requiring 15 days [3]. It was also found that dypingite precipitation outpaced the uptake of CO2 gas into solution. CO2 uptake is limited by the hydration of CO2 to form carbonate ions [4]. Carbonic anhydrase (CA) enzymes are among the fastest known in nature and are able to catalyze the hydration of CO2, i.e., converting CO2(aq) to CO32- and HCO3- [5]. CA plays an important role in the carbon concentrating mechanism of photoautotrophic, chemoautotrophic, and heterotrophic prokaryotes and is involved in pH homeostasis, facilitated diffusion of CO2, ion transport, and the interconversion of CO2 and HCO3- [6]. Introducing CA into buffered Mg-rich solutions should allow for more rapid precipitation of hydrated magnesium carbonate minerals. Batch experiments were conducted using 125 mL flasks containing 100 mL of Millipore deionized water with 0.2 M of MgCl2-6H2O. To buffer pH, 1.0 g of pulverized brucite [Mg(OH)2] or 1.0 g of NaOH was added to the systems, which were amended with Bovine carbonic anhydrase (BCA) (Sigma-Aldrich). Solutions were stirred continuously and kept at room temperature (~22°C) with laboratory air introduced by bubbling. Temperature and pH were measured routinely

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

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

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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

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

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

Science.gov (United States)

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

2001-12-01

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

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.

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

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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.

Preclinical molecular imaging: development of instrumentation for translational research with small laboratory animals.

Science.gov (United States)

Mejia, Jorge; Miranda, Ana Claudia Camargo; Durante, Ana Claudia Ranucci; Oliveira, Larissa Rolim de; Barboza, Marycel Rosa Felisa Figols de; Rosell, Katerin Taboada; Jardim, Daniele Pereira; Campos, Alexandre Holthausen; Reis, Marilia Alves Dos; Catanoso, Marcela Forli; Galvis-Alonso, Orfa Yineth; Cabral, Francisco Romero

2016-01-01

ção miniSPECT, composto por três subsistemas: mecânico, eletrônico e de software. O dispositivo foi montado em uma câmara Discovery VH da General Electric Healthcare, retirada do serviço clínico e instalada no Centro de Imagem Pré-Clínica do Hospital Israelita Albert Einstein. O sistema combinado foi caracterizado, determinando parâmetros de funcionamento como resolução espacial, magnificação, limites de tamanho dos alvos de estudo, número de projeções, tempo de registro e tempo de reconstrução das imagens tomográficas. Foram obtidas imagens com resolução espacial de até 0,5mm, com tempos de registro e reconstrução de 30 a 45 minutos, utilizando reconstrução iterativa com 10 a 20 iterações e 4 subconjuntos de projeções. O sistema foi validado obtendo imagens tomográficas in vivo do coração, dos rins e do cérebro de animais normais (camundongos e ratos adultos), utilizando os radiofármacos hexaquis-2-metoxi-isobutil-isonitrila marcado com 99mTc (Sestamibi-99mTc), ácido dimercaptosuccínico marcado com 99mTc (DMSA-99mTc) e hexametil-propileno-amina-oxima marcada com 99mTc (HMPAO-99mTc). Este tipo de aplicação, que consiste na adaptação para um objetivo alternativo de instrumentação já existente, constituiu-se em uma opção de infraestrutura de baixo custo, que permite realizar estudos in vivo em larga escala, com qualidade aprimorada, em áreas diversas, como neurologia, nefrologia, cardiologia, entre outras.

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

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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

Worldwide Eutrophication of Water Bodies: Causes, Concerns, Controls

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Prepas, E. E.; Charette, T.

2003-12-01

depletion is one of the most harmful side effects of eutrophication because it can cause catastrophic fish kills, devastating local fisheries.The accumulation of plant biomass depends on the addition of factors that stimulate plant growth. On average, the macronutrients nitrogen and phosphorus are present in marine phytoplankton at an atomic ratio 16 : 1 (Redfield, 1958). The ratio of nitrogen to phosphorus in freshwaters tends to be greater than the ratio in phytoplankton; therefore, phosphorus most often limits the growth of phytoplankton. As a result, phosphorus enrichment of freshwater often causes its eutrophication ( Schindler, 1977). In lakes, nitrogen is usually present in concentrations equal to or beyond what is required for aquatic plant growth because, unlike phosphorus, it has an atmospheric source. In marine systems, nitrogen concentrations are often limiting because bacterial nitrogen fixation, while a considerable source of nitrogen in lakes, not as important in marine waters. A wide variety of prokaryotic organisms (i.e., certain 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

Development of biological platform for the autotrophic production of biofuels

Science.gov (United States)

Khan, Nymul

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

Aspectos Históricos de la deficiencia de Yodo en América

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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

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

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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