Antigen bias in T cell cross-priming   总被引：1，自引：0，他引：1  

Wolkers MC  Brouwenstijn N  Bakker AH  Toebes M  Schumacher TN 《Science (New York, N.Y.)》2004,304(5675):1314-1317

Activated CD8+ T cells detect virally infected cells and tumor cells by recognition of major histocompatibility complex class I-bound peptides derived from degraded, endogenously produced proteins. In contrast, CD8+ T cell activation often occurs through interaction with specialized antigen-presenting cells displaying peptides acquired from an exogenous cellular source, a process termed cross-priming. Here, we observed a marked inefficiency in exogenous presentation of epitopes derived from signal sequences in mouse models. These data indicate that certain virus- and tumor-associated antigens may not be detected by CD8+ T cells because of impaired cross-priming. Such differences in the ability to cross-present antigens should form important considerations in vaccine design.  相似文献   

Acrosomal proteinase and proteinase inhibitor of human spermatozoa   总被引：2，自引：0，他引：2  

L J Zaneveld  B M Dragoje  G F Schumacher 《Science (New York, N.Y.)》1972,177(50):702-703

The acrosomal proteinase of human spermatozoa was characterized and differs from other human proteinases. The enzyme has optimal activity at pH 8.0, is inactive below pH 5.0 or above pH 10.5, requires calcium for maximum activity, hydrolyzes fibrinogen, gelatin, and benzoylarginine ethyl ester, and is inhibited by various synthetic and natural proteinase inhibitors. The molecular weight was estimated to be 30,000. Human spermatozoa also possess a proteinase inhibitor that is similar to one of the proteinase inhibitors from human seminal plasma.  相似文献   

基于AutoCAD环境前处理接口程序的开发     

霍俊芳 《内蒙古农业大学学报(自然科学版)》2003,24(2):92-95

本文通过分析传统的结构数据处理方法的缺陷，提出了基于AutoCAD环境下的前处理模式的开发；详细研究了Auto CAD的DXF文件结构，叙述了如何运用嵌套于AutoCAD内部的AutoLISP语言来读取、处理AutoCAD图形文件，进而生成计算程序所需要的数据文件；最后总结了前处理的主要工作。  相似文献   

NaCl胁迫对黄瓜种子萌发的影响   总被引：7，自引：0，他引：7  

王广印张百俊  赵一鹏张建伟 沈军 《吉林农业大学学报》2004,26(6):624-627

采用培养皿发芽法研究了NaCl胁迫处理对黄瓜种子萌发的影响。结果表明：NaCl胁迫浸种、水环境下发芽对黄瓜种子萌发的影响较小，只有在高浓度NaCl胁迫下，才对种子萌发起抑制作用。不同浓度的NaCl胁迫对黄瓜种子发芽的影响有显著差异；随着NaCl胁迫浓度的增大。对发芽的抑制作用明显增强。种子活力指数、发芽指数、胚根一级侧根数比发芽率对NaCl胁迫的反应更敏感。在225mmol／L NaCl胁迫下，黄瓜种子萌发对外源Ca^2 反应较为敏感，适量的外源Ca^2 (10mmol／L CaCl2)对盐胁迫有一定的缓解效应，浓度过高对发芽起抑制作用。适当时间的吸湿-回干处理能缓解NaCl胁迫对黄瓜种子萌发的抑制作用。  相似文献   

套作玉米产量与栽培密度及氮磷钾肥施用量的关系     

马俊梅艳  吴嵩梁黔云  范厚明罗新颖 陈森林 《勤云标准版测试》2005,(4)

采用二次回归通用旋转组合设计方法试验,以马铃薯套作玉米产量为目标,以套作的玉米密度、氮、磷、钾肥施用量为探讨对象,建立了套作玉米产量与密度、氮、磷、钾肥施用量间关系的数学模型(y=7396.05-536.7x1 129.0x2 135.6x3 104.7x4-19.65x1x2-5.4x1x3 147.75x1x4 165.15x2x3-86.55x2x4 113.7x3x4-478.8x12-407.7x22-446.25x32-450.3x42),通过模拟寻优,提出了玉米产量≥6750.00kg/hm2的综合农艺栽培方案(玉米密度44856-51135株/hm2,平均48000株/hm2;N279.30-350.70kg/hm2,平均315.00kg/hm2;P2O5189.00-231.00kg/hm2,平均210.00kg/hm2;K2O167.70-222.30kg/hm2,平均195.00kg/hm2。N:P:K=1:0.667:0.619)。  相似文献   

Acute phase protein in serum of women using hormonal contraceptives     

G F Schumacher 《Science (New York, N.Y.)》1966,153(738):901-902

Acute phase protein precipitating sonatic C-polysaccharide of pneumococci appears in serum of women under treatment with hormonal contraceptives in a significantly higher number of cases when compared with control groups. The summarized results of three preliminary studies show that in 80 control serums there were four positive specimens (5 percent) and in 80 serums from women using hormonal contraceptives there were 58 positive specimens (72.5 percent).  相似文献   

Buddenbrockia is a cnidarian worm     

Jiménez-Guri E  Philippe H  Okamura B  Holland PW 《Science (New York, N.Y.)》2007,317(5834):116-118

A major evolutionary divide occurs in the animal kingdom between the so-called radially symmetric animals, which includes the cnidarians, and the bilaterally symmetric animals, which includes all worm phyla. Buddenbrockia plumatellae is an active, muscular, parasitic worm that belongs to the phylum Myxozoa, a group of morphologically simplified microscopic endoparasites that has proved difficult to place phylogenetically. Phylogenetic analyses of multiple protein-coding genes demonstrate that Buddenbrockia is a cnidarian. This active muscular worm increases the known diversity in cnidarian body plans and demonstrates that a muscular, wormlike form can evolve in the absence of overt bilateral symmetry.  相似文献   

台湾青枣在北方日光温室的试栽表现   总被引：1，自引：0，他引：1  

刘慧纯  蒋锦标  邢军 《辽宁农业职业技术学院学报》2003,5(1):15-16

台湾青枣是一种新兴的热带、亚热带水果。果实形似苹果,叶似梨,其风味独特、清脆香甜、爽口,营养丰富。突出特点是当年种植,当年结果。在北方利用日光温室栽培还是空白。在温室内通过对其丰产优质栽培技术进行专门研究,以开发这一极具前景的珍奇果树。  相似文献   

Standards and corporate reconstruction in the Michigan dry bean industry     

Jim Bingen  Andile Siyengo 《Agriculture and Human Values》2002,19(4):311-323

Since the turn of the lastcentury, Michigan farmers, elevators, and stategovernment have used production and processstandards to shape the dry bean industry totheir interests and set a worldwide standardfor quality dry beans. Over the last 20 years,however, multinational agro/food firms haveintroduced their market criteria into standardssetting, and recent changes in Michigan beanstandards largely accommodate the interests ofthese firms. A review of the changes in thesestandards over time allows us to explore howconcepts of accountability and control improveour understanding of changes in the structureand operation of food production and marketing.What is the measure of state governmentaccountability to corporate capital and to thestate's bean farmers? In what ways can farmersuse standards to re-assert their priorities andgain a greater measure of influence overmarketing? What challenges do changing qualitystandards pose for public research as well asfor the institutions representing Michiganfarmers and elevators?  相似文献   

Agriculture. Transforming U.S. agriculture     

Reganold JP  Jackson-Smith D  Batie SS  Harwood RR  Kornegay JL  Bucks D  Flora CB  Hanson JC  Jury WA  Meyer D  Schumacher A  Sehmsdorf H  Shennan C  Thrupp LA  Willis P 《Science (New York, N.Y.)》2011,332(6030):670-671

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