A5091849321- Microbial Community Ecology and Physiology
- Protist diversity and phylogeny
- Genomics and Phylogenetic Studies
- Marine and coastal ecosystems
- Drug Transport and Resistance Mechanisms
- Polar Research and Ecology
- Methane Hydrates and Related Phenomena
- Bacterial Genetics and Biotechnology
- Antibiotic Resistance in Bacteria
- Image Processing and 3D Reconstruction
- Seaweed-derived Bioactive Compounds
- DNA and Nucleic Acid Chemistry
- Bacteriophages and microbial interactions
- Algal biology and biofuel production
- Wastewater Treatment and Nitrogen Removal
- Marine Sponges and Natural Products
- Marine and coastal plant biology
- Probiotics and Fermented Foods
- Coastal wetland ecosystem dynamics
- Gut microbiota and health
- Fungal and yeast genetics research
- Respiratory viral infections research
- Biocrusts and Microbial Ecology
- Marine Bivalve and Aquaculture Studies
- Microbial Natural Products and Biosynthesis
Royal Netherlands Institute for Sea Research
2016-2025
Utrecht University
2005-2024
National Center for Biotechnology Information
2024
National Institutes of Health
2024
Friedrich Schiller University Jena
2024
University of Amsterdam
2024
University of Oxford
2024
Max Planck Institute for Medical Research
2024
Netherlands Institute of Ecology
2008-2011
Molecular Research Institute
2008
Deep hypersaline anoxic basins in the Mediterranean Sea are a legacy of dissolution ancient subterranean salt deposits from Miocene period. Our study revealed that these not biogeochemical dead ends, but support situ sulfate reduction, methanogenesis, and heterotrophic activity. A wide diversity prokaryotes was observed, including new, abundant, deeply branching order within Euryarchaeota . Furthermore, we demonstrated presence unique, metabolically active microbial community Discovery...
The square halophilic archaeon Haloquadratum walsbyi dominates NaCl-saturated and MgCl2 enriched aquatic ecosystems, which imposes a serious desiccation stress, caused by the extremely low water activity. genome sequence was analyzed physiological physical experiments were carried out in order to reveal how H. has specialized into its narrow hostile ecological niche found ways cope with stress. A rich repertoire of proteins involved phosphate metabolism, phototrophic growth extracellular...
Resistance of Lactococcus lactis to cytotoxic compounds shares features with the multidrug resistance phenotype mammalian tumor cells. Here, we report gene cloning and functional characterization in Escherichia coli LmrA, a lactococcal structural homolog human P-glycoprotein MDR1. LmrA is 590-aa polypeptide that has putative topology six alpha-helical transmembrane segments N-terminal hydrophobic domain, followed by hydrophilic domain containing ATP-binding site. similar each two halves MDR1...
The algal storage glucan laminarin is one of the most abundant carbon sources for marine prokaryotes. Its degradation was investigated in bacteria isolated during and after a spring phytoplankton bloom coastal North Sea. On average, 13% prokaryotes detected by epifluorescence counts were able to grow Most Probable Number dilution series on as sole source. Several bacterial strains from different dilutions, phylogenetic characterization revealed that they belonged groups. activity...
Strains C23T and HBSQ001 were isolated from solar salterns are novel square-shaped, aerobic, extremely halophilic members of the domain Archaea family Halobacteriaceae. Cells stained Gram-negative grew optimally in media containing 18 % salts at around neutral pH. Mg2+ is not required. The DNA G+C content both isolates was 46.9 mol% DNA-DNA cross-hybridization showed a relatedness 80 %. Their 16S rRNA gene sequences only 2 nucleotide differences (99.9 identity) phylogenetic tree...
Abstract. The hydrographic properties of the Kongsfjorden–Krossfjorden system (79° N, Spitsbergen) are affected by Atlantic water incursions as well glacier meltwater runoff. This results in strong physical gradients (temperature, salinity and irradiance) within fjords. Here, we tested hypothesis that glaciers affect phytoplankton dynamics early productive spring bloom period. During two campaigns 2007 (late spring) 2008 (early studied characteristics variability along transects both fjords,...
