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981.
982.
Reconstructing the phylogeny of the Sipuncula 总被引:9,自引:0,他引:9
Sipunculans are marine spiralian worms with possible close affinities to the Mollusca or Annelida. Currently 147 species,
17 genera, 6 families, 4 orders and 2 classes are recognized. In this paper we review sipunculan morphology, anatomy, paleontological
data and historical affiliations. We have conducted cladistic analyses for two data sets to elucidate the phylogenetic relationships
among sipunculan species. We first analyzed the relationships among the 45 species of Phascolosomatidea with representatives
of the Sipunculidea as outgroups, using 35 morphological characters. The resulting consensus tree has low resolution and branch
support is low for most branches. The second analysis was based on DNA sequence data from two nuclear ribosomal genes (18S
rRNA and 28S rRNA) and one nuclear protein-coding gene, histone H3. Outgroups were chosen among representative spiralians.
In a third analysis, the molecular data were combined with the morphological data. Data were analyzed using parsimony as the
optimality criterion and branch support evaluated with jackknifing and Bremer support values. Branch support for outgroup
relationships is low but the monophyly of the Sipuncula is well supported. Within Sipuncula, the monophyly of the two major
groups, Phascolosomatidea and Sipunculidea is not confirmed. Of the currently recognized families, only Themistidae appears
monophyletic. The Aspidosiphonidae, Phascolosomatidae and Golfingiidae would be monophyletic with some adjustments in their
definition. The Sipunculidae is clearly polyphyletic, with Sipunculus nudus as the sister group to the remaining Sipuncula, Siphonosoma cumanense the sister group to a clade containing Siphonosoma vastumand the Phascolosomatidea, and Phascolopsis gouldi grouping within the Golfingiiformes, as suggested previously by some authors. Of the genera with multiple representatives,
only Phascolosoma and Themiste are monophyletic as currently defined. We are aiming to expand our current dataset with more species in our molecular database
and more detailed morphological studies. 相似文献
983.
Anna Lampa Angelica E. Ehrenberg Sofia S. Gustafsson Aparna Vema Eva Åkerblom Gunnar Lindeberg Anders Karlén U. Helena Danielson Anja Sandström 《Bioorganic & medicinal chemistry》2010,18(14):5413-5424
Phenylglycine has proved to be a useful P2 residue in HCV NS3 protease inhibitors. A novel π–π-interaction between the phenylglycine and the catalytic H57 residue of the protease is postulated. We hypothesized that the introduction of a vinyl on the phenylglycine might strengthen this π–π-interaction. Thus, herein is presented the synthesis and inhibitory potency of a series of acyclic vinylated phenylglycine-based HCV NS3 protease inhibitors. Surprisingly, inhibitors based on both d- and l-phenylglycine were found to be effective inhibitors, with a slight preference for the d-epimers. Furthermore, prime-side alkenylic extension of the C-terminal acylsulfonamide group gave significantly improved inhibitors with potencies in the nanomolar range (~35 nM), potencies which were retained on mutant variants of the protease. 相似文献
984.
985.
AG Dossetter J Bowyer CR Cook JJ Crawford JE Finlayson NM Heron C Heyes AJ Highton JA Hudson A Jestel S Krapp PA Macfaul TM McGuire AD Morley JJ Morris KM Page LR Ribeiro H Sawney S Steinbacher C Smith 《Bioorganic & medicinal chemistry letters》2012,22(17):5563-5568
The discovery of nitrile compound 4, a potent inhibitor of Cathepsin K (Cat K) with good bioavailability in dog is described. The compound was used to demonstrate target engagement and inhibition of Cat K in an in vivo dog PD model. The margin to hERG ion channel inhibition was deemed too low for a clinical candidate and an optimisation program to find isosteres or substitutions on benzothiazole group led to the discovery of 20, 24 and 27; all three free from hERG inhibition. 相似文献
986.
