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1.
Three-dimensional reconstruction of the connector of bacteriophage phi 29 at 1.8 nm resolution 总被引:8,自引:0,他引:8
J M Carazo L E Donate L Herranz J P Secilla J L Carrascosa 《Journal of molecular biology》1986,192(4):853-867
The three-dimensional reconstruction of the connector of bacteriophage phi 29 has been obtained from tilt series of negatively stained tetragonal ordered aggregates under low-dose conditions and up to a resolution of (1/1.8) nm-1. These connectors are built up as dodecamers of only one structural polypeptide (p10). Two connectors form the crystal unit cell, each one facing in the opposite direction with respect to the plane of the crystal and partially overlapping. The main features of the two connectors that build the unit cell were essentially the same, although they were negatively stained in slightly different ways, probably due to their situations with respect to the carbon-coated support grid. The main features of the phi 29 connector structure revealed by this three-dimensional reconstruction are: the existence of two clearly defined domains, one with a diameter of around 14 nm and the other narrower (diameter approximately equal to 7.5 nm); an inner hole running all along the structure (around 7 to 8 nm in height) with a cylindrical profile and an average diameter of 4 nm; a general 6-fold symmetry along the whole structure and a 12-fold one in the wider domain; a clockwise twist of the more contrasted regions of both domains from the narrower towards the wider domain (the direction of DNA encapsidation). These features are compatible with an active role for the connector in the process of DNA packaging. 相似文献
2.
M. Teresa García-López Rosario Herranz Paloma P. Méndez-Castrillón 《Nucleosides, nucleotides & nucleic acids》2013,32(2):127-138
Abstract The synthesis of 2-(β-D-ribofuranosyl)-and 2-(tetrahydropyran-2-yl)-4-halomethylthiazoles from 2, 5-anhydro-D-allonthioamide and tetrahydropyran-2-thiocarboxamide is described. Bromination of 2-(β-D-ribofuranosyl)- and 2-tetrahydropyran-2-yl)-4-methylthiazole with NBS is studied. Cytostatic activity against HeLa cells of all the compounds is reported. 相似文献
3.
Luengo Javier G. Muñoz María-Dolores Álvarez-Merz Iris Herranz Antonio S. González José C. Martín del Río Rafael Hernández-Guijo Jesús M. Solís José M. 《Amino acids》2019,51(9):1337-1351
Amino Acids - The application of high concentrations of taurine induces long-lasting potentiation of synaptic responses and axon excitability. This phenomenon seems to require the contribution of a... 相似文献
4.
Javier del Campo Maria J. Pons Maria Herranz Kevin C. Wakeman Juana del Valle Mark J. A. Vermeij Brian S. Leander Patrick J. Keeling 《Environmental microbiology》2019,21(10):3855-3861
The application of metabarcoding to study animal-associated microeukaryotes has been restricted because the universal barcode used to study microeukaryotic ecology and distribution in the environment, the Small Subunit of the Ribosomal RNA gene (18S rRNA), is also present in the host. As a result, when host-associated microbial eukaryotes are analysed by metabarcoding, the reads tend to be dominated by host sequences. We have done an in silico validation against the SILVA 18S rRNA database of a non-metazoan primer set (primers that are biased against the metazoan 18S rRNA) that recovers only 2.6% of all the metazoan sequences, while recovering most of the other eukaryotes (80.4%). Among metazoans, the non-metazoan primers are predicted to amplify 74% of Porifera sequences, 4% of Ctenophora, and 15% of Cnidaria, while amplifying almost no sequences within Bilateria. In vivo, these non-metazoan primers reduce significantly the animal signal from coral and human samples, and when compared against universal primers provide at worst a 2-fold decrease in the number of metazoan reads and at best a 2800-fold decrease. This easy, inexpensive, and near-universal method for the study of animal-associated microeukaryotes diversity will contribute to a better understanding of the microbiome. 相似文献
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María Herranz Jonas Thormar Jesús BenitoNuria Sánchez Fernando Pardos 《Zoologischer Anzeiger》2012,251(3):161-179
A new kinorhynch genus, Meristoderes gen. nov., and two new species from Spain and the Solomon Islands, respectively, are described. The new genus is distinguished from all other genera by the first segment consisting of a closed cuticular ring, and the second segment having partial tergosternal junctions, and a superficial midventral fold. This is a new cuticular configuration that may shed light into the phylogenetic relationships of echinoderid kinorhynchs. Meristoderes macracanthus gen. et sp. nov. from the Mediterranean coast of Spain is recognised by the presence of middorsal spines on segments 4, 6 and 8, ventrolateral tubules on segment 2, lateroventral tubules on segment 5, lateroventral spines on segments 6-9, lateral accessory tubules on segment 8, one pair of laterodorsal tubules on segment 10. Meristoderes galatheae sp. nov. from the Solomon Islands is recognized by having a middorsal spine on segment 4 only, ventrolateral tubules on segment 2, lateroventral tubules on segment 5, lateroventral spines on segments 6-9, lateral accessory tubules on segment 8 and subdorsal tubules on segment 10. Both species have a pattern of paraventral perforation site clusters on segments 3-9, with conspicuously long bracteate hairs from the posteriormost perforations sites on the segments 3-7 and 3-6, respectively.The new genus Meristoderes gen. nov. is included into the family Echinoderidae Bütschli, 1876 and appears closely related with the genera Cephalorhyncha Adrianov, 1999 and Echinoderes Claparède, 1863. The new information it provides is discussed to clarify the internal phylogeny of Echinoderidae. The terminology for cuticular characters in the overlapping area between consecutive segments is also standardized. 相似文献
8.
