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排序方式: 共有449条查询结果,搜索用时 15 毫秒
381.
382.
Jones WJ Johnson SB Rouse GW Vrijenhoek RC 《Proceedings. Biological sciences / The Royal Society》2008,275(1633):387-391
Bone-eating worms of the genus Osedax colonized and grew on cow bones deployed at depths ranging from 385 to 2893m in Monterey Bay, California. Colonization occurred as rapidly as two months following deployment of the cow bones, similar to the time it takes to colonize exposed whalebones. Some Osedax females found on the cow bones were producing eggs and some hosted dwarf males in their tubes. Morphological and molecular examinations of these worms confirmed the presence of six Osedax species, out of the eight species presently known from Monterey Bay. The ability of Osedax species to colonize, grow and reproduce on cow bones challenges previous notions that these worms are 'whale-fall specialists.' 相似文献
383.
Yeast cells lacking MMS22 or MMS1 are hypersensitive to agents that perturb replisome progression but the cellular functions of these genes are unknown. In this study we investigate the involvement of budding yeast MMS22 and MMS1 in homologous recombination (HR). Recombination between sister chromatids or between homologous chromosomes induced by agents that block replisomes was severely defective in cells lacking MMS22 or MMS1. In contrast, HR induced by double-strand breaks was not affected by the absence of these genes. Major defects in MMS-induced HR were also observed in cells lacking the cullin RTT101, the histone acetyltransferase RTT109 and in cells lacking the histone chaperone ASF1, all of which interact genetically with MMS22 and MMS1. Finally, we show that cells lacking either MMS22 or MMS1 are defective in recovery from MMS-induced replisome stalling. These results identify Mms22 and Mms1 as S-phase specific recombination-promoting factors. 相似文献
384.
SUMMARY: Compared to the wealth of online resources covering genomic, proteomic and derived data the Bioinformatics community is rather underserved when it comes to patent information related to biological sequences. The current online resources are either incomplete or rather expensive. This paper describes, PatGen, an integrated database containing data from bioinformatic and patent resources. This effort addresses the inconsistency of publicly available genetic patent data coverage by providing access to a consolidated dataset. AVAILABILITY: PatGen can be searched at http://www.patgendb.com CONTACT: rjdrouse@patentinformatics.com. 相似文献
385.
Antigenic peptides complexed to phylogenically diverse Hsp70s induce differential immune responses 总被引:6,自引:0,他引:6 下载免费PDF全文
The Hsp70 class of heat shock proteins (Hsps) has been implicated at multiple points in the immune response, including initiation of proinflammatory cytokine production, antigen recognition and processing, and phenotypic maturation of antigen-presenting cells (APCs). This class of chaperones is highly conserved in both sequence and structure, from prokaryotes to higher eukaryotes. In all cases, these chaperones function to bind short segments of either peptides or proteins through an adenosine triphosphate-dependent process. In addition to a possible role in antigen presentation, these chaperones have also been proposed to function as a potent adjuvant. We compared 4 evolutionary diverse Hsp70s, E. coli DnaK, wheat cytosolic Hsc70, plant chloroplastic CCS1, and human Hsp70, for their ability to prime and augment a primary immune response against herpes simplex virus-1 (HSV1). We discovered that all 4 Hsp70s were highly effective as adjuvants displaying similar ability to lipopolysaccharides in upregulating cytokine gene expression. In addition, they were all capable of inducing phenotypic maturation of APCs, as measured by the display of various costimulatory molecules. However, only the human Hsp70 was able to mediate sufficient cross-priming activity to afford a protective immune response to HSV1, as judged by protection from a lethal viral challenge, in vitro proliferation, cytotoxicity, and intracellular interferon-gamma production. The difference in immune response generated by the various Hsp70s could possibly be due to their differential ability to interact productively with other coreceptors and different regulatory cochaperones. 相似文献
386.
At present, mass spectrometry provides a rapid and sensitive means for making conclusive protein identifications from complex mixtures. Sequencing tryptic peptides derived from proteolyzed protein samples, also known as the "Bottom Up" approach, is the mass spectrometric gold standard for identifying unknowns. An alternative technology, "Top Down" characterization, is emerging as a viable option for protein identifications, which involves analyzing the intact unknowns for accurate mass and amino acid sequence tags. In this paper, both characterization methods were employed to more comprehensively differentiate two early-eluting peaks in a process-scale size-exclusion chromatography (SEC) step for a recombinant, immunoglobulin gamma-1 (IgG-1) fusion protein. The contents of each SEC peak were enzymatically digested, and the resulting peptides were mapped using reversed-phase (RP) HPLC-ion trap MS. Many low-level UV signals were observed among the fusion protein-related peptide peaks. These unknowns were collected, concentrated, and analyzed using nanoelectrospray (nanoES) collision-induced dissociation (CID) tandem (MS/MS) mass spectrometry for identification. The peptide sequencing experiments resulted in the identification of twenty host cell-related proteins. Following peptide mapping, the contents of the two SEC peaks were protein mass profiled using on-line RP HPLC coupled to a high-resolution, quadrupole time-of-flight (Qq/TOF) MS. Unknown proteins were also collected, concentrated, and dissociated using nanoES CID MS/MS. Intact protein CID experiments and accurate molecular weight information allowed for the identification of three full length host cell-derived proteins and numerous clips from these and additional proteins. The accurate molecular weight values allowed for the assignment of N- and C-terminal processing, which is difficult to conclusively access from peptide mapping data. The peptide-mapping experiments proved to be far more effective for making protein identifications from complex mixtures, whereas the protein mass profiling was useful for assessing modifications and distinguishing protein clips from full length species. 相似文献
387.
