Ansgar Gruber

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Diatoms are photosynthetic secondary endosymbionts found throughout marine and freshwater environments, and are believed to be responsible for around one-fifth of the primary productivity on Earth. The genome sequence of the marine centric diatom Thalassiosira pseudonana was recently reported, revealing a wealth of information about diatom biology. Here we(More)
Cryptophyte and chlorarachniophyte algae are transitional forms in the widespread secondary endosymbiotic acquisition of photosynthesis by engulfment of eukaryotic algae. Unlike most secondary plastid-bearing algae, miniaturized versions of the endosymbiont nuclei (nucleomorphs) persist in cryptophytes and chlorarachniophytes. To determine why, and to(More)
Xylella fastidiosa is a fastidious, xylem-limited bacterium that causes a range of economically important plant diseases. Here we report the complete genome sequence of X. fastidiosa clone 9a5c, which causes citrus variegated chlorosis--a serious disease of orange trees. The genome comprises a 52.7% GC-rich 2,679,305-base-pair (bp) circular chromosome and(More)
Plastids of diatoms and related algae evolved by secondary endocytobiosis, the uptake of a eukaryotic alga into a eukaryotic host cell and its subsequent reduction into an organelle. As a result diatom plastids are surrounded by four membranes. Protein targeting of nucleus encoded plastid proteins across these membranes depends on N-terminal bipartite(More)
Phototrophic chromalveolates possess plastids surrounded by either 3 or 4 membranes, revealing their secondary endosymbiotic origin from an engulfed eukaryotic alga. In cryptophytes, a member of the chromalveolates, the organelle is embedded within a designated region of the host's rough endoplasmic reticulum (RER). Its eukaryotic compartments other than(More)
The plastids of ecologically and economically important algae from phyla such as stramenopiles, dinoflagellates and cryptophytes were acquired via a secondary endosymbiosis and are surrounded by three or four membranes. Nuclear-encoded plastid-localized proteins contain N-terminal bipartite targeting peptides with the conserved amino acid sequence motif(More)
This study reports the development of a novel multiplex PCR assay based on SCAR (Sequence-Characterised Amplified Region) markers for the simultaneous diagnosis of the 7 Eimeria species that infect domestic fowl. Primer pairs specific for each species were designed in order to generate a ladder of amplification products ranging from 200 to 811 bp.(More)
BACKGROUND Diatoms are unicellular algae responsible for approximately 20% of global carbon fixation. Their evolution by secondary endocytobiosis resulted in a complex cellular structure and metabolism compared to algae with primary plastids. METHODOLOGY/PRINCIPAL FINDINGS The whole genome sequence of the diatom Phaeodactylum tricornutum has recently been(More)
1 Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, D-27570 Bremerhaven, Germany, 2 Biologische Anstalt Helgoland, Alfred Wegener Institute for Polar and Marine Research, PO Box 180, D-27483 Helgoland, Germany, 3 Plant Ecophysiology, University of Konstanz, Universitätsstr. 10, D-78464 Konstanz, Germany, 4 School of Biological(More)
In diatoms, the process of energy-dependent chlorophyll fluorescence quenching (qE) has an important role in photoprotection. Three components are essential for qE: (1) the light-dependent generation of a transthylakoidal proton gradient; (2) the deepoxidation of the xanthophyll diadinoxanthin (Dd) into diatoxanthin (Dt); and (3) specific nucleus-encoded(More)