DNA from two novel HPV genotypes, HPV-150 and HPV-151, isolated from hair follicles of immuno-competent individuals, was fully cloned, sequenced and characterized. The complete genomes of HPV-150 and HPV-151 are 7,436-bp and 7,386-bp in length, respectively. Both contain genes for at least six proteins, namely E6, E7, E1, E2, L2, L1, as well as a non-coding upstream regulatory region located between the L1 and E6 genes: spanning 416-bp in HPV-150 (genomic positions 7,371 to 350) and 322-bp in HPV-151 (genomic positions 7,213 to 148). HPV-150 and HPV-151 are phylogenetically placed within the Betapapillomavirus genus and are most closely related to HPV-96 and HPV-22, respectively. As in other members of this genus, the intergenic E2-L2 region is very short and does not encode for an E5 gene. Both genotypes contain typical zinc binding domains in their E6 and E7 proteins, but HPV-151 lacks the regular pRb-binding core sequence within its E7 protein. In order to assess the tissue predilection and clinical significance of the novel genotypes, quantitative type-specific real-time PCR assays were developed. The 95% detection limits of the HPV-150 and HPV-151 assays were 7.3 copies/reaction (range 5.6 to 11.4) and 3.4 copies/reaction (range 2.5 to 6.0), respectively. Testing of a representative collection of HPV-associated mucosal and cutaneous benign and malignant neoplasms and hair follicles (total of 540 samples) revealed that HPV-150 and HPV-151 are relatively rare genotypes with a cutaneous tropism. Both genotypes were found in sporadic cases of common warts and SCC and BCC of the skin as single or multiple infections usually with low viral loads. HPV-150 can establish persistent infection of hair follicles in immuno-competent individuals. A partial L1 sequence of a putative novel HPV genotype, related to HPV-150, was identified in a squamous cell carcinoma of the skin obtained from a 64-year old immuno-compromised male patient. 相似文献
987.
988.
Anja Martin ;Daniel Lang ;Sebastian T. Hanke ;Stefanie J.X. Mueller ;Eric Sarnighausen ;Marco Vervliet-Scheebaum ;Ralf Reski 《植物生理学报》2009,(6):1359-1372
Chloroplasts and bacterial cells divide by binary fission. The key protein in this constriction division is FtsZ, a self-assembling GTPase similar to eukaryotic tubulin. In prokaryotes, FtsZ is almost always encoded by a single gene, whereas plants harbor several nuclear-encoded FtsZ homologs. In seed plants, these proteins group in two families and all are exclusively imported into plastids. In contrast, the basal land plant Physcomitrella patens, a moss, encodes a third FtsZ family with one member. This protein is dually targeted to the plastids and to the cytosol. Here, we report on the targeted gene disruption of all ftsZ genes in R patens. Subsequent analysis of single and double knockout mutants revealed a complex interaction of the different FtsZ isoforms not only in plastid division, but also in chloroplast shaping, cell patterning, plant development, and gravity sensing. These results support the concept of a plastoskeleton and its functional integration into the cytoskeleton, at least in the moss R patens. 相似文献
989.
The chloroplasts genome (plastome) occurs at high copy numbers per cell. Several chloroplast genome copies are densely packed into nucleoprotein particles called nucleoids. How genome packaging occurs and which proteins organize chloroplast nucleoids are largely unknown. Here, we have analyzed the Chlamydornonas reinhardtii homolog of the bacterial architectural DNA-binding protein HU, the histone-like protein HLP. We show that the Chlarnydornonas HLP protein is targeted to chloroplasts and associates with nucleoids. Knockdown of HLP gene expression by RNA interference (RNAi) alters the structure of chloroplast nucleoids and appears to reduce the level of compaction of chloroplast DNA. Unexpectedly, also chloroplast genome copy numbers are significantly decreased in the RNAi strains, suggesting that, in addition to its architectural role in nucleoid formation, the HIP protein is also involved in chloroplast genome maintenance. 相似文献
990.
Hammerschmidt S Agarwal V Kunert A Haelbich S Skerka C Zipfel PF 《Journal of immunology (Baltimore, Md. : 1950)》2007,178(9):5848-5858
Pneumococcal surface protein C (PspC) of Streptococcus pneumoniae is a key virulence factor that mediates adhesion to host cells and immune evasion of the host complement. PspC binds the host immune and complement regulator factor H, which is composed of 20 short consensus repeats (SCR). This interaction contributes to pneumococcal virulence. In this study, we identified within the factor H protein two separate PspC binding regions, which were localized to SCR8-11 and SCR19-20, by using recombinant factor H deletion constructs for Western blotting assays and surface plasmon resonance studies. A detailed analysis of binding epitopes in these SCR by peptide spot arrays identified several linear binding regions within the sequences of SCR8-11 and SCR19-20. In addition, the factor H binding site was mapped within the pneumococcal PspC protein to a 121-aa-long stretch positioned in the N terminus (residues 38-158). Factor H attached to the surface of pneumococci via PspC significantly enhanced pneumococcal adherence to host epithelial and endothelial cells. This adhesion was specific and was blocked with a truncated N-terminal factor H-binding fragment of PspC. In conclusion, the acquisition of factor H by pneumococci via PspC occurs via two contact sites located in SCR8-11 and SCR19-20, and factor H attached to the surface of the pneumococcus promotes adhesion to both host epithelial and endothelial cells. 相似文献