Lake Meyghan is one of the largest and commercially most important salt lakes in Iran. Despite its inland location high altitude, has a thalassohaline composition suggesting marine origin. Inputs fresh water by rivers rainfall formed various basins characterized different salinities. We analyzed microbial community three isolation culturing microorganisms analysis metagenome. The that were investigated comprised green ~50 g kg-1 salinity brine, red ~180 brine white ~300 brine. Using growth...
Summary In 1980, A. E. Walsby described a square halophilic archaeon. This archaeon is of specific interest because its unique shape and abundance in hypersaline ecosystems, which suggests an important ecophysiological role. Ever since discovery, the isolation cultivation ‘Walsby's archaeon’ has been holy grail for many microbiologists working on halophiles. Despite their easy recognition by microscopy, all attempts have failed up to now, marking organism as one unculturables. Cultivation...
Abstract Background Mature saturated brine (crystallizers) communities are largely dominated (>80% of cells) by the square halophilic archaeon " Haloquadratum walsbyi ". The recent cultivation strain HBSQ001 and thesequencing its genome allows comparison with metagenome this taxonomically simplified environment. Similar studies carried out in other extreme environments have revealed very little diversity gene content among cell lineages present. Results microbial community a crystallizer...
Urania basin in the deep Mediterranean Sea houses a lake that is >100 m deep, devoid of oxygen, 6 times more saline than seawater, and has very high levels methane particularly sulfide (up to 16 mM), making it among most sulfidic water bodies on Earth. Along depth profile there are 2 chemoclines, steep one with overlying oxic another between anoxic brines different density, where gradients salinity, electron donors acceptors occur. To identify differentiate microbes processes contributing...
Nodularia spumigena is a filamentous diazotrophic cyanobacterium that dominates the annual late summer cyanobacterial blooms in Baltic Sea. But N. also common brackish water bodies worldwide, suggesting special adaptation allowing it to thrive at moderate salinities. A draft genome analysis of sp. CCY9414 yielded single scaffold 5,462,271 nucleotides length on which genes for 5,294 proteins were annotated. subsequent strand-specific transcriptome identified more than 6,000 putative...
Chemoautotrophy has been little studied in typical coastal marine sediments, but may be an important component of carbon recycling as intense anaerobic mineralization processes these sediments lead to accumulation high amounts reduced compounds, such sulfides and ammonium. We chemoautotrophy by measuring dark-fixation 13C-bicarbonate into phospholipid derived fatty acid (PLFA) biomarkers at two sediment sites with contrasting sulfur chemistry the Eastern Scheldt estuary, Netherlands. At one...
Macroalgae belonging to the genus Padina are known produce antibacterial compounds that may inhibit growth of human- and animal pathogens. Hitherto, it was unclear whether this activity is produced by macroalga itself or secondary metabolite producing epiphytic bacteria. Here we report activities bacteria isolated from pavonica (Peacocks tail) located on northern coast Tunisia. Eighteen isolates were obtained in pure culture tested for antimicrobial activities. Based 16S rRNA gene sequences...
Three mutants of Lactococcus lactis subsp. MG1363, termed EthR, DauR, and RhoR, were selected for resistance to high concentrations ethidium bromide, daunomycin, rhodamine 6G, respectively. These found be cross resistant a number structurally functionally unrelated drugs, among which typical substrates the mammalian multidrug transporter (P-glycoprotein) such as quinine, actinomycin D, gramicidin 6G. The three multidrug-resistant strains showed an increased rate energy-dependent daunomycin...
The gene encoding the secondary multidrug transporter LmrP of Lactococcus lactis was heterologously expressed in Escherichia coli. energetics and mechanism drug extrusion mediated by were studied membrane vesicles E. LmrP-mediated tetraphenyl phosphonium (TPP+) from right-side-out uptake fluorescent probe 1-[4-(trimethylamino)phenyl]-6-phenylhexa-1,3,5-triene (TMA-DPH) into inside-out are driven potential (Deltapsi) transmembrane proton gradient (DeltapH), pointing to an electrogenic...
Antarctic coastal waters undergo major physical alterations during summer. Increased temperatures induce sea-ice melting and glacial melt water input, leading to strong stratification of the upper column. We investigated composition micro-eukaryotic bacterial communities in Ryder Bay, Peninsula, after summertime stratification, applying community fingerprinting (denaturing gradient gel electrophoresis) sequencing analysis partial 18S 16S rRNA genes. Community eukaryotic revealed two...