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排序方式: 共有275条查询结果,搜索用时 62 毫秒
101.
Isolation of multiple TT virus genotypes from spleen biopsy tissue from a Hodgkin's disease patient: genome reorganization and diversity in the hypervariable region
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Jelcic I Hotz-Wagenblatt A Hunziker A Zur Hausen H de Villiers EM 《Journal of virology》2004,78(14):7498-7507
We report the isolation of 24 novel genotypes of TT viruses from a surgically removed spleen of a patient with Hodgkin's disease. The sequence analysis of our 24 isolates revealed the remarkable heterogeneity of TT virus isolates not only from the same patient but also from the same biopsy material. These isolates belong to four phylogenetic groups of TT viruses. Nucleotide sequence analyses revealed five distinct genotypes (tth3, tth4, tth5, tth6, and tth7). The limited variation in sequence identity of the other isolates defines the latter as variants of four of these genotypes. A group of 6 isolates (the tth7 group) revealed a reorganization of open reading frame 1 (ORF1) leading to one larger and a varying number of smaller ORFs. The nucleotide difference of the full-length genomes was less than 1%. A variation of 69 to 97% in amino acids of a second group of 8 isolates (the tth3 group) was restricted to the hypervariable region of ORF1, indicating the existence of a quasi-species. These isolates differed by less than 2% in the remainder of their nucleotide sequences. An alignment of these isolates with 79 previously reported TT virus genotypes permits the proposal of TT virus genera and species within the family Anelloviridae in analogy to a previous proposal for the papillomaviruses (family Papillomaviridae). 相似文献
102.
Endoplasmic reticular Ca(2+) stores, instrumental for intra- and intercellular calcium signalling, can be depleted by different receptor agonists. In the present study, the functional status of ER Ca(2+) stores was probed by cyclopiazonic acid (CPA, 10-30 microM, inhibitor of SERCA-dependent ER Ca(2+) uptake) and/or caffeine (20 mM, ryanodine receptor activator) in astrocytes and neurons of rat and mouse acute hippocampal brain slices (Stratum radiatum, Stratum moleculare), and in cultured astrocytes, using confocal microscopy and conventional Ca(2+) imaging. Astrocytes and neurons in situ, identified by their Ca(2+) response in K(+)-free saline (Dallwig and Deitmer [J. Neurosci. Methods 116 (2002) 77]), had a resting cytosolic Ca(2+) level of 105 and 157 nM, respectively (P<0.05). CPA evoked a Ca(2+) transient, which was faster and larger in neurons than in astrocytes, indicating larger Ca(2+) leak of neuronal Ca(2+) stores. Caffeine evoked a Ca(2+) rise in most neurons (>80%), but only in less than 40% of astrocytes. The glial Ca(2+) transients in the presence of caffeine had a large and variable delay (>50 s), as compared to those in neurons (< or =10 s), and appeared to be spontaneous and/or secondary to the neuronal Ca(2+) response, leading to release of neuronal transmitters. Astrocytes in culture responded to CPA, but never to caffeine with a Ca(2+) rise. Our results indicate that astrocytes, in contrast to neurons, lack caffeine-sensitive Ca(2+) stores, and have a relatively smaller leak from CPA-sensitive Ca(2+) stores than neurons. 相似文献
103.
The Apc5 subunit of the anaphase-promoting complex/cyclosome interacts with poly(A) binding protein and represses internal ribosome entry site-mediated translation
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Koloteva-Levine N Pinchasi D Pereman I Zur A Brandeis M Elroy-Stein O 《Molecular and cellular biology》2004,24(9):3577-3587
The anaphase-promoting complex/cyclosome (APC/C) is a multisubunit ubiquitin ligase that mediates the proteolysis of cell cycle proteins in mitosis and G(1). We used a yeast three-hybrid screen to identify proteins that interact with the internal ribosome entry site (IRES) of platelet-derived growth factor 2 mRNA. Surprisingly, this screen identified Apc5, although it does not harbor a classical RNA binding domain. We found that Apc5 binds the poly(A) binding protein (PABP), which directly binds the IRES element. PABP was found to enhance IRES-mediated translation, whereas Apc5 overexpression counteracted this effect. In addition to its association with the APC/C complex, Apc5 binds much heavier complexes and cosediments with the ribosomal fraction. In contrast to Apc3, which is associated only with the APC/C and remains intact during differentiation, Apc5 is degraded upon megakaryocytic differentiation in correlation with IRES activation. Expression of Apc5 in differentiated cells abolished IRES activation. This is the first report implying an additional role for an APC/C subunit, apart from its being part of the APC/C complex. 相似文献
104.
