Variation in coat protein genes among five geographicallydifferent isolates of rice tungro spherical virus

Summary.  The variation in the sequence of the coat protein genes of four isolates of rice tungro spherical virus from different countries, Malaysia, Thailand, India and Bangladesh, was compared with an isolate from the Philippines. The evidence from RT-PCR, Southern blot hybridization and sequences of the coat protein genes indicated that the isolates appeared to fall into two groups. One comprised the Philippine and Malaysian isolates (about 95% sequence similarity) and the other the Bangladeshi and Indian isolates, the sequences of which differed by about 15% from that of the Philippine isolate. The Thai isolate seemed to be a mixture of these two subgroups. Received March 4, 1997 Accepted April 23, 1997     

硝苯啶、硫氮(艹卓)酮对兔实验性动脉粥样硬化症的影响

硝苯啶和硫氮(艹桌)酮不明显影响血清脂蛋白组分水平,但均显著抑制家兔主动脉动脉粥样硬化形成,降低血浆过氧化脂质、血栓烷和主动脉内中膜胆固醇、磷脂及钙含量,升高血浆6-酮-PGF_(1α),使,TXB_2/6-酮-PGF_(1α)趋于平衡。说明钙在血栓烷-前列环素代谢中起重要作用。     

病毒性肝炎患者IL－1、IL－6和TNFα活性的检测

检测了甲、乙型病毒性肝炎患者外周血单个核细胞（ＰＢＭＣｓ）ＩＬ－１、ＩＬ－６和ＴＮＦα的诱生活性及其血清中活性。结果表明，乙型慢性活动性肝炎（ＣＡＨ）、乙型肝炎后肝硬化（ＨＣ）和乙型重型肝炎（ＳＨ）ＰＢＭＣｓ经脂多糖诱导后，ＩＬ－１活性分别为３５３１．１±８８２．７Ｕ／ｍ１、２７６９．７±７３０．４±Ｕ／ｍｌ和５３２９．３±１０８９．３Ｕ／ｍｌ，高于正常对照组（Ｐ＜０．０５或（０．０１）；ＩＬ－６诱生活性分别为３８．９０±１４．７５Ｕ／ｍ１、２．４５±１８．８５Ｕ／ｍｌ和７１．９５±２８．０５Ｕ／ｍｌ（与正常对照组相比，ｐ＜０．０５或＜０．０１）；ＴＮＦα诱生活性在乙型慢性迁延性肝炎（ＣＰＨ）、ＣＡＨ、ＨＣ和ＳＨ中分别为３３．２３±７．２５Ｕ／ｍｌ、６．９９±１．８４Ｕ／ｍ１、４．２９±２．１７Ｕ／ｍｌ和８６．７０±２４．１８Ｕ／ｍｌ，与对照组相比Ｐ＜０．０５或Ｐ＜０．０１。各型患者血清中ＩＬ－１、ＩＬ－６和ＴＮＦα活性均有不同程度的增高。文中对ＳＨ患者ＩＬ－１、ＩＬ－６和ＴＮＦα之间的相互关系进行了探讨。     

KChIP1 and frequenin modify shal-evoked potassium currents in pyloric neurons in the lobster stomatogastric ganglion

The transient potassium current (I(A)) plays an important role in shaping the firing properties of pyloric neurons in the stomatogastric ganglion (STG) of the spiny lobster, Panulirus interruptus. The shal gene encodes I(A) in pyloric neurons. However, when we over-expressed the lobster Shal protein by shal RNA injection into the pyloric dilator (PD) neuron, the increased I(A) had somewhat different properties from the endogenous I(A). The recently cloned K-channel interacting proteins (KChIPs) can modify vertebrate Kv4 channels in cloned cell lines. When we co-expressed hKChIP1 with lobster shal in Xenopus oocytes or lobster PD neurons, they produced A-currents resembling the endogenous I(A) in PD neurons; compared with currents evoked by shal alone, their voltage for half inactivation was depolarized, their kinetics of inactivation were slowed, and their recovery from inactivation was accelerated. We also co-expressed shal in PD neurons with lobster frequenin, which encodes a protein belonging to the same EF-hand family of Ca(2+) sensing proteins as hKChIP. Frequenin also restored most of properties of the shal-evoked currents to those of the endogenous A-currents, but the time course of recovery from inactivation was not corrected. These results suggest that lobster shal proteins normally interact with proteins in the KChIP/frequenin family to produce the transient potassium current in pyloric neurons.     

糖皮质激素受体对大鼠中性粒细胞粘附的影响

本文通过Percoll梯度离心法分离获得大鼠中性粒细胞(PMNS)后,采用PMNS与玻璃珠粘附的模型,通过给予Dex及糖皮质激素受体(GR)阻断剂Mifepristone(RU_(38486))研究大鼠PMNS粘附过程中GR的作用。结果显示,Dex可以明显抑制PMNS的粘附,其作用随着Dex浓度的增大而增强;单纯给予不同浓度的RU_(38486)未发现明显的PMNS粘附增强,说明RU_(38486)本身对离体的PMNS粘附没有明显的作用;若同时给予Dex和RU_(38486),则Dex抑制PMNS粘附的作用逐渐减小,直至完全逆转。该结果强烈提示:糖皮质激素(GC)具有抑制PMNS粘附的作用,其作用是通过GR介导的,当GR被阻断时,这一抑制作用减弱,甚至消失。     

The FREP gene family in the snail Biomphalaria glabrata: additional members,and evidence consistent with alternative splicing and FREP retrosequences. Fibrinogen-related proteins

Fibrinogen-related proteins (FREPs) found in hemolymph of the snail Biomphalara glabrata are hypothesized to be involved in non-self recognition. Among 150 cloned FREP cDNAs examined, we have identified three additional FREP members, FREPs 3.3, 12.1 and 13.1, bringing the total of FREP subfamilies to 13. The new FREPs each encode two immunoglobulin superfamily domains and a fibrinogen domain. Additionally, five truncated cDNAs with >99% nucleotide identity in coding regions to FREPs 3.2, 12.1 or 13.1 were identified. The truncated forms, the first reported for FREPs, lack a partial exon, one complete exon, or two complete exons plus the 3'UTR. Our preferred hypothesis is that all five truncated cDNAs observed arise from alternative splicing of full-length FREP genes. Genomic sequences lacking at least two introns and corresponding to the 3' ends of the cDNAs of FREP12.1 and its two truncated forms were also recovered. Although these could be the source of the truncated cDNAs, they are believed to be retrosequences.     

Reversible blockade of experience-dependent plasticity by calcineurin in mouse visual cortex

Numerous protein kinases have been implicated in visual cortex plasticity, but the role of serine/threonine protein phosphatases has not yet been established. Calcineurin, the only known Ca2+/calmodulin-activated protein phosphatase in the brain, has been identified as a molecular constraint on synaptic plasticity in the hippocampus and on memory. Using transgenic mice overexpressing calcineurin inducibly in forebrain neurons, we now provide evidence that calcineurin is also involved in ocular dominance plasticity. A transient increase in calcineurin activity is found to prevent the shift of responsiveness in the visual cortex following monocular deprivation, and this effect is reversible. These results imply that the balance between protein kinases and phosphatases is critical for visual cortex plasticity.     

Latent variable discovery in classification models

The naive Bayes model makes the often unrealistic assumption that the feature variables are mutually independent given the class variable. We interpret a violation of this assumption as an indication of the presence of latent variables, and we show how latent variables can be detected. Latent variable discovery is interesting, especially for medical applications, because it can lead to a better understanding of application domains. It can also improve classification accuracy and boost user confidence in classification models.