RNA干扰现象研究获诺贝尔奖的启示

RNA干扰现象是目前生命科学领域的研究热点.由于RNA干扰具有十分重要的理论和应用价值,因此该现象在揭示后仅8年其研究者就获得了诺贝尔生理与医学奖.通过回顾RNA干扰现象的发现历程,可以为今后的科研探索过程提供许多有益的启示.     

抑制对老年人舌尖现象的影响

抑制不足理论认为老年人抑制能力不足, 易受干扰信息的影响, 阻碍对目标词的检索, 故比年轻人有更多舌尖现象。实验1操纵抑制通达子功能探讨其在老年人舌尖现象中的作用, 采用2(干扰条件：有、无)×2(年龄组：老年、年轻)的混合设计, 相比于无干扰条件, 干扰条件下舌尖现象年龄差异变得更大, 表明老年人舌尖现象和通达功能有关。实验2操纵抑制删除子功能, 采用2(是否激活干扰：是、否)×2(年龄组：老年、年轻)的混合设计, 不激活干扰条件下舌尖现象年龄差异不显著, 而激活干扰条件下舌尖现象年龄差异显著, 舌尖现象随龄增多与删除功能不足有关。通达和删除功能不足是老年人舌尖现象增多的重要原因。     

从反义RNA到RNA干扰:科学突破的机遇与创新

RNA干扰是近年发现的存在于真核细胞内的一种重要防御机制,现已发展成为一种全新的基因阻断技术,广泛用于抗病毒、抗肿瘤和后基因组时代基因功能研究.它是在反义RNA研究中意外获得的重大科学突破,其发现过程对科学研究有重要启示意义.     

2006年诺贝尔医学奖所遭质疑

2006年诺贝尔生理学或医学奖授予两位美国医学遗传学家法尔(Andrew Z.Fire)和梅洛(Craig C.Mello)以表彰他们发现了“RNA干扰———由双链RNA引起的(基因)沉默”,但是这一宣布迅即遭到部分植物学家的质疑,例如著名的英国综合科技期刊《自然》,就在当年10月26日出版物上刊登了这     

RNAi与诺贝尔医学奖的不解之缘

1 春花秋实 2006年诺贝尔生理学或医学奖授予了美国斯坦福医学院病理学和遗传学教授安德鲁·菲尔(Andrew Z.Fire)和马萨诸塞州医学院分子医学教授克雷格·梅洛(Craig C.Mello)两人,以表扬他们发现一种全新的基因调控方式-RNA干扰(RNAi),即"RNA干扰机制"或者"基因沉默"的巨大贡献[1].     

时空干扰效应：基于贝叶斯模型的解释

时空干扰效应是指时间知觉受空间信息干扰或空间知觉受时间信息干扰而出现错觉的现象。部分研究认为时空干扰是不对称的,空间对时间的干扰总是更大;还有研究认为时间和空间相互干扰的强度受实验因素影响,一般来说,空间对时间的干扰更大,但时间也能对空间产生同等程度甚至更大的干扰。在回顾隐喻理论和量值理论的主要观点之后,重点分析贝叶斯模型对时空干扰效应的解释,最后提出未来研究应关注的三个问题,即拓展贝叶斯模型对时空干扰效应的解释范围,探明基于贝叶斯推断的时空干扰神经机制和探索时空干扰的调控方法。     

2006年诺贝尔医学奖所遭质疑

2006年诺贝尔生理学或医学奖授予两位美国医学遗传学家法尔(Andrew Z.Fire)和梅洛(Craig C.Mello)以表彰他们发现了"RNA干扰--由双链RNA引起的(基因)沉默",但是这一宣布迅即遭到部分植物学家的质疑,例如著名的英国综合科技期刊《自然》,就在当年10月26日出版物上刊登了这样质疑的短文,而诺贝尔医学奖的宣布是在此之前24天的10月2日[1].     

