Contrasting mafic to felsic HP-HT granulites of the Blanský les Massif (Moldanubian Zone of southern Bohemia): complexity of mineral assemblages and metamorphic reactions

En la actualidad, se dan diversos casos de edentulismo parciales y totales que afectan la salud y la autoestima de las personas, ocasionando la ausencia de dientes, reabsorción del hueso alveolar y/o un desplazamiento de los dientes anexos o colindantes. La odontología junto con la ingeniería mecánica buscan dar una solución efectiva a estos problemas a través de la implantología, la cual consiste en reemplazar los dientes perdidos con piezas elaboradas a base de titanio. Por lo anteriormente expuesto, la presente tesis busca formular un modo de diseñar implantes dentales, así como estudiar el comportamiento mecánico del implante dentro del maxilar utilizando herramientas de simulación virtual. En la investigación se utilizó el software Mimics para la reconstrucción de la mandíbula mediante imágenes médicas, toma de propiedades, geometría, etc.; siendo el primer paso para un diseño personalizado. También se utilizó el software Solidworks para la construcción, simulación y representación de huesos maxilares, ensamblaje de implantes y obtención de tensiones y desplazamientos máximos y mínimos, los cuales son interpretados para una correcta selección de implante

Instability of Alien Chromosome Introgressions in Wheat Associated with Improper Positioning in the Nucleus

Alien introgressions introduce beneficial alleles into existing crops and hence, are widely used in plant breeding. Generally, introgressed alien chromosomes show reduced meiotic pairing relative to the host genome, and may be eliminated over generations. Reduced pairing appears to result from a failure of some telomeres of alien chromosomes to incorporate into the leptotene bouquet at the onset of meiosis, thereby preventing chiasmate pairing. In this study, we analysed somatic nuclei of rye introgressions in wheat using 3D-FISH and found that while introgressed rye chromosomes or chromosome arms occupied discrete positions in the Rabl’s orientation similar to chromosomes of the wheat host, their telomeres frequently occupied positions away from the nuclear periphery. The frequencies of such abnormal telomere positioning were similar to the frequencies of out-of-bouquet telomere positioning at leptotene, and of pairing failure at metaphase I. This study indicates that improper positioning of alien chromosomes that leads to reduced pairing is not a strictly meiotic event but rather a consequence of a more systemic problem. Improper positioning in the nuclei probably impacts the ability of introgressed chromosomes to migrate into the telomere bouquet at the onset of meiosis, preventing synapsis and chiasma establishment, and leading to their gradual elimination over generations

The genome of cowpea (Vigna unguiculata [L.] Walp.)

[EN] Cowpea (Vigna unguiculata [L.] Walp.) is a major crop for worldwide food and nutritional security, especially in sub-Saharan Africa, that is resilient to hot and drought-prone environments. An assembly of the single-haplotype inbred genome of cowpea IT97K-499-35 was developed by exploiting the synergies between single-molecule real-time sequencing, optical and genetic mapping, and an assembly reconciliation algorithm. A total of 519 Mb is included in the assembled sequences. Nearly half of the assembled sequence is composed of repetitive elements, which are enriched within recombination-poor pericentromeric regions. A comparative analysis of these elements suggests that genome size differences between Vigna species are mainly attributable to changes in the amount of Gypsy retrotransposons. Conversely, genes are more abundant in more distal, high-recombination regions of the chromosomes; there appears to be more duplication of genes within the NBS-LRR and the SAUR-like auxin superfamilies compared with other warm-season legumes that have been sequenced. A surprising outcome is the identification of an inversion of 4.2 Mb among landraces and cultivars, which includes a gene that has been associated in other plants with interactions with the parasitic weed Striga gesnerioides. The genome sequence facilitated the identification of a putative syntelog for multiple organ gigantism in legumes. A revised numbering system has been adopted for cowpea chromosomes based on synteny with common bean (Phaseolus vulgaris). An estimate of nuclear genome size of 640.6 Mbp based on cytometry is presentedS

