A domain in TNF receptors that mediates ligand-independent receptor assembly and signaling

A conserved domain in the extracellular region of the 60- and 80-kilodalton tumor necrosis factor receptors (TNFRs) was identified that mediates specific ligand-independent assembly of receptor trimers. This pre-ligand-binding assembly domain (PLAD) is physically distinct from the domain that forms the major contacts with ligand, but is necessary and sufficient for the assembly of TNFR complexes that bind TNF-alpha and mediate signaling. Other members of the TNFR superfamily, including TRAIL receptor 1 and CD40, show similar homotypic association. Thus, TNFRs and related receptors appear to function as preformed complexes rather than as individual receptor subunits that oligomerize after ligand binding.     

Spinophilin blocks arrestin actions in vitro and in vivo at G protein-coupled receptors

Arrestin regulates almost all G protein-coupled receptor (GPCR)-mediated signaling and trafficking. We report that the multidomain protein, spinophilin, antagonizes these multiple arrestin functions. Through blocking G protein receptor kinase 2 (GRK2) association with receptor-Gbetagamma complexes, spinophilin reduces arrestin-stabilized receptor phosphorylation, receptor endocytosis, and the acceleration of mitogen-activated protein kinase (MAPK) activity following endocytosis. Spinophilin knockout mice were more sensitive than wild-type mice to sedation elicited by stimulation of alpha2 adrenergic receptors, whereas arrestin 3 knockout mice were more resistant, indicating that the signal-promoting, rather than the signal-terminating, roles of arrestin are more important for certain response pathways. The reciprocal interactions of GPCRs with spinophilin and arrestin represent a regulatory mechanism for fine-tuning complex receptor-orchestrated cell signaling and responses.     

Synaptic transmission in the crayfish: increased release of transmitter substance by bacterial endotoxin

Bacterial endotoxin increases the frequency of miniature excitatory postsynaptic potentials, decreases facilitation, and increases the evoked excitatory postsynaptic potential without changing membrane resistance. These data indicate that endotoxin acts on the presynaptic nerve terminal by increasing the amount of transmitter substance released in response to an applied stimulus.     

The growth factor progranulin binds to TNF receptors and is therapeutic against inflammatory arthritis in mice

The growth factor progranulin (PGRN) has been implicated in embryonic development, tissue repair, tumorigenesis, and inflammation, but its receptors remain unidentified. We report that PGRN bound directly to tumor necrosis factor receptors (TNFRs) and disturbed the TNFα-TNFR interaction. PGRN-deficient mice were susceptible to collagen-induced arthritis, and administration of PGRN reversed inflammatory arthritis. Atsttrin, an engineered protein composed of three PGRN fragments, exhibited selective TNFR binding. PGRN and Atsttrin prevented inflammation in multiple arthritis mouse models and inhibited TNFα-activated intracellular signaling. Collectively, these findings demonstrate that PGRN is a ligand of TNFR, an antagonist of TNFα signaling, and plays a critical role in the pathogenesis of inflammatory arthritis in mice. They also suggest new potential therapeutic interventions for various TNFα-mediated pathologies and conditions, including rheumatoid arthritis.     

Lithium increases serotonin release and decreases serotonin receptors in the hippocampus

The effects of long-term lithium administration on pre- and postsynaptic processes involved in serotonergic neurotransmission were measured in rat hippocampus and cerebral cortex. Long-term lithium administration increased both basal and potassium chloride-stimulated release of endogenous serotonin from the hippocampus but not from the cortex. Serotonergic receptor binding was reduced in the hippocampus but not in the cortex. These results suggest a mechanism by which lithium may stabilize serotonin neurotransmission.     

营养胁迫对曼地亚红豆杉生长与生理指标及紫杉醇含量的影响

为探讨营养胁迫对曼地亚红豆杉生长、生理和紫杉醇含量的影响,于休眠期对曼地亚红豆杉幼苗进行氮、磷、钾3因素3水平正交试验共9种营养胁迫处理,于生长期测量其生长、生理指标及紫杉醇含量.结果表明:(1)休眠期营养胁迫促进了曼地亚红豆杉生长期的生长;(2)休眠期不同营养胁迫均提高了曼地亚红豆杉叶片中叶绿素含量;(3)脯氨酸和丙二醛含量随氮肥用量增加而升高;(4)可溶性糖含量随氮肥用量增加先升后降;(5)紫杉醇含量与脯氨酸、丙二醛、可溶性糖含量均呈现极显著负相关,而与叶绿素含量无显著相关性.     