学习、频率和结构方式对汉字知觉干扰效应的影响

知觉干扰存效应是指之前更模糊的刺激的呈现对之后同一模糊刺激的识别的抑制。实验-考察了学习和频率、实验二考察了学习和结构方式对汉字知觉干扰存效应的影响。结果发现：1．汉字与图片一样,不存在材料有限现象,在学习和不学习条件下,汉字识别中均存在知觉干扰效应;2．学习以及频率和结构方式对汉字知觉干扰效应的影响也不显著;3．频率、学习和结构方式对汉字识别的影响显著。这些结果似乎表明当激活超过一定的水平时,和汉字激活水平有关的因素对知觉干扰效应不再起作用。失匹配假说可更好的解释激活水平的作用以及材料有限现象。     

干扰条件与情绪启动关系的实验研究

在线索提示范式下,设置无干扰条件和干扰条件的阈上和阈下情绪启动,以此考察干扰条件与情绪启动的关系.研究发现:在无干扰条件与干扰条件下均存在显著的阈上情绪启动和阈下情绪启动,并且干扰条件下阈上情绪启动程度明显降低而阈下情绪启动程度不受影响.文章从情绪启动与注意关系的角度讨论了干扰条件与情绪启动的这种表现对于理解情绪启动加工属性及意识与无意识分离现象的意义.     

非目标工作记忆表征下颜色关联和抽象关联的注意捕获和抑制

采用工作记忆—视觉搜索双任务范式,探讨在非目标工作记忆表征下,颜色关联和抽象关联干扰子的注意捕获和抑制现象。实验一结果发现,颜色关联干扰子在快速反应阶段捕获注意,随后被成功抑制;抽象关联干扰子仍能捕获注意。实验二消除知觉凸显后,结果发现颜色关联条件的抑制消失,干扰子重新捕获注意。结果表明,有效抑制策略受不同关联干扰子加工先后顺序的影响,选择性抑制颜色关联干扰子,而颜色特征的凸显有助于抑制策略形成。     

耳聋基因治疗进展及评价

基因治疗为感音性聋的治疗提供新的生物治疗模式,通过预防毛细胞死亡、调控毛细胞分化和再生、基因操纵、干细胞移植、RNA干扰等手段而恢复内耳功能。耳聋基因治疗体现了多学科联合发展的要求及求异性思维的重要性,但仍面临诸多问题,从哲学的角度思考及正确对待耳聋基因治疗,必将有利于促进该技术最终服务于人类。     

Overexpression of and RNA interference with the CCAAT enhancer-binding protein on long-term facilitation of Aplysia sensory to motor synapses

In the marine mollusk Aplysia, the CCAAT/enhancer-binding protein, ApC/EBP, serves as an immediate early gene in the consolidation of long-term facilitation in the synaptic connection between the sensory and motor neurons of the gill-withdrawal reflex. To further examine the role of ApC/EBP as a molecular switch of a stable form of long-term memory, we cloned the full-length coding regions of two alternatively spliced forms, the short and long form of ApC/EBP. Overexpression of each isoform by DNA microinjection resulted in a l6-fold increase in the expression of the coinjected luciferase reporter gene driven by an ERE promoter. In addition, when we overexpressed ApC/EBP in Aplysia sensory neurons, we found that the application of a single pulse of 5-HT that normally induced only short-term facilitation now induced long-term facilitation. Conversely, when we attempted to block the synthesis of native ApC/EBP by microinjecting double-strand RNA or antisense RNA, we blocked long-term facilitation in a sequence-specific manner. These data support the idea that ApC/EBP is both necessary and sufficient to consolidate short-term memory into long-term memory. Furthermore, our results suggest that this double-strand RNA interference provides a powerful tool in the study of the genes functioning in learning and memory in Aplysia by specifically inhibiting both the constitutive and induced expression of the genes.     

Picture-word interference increases with target-set size

In the picture-word interference task the naming of a picture is hampered by the presence of a distractor word that is to be ignored. Two main components of this interference effect can be distinguished: an interference effect induced by an unrelated distractor word in comparison with a nonword control, and an additional interference effect that is due to a semantic similarity between target and distractor (calledsemantic interference). We examine whether the size of these two interference effects is affected by the number of different target pictures in an experiment. The results show that both interference effects increase with the size of the target set. This finding has two implications. First, at an empirical level, the use of a relatively small number of target pictures may account for remarkably small, or even nonsignificant, picture-word interference effects in a number of previous studies. Second, at a theoretical level, the present finding is in accordance with a name-retrieval account of picture-word interference.     

Color-word interference in relation to comparative compatibility: evidence for two sources of interference]

In previous studies on colour-word interference ('Stroop-phenomenon') stimulus-response-compatibility (word-speech, colour-speech) and task mode (word reading, colour determining) have usually been confounded or not been crossed completely. An experiment is reported where these two factors were varied orthogonally (besides type of stimulus: incongruent, congruent and control). Compