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排序方式: 共有379条查询结果,搜索用时 15 毫秒
1.
Nir Dover Jason R. Barash Karen K. Hill Karen W. Davenport Hazuki Teshima Gary Xie Stephen S. Arnon 《PloS one》2013,8(4)
Sanger and shotgun sequencing of Clostridium botulinum strain Af84 type Af and its botulinum neurotoxin gene (bont) clusters identified the presence of three bont gene clusters rather than the expected two. The three toxin gene clusters consisted of bont subtypes A2, F4 and F5. The bont/A2 and bont/F4 gene clusters were located within the chromosome (the latter in a novel location), while the bont/F5 toxin gene cluster was located within a large 246 kb plasmid. These findings are the first identification of a C. botulinum strain that contains three botulinum neurotoxin gene clusters. 相似文献
2.
Schistosoma mansoni: killing of transformed schistosomula by the alternative pathway of human complement 总被引:2,自引:0,他引:2
The interaction of mechanically transformed schistosomula of Schistosoma mansoni with the alternative pathway of human complement was studied in vitro. To detect early changes in transformation, the schistosomula were prepared at a low temperature and used immediately. As shown previously, freshly transformed schistosomula were highly susceptible to killing by normal human serum and by C4-depleted normal human serum. This serum activity was concentration dependent and was markedly reduced on a twofold serum dilution. Upon incubation at 37 C in defined synthetic medium, schistosomula rapidly became refractory to killing by the alternative pathway of complement. After 1 hr of incubation at 37 C, the percentage of schistosomula which were resistant to killing increased from 16 to 85. This conversion was accompanied by a fivefold decrease in deposition of C3b on schistosomula which had been exposed to 37 C for 1 hr and then further incubated with C4-depleted normal human serum. The following events occurred concomitantly during incubation of freshly transformed schistosomula at 37 C with a half-life of 30-60 min: (1) Decrease in activation and consumption of the alternative pathway of complement by schistosomula; (2) appearance of a strong complement consuming activity in the supernatant of incubating schistosomula; and (3) shedding of protein- and carbohydrate-containing substances from the surface of schistosomula into the supernatant. Isolated external membranes of freshly transformed schistosomula consumed the alternative pathway of complement to a greater extent than membranes of schistosomula preincubated in medium at 37 C. The results demonstrate that transformed schistosomula acquire resistance to complement killing via the alternative pathway by shedding complement-activating substances.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
3.
Michal J. Besser Tsipi Shoham Orit Harari-Steinberg Naama Zabari Rona Ortenberg Arkadi Yakirevitch Arnon Nagler Ron Loewenthal Jacob Schachter Gal Markel 《PloS one》2013,8(3)
Natural killer (NK) cells have long been considered as potential agents for adoptive cell therapy for solid cancer patients. Until today most studies utilized autologous NK cells and yielded disappointing results. Here we analyze various modular strategies to employ allogeneic NK cells for adoptive cell transfer, including donor-recipient HLA-C mismatching, selective activation and induction of melanoma-recognizing lysis receptors, and co-administration of antibodies to elicit antibody-dependent cell cytotoxicity (ADCC). We show that NK cell activation and induction of the relevant lysis receptors, as well as co-administration of antibodies yield substantial anti-cancer effects, which are functionally superior to HLA-C mismatching. Combination of the various strategies yielded improved effects. In addition, we developed various clinically-compatible ex vivo expansion protocols that were optimized according to fold expansion, purity and expression of lysis receptors. The main advantages of employing allogeneic NK cells are accessibility, the ability to use a single donor for many patients, combination with various strategies associated with the mechanism of action, e.g. antibodies and specific activation, as well as donor selection according to HLA or CD16 genotypes. This study rationalizes a clinical trial that combines adoptive transfer of highly potent allogeneic NK cells and antibody therapy. 相似文献
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Arnon Levy 《Biology & philosophy》2011,26(3):459-467
Michael Strevens has produced an ambitious and comprehensive new account of scientific explanation. This review discusses
its main themes, focusing on regularity explanation and a number of methodological concerns. 相似文献
9.
Shilman Florin Brand Yael Brand Arnon Hedvat Ilan Hovav Ran 《Plant Molecular Biology Reporter》2011,29(1):232-241
The stearoyl–acyl carrier protein (ACP) desaturase (SAD) is a nuclear-encoded, plastid-localized soluble desaturase that catalyzes the
conversion of stearoyl-ACP to oleoyl-ACP and plays a key role in the determination of the properties of the majority of cellular
glycerolipids. Sad genes from a variety of plant species have been cloned and characterized. However, in peanut (Arachis hypogaea), an important edible and oilseed crop, these genes have not yet been characterized. By searching peanut expressed sequence
tag (EST) and parallel sequencing (454) libraries, we have identified three members of the ahSad gene family. Among them, only one gene, ahSad3, was exclusively expressed during seed development and in a manner fully corresponding to oil accumulation. Both ahSad3 homeologous genes (ahSad3A and ahSad3B) were recovered from the allotetraploid peanut, and their mRNA expression levels were characterized. The open reading frames
for ahSad3A and ahSad3B are 98% identical and consist of 1,158 bp, encoding a 386-full-amino-acid protein, with one intron in the coding sequence.
Comparisons of the sequences of these two homeologous genes revealed seven single-nucleotide polymorphisms and one triplet
insertion in the coding region. Southern blot analysis indicated that there are only two copies of the ahSad3 gene in the peanut genome. Homeolog-specific gene expression analysis showed that both ahSad3 homeologs are expressed in developing seeds, but gene expression is significantly biased toward the B genome. Our results
point to ahSad3 as a possible target gene for manipulation of fatty acid saturation in A. hypogaea. 相似文献
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