紫杉醇在猪体外成熟卵母细胞玻璃化冷冻中的作用探讨

使用1．00μmol／L紫杉醇预处理卵母细胞,冷冻后其形态完整率（89．93％）和FDA染色存活率（83．33％）均显著高于未处理组的79．12％和70．97％。不同预处理时间试验表明：预处理30min组冷冻后卵母细胞形态完整率和FDA染色存活率最高,分别达到90．21％和84．13％。预处理浓度1．0μmol／L,30min是比较合适的处理方法;紫杉醇、细胞松弛素B前处理能显著提高猪成熟卵母细胞的玻璃化冷冻的效果,但两者之间没有显著差异。     

ATP release guides neutrophil chemotaxis via P2Y2 and A3 receptors

Cells must amplify external signals to orient and migrate in chemotactic gradient fields. We find that human neutrophils release adenosine triphosphate (ATP) from the leading edge of the cell surface to amplify chemotactic signals and direct cell orientation by feedback through P2Y2 nucleotide receptors. Neutrophils rapidly hydrolyze released ATP to adenosine that then acts via A3-type adenosine receptors, which are recruited to the leading edge, to promote cell migration. Thus, ATP release and autocrine feedback through P2Y2 and A3 receptors provide signal amplification, controlling gradient sensing and migration of neutrophils.     

一株产紫杉醇云南红豆杉内生真菌分离和筛选

紫杉醇是临床上所用的非常重要的天然抗癌药物.从云南丽江塔城地区分离的云南红豆杉中采用无菌技术分离得到110株内生真菌,经过PDA液体培养基发酵后用TLC、紫外分光光度法、HPLC、质谱等方法检测,发现其中有1株的胞外分泌物中含有紫杉醇,标记为G7-B1.经过形态学鉴别,属于拟盘多毛孢属(Pestalotiopsis sp.),紫杉醇产率为360.75 μg/L.该种菌具有进一步研究的价值.     

肉毒素对鹅繁殖性能的影响

以广东省3家种鹅场(代号为A、B、C)为对象,检测了洗浴池和鹅血浆的内毒素水平,并比较和分析了各场种鹅的产蛋数、受精率和活胚率.结果显示:A场和B场洗浴池的内毒素水平无显著差异,均显著高于C场(P<0.05);A场的鹅血浆内毒素水平与B场无显著差异,显著高于C场,而B场与C场则无显著差异.此外,试验期间3家鹅场的鹅产蛋数相当;A场的鹅蛋受精率显著高于B场、但明显低于C场,C场则极显著高于B场(P<0.01);A场活胚率极显著低于B场,显著低于C场,B场则显著高于C场.表明洗浴池内毒素含量高的鹅场,其种鹅体内内毒素水平也相对较高,鹅蛋受精率和胚胎成活率偏低,影响种鹅生产水平.     

内毒素对鹅胚胎发育的影响

以广东省台山市2家活胚率差异明显的鹅场为对象,检测了活胚与死胚的囊胚液内毒素水平,并比较了家鹅场的受精率、活胚率与血浆内毒素水平之间的关系.结果表明,2家鹅场的活胚囊胚液中的内毒素水平均明显低于各自死胚中的内毒素(P<0.05),但鹅场间的活胚或死胚内毒素水平均无显著差异:活胚率明显高的鹅场.其血浆内毒素水平显著低于活胚率低的鹅场(P<0.05),受精率在2家鹅场间则无显著差异.从而证明,种鹅生产中内毒素能明显影响胚胎的成活率.     

不同光照时间对肉鹅生长性能及内毒素的影响

为研究不同光照时间对肉鹅生长性能和血清内毒素含量的影响,试验选取３个组,每组随机不分性别选取３２只４周龄马岗鹅．对照组接受正常光照（１２Ｌ∶１２Ｄ）（Ｌ∶光照ｌｉｇｈｔ,Ｄ：黑暗ｄａｒｋ）,短日照组每天９ｈ日照（９Ｌ∶１５Ｄ）;长日照组每天１５ｈ日照（１５Ｌ∶９Ｄ）,试验持续８周后,测定体质量增长速度、存活率、料重比、血 清内毒素等指标．结果表明,体质量从第７周开始对照组要显著高于短日照组和长日照组（Ｐ＜０.０５）．鹅生长发育早期（４～８周）对照组的饲料转化率最高,而后期（９～１２周）则是长光照组的饲料转化率最高．对照组和长光照组的存活率都达到８０.０％以上,而短日照组只有６６.７％．在整个试验期间对照组的血清内毒素含量均比其余两组小．试验表明,接受正常光照（１２Ｌ∶１２Ｄ）的鹅群有较好的生长性能,而长光照可提高鹅生长发育后期的饲料转化率．     

涉及全纯函数分担值的正规定则

设F为区域D内的一族全纯函数,a1、a2为2个不同的有穷复数,M为正整数.若对任意的f∈F,f(z)-a1至多有M个零点,且f-ai(i=1,2)的零点重级至少为2,则F在区域D内正规.     

