Analysis of a <Emphasis Type="Italic">c</Emphasis><Subscript>0</Subscript><Emphasis Type="Italic">t-1</Emphasis> library enables the targeted identification of minisatellite and satellite families in <Emphasis Type="Italic">Beta vulgaris</Emphasis>

Background  

Repetitive DNA is a major fraction of eukaryotic genomes and occurs particularly often in plants. Currently, the sequencing of the sugar beet (Beta vulgaris) genome is under way and knowledge of repetitive DNA sequences is critical for the genome annotation. We generated a c ₀ t-1 library, representing highly to moderately repetitive sequences, for the characterization of the major B. vulgaris repeat families. While highly abundant satellites are well-described, minisatellites are only poorly investigated in plants. Therefore, we focused on the identification and characterization of these tandemly repeated sequences.     

One-step purification of rat heart-type fatty acid-binding protein expressed in Escherichia coli

Heart-type fatty acid-binding protein (H-FABP) is a member of a family of 14–15 kDa lipid binding proteins which are believed to enhance intracellular transport of lipids by facilitating their cytoplasmic diffusion. To obtain sufficient amounts of protein for in vitro studies, we expressed rat H-FABP in Escherichia coli and compared its biochemical properties with the protein isolated from rat heart. An effective method was developed to purify recombinant rat H-FABP from cell lysates in a single step using anion-exchange chromatography. This method also proved to be applicable for purifying heterologously expressed human H-FABP. Recombinant rat H-FABP, which made up approximately 25% of the soluble proteins in E. coli, was obtained in a yield of 30–40 mg/l culture. Characterization showed that recombinant rat H-FABP was indistinguishable from the protein isolated from rat heart regarding molecular mass and oleic acid binding. Some heterogeneity upon isoelectric focusing was observed, presumably due to differences in N-terminal processing of the proteins. In conclusion, a method is presented for efficient high-yield production of recombinant rat H-FABP.     

Functional genomic analysis of an uncultured δ-proteobacterium in the sponge Cymbastela concentrica

Marine sponges are ancient, sessile, filter-feeding metazoans, which represent a significant component of the benthic communities throughout the world. Sponges harbor a remarkable diversity of bacteria, however, little is known about the functional properties of such bacterial symbionts. In this study, we present the genomic and functional characterization of an uncultured δ-proteobacterium associated with the sponge Cymbastela concentrica. We show that this organism represents a novel phylogenetic clade and propose that it lives in association with a cyanobacterium. We also provide an overview of the predicted functional and ecological properties of this δ-proteobacterium, and discuss its complex interactions with surrounding cells and milieu, including traits of cell attachment, nutrient transport and protein–protein interactions.