454 sequencing of pooled BAC clones on chromosome 3H of barley

<p>Abstract</p> <p>Background</p> <p>Genome sequencing of barley has been delayed due to its large genome size (ca. 5,000Mbp). Among the fast sequencing systems, 454 liquid phase pyrosequencing provides the longest reads and is the most promising method for BAC clones. Here we report the results of pooled sequencing of BAC clones selected with ESTs genetically mapped to chromosome 3H.</p> <p>Results</p> <p>We sequenced pooled barley BAC clones using a 454 parallel genome sequencer. A PCR screening system based on primer sets derived from genetically mapped ESTs on chromosome 3H was used for clone selection in a BAC library developed from cultivar "Haruna Nijo". The DNA samples of 10 or 20 BAC clones were pooled and used for shotgun library development. The homology between contig sequences generated in each pooled library and mapped EST sequences was studied. The number of contigs assigned on chromosome 3H was 372. Their lengths ranged from 1,230 bp to 58,322 bp with an average 14,891 bp. Of these contigs, 240 showed homology and colinearity with the genome sequence of rice chromosome 1. A contig annotation browser supplemented with query search by unique sequence or genetic map position was developed. The identified contigs can be annotated with barley cDNAs and reference sequences on the browser. Homology analysis of these contigs with rice genes indicated that 1,239 rice genes can be assigned to barley contigs by the simple comparison of sequence lengths in both species. Of these genes, 492 are assigned to rice chromosome 1.</p> <p>Conclusions</p> <p>We demonstrate the efficiency of sequencing gene rich regions from barley chromosome 3H, with special reference to syntenic relationships with rice chromosome 1.</p

Physical Mapping of Bread Wheat Chromosome 5A: An Integrated Approach

The huge size, redundancy, and highly repetitive nature of the bread wheat [Triticum aestivum (L.)] genome, makes it among the most difficult species to be sequenced. To overcome these limitations, a strategy based on the separation of individual chromosomes or chromosome arms and the subsequent production of physical maps was established within the frame of the International Wheat Genome Sequence Consortium (IWGSC). A total of 95,812 bacterial artificial chromosome (BAC) clones of short-arm chromosome 5A (5AS) and long-arm chromosome 5A (5AL) arm-specific BAC libraries were fingerprinted and assembled into contigs by complementary analytical approaches based on the FingerPrinted Contig (FPC) and Linear Topological Contig (LTC) tools. Combined anchoring approaches based on polymerase chain reaction (PCR) marker screening, microarray, and sequence homology searches applied to several genomic tools (i. e., genetic maps, deletion bin map, neighbor maps, BAC end sequences (BESs), genome zipper, and chromosome survey sequences) allowed the development of a high-quality physical map with an anchored physical coverage of 75% for 5AS and 53% for 5AL with high portions (64 and 48%, respectively) of contigs ordered along the chromosome. In the genome of grasses, Brachypodium [Brachypodium distachyon (L.) Beauv.], rice (Oryza sativa L.), and sorghum [Sorghum bicolor (L.) Moench] homologs of genes on wheat chromosome 5A were separated into syntenic blocks on different chromosomes as a result of translocations and inversions during evolution. The physical map presented represents an essential resource for fine genetic mapping and map-based cloning of agronomically relevant traits and a reference for the 5A sequencing projects

Subtelomeric assembly of a multi-gene pathway for antimicrobial defense compounds in cereals

Non-random gene organization in eukaryotes plays a significant role in genome evolution. Here, we investigate the origin of a biosynthetic gene cluster for production of defence compounds in oat—the avenacin cluster. We elucidate the structure and organisation of this 12-gene cluster, characterise the last two missing pathway steps, and reconstitute the entire pathway in tobacco by transient expression. We show that the cluster has formed de novo since the divergence of oats in a subtelomeric region of the genome that lacks homology with other grasses, and that gene order is approximately colinear with the biosynthetic pathway. We speculate that the positioning of the late pathway genes furthest away from the telomere may mitigate against a ‘self-poisoning’ scenario in which toxic intermediates accumulate as a result of telomeric gene deletions. Our investigations reveal a striking example of adaptive evolution underpinned by remarkable genome plasticity

Stem rust resistance in wheat is suppressed by a subunit of the mediator complex

Stem rust is an important disease of wheat that can be controlled using resistance genes. The gene SuSr-D1 identified in cultivar 'Canthatch' suppresses stem rust resistance. SuSr-D1 mutants are resistant to several races of stem rust that are virulent on wild-type plants. Here we identify SuSr-D1 by sequencing flow-sorted chromosomes, mutagenesis, and map-based cloning. The gene encodes Med15, a subunit of the Mediator Complex, a conserved protein complex in eukaryotes that regulates expression of protein-coding genes. Nonsense mutations in Med15b.D result in expression of stem rust resistance. Time-course RNAseq analysis show a significant reduction or complete loss of differential gene expression at 24h post inoculation in med15b.D mutants, suggesting that transcriptional reprogramming at this time point is not required for immunity to stem rust. Suppression is a common phenomenon and this study provides novel insight into suppression of rust resistance in wheat. Stem rust is an important disease of wheat and resistance present in some cultivars can be suppressed by the SuSr-D1 locus. Here the authors show that SuSr-D1 encodes a subunit of the Mediator Complex and that nonsense mutations are sufficient to abolish suppression and confer stem rust resistance