M Alonso N Alonso Rodriguez C Garzelli M Martínez Lirola M Herranz S Samper MJ Ruiz Serrano E Bouza D García de Viedma 《BMC microbiology》2010,10(1):151
Background
The Beijing lineage of Mycobacterium tuberculosis is causing concern due to its global distribution and its involvement in severe outbreaks. Studies focused on this lineage are mainly restricted to geographical settings where its prevalence is high, whereas those in other areas are scarce. In this study, we analyze Beijing isolates in the Mediterranean area, where this lineage is not prevalent and is mainly associated with immigrant cases. 相似文献9.
Seeds of Delphinium fissum subsp. sordidum are physiologically dormant at maturity, with underdeveloped embryos; thus they have morphophysiological dormancy (MPD).
The aims of this study were to determine the requirements for embryo growth, dormancy break and germination, to characterise
the type of seed dormancy and to evaluate the effects of light, seed age, pollination mechanism, and inter-annual and inter-population
variability on germinative ability. After 3 months of incubation at 5°C (cold stratification) in darkness conditions, the
mean embryo length increased from 5.6 to 2.07 mm, with 76% of seeds germinating. Conversely, embryos of seeds incubated during
3 months at 20/7 or 28/14°C hardly grew and no germination was recorded. Since cold stratification was the only requirement
for the loss of MPD, and both dry storage in laboratory conditions and warm stratification prior to cold stratification shortened
the cold stratification period required for germination, it could be concluded that D. fissum subsp. sordidum seeds have intermediate complex MPD. Cold stratification and incubation in darkness conditions promoted higher germination
percentages than those in light. In addition, germinative ability increased with seed age up to 8 months (reaching 96% at
5°C in darkness), showed a pronounced inter-annual and inter-population variability, as well as a significant decrease in
seeds coming from pollination by geitonogamy. High temperatures (25/10 or 28/14°C) induced seeds to secondary dormancy, so
seedling emergence in the greenhouse was restricted to February–March. The requirements for dormancy break and germination
reflect an adaptation to trigger germination in late winter. This study is the first one to document a gradual increase in
germination percentage with seed age for plant species with intermediate complex MPD. 相似文献
10.
Gene regulatory networks have been conserved during evolution. The Drosophila wing and the vertebrate hindbrain share the gene network involved in the establishment of the boundary between dorsal and ventral compartments in the wing and adjacent rhombomeres in the hindbrain. A positive feedback-loop between boundary and non-boundary cells and mediated by the activities of Notch and Wingless/Wnt-1 leads to the establishment of a Notch dependent organizer at the boundary. By means of a Systems Biology approach that combines mathematical modeling and both in silico and in vivo experiments in the Drosophila wing primordium, we modeled and tested this regulatory network and present evidence that a novel property, namely refractoriness to the Wingless signaling molecule, is required in boundary cells for the formation of a stable dorsal-ventral boundary. This new property has been validated in vivo, promotes mutually exclusive domains of Notch and Wingless activities and confers stability to the dorsal-ventral boundary. A robustness analysis of the regulatory network complements our results and ensures its biological plausibility. 相似文献