Distinguishing between Incomplete Lineage Sorting and Genomic Introgressions : Complete Fixation of Allospecific Mitochondrial DNA in a Sexually Reproducing Fish (Cobitis; Teleostei), despite Clonal Reproduction of Hybrids

Peer reviewe

Diversity, Phylogeny and Expression Patterns of Pou and Six Homeodomain Transcription Factors in Hydrozoan Jellyfish Craspedacusta sowerbyi

Formation of all metazoan bodies is controlled by a group of selector genes including homeobox genes, highly conserved across the entire animal kingdom. The homeobox genes from Pou and Six classes are key members of the regulation cascades determining development of sensory organs, nervous system, gonads and muscles. Besides using common bilaterian models, more attention has recently been targeted at the identification and characterization of these genes within the basal metazoan phyla. Cnidaria as a diploblastic sister group to bilateria with simple and yet specialized organs are suitable models for studies on the sensory organ origin and the associated role of homeobox genes. In this work, Pou and Six homeobox genes, together with a broad range of other sensory-specific transcription factors, were identified in the transcriptome of hydrozoan jellyfish Craspedacusta sowerbyi. Phylogenetic analyses of Pou and Six proteins revealed cnidarian-specific sequence motifs and contributed to the classification of individual factors. The majority of the Craspedacusta sowerbyi Pou and Six homeobox genes are predominantly expressed in statocysts, manubrium and nerve ring, the tissues with sensory and nervous activities. The described diversity and expression patterns of Pou and Six factors in hydrozoan jellyfish highlight their evolutionarily conserved functions. This study extends the knowledge of the cnidarian genome complexity and shows that the transcriptome of hydrozoan jellyfish is generally rich in homeodomain transcription factors employed in the regulation of sensory and nervous functions

Functional characterization of PaLAX1, a putative auxin permease, in heterologous plant systems

We have isolated the cDNA of the gene PaLAX1 from a wild cherry tree ( Prunus avium). The gene and its product are highly similar in sequences to both the cDNAs and the corresponding protein products of AUX/LAX-type genes, coding for putative auxin influx carriers. We have prepared and characterized transformed Nicotiana tabacum and Arabidopsis thaliana plants carrying the gene PaLAX1. We have proved that constitutive overexpression of PaLAX1 is accompanied by changes in the content and distribution of free indole-3-acetic acid, the major endogenous auxin. The increase in free indole-3-acetic acid content in transgenic plants resulted in various phenotype changes, typical for the auxin-overproducing plants. The uptake of synthetic auxin, 2,4-dichlorophenoxyacetic acid, was 3 times higher in transgenic lines compared to the wild-type lines and the treatment with the auxin uptake inhibitor 1-naphthoxyacetic acid reverted the changes caused by the expression of PaLAX1. Moreover, the agravitropic response could be restored by expression of PaLAX1 in the mutant aux1 plants, which are deficient in auxin influx carrier activity. Based on our data, we have concluded that the product of the gene PaLAX1 promotes the uptake of auxin into cells, and, as a putative auxin influx carrier, it affects the content and distribution of free endogenous auxin in transgenic plants

Complete Genome Sequence of the Haloaromatic Acid-Degrading Bacterium Achromobacter xylosoxidans A8 ▿

Achromobacter xylosoxidans strain A8 was isolated from soil contaminated with polychlorinated biphenyls. It can use 2-chlorobenzoate and 2,5-dichlorobenzoate as sole sources of carbon and energy. This property makes it a good starting microorganism for further development toward a bioremediation tool. The genome of A. xylosoxidans consists of a 7-Mb chromosome and two large plasmids (98 kb and 248 kb). Besides genes for the utilization of xenobiotic organic substrates, it contains genes associated with pathogenesis, toxin production, and resistance. Here, we report the complete genome sequence

Complete Genome Sequence of the Photosynthetic Purple Nonsulfur Bacterium Rhodobacter capsulatus SB 1003▿

Rhodobacter capsulatus SB 1003 belongs to the group of purple nonsulfur bacteria. Its genome consists of a 3.7-Mb chromosome and a 133-kb plasmid. The genome encodes genes for photosynthesis, nitrogen fixation, utilization of xenobiotic organic substrates, and synthesis of polyhydroxyalkanoates. These features made it a favorite research tool for studying these processes. Here we report its complete genome sequence

Organizace genomu: isochory, repetitivni a cizoroda DNA.

This dissertation should bring a comparative view on genome structure in various types of organisms. This may facilitate studies of mechanisms that change genomes in evolution.Text also in EnglishAvailable from STL, Prague, CZ / NTK - National Technical LibrarySIGLECZCzech Republi

Comparison of phylogenetic trees of HD (A) and SD (B) regions of Six class transcription factors.

<p>The phylogenetic trees were calculated by the maximum likelihood method (WAG protein substitution model, bootstrap 1000) and processed by NJ Plot software. Phylogenetically representative sequences from the following metazoan animals were selected for comparison: sponges (<i>Chalinula loosanoffi, Ephydatia fluviatilis, Sycon calcaravis</i>), cnidarians (<i>Nematostella vectensis</i>, <i>Anthopleura japonica</i>, <i>Podocoryne carnea</i>, <i>Hydra magnipapillata</i>, <i>Cladonema radiatum</i>, <i>Aurelia aurita</i>), invertebrates (<i>Saccoglossus kowalevskii</i>, <i>Drosophila melanogaster</i>, <i>Branchistoma floridae</i>) and vertebrates (<i>Danio rerio</i> and <i>Homo sapiens</i>). For the list of ID numbers of reference sequences see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0036420#pone.0036420.s011" target="_blank">Text S1</a>.</p

<i>Craspedacusta sowerbyi</i> body plan scheme.

<p>Radial symmetric body plan of <i>Craspedacusta sowerbyi</i> is divided in subumbrella and exumbrella regions from the side projection. The most distinct features are four gonads and the presence of up to two hundreds of tentacles. Particular organs are described in the scheme. Body size is up to 2.5 cm in diameter.</p