Geoglobus acetivorans sp. nov., an iron(III)-reducing archaeon from a deep-sea hydrothermal vent

En libre-accès sur Archimer : http://archimer.ifremer.fr/doc/2009/publication-6977.pdfInternational audienceA hyperthermophilic, anaerobic, dissimilatory Fe(III)-reducing, facultatively chemolithoautotrophic archaeon (strain SBH6(T)) was isolated from a hydrothermal sample collected from the deepest of the known World Ocean hydrothermal fields, Ashadze field (1 degrees 58' 21'' N 4 degrees 51' 47'' W) on the Mid-Atlantic Ridge, at a depth of 4100 m. The strain was enriched using acetate as the electron donor and Fe(III) oxide as the electron acceptor. Cells of strain SBH6(T) were irregular cocci, 0.3-0.5 mum in diameter. The temperature range for growth was 50-85 degrees C, with an optimum at 81 degrees C. The pH range for growth was 5.0-7.5, with an optimum at pH 6.8. Growth of SBH6(T) was observed at NaCl concentrations ranging from 1 to 6 % (w/v) with an optimum at 2.5 % (w/v). The isolate utilized acetate, formate, pyruvate, fumarate, malate, propionate, butyrate, succinate, glycerol, stearate, palmitate, peptone and yeast extract as electron donors for Fe(III) reduction. It was also capable of growth with H(2) as the sole electron donor, CO(2) as a carbon source and Fe(III) as an electron acceptor without the need for organic substances. Fe(III) [in the form of poorly crystalline Fe(III) oxide or Fe(III) citrate] was the only electron acceptor that supported growth. 16S rRNA gene sequence analysis revealed that the closest relative of the isolated organism was Geoglobus ahangari 234(T) (97.0 %). On the basis of its physiological properties and phylogenetic analyses, the isolate is considered to represent a novel species, for which the name Geoglobus acetivorans sp. nov. is proposed. The type strain is SBH6(T) (=DSM 21716(T) =VKM B-2522(T))

Deferribacter autotrophicus sp. nov., an iron(III)-reducing bacterium from a deep-sea hydrothermal vent

En libre-accès sur Archimer : http://archimer.ifremer.fr/doc/2009/publication-6598.pdfInternational audienceA thermophilic, anaerobic, chemolithoautotrophic bacterium (designated strain SL50(T)) was isolated from a hydrothermal sample collected at the Mid-Atlantic Ridge from the deepest of the known World ocean hydrothermal fields, Ashadze field (1 degrees 58' 21'' N 4 degrees 51' 47'' W) at a depth of 4100 m. Cells of strain SL50(T) were motile, straight to bent rods with one polar flagellum, 0.5-0.6 mum in width and 3.0-3.5 mum in length. The temperature range for growth was 25-75 degrees C, with an optimum at 60 degrees C. The pH range for growth was 5.0-7.5, with an optimum at pH 6.5. Growth of strain SL50(T) was observed at NaCl concentrations ranging from 1.0 to 6.0 % (w/v) with an optimum at 2.5 % (w/v). The generation time under optimal growth conditions for strain SL50(T) was 60 min. Strain SL50(T) used molecular hydrogen, acetate, lactate, succinate, pyruvate and complex proteinaceous compounds as electron donors, and Fe(III), Mn(IV), nitrate or elemental sulfur as electron acceptors. The G+C content of the DNA of strain SL50(T) was 28.7 mol%. 16S rRNA gene sequence analysis revealed that the closest relative of strain SL50(T) was Deferribacter abyssi JR(T) (95.5 % similarity). On the basis of its physiological properties and phylogenetic analyses, the isolate is considered to represent a novel species, for which the name Deferribacter autotrophicus sp. nov. is proposed. The type strain is SL50(T) (=DSM 21529(T)=VKPM B-10097(T)). Deferribacter autotrophicus sp. nov. is the first described deep-sea bacterium capable of chemolithoautotrophic growth using molecular hydrogen as an electron donor and ferric iron as electron acceptor and CO(2) as the carbon source

