“Candidatus Thiobios zoothamnicoli,” an Ectosymbiotic Bacterium Covering the Giant Marine Ciliate Zoothamnium niveum

Zoothamnium niveum is a giant, colonial marine ciliate from sulfide-rich habitats obligatorily covered with chemoautotrophic, sulfide-oxidizing bacteria which appear as coccoid rods and rods with a series of intermediate shapes. Comparative 16S rRNA gene sequence analysis and fluorescence in situ hybridization showed that the ectosymbiont of Z. niveum belongs to only one pleomorphic phylotype. The Z. niveum ectosymbiont is only moderately related to previously identified groups of thiotrophic symbionts within the Gammaproteobacteria, and shows highest 16S rRNA sequence similarity with the free-living sulfur-oxidizing bacterial strain ODIII6 from shallow-water hydrothermal vents of the Mediterranean Sea (94.5%) and an endosymbiont from a deep-sea hydrothermal vent gastropod of the Indian Ocean Ridge (93.1%). A replacement of this specific ectosymbiont by a variety of other bacteria was observed only for senescent basal parts of the host colonies. The taxonomic status “Candidatus Thiobios zoothamnicoli” is proposed for the ectosymbiont of Z. niveum based on its ultrastructure, its 16S rRNA gene, the intergenic spacer region, and its partial 23S rRNA gene sequence.     

Galvechelone lopezmartinezae gen. et sp. nov., a new cryptodiran turtle in the Lower Cretaceous of Europe

Abstract: The Spanish town of Galve (Teruel) is notable because of the abundance of Upper Jurassic and, especially, Lower Cretaceous vertebrates recorded there. Although most groups have been studied in detail, information on turtles is very limited even though the material is relatively abundant. So far, no turtle taxa have been identified at the generic level. The only Lower Cretaceous articulated specimen from Galve is analysed here. It is identified as a representative of Cryptodira, Galvechelone lopezmartinezae gen. et sp. nov. Galvechelone lopezmartinezae is determined as a taxon belonging to the node that groups the turtles traditionally assigned to ‘Macrobaenidae’ and ‘Sinemydidae’, and other taxa such as the members of Panchelonioidea. This node, very abundant in the Lower Cretaceous of Asia, and with a broad subsequent distribution, has recently been recognized in the Lower Cretaceous of Europe. The diversity of basal members of Eucryptodira in the European Late Jurassic (represented by Thalassemydidae, Plesiochelyidae and Eurysternidae) was high. Owing to a relative scarcity of well‐preserved early Cretaceous turtles from Europe, the knowledge of this group of reptiles is limited. The study of the new turtle from Galve, together with the recently described Hoyasemys jimenezi, and the recently completed review of the enigmatic Chitracephalus dumonii demonstrate that members of the cryptodiran node grouping ‘Macrobaenidae’, ‘Sinemydidae’ and Panchelonioidea were also very diverse in this period.     

New fluorogenic substrate for the first continuous steroid sulfatase assay

The screening for new inhibitors of steroid sulfatase requires an efficient test system. To overcome the shortcomings of the available discontinuous fluorimetric assay, several coumarin-type compounds were investigated as potential new substrates. 3,4-Benzocoumarin 7-O-sulfate was found to have appropriate substrate properties for the establishment of the first direct continuous assay of steroid sulfatase.     

Regulation of mevalonate metabolism in cancer and immune cells

The mevalonate pathway is a highly conserved metabolic cascade and provides isoprenoid building blocks for the biosynthesis of vital cellular products such as cholesterol or prenyl pyrophosphates that serve as substrates for the posttranslational prenylation of numerous proteins. The pathway, which is frequently hyperactive in cancer cells, is considered an important target in cancer therapy, since prenylated members of the Ras superfamily are crucially involved in the control of proliferation, survival, invasion and metastasis of tumour cells. Upstream accumulation and downstream depletion of mevalonate pathway intermediates as induced for instance by aminobisphosphonates translate into different effects in cancer and immune cells. Thus, mevalonate pathway regulation can affect tumour biology either directly or exhibit indirect antitumour effects through stimulating cancer immune surveillance. The present review summarizes major effects of pharmacologic mevalonate pathway regulation in cancer and immune cells that may collaboratively contribute to the efficacy of cancer therapy.     

