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61.
Slapeta JR Modrý D Votýpka J Jirků M Lukes J Koudela B 《Molecular phylogenetics and evolution》2003,27(3):464-475
Cyst-forming coccidia of the genus Sarcocystis (Alveolata: Apicomplexa: Coccidea) parasitize vertebrates worldwide. Data from the small subunit rRNA genes (SSU) and the D2 domain of the large subunit rRNA genes were used to reconstruct phylogeny for all species in the Sarcocystidae for which sequences are currently available. We have focused on the evolutionary history of species that circulate between snakes as definitive hosts and rodents as intermediate hosts. Trees were reconstructed using maximum parsimony, minimum evolution, maximum likelihood and the bayesian phylogenetics. Our reconstructions support monophyly of Sarcocystidae but fail to robustly resolve the relationship within clades. Using a concatenated dataset of available rDNAs, the "isosporoid" coccidia Neospora, Toxoplasma, Besnoitia, Isospora and Hyaloklossia form a sister group to the monophyletic Sarcocystis. Moreover, we show that Sarcocystis from arboreal vipers of the genus Atheris, which are endemic to the mountain rain forests of the Equatorial Africa, are monophyletic, with sister species parasitizing the desert viper Pseudocerastes persicus from the Near East. We report the co-evolution of Sarcocystis spp. with their final snake hosts. The geological history of the African continent, mountain ranges, forests and general SSU rDNA rates were used to construct a linearized tree. Possible origin of the heteroxenous life cycle of Sarcocystis is discussed. 相似文献
62.
Serial in vivo imaging of the targeted migration of human HSV-TK-transduced antigen-specific lymphocytes 总被引:13,自引:0,他引:13
Koehne G Doubrovin M Doubrovina E Zanzonico P Gallardo HF Ivanova A Balatoni J Teruya-Feldstein J Heller G May C Ponomarev V Ruan S Finn R Blasberg RG Bornmann W Riviere I Sadelain M O'Reilly RJ Larson SM Tjuvajev JG 《Nature biotechnology》2003,21(4):405-413
New technologies are needed to characterize the migration, survival, and function of antigen-specific T cells in vivo. Here, we demonstrate that Epstein-Barr virus (EBV)--specific T cells transduced with vectors encoding herpes simplex virus-1 thymidine kinase (HSV-TK) selectively accumulate radiolabeled 2'-fluoro-2'-deoxy-1-beta-D-arabinofuranosyl-5-iodouracil (FIAU). After adoptive transfer, HSV-TK+ T cells labeled in vitro or in vivo with [131I]FIAU or [124I]FIAU can be noninvasively tracked in SCID mice bearing human tumor xenografts by serial images obtained by scintigraphy or positron emission tomography (PET), respectively. These T cells selectively accumulate in EBV+ tumors expressing the T cells' restricting HLA allele but not in EBV- or HLA-mismatched tumors. The concentrations of transduced T cells detected in tumors and tissues are closely correlated with the concentrations of label retained at each site. Radiolabeled transduced T cells retain their capacity to eliminate targeted tumors selectively. This technique for imaging the migration of ex vivo-transduced antigen-specific T cells in vivo is informative, nontoxic, and potentially applicable to humans. 相似文献
63.
Recent cloning and computational studies have sought to catalog all the microRNA genes encoded in animal genomes. Here, we highlight recent advances in identifying Caenorhabditis elegans and Drosophila melanogaster microRNAs. 相似文献
64.
Towards a framework for the evolutionary genomics of Kinetoplastids: what kind of data and how much?
The current status of kinetoplastids phylogeny and evolution is discussed in view of the recent progresses on genomics. Some ideas on a potential framework for the evolutionary genomics of kinetoplastids are presented. 相似文献
65.
66.
Glutamatergic plasticity by synaptic delivery of GluR-B(long)-containing AMPA receptors 总被引:3,自引:0,他引:3
Kolleker A Zhu JJ Schupp BJ Qin Y Mack V Borchardt T Köhr G Malinow R Seeburg PH Osten P 《Neuron》2003,40(6):1199-1212
Activity-driven delivery of AMPA receptors is proposed to mediate glutamatergic synaptic plasticity, both during development and learning. In hippocampal CA1 principal neurons, such trafficking is primarily mediated by the abundant GluR-A subunit. We now report a study of GluR-B(long), a C-terminal splice variant of the GluR-B subunit. GluR-B(long) synaptic delivery is regulated by two forms of activity. Spontaneous synaptic activity-driven GluR-B(long) transport maintains one-third of the steady-state AMPA receptor-mediated responses, while GluR-B(long) delivery following the induction of LTP is responsible for approximately 50% of the resulting potentiation at the hippocampal CA3 to CA1 synapses at the time of GluR-B(long) peak expression-the second postnatal week. Trafficking of GluR-B(long)-containing receptors thus mediates a GluR-A-independent form of glutamatergic synaptic plasticity in the juvenile hippocampus. 相似文献
67.