Verbs of pain and accusative subjects in Romanian

Verbs of pain in Romanian such as durea ‘ache’, ustura ‘burn’, and furnica ‘itch’ assign the accusative to their experiencer arguments, unlike other Romance languages, where the experiencer is dative-marked. The use of the accusative raises interesting problems in that it gives rise to a mismatch between the hypothesis on the syntax of inalienability in Romance in Generative Grammar (Guéron 1985) and Burzio’s (1986) Generalization. This article shows that the inversed nominative NP denoting the body part does not show subject properties, and that the accusative experiencer in sentence initial position does not show object properties, but instead displays subject properties, just like the dative in similar constructions. However, the difference between accusative and dative subjects in this construction is that the accusative is assigned to verb arguments and is a lexical case, whereas the dative is assigned to external possessors and is an inherent case. Surprisingly, the argument status of the accusative experiencer makes it even more subject-like than the dative experiencer, which is an adjunct and is dependent on the presence of an internal argument triggering verb agreement, whereas the accusative subject can also occur without an internal argument or with a locative PP

Corpora in Text-Based Russian Studies

This chapter focuses on textual data that are collected for a specific purpose, which are usually referred to as corpora. Scholars use corpora when they examine existing instances of a certain phenomenon or to conduct systematic quantitative analyses of occurrences, which in turn reflect habits, attitudes, opinions, or trends. For these contexts, it is extremely useful to combine different approaches. For example, a linguist might analyze the frequency of a certain buzzword, whereas a scholar in the political, cultural, or sociological sciences might attempt to explain the change in language usage from the data in question.Peer reviewe

Observation of time quasicrystal and its transition to superfluid time crystal

We report experimental realization of a quantum time quasicrystal, and its transformation to a quantum time crystal. We study Bose-Einstein condensation of magnons, associated with coherent spin precession, created in a flexible trap in superfluid $^3$He-B. Under a periodic drive with an oscillating magnetic field, the coherent spin precession is stabilized at a frequency smaller than that of the drive, demonstrating spontaneous breaking of discrete time translation symmetry. The induced precession frequency is incommensurate with the drive, and hence the obtained state is a time quasicrystal. When the drive is turned off, the self-sustained coherent precession lives a macroscopically-long time, now representing a time crystal with broken symmetry with respect to continuous time translations. Additionally, the magnon condensate manifests spin superfluidity, justifying calling the obtained state a time supersolid or a time super-crystal

YARN begins

В статье представлен проект создания большого открытого тезауруса русского языка YARN (Yet Another RussNet). Основная особенность проекта — использование wiki-подхода к наполнению и редактированию ресурса. В статье описаны лингвистические принципы создания тезауруса YARN, формат данных, а также ближайшие практические шаги, которые планируется предпринять в рамках проекта.YARN (Yet Another RussNet) is a work-in-progress on development of a large and open WordNet-like thesaurus for Russian. The paper reports on linguistic design, development and organizational principles, and interchange format of YARN.Исследование осуществляется при финансовой поддержке РГНФ (проект № 13-04-12020 «Новый открытый электронный тезаурус русского языка»). Мы благодарим участников группы yarn_org за активность, замечания и предложения. Работа Андрея Крижановского выполнена при частичной финансовой поддержке РФФИ (проект № 11-01-00251, № 12-01-00481, № 12-07-00070) и РГНФ (проект № 12-04-12062). Работа Ольги Ляшевской и Анастасии Бонч-Осмоловской отражает результаты исследований, проведенных при поддержке Программы фундаментальных исследований НИУ Высшая школа экономики (2013), проект «Корпусные технологии в лингвистических и междисциплинарных исследованиях». Павел Браславский благодарит группу разработчиков GermaNet под руководством проф. Эрхарда Хинрихса из университета Тюбингена за гостеприимство, плодотворное обсуждение проекта и обмен опытом, а также MUMIA Network30 за финансовую поддержку визита в Тюбинген в рамках программы Short Term Scientific Missions (STSM)

Akkermansia muciniphila - friend or foe in colorectal cancer?