曼地亚红豆杉中紫杉醇等与产地因子的相关性

从国内8个不同产地采集曼地亚红豆杉Taxus media枝条和林下土壤,利用高效液相色谱（HPLC）法测定了紫杉醇（taxol）和10-脱乙酰基巴卡亭Ⅲ（10-deacetylbaccatin,10-DAB）质量分数,用常规方法测定了土壤的矿质元素及肥力结构等。结果表明：不同产地的曼地亚红豆杉紫杉醇和10-DAB质量分数差异很大,紫杉醇有随北纬纬度增高而递减的趋势;紫杉醇和10-DAB与多数土壤因子相关性不显著,其中：紫杉醇与有机质呈显著正相关,与北纬纬度呈显著负相关,10-DAB与土壤矿质元素钴和锰质量分数呈显著负相关;紫杉醇与10-DAB之间不存在相关性（r = - 0.197）;用多元逐步回归分析建立了紫杉醇质量分数的回归方程。推测：曼地亚红豆杉的紫杉醇及其衍生物质量分数变化规律与红豆杉属其他种相似,受生长必需环境因子影响明显。图2表3参23     

Nerve growth factor attenuates neurotoxic effects of taxol on spinal cord-ganglion explants from fetal mice

Most neurons in organotypic cultures of dorsal root ganglia from 13-day-old fetal mice require high concentrations of nerve growth factor for survival during the first week after explanation. These nerve growth factor-enhanced sensory neurons mature and innervate the dorsal regions of attached spinal cord tissue even after the removal of exogenous growth factor after 4 days. In cultures exposed for 4 days to nerve growth factor and taxol (a plant alkaloid that promotes the assembly of microtubules) and returned to medium without growth factor, greater than 95 percent of the ganglionic neurons degenerated and the spinal cord tissues were reduced almost to monolayers. In contrast, when the recovery medium was supplemented with nerve growth factor, the ganglionic neurons and dorsal (but not ventral) cord tissue survived remarkably well. Dorsal cord neurons do not normally require an input from dorsal root ganglia for long-term maintenance in vitro, but during and after taxol exposure they become dependent for survival and recovery on the presence of neurite projections from nerve growth-factor-enhanced dorsal root ganglia.     

小议知识经济整体中的产权知识和共享知识

本文对共同支撑知识经济的两种重要知识即产权知识和共享知识的优势和不足分别进行了分析和论述,在此基础上得出这两种知识是相互促进,相辅相成,对知识经济缺一不可的,希望则在于两者的有效结合与合理均衡的结论。     

坚持“先行先试” 构建闽台“共同家园”

从经济合作、文化交流、"三通"等方面,提出先行先试,构建闽台"共同家园"的具体举措。     

农业GIS通用共享式平台的研究与示范

为解决北京市农业局各业务系统应用、数据深化整合问题,实现统一技术架构、统一技术规范,开发一套专门用于农业GIS应用的通用开发平台。平台可以实现三方面应用:利用平台快速搭建全新农业GIS应用、将GIS应用嵌入非GIS业务系统、平台搭建的农业GIS应用整合和对接已有GIS应用,从而全面满足农业局全局GIS应用需求,实现全局GIS应用的快速定制和空间数据全面共享。     

卵黄油的药理作用及提取工艺研究进展

<正>卵黄油又称蛋黄油、鸡子黄油(《日华子本草》)[1],为我国传统中药,备受国内外学者的青睐。除了具有消肿解毒,敛疮生肌[2]之传统的功效外,现代研究结果表明卵黄油在医药业、食品业、化妆业、饲料业等行业具有广阔的应用前景。本文就近年来国内外学者在卵黄油的药理作用、提取工艺方面的研究进展     

黄芪多糖对内毒素诱发大鼠实验性乳腺炎的影响

选取40只SD雌性大鼠使之交配受孕。在确定其怀孕后,30只孕鼠随机分成正常对照组、阳性对照组和试验组,每组10只。试验组大鼠每天按100 mg/kg体重灌喂黄芪多糖(APS),直至试验结束,而对照组大鼠灌喂相应体积的生理盐水(PSS)。孕鼠于产后72 h分别用灭菌PSS和50μg大肠杆菌内毒素经乳头管灌注到大鼠第4对乳腺内。灌注后24 h处死大鼠,取乳腺组织和颈静脉血进行指标测定。结果显示,阳性对照组大鼠乳腺组织中肿瘤坏死因子α(TNF-α)浓度、N-乙酰-β-D-氨基葡萄糖苷酶(NAGase)活性,与正常对照组相比显著升高(P<0.05);试验组大鼠乳腺组织中TNF-α浓度、NAGase活性与阳性对照组相比,显著降低(P<0.05)。结果表明,灌喂APS可以抑制乳腺组织内炎性细胞因子TNF-α的过度释放,对内毒素诱发的大鼠实验性乳腺炎有一定的保护作用。