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Ammonia oxidation is the first step in nitrification, a key process in the global nitrogen cycle that results in the formation of nitrate through microbial activity. The increase in nitrate availability in soils is important for plant nutrition, but it also has considerable impact on groundwater pollution owing to leaching. Here we show that archaeal(More)
Autotrophic ammonia oxidation occurs in acid soils, even though laboratory cultures of isolated ammonia oxidizing bacteria fail to grow below neutral pH. To investigate whether archaea possessing ammonia monooxygenase genes were responsible for autotrophic nitrification in acid soils, the community structure and phylogeny of ammonia oxidizing bacteria and(More)
Mesophilic crenarchaeota are frequently found in terrestrial and marine habitats worldwide, but despite their considerable abundance the physiology of these as yet uncultivated archaea has remained unknown. From a 1.2 Gb large-insert environmental fosmid library of a calcareous grassland soil, a 43 kb genomic fragment was isolated with a ribosomal RNA that(More)
Crucial steps in geochemical cycles are in many cases performed by more than one group of microorganisms, but the significance of this functional redundancy with respect to ecosystem functioning is poorly understood. Ammonia-oxidizing archaea (AOA) and their bacterial counterparts (AOB) are a perfect system to address this question: although performing the(More)
Sponges are simple animals with few cell types, but their genomes paradoxically contain a wide variety of developmental transcription factors, including homeobox genes belonging to the Antennapedia (ANTP) class, which in bilaterians encompass Hox, ParaHox and NK genes. In the genome of the demosponge Amphimedon queenslandica, no Hox or ParaHox genes are(More)
A stable and specific bacterial community was shown to be associated with the Mediterranean sponge Chondrilla nucula. The associated bacterial communities were demonstrated to be highly similar for all studied specimens regardless of sampling time and geographical region. In addition, analysis of 16S rDNA clone libraries revealed three constantly C.(More)
BACKGROUND/AIMS The effect of heterozygosity for the C282Y mutation in the HFE hemochromatosis gene on iron accumulation and disease progression in liver disease patients is unclear. METHODS We investigated the prevalence of this mutation in 531 patients and 205 healthy controls. In addition, we assessed the influence of the mutation on liver histology in(More)
The Pax-Six-Eya-Dach network (PSEDN) is involved in a variety of developmental processes, including well documented roles in determination of sensory organs and morphogenesis in bilaterian animals. Expression of PSEDN components in cnidarians is consistent with function in sensory organ development. Recent work in demosponges demonstrated the presence of(More)
Developmental transcription factors are key players in animal multicellularity, being members of the T-box family that are among the most important. Until recently, T-box transcription factors were thought to be exclusively present in metazoans. Here, we report the presence of T-box genes in several nonmetazoan lineages, including ichthyosporeans,(More)
Elucidation of macroevolutionary transitions between diverse animal body plans remains a major challenge in evolutionary biology. We address the sponge-eumetazoan transition by analyzing expression of a broad range of eumetazoan developmental regulatory genes in Sycon ciliatum (Calcispongiae). Here we show that many members of surprisingly numerous Wnt and(More)