Akkermansia muciniphila is a gram-negative anaerobic bacterium, which represents a part of the commensal human microbiota. Decline in the abundance of A. muciniphila among other microbial species in the gut correlates with severe systemic diseases such as diabetes, obesity, intestinal inflammation and colorectal cancer. Due to its mucin-reducing and immunomodulatory properties, the use of probiotics containing Akkermansia sp. appears as a promising approach to the treatment of metabolic and inflammatory diseases. In particular, a number of studies have focused on the role of A. muciniphila in colorectal cancer. Of note, the results of these studies in mice are contradictory: some reported a protective role of A. muciniphila in colorectal cancer, while others demonstrated that administration of A. muciniphila could aggravate the course of the disease resulting in increased tumor burden. More recent studies suggested the immunomodulatory effect of certain unique surface antigens of A. muciniphila on the intestinal immune system. In this Perspective, we attempt to explain how A. muciniphila contributes to protection against colorectal cancer in some models, while being pathogenic in others. We argue that differences in the experimental protocols of administration of A. muciniphila, as well as viability of bacteria, may significantly affect the results. In addition, we hypothesize that antigens presented by pasteurized bacteria or live A. muciniphila may exert distinct effects on the barrier functions of the gut. Finally, A. muciniphila may reduce the mucin barrier and exerts combined effects with other bacterial species in either promoting or inhibiting cancer development

Genome sequence of Desulfurella amilsii strain TR1 and comparative genomics of Desulfurellaceae family

The acidotolerant sulfur reducer Desulfurella amilsii was isolated from sediments of Tinto river, an extremely acidic environment. Its ability to grow in a broad range of pH and to tolerate certain heavy metals offers potential for metal recovery processes. Here we report its high-quality draft genome sequence and compare it to the available genome sequences of other members of Desulfurellaceae family: D. acetivorans, D. multipotens, Hippea maritima, H. alviniae, H. medeae and H. jasoniae. For most species, pairwise comparisons for average nucleotide identity (ANI) and in silico DNA-DNA hybridization (DDH) revealed ANI values from 67.5 to 80% and DDH values from 12.9 to 24.2%. D. acetivorans and D. multipotens, however, surpassed the estimated thresholds of species definition for both DDH (98.6%) and ANI (88.1%). Therefore, they should be merged to a single species. Comparative analysis of Desulfurellaceae genomes revealed different gene content for sulfur respiration between Desulfurella and Hippea species. Sulfur reductase is only encoded in D. amilsii, in which it is suggested to play a role in sulfur respiration, especially at low pH. Polysulfide reductase is only encoded in Hippea species; it is likely that this genus uses polysulfide as electron acceptor. Genes encoding thiosulfate reductase are present in all the genomes, but dissimilatory sulfite reductase is only present in Desulfurella species. Thus, thiosulfate respiration via sulfite is only likely in this genus. Although sulfur disproportionation occurs in Desulfurella species, the molecular mechanism behind this process is not yet understood, hampering a genome prediction. The metabolism of acetate in Desulfurella species can occur via the acetyl-CoA synthetase or via acetate kinase in combination with phosphate acetyltransferase, while in Hippea species, it might occur via the acetate kinase. Large differences in gene sets involved in resistance to acidic conditions were not detected among the genomes. Therefore, the regulation of those genes, or a mechanism not yet known, might be responsible for the unique ability of D. amilsii. This is the first report on comparative genomics of sulfur-reducing bacteria, which is valuable to give insight into this poorly understood metabolism, but of great potential for biotechnological purposes and of environmental significance.The authors thank CNPq (Conselho Nacional de Desenvolvimento Cientifiìco e Tecnoloìgico),organization of the Brazilian Government for supporting the doctoral study program for the development of Science and Technology. Research of IS-A and AM Stams is financed by ERC grant project 323009, and Gravitation grant project 024.002.002 fromTheNetherlands Ministry of Education, Culture and Science. Thanks to Bastian Hornung for the bioinformatics support and to Robert Smith for the English revision.info:eu-repo/semantics/publishedVersio