105.
Evaluation of envelope vaccines derived from the South African subtype C human immunodeficiency virus type 1 TV1 strain
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Lian Y Srivastava I Gómez-Román VR Zur Megede J Sun Y Kan E Hilt S Engelbrecht S Himathongkham S Luciw PA Otten G Ulmer JB Donnelly JJ Rabussay D Montefiori D van Rensburg EJ Barnett SW 《Journal of virology》2005,79(21):13338-13349
Human immunodeficiency virus type 1 (HIV-1) subtype C infections are on the rise in Sub-Saharan Africa and Asia. Therefore, there is a need to develop an HIV vaccine capable of eliciting broadly reactive immune responses against members of this subtype. We show here that modified HIV envelope (env) DNA vaccines derived from the South African subtype C TV1 strain are able to prime for humoral responses in rabbits and rhesus macaques. Priming rabbits with DNA plasmids encoding V2-deleted TV1 gp140 (gp140TV1DeltaV2), followed by boosting with oligomeric protein (o-gp140TV1DeltaV2) in MF59 adjuvant, elicited higher titers of env-binding and autologous neutralizing antibodies than priming with DNA vaccines encoding the full-length TV1 env (gp160) or the intact TV1 gp140. Immunization with V2-deleted subtype B SF162 env and V2-deleted TV1 env together using a multivalent vaccine approach induced high titers of oligomeric env-binding antibodies and autologous neutralizing antibodies against both the subtypes B and C vaccine strains, HIV-1 SF162 and TV1, respectively. Low-level neutralizing activity against the heterologous South African subtype C TV2 strain, as well as a small subset of viruses in a panel of 13 heterologous primary isolates, was observed in some rabbits immunized with the V2-deleted vaccines. Immunization of rhesus macaques with the V2-deleted TV1 DNA prime/protein boost also elicited high titers of env-binding antibodies and moderate titers of autologous TV1 neutralizing antibodies. The pilot-scale production of the various TV1 DNA vaccine constructs and env proteins described here should provide an initial platform upon which to improve the immunogenicity of these subtype C HIV envelope vaccines. 相似文献
106.
Low-dose adenovirus vaccine encoding chimeric hepatitis B virus surface antigen-human papillomavirus type 16 E7 proteins induces enhanced E7-specific antibody and cytotoxic T-cell responses 总被引:2,自引:0,他引:2
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Báez-Astúa A Herráez-Hernández E Garbi N Pasolli HA Juárez V Zur Hausen H Cid-Arregui A 《Journal of virology》2005,79(20):12807-12817
Induction of effective immune responses may help prevent cancer progression. Tumor-specific antigens, such as those of human papillomaviruses involved in cervical cancer, are targets with limited intrinsic immunogenicity. Here we show that immunization with low doses (10(6) infectious units/dose) of a recombinant human adenovirus type 5 encoding a fusion of the E7 oncoprotein of human papillomavirus type 16 to the carboxyl terminus of the surface antigen of hepatitis B virus (HBsAg) induces remarkable E7-specific humoral and cellular immune responses. The HBsAg/E7 fusion protein assembled efficiently into virus-like particles, which stimulated antibody responses against both carrier and foreign antigens, and evoked antigen-specific kill of an indicator cell population in vivo. Antibody and T-cell responses were significantly higher than those induced by a control adenovirus vector expressing wild-type E7. Such responses were not affected by preexisting immunity against either HBsAg or adenovirus. These data demonstrate that the presence of E7 on HBsAg particles does not interfere with particle secretion, as it occurs with bigger proteins fused to the C terminus of HBsAg, and results in enhancement of CD8(+)-mediated T-cell responses to E7. Thus, fusion to HBsAg is a convenient strategy for developing cervical cancer therapeutic vaccines, since it enhances the immunogenicity of E7 while turning it into an innocuous secreted fusion protein. 相似文献
107.