Synergistic regulation of immunoreceptor signaling by SLP-76-related adaptor Clnk and serine/threonine protein kinase HPK-1 下载免费PDF全文
Yu J Riou C Davidson D Minhas R Robson JD Julius M Arnold R Kiefer F Veillette A 《Molecular and cellular biology》2001,21(18):6102-6112
Recently, the identification of Clnk, a third member of the SLP-76 family of adaptors expressed exclusively in cytokine-stimulated hemopoietic cells, has been reported by us and by others. Like SLP-76 and Blnk, Clnk was shown to act as a positive regulator of immunoreceptor signaling. Interestingly, however, it did not detectably associate with known binding partners of SLP-76, including Vav, Nck, and GADS. In contrast, it became complexed in activated T cells and myeloid cells with an as yet unknown tyrosine-phosphorylated polypeptide of approximately 92 kDa (p92). In order to understand better the function of Clnk, we sought to identify the Clnk-associated p92. Using a yeast two-hybrid screen and cotransfection experiments with Cos-1 cells, evidence was adduced that p92 is HPK-1, a serine/threonine-specific protein kinase expressed in hemopoietic cells. Further studies showed that Clnk and HPK-1 were also associated in hemopoietic cells and that their interaction was augmented by immunoreceptor stimulation. A much weaker association was detected between HPK-1 and SLP-76. Transient transfections in Jurkat T cells revealed that Clnk and HPK-1 cooperated to increase immunoreceptor-mediated activation of the interleukin 2 (IL-2) promoter. Moreover, the ability of Clnk to stimulate IL-2 promoter activity could be blocked by expression of a kinase-defective version of HPK-1. Lastly we found that in spite of the differential ability of Clnk and SLP-76 to bind cellular proteins, Clnk was apt at rescuing immunoreceptor signaling in a Jurkat T-cell variant lacking SLP-76. Taken together, these results show that Clnk physically and functionally interacts with HPK-1 in hemopoietic cells. Moreover, they suggest that Clnk is capable of functionally substituting for SLP-76 in immunoreceptor signaling, albeit by using a distinct set of intracellular effectors. 相似文献
68.
Many glycosylphosphatidyl-inositol-anchored proteins (GPI-AP) are expressed on T lymphocytes. Ligand or mAb-mediated aggregation of all GPI-AP tested to date results in the initiation of signal transduction pathways via the activation of src family protein tyrosine kinases. Src family kinases co-localise with GPI-AP in specialised sub-domains of the plasma membrane, referred to as detergent insoluble membrane microdomains (DIGS), which are thought to function as signalling platforms. GPI-AP may play a role in the regulation of T cell clonal expansion and effector functions at multiple levels, including the initiation of T cell activation through the antigen receptor complex, the regulation of ongoing responses supported by persisting antigen, as well as proliferative responses to the major T cell growth factor, IL-2. Evidence supporting the role of GPI-AP in the regulation of T cell development, activation and homeostasis is discussed, as well as insights provided by studies in humans and mice lacking GPI-AP. 相似文献
69.
Q vectors, bicistronic retroviral vectors for gene transfer 总被引:3,自引:0,他引:3
We have developed a retroviral vector that incorporates unique features of some previously described vectors. This vector includes: 3' long terminal repeats (LTRs) of the self-inactivating class; a 5' LTR that is a hybrid of the cytomegalovirus (CMV) enhancer and the mouse sarcoma virus promoter; an internal CMV immediate early region promoter to drive expression of the transduced gene and the neomycin phosphotransferase selectable marker; an expanded multiple cloning site and an internal ribosome entry site. An SV40 ori was introduced into the vector backbone to promote high copy number replication in packaging cell lines that express the SV40 large T antigen. We demonstrate that these retroviral constructs, designated Q vectors, can be used in applications where high viral titers and high level stable or transient gene expression are desirable. 相似文献
70.
Martyn Lewis Linda S. Chesterton Julius Sim Christian D. Mallen Elaine M. Hay Dani?lle A. van der Windt 《PloS one》2015,10(8)