Diversity and distribution of subseafloor Thermococcales populations in diffuse hydrothermal vents at an active deep-sea volcano in the northeast Pacific Ocean

Author Posting. © American Geophysical Union, 2006. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 111 (2006): G04016, doi:10.1029/2005JG000097.The presence, diversity, and distribution of a key group of subseafloor archaea, the Thermococcales, was examined in multiple diffuse flow hydrothermal vents at Axial Seamount, an active deep-sea volcano located in the northeast Pacific Ocean. A polymerase chain reaction (PCR) approach was used to determine if this group of subseafloor indicator organisms showed any phylogenetic distribution that may indicate distinct subseafloor communities at vents with different physical and chemical characteristics. Targeted primers for the Thermococcales 16S rRNA (small subunit ribosomal RNA) gene and intergenic transcribed spacer (ITS) region were designed and applied to organisms filtered in-situ directly from a variety of diffuse flow vents. Thermococcales were amplified from 9 of 11 samples examined, and it was determined that the ITS region is a better phylogenetic marker than the 16S rRNA in defining consistent groups of closely related sequences. Results show a relationship between environmental clone distribution and source vent chemistry. The most highly diluted vents with elevated iron and alkalinity contained a distinct group of Thermococcales as defined by the ITS region, suggesting separate subseafloor Thermococcales populations at diffuse vents within the Axial caldera.This work was supported by Washington Sea Grant (NA76RG0119), National Science Foundation (OCE 9816491), NSF IGERT (DGE- 9870713), NASA Astrobiology Institute through the Carnegie Geophysical Institute, the NOAA/PMEL Vents Program, NOAA West Coast and Polar Undersea Research Center, and by the Joint Institute for the Study of the Atmosphere and Ocean under NOAA Cooperative Agreement No. NA117RJ1232

Molecular Detection of Anaerobic Ammonium-Oxidizing (Anammox) Bacteria in High-Temperature Petroleum Reservoirs

Anaerobic ammonium-oxidizing (anammox) process plays an important role in the nitrogen cycle of the worldwide anoxic and mesophilic habitats. Recently, the existence and activity of anammox bacteria have been detected in some thermophilic environments, but their existence in the geothermal subterranean oil reservoirs is still not reported. This study investigated the abundance, distribution and functional diversity of anammox bacteria in nine out of 17 high-temperature oil reservoirs by molecular ecology analysis. High concentration (5.31–39.2 mg l−1) of ammonium was detected in the production water from these oilfields with temperatures between 55°C and 75°C. Both 16S rRNA and hzo molecular biomarkers indicated the occurrence of anammox bacteria in nine out of 17 samples. Most of 16S rRNA gene phylotypes are closely related to the known anammox bacterial genera Candidatus Brocadia, Candidatus Kuenenia, Candidatus Scalindua, and Candidatus Jettenia, while hzo gene phylotypes are closely related to the genera Candidatus Anammoxoglobus, Candidatus Kuenenia, Candidatus Scalindua, and Candidatus Jettenia. The total bacterial and anammox bacterial densities were 6.4 ± 0.5 × 103 to 2.0 ± 0.18 × 106 cells ml−1 and 6.6 ± 0.51 × 102 to 4.9 ± 0.36 × 104 cell ml−1, respectively. The cluster I of 16S rRNA gene sequences showed distant identity (<92%) to the known Candidatus Scalindua species, inferring this cluster of anammox bacteria to be a new species, and a tentative name Candidatus “Scalindua sinooilfield” was proposed. The results extended the existence of anammox bacteria to the high-temperature oil reservoirs