The ‘TranSeq’ 3′‐end sequencing method for high‐throughput transcriptomics and gene space refinement in plant genomes
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108.
Asaph Ahroni Amir Zuker Yael Rozen Hadas Shejtman Alexander Vainstein 《Plant Cell, Tissue and Organ Culture》1997,49(2):101-106
An efficient adventitious shoot regeneration procedure was developed for Gypsophila paniculata L. Using cultivar Arbel, shoot
regeneration from the three upper internodes of the stem was monitored on MS media supplemented with different cytokinins
(thidiazuron, benzyladenine, kinetin or zeatin) and an auxin (naphthaleneacetic acid). Thidiazuron was found to be the most
efficient cytokinin, with up to 100% of the explants forming shoots, at an average of up to 19 shoots per explant being regenerated.
The highest percentage of shoot formation was observed in the stem explants originating from the first internode, with all
cytokinins tested. The adventitious origin of shoots regenerated from stem explants was confirmed by scanning electron microscopy.
The regeneration procedure was found to be applicable to five other gypsophila cultivars (Perfecta, Golan, Gilboa, Flamingo
and Tavor). Regenerating plants were successfully transferred to soil, and did not differ in flower color, size or shape from
standard vegetatively propagated plants derived from cuttings.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
109.
Benefits, Costs and Constraints of Anti-Parasitic Grooming in Adult and Juvenile Rodents 总被引:1,自引:1,他引:1
Hadas Hawlena†‡ Dikla Bashary†‡ Zvika Abramsky & Boris R. Krasnov†‡ 《Ethology : formerly Zeitschrift fur Tierpsychologie》2007,113(4):394-402
Grooming behaviour plays various roles in the health care, reproduction, and social life of an individual vertebrate. However, the reasons for the variability in time spent grooming amongst species, populations and individuals are not fully understood. We tested the hypothesis that the main role of grooming is ectoparasite removal and thus that time spent grooming by an animal reflects the costs of parasite infestation offset against the costs of grooming. The test was conducted on a rodent, Meriones crassus, that is parasitised by a flea, Xenopsylla conformis. We monitored behaviour of juvenile and adult rodents before and after flea infestation and quantified the probability of mortality of fleas with respect to the time spent grooming in adults compared with juvenile rodents. We predicted that: (1) increased costs of flea infestation (e.g. in parasitised as opposed to flea‐free rodents and in juveniles as opposed to adults) increases time spent grooming and (2) mortality probability per flea increases with increasing time spent grooming and is higher for fleas on juveniles than for fleas on adult rodents. We were interested to discover at the expense of which activity grooming is increased. Our findings established that the major role of grooming is in flea removal, as exposure to fleas evoked grooming activity in all rodents and grooming activity explained 57–70% of the variation in flea mortality. Furthermore, we showed that the rise in grooming activity was at the expense of resting. However, we found only partial support for the predicted increase in grooming time with increasing costs of flea infestation. Flea infestation did indeed increase the time spent grooming by rodents. Nevertheless, juvenile rodents who incur higher costs of flea infestation spent less time grooming than adults and sustained similar flea densities, suggesting that these hosts are constrained by some other factors, such as feeding time. 相似文献
110.
Hadas Weiss 《Dialectical Anthropology》2016,40(3):287-303
Working households have never owned so much, but the value of their property—especially in the wake of the recent economic crisis, which has priced people out of their homes and devalued their pension savings—is unstable. Liberal economic thought promotes private property as a self-evident vehicle of investment for the future. In contrast, anthropology highlights the social foundations of property, while value theory foregrounds the exigencies of accumulation. Drawing on the latters’ sensitivities and on my fieldwork in Israel on property divisions upon divorce, I examine contested meanings and uses of household property to argue that financialization, a new regime of accumulation that places property values in flux, amplifies tensions in economic liberalism, thereby exposing its ideological underpinnings. 相似文献