Схиигумен Сергий как маргинальная языковая личность в пространстве религиозно-политической коммуникации

SummaryThaumarchaeota are globally distributed and abundantmicroorganisms occurring in diverse habitats and thusrepresent a major source of archaeal lipids. The scopeof lipids as taxonomic markers in microbial ecologicalstudies is limited by the scarcity of comparative dataon the membrane lipid composition of cultivated representatives,including the phylum Thaumarchaeota.Here, we comprehensively describe the core and intactpolar lipid (IPL) inventory of ten ammonia-oxidisingthaumarchaeal cultures representing all four characterizedphylogenetic clades. IPLs of these thaumarchaealstrains are generally similar and consist of membranespanning,glycerol dibiphytanyl glycerol tetraetherswith monoglycosyl, diglycosyl, phosphohexose andhexose-phosphohexose headgroups. However, the relativeabundances of these IPLs and their core lipidcompositions differ systematically between the phylogeneticsubgroups, indicating high potential forchemotaxonomic distinction of thaumarchaeal clades.Comparative lipidomic analyses of 19 euryarchaeal andcrenarchaeal strains suggested that the lipid methoxyarchaeol is synthesized exclusively by Thaumarchaeotaand may thus represent a diagnostic lipidbiomarker for this phylum. The unprecedented diversityof the thaumarchaeal lipidome with 118 differentlipids suggests that membrane lipid composition andadaptation mechanisms in Thaumarchaeota are morecomplex than previously thought and include uniquelipids with as yet unresolved properties

Rearrangement of the RNA polymerase subunit H and the lower jaw in archaeal elongation complexes

The lower jaws of archaeal RNA polymerase and eukaryotic RNA polymerase II include orthologous subunits H and Rpb5, respectively. The tertiary structure of H is very similar to the structure of the C-terminal domain of Rpb5, and both subunits are proximal to downstream DNA in pre-initiation complexes. Analyses of reconstituted euryarchaeal polymerase lacking subunit H revealed that H is important for open complex formation and initial transcription. Eukaryotic Rpb5 rescues activity of the ΔH enzyme indicating a strong conservation of function for this subunit from archaea to eukaryotes. Photochemical cross-linking in elongation complexes revealed a striking structural rearrangement of RNA polymerase, bringing subunit H near the transcribed DNA strand one helical turn downstream of the active center, in contrast to the positioning observed in preinitiation complexes. The rearrangement of subunits H and A′′ suggest a major conformational change in the archaeal RNAP lower jaw upon formation of the elongation complex

Genetic and transcriptomic analysis of transcription factor genes in the model halophilic Archaeon: coordinate action of TbpD and TfbA

<p>Abstract</p> <p>Background</p> <p>Archaea are prokaryotic organisms with simplified versions of eukaryotic transcription systems. Genes coding for the general transcription factors TBP and TFB are present in multiple copies in several Archaea, including <it>Halobacterium </it>sp. NRC-1. Multiple TBP and TFBs have been proposed to participate in transcription of genes via recognition and recruitment of RNA polymerase to different classes of promoters.</p> <p>Results</p> <p>We attempted to knock out all six TBP and seven TFB genes in <it>Halobacterium </it>sp. NRC-1 using the <it>ura</it>3-based gene deletion system. Knockouts were obtained for six out of thirteen genes, <it>tbp</it>CDF and <it>tfb</it>ACG, indicating that they are not essential for cell viability under standard conditions. Screening of a population of 1,000 candidate mutants showed that genes which did not yield mutants contained less that 0.1% knockouts, strongly suggesting that they are essential. The transcriptomes of two mutants, Δ<it>tbp</it>D and Δ<it>tfb</it>A, were compared to the parental strain and showed coordinate down regulation of many genes. Over 500 out of 2,677 total genes were regulated in the Δ<it>tbp</it>D and Δ<it>tfb</it>A mutants with 363 regulated in both, indicating that over 10% of genes in both strains require the action of both TbpD and TfbA for normal transcription. Culturing studies on the Δ<it>tbp</it>D and Δ<it>tfb</it>A mutant strains showed them to grow more slowly than the wild-type at an elevated temperature, 49°C, and they showed reduced viability at 56°C, suggesting TbpD and TfbA are involved in the heat shock response. Alignment of TBP and TFB protein sequences suggested the expansion of the TBP gene family, especially in <it>Halobacterium </it>sp. NRC-1, and TFB gene family in representatives of five different genera of haloarchaea in which genome sequences are available.</p> <p>Conclusion</p> <p>Six of thirteen TBP and TFB genes of <it>Halobacterium </it>sp. NRC-1 are non-essential under standard growth conditions. TbpD and TfbA coordinate the expression of over 10% of the genes in the NRC-1 genome. The Δ<it>tbp</it>D and Δ<it>tfb</it>A mutant strains are temperature sensitive, possibly as a result of down regulation of heat shock genes. Sequence alignments suggest the existence of several families of TBP and TFB transcription factors in <it>Halobacterium </it>which may function in transcription of different classes of genes.</p

Selektion, Integration und Evaluation: Wie wir das Internet nutzen, wenn wir uns über Wissenschaft informieren wollen

Laien treffen heute im Internet auf eine besonders große Vielfalt an Wissenschaftsinformationen. Wer hiervon profitieren will, muss Informationen auswählen, Verknüpfungen zwischen verschiedenen, oftmals konfligierenden Aussagen herstellen und deren Gültigkeit kritisch überprüfen. Anhand der Ergebnisse aus zwei Projekten aus dem SPP 1409 ‚Wissenschaft und Öffentlichkeit‘ zeigen wir, wie Laien diese Anforderungen bewältigen und auf welche kognitiven und motivationalen Ressourcen sie dabei zurückgreifen können. Obwohl erwachsene Laien bereits über vielfältige Kompetenzen im Umgang mit Wissenschaftsinformationen verfügen, deuten unsere Befunde auch auf einen Bedarf an pädagogischen Interventionen hin, um diese weiter zu verfeinern