We describe Lizardia hirschi, a new hesionid genus and species, from shallow water on the Great Barrier Reef. It is characterized by small size (maximally around 2 mm long) and by males with paired penes on the last segment or the pygidium. The sperm are elongated, with a conical acrosome; extended, cylindrical nucleus; and three mitochondria. The females have three to four pairs of eggs in segments 10-13, up to 150 microm in diameter. The female reproductive system consists of spermathecae, situated in the notopodia of segments 10-12, and oviducts opening ventrally on segment 11. Fertilization may be internal. The female (but not the male) reproductive system appears to be homologous to that in another small hesionid, capricornia. The phylogenetic position of L. hirschi within Hesionidae is currently uncertain due to the retention of many apparently larval features in the adults. 相似文献
388.
CD4+ CD25+ T cells regulate vaccine-generated primary and memory CD8+ T-cell responses against herpes simplex virus type 1 总被引:1,自引:0,他引:1 下载免费PDF全文
It has become evident that naturally occurring CD25(+) regulatory T cells (T(reg) cells) not only influence self-antigen specific immune response but also dampen foreign antigen specific immunity. This report extends our previous findings by demonstrating that immunity to certain herpes simplex virus (HSV) vaccines is significantly elevated and more effective if T(reg) cell response is curtailed during either primary or recall immunization. The data presented here show that removal of CD25(+) T(reg) cells prior to SSIEFARL-CpG or gB-DNA immunization significantly enhanced the resultant CD8(+) T-cell response to the immunodominant SSIEFARL peptide. The enhanced CD8(+) T-cell reactivity in T(reg) cell-depleted animals was between two- and threefold and evident in both acute and memory stages. Interestingly, removal of CD25(+) T(reg) cells during the memory recall response to plasmid immunization resulted in a twofold increase in CD8(+) T-cell memory pool. Moreover, in the challenge experiments, memory CD8(+) T cells generated with plasmid DNA in the absence of T(reg) cells cleared the virus more effectively compared with control groups. We conclude that CD25(+) T(reg) cells quantitatively as well as qualitatively affect the memory CD8(+) T-cell response generated by gB-DNA vaccination against HSV. However, it remains to be seen if all types of vaccines against HSV are similarly affected by CD25(+) T(reg) cells and if it is possible to devise means of limiting T(reg) cell activity to enhance vaccine efficacy. 相似文献
389.
390.
Contribution of vascular endothelial growth factor in the neovascularization process during the pathogenesis of herpetic stromal keratitis 总被引:4,自引:0,他引:4 下载免费PDF全文
This report analyzes the role of vascular endothelial growth factor (VEGF)-induced angiogenesis in the immunoinflammatory lesion stromal keratitis induced by ocular infection with herpes simplex virus (HSV). Our results show that infection with replication-competent, but not mutant, viruses results in the expression of VEGF mRNA and protein in the cornea. This a rapid event, with VEGF mRNA detectable by 12 h postinfection (p.i.) and proteins detectable by 24 h p.i. VEGF production occurred both in the virus-infected corneal epithelium and in the underlying stroma, in which viral antigens were undetectable. In the stroma, VEGF was produced by inflammatory cells; these initially were predominantly polymorphonuclear leukocytes (PMN), but at later time points both PMN and macrophage-like cells were VEGF producers. In the epithelium, the major site of VEGF-expressing cells in early infection, the infected cells themselves were usually negative for VEGF. Similarly, in vitro infection studies indicated that the cells which produced VEGF were not those which expressed virus. Attesting to the possible role of VEGF-induced angiogenesis in the pathogenesis of herpetic stromal keratitis were experiments showing that VEGF inhibition with mFlt(1-3)-immunoglobulin G diminished angiogenesis and the severity of lesions after HSV infection. These observations are the first to evaluate VEGF-induced angiogenesis in the pathogenesis of stromal keratitis. Our results indicate that the control of angiogenesis represents a useful adjunct to therapy of herpetic ocular disease, an important cause of human blindness. 相似文献