Towards Positional Isolation of Three Quantitative Trait Loci Conferring Resistance to Powdery Mildew in Two Spanish Barley Landraces

Three quantitative trait loci (QTL) conferring broad spectrum resistance to powdery mildew, caused by the fungus Blumeria graminis f. sp. hordei, were previously identified on chromosomes 7HS, 7HL and 6HL in the Spanish barley landrace-derived lines SBCC097 and SBCC145. In the present work, a genome-wide putative linear gene index of barley (Genome Zipper) and the first draft of the physical, genetic and functional sequence of the barley genome were used to go one step further in the shortening and explicit demarcation on the barley genome of these regions conferring resistance to powdery mildew as well as in the identification of candidate genes. First, a comparative analysis of the target regions to the barley Genome Zippers of chromosomes 7H and 6H allowed the development of 25 new gene-based molecular markers, which slightly better delimit the QTL intervals. These new markers provided the framework for anchoring of genetic and physical maps, figuring out the outline of the barley genome at the target regions in SBCC097 and SBCC145. The outermost flanking markers of QTLs on 7HS, 7HL and 6HL defined a physical area of 4 Mb, 3.7 Mb and 3.2 Mb, respectively. In total, 21, 10 and 16 genes on 7HS, 7HL and 6HL, respectively, could be interpreted as potential candidates to explain the resistance to powdery mildew, as they encode proteins of related functions with respect to the known pathogen defense-related processes. The majority of these were annotated as belonging to the NBS-LRR class or protein kinase family.     

Whole‐genome profiling and shotgun sequencing delivers an anchored,gene‐decorated,physical map assembly of bread wheat chromosome 6A

Bread wheat (Triticum aestivum L.) is the most important staple food crop for 35% of the world's population. International efforts are underway to facilitate an increase in wheat production, of which the International Wheat Genome Sequencing Consortium (IWGSC) plays an important role. As part of this effort, we have developed a sequence‐based physical map of wheat chromosome 6A using whole‐genome profiling (WGP^?). The bacterial artificial chromosome (BAC) contig assembly tools fingerprinted contig (fpc ) and linear topological contig (ltc ) were used and their contig assemblies were compared. A detailed investigation of the contigs structure revealed that ltc created a highly robust assembly compared with those formed by fpc . The ltc assemblies contained 1217 contigs for the short arm and 1113 contigs for the long arm, with an L₅₀ of 1 Mb. To facilitate in silico anchoring, WGP^? tags underlying BAC contigs were extended by wheat and wheat progenitor genome sequence information. Sequence data were used for in silico anchoring against genetic markers with known sequences, of which almost 79% of the physical map could be anchored. Moreover, the assigned sequence information led to the ‘decoration’ of the respective physical map with 3359 anchored genes. Thus, this robust and genetically anchored physical map will serve as a framework for the sequencing of wheat chromosome 6A, and is of immediate use for map‐based isolation of agronomically important genes/quantitative trait loci located on this chromosome.     

A HOX complex, a repressor element and a 50 bp sequence confer regional specificity to a DPP-responsive enhancer

A central theme during development and homeostasis is the generation of cell type-specific responses to the action of a limited number of extant signaling cascades triggered by extracellular ligands. The molecular mechanisms by which information from such signals are integrated in responding cells in a cell-type specific manner remain poorly understood. We have undertaken a detailed characterization of an enhancer that is regulated by DPP signaling and by the homeotic protein Labial and its partners, Extradenticle and Homothorax. The expression driven by this enhancer (lab550) and numerous deletions and point mutants thereof was studied in wild-type and mutant Drosophila embryos as well as in cultured cells. We find that the lab550 enhancer is composed of two elements, a Homeotic Response Element (HOMRE) and a DPP Response Element (DPPRE) that synergize. None of these two elements can reproduce the expression of lab550, either with regard to expression level or with regard to spatial restriction. The isolated DPPRE of lab550 responds extremely weakly to DPP. Interestingly, we found that the inducibility of this DPPRE is weak because it is tuned down by the action of a repressor element. This repressor element and an additional 50 bp element appear to be crucial for the cooperation of the HOMRE and the DPPRE, and might tightly link the DPP response to the homeotic input. The cooperation between the different elements of the enhancer leads to the segmentally restricted activity of lab550 in the endoderm and provides a mechanism to create specific responses to DPP signaling with the help of a HOX protein complex.