Ben A. Abbas

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Marine Crenarchaeota are the most abundant single group of prokaryotes in the ocean, but their physiology and role in marine biogeochemical cycles are unknown. Recently, a member of this clade was isolated from a sea aquarium and shown to be capable of nitrification, tentatively suggesting that Crenarchaeota may play a role in the oceanic nitrogen cycle. We(More)
Heterochromatin is important for gene regulation and chromosome structure, but the genes that are occupied by heterochromatin proteins in the mammalian genome are largely unknown. We have adapted the DamID method to systematically identify target genes of the heterochromatin proteins HP1 and SUV39H1 in human and mouse cells. Unexpectedly, we found that CBX1(More)
Within the upper 400 m at western, central and eastern stations in the world's largest stratified basin, the Black Sea, we studied the qualitative and quantitative distribution of putative nitrifying Archaea based on their genetic markers (16S rDNA, amoA encoding for the alpha-subunit of archaeal ammonia monooxygenase), and crenarchaeol, the specific(More)
Abstract Uni-algal, non-axenic cultures of six marine diatoms were screened by polymerase chain reaction-denaturing gradient gel electrophoresis for the diversity of the accompanying bacterial communities ('satellite' bacteria) in order to test the hypothesis that algal cells constitute niches for specific bacterial species. The complexity of the satellite(More)
Thiopaq biotechnology for partial sulfide oxidation to elemental sulfur is an efficient way to remove H2S from biogases. However, its application for high-pressure natural gas desulfurization needs upgrading. Particularly, an increase in alkalinity of the scrubbing liquid is required. Therefore, the feasibility of sulfide oxidation into elemental sulfur(More)
Inputs of CH(4) from sediments, including methane seeps on the continental margin and methane-rich mud volcanoes on the abyssal plain, make the Black Sea the world's largest surface water reservoir of dissolved methane and drive a high rate of aerobic and anaerobic oxidation of methane in the water column. Here we present the first combined organic(More)
The 18S ribosomal DNA molecular phylogeny and lipid composition of over 120 marine diatoms showed that the capability to biosynthesize highly branched isoprenoid (HBI) alkenes is restricted to two specific phylogenetic clusters, which independently evolved in centric and pennate diatoms. The molecular record of C25 HBI chemical fossils in a large suite of(More)
Denitrification and dissimilatory nitrate reduction to ammonium (DNRA) are competing microbial nitrate-reduction processes. The occurrence of DNRA has been shown to be effected qualitatively by various parameters in the environment. A more quantitative understanding can be obtained using enrichment cultures in a laboratory reactor, yet no successful DNRA(More)
In this study, we investigated during 400 days the microbial community variations as observed from 16S DNA gene DGGE banding patterns from an aerobic granular sludge pilot plant as well as the from a full-scale activated sludge treatment plant in Epe, the Netherlands. Both plants obtained the same wastewater and had the same relative hydraulic variations(More)
Several wastewater stabilization ponds (WSP) in Tunisia suffer periodically from the ‘red-water’ phenomenon due to blooming of purple sulfur bacteria, indicating that sulfur cycle is one of the main element cycles in these ponds. In this study, we investigated the microbial diversity of the El Menzeh WSP and focused in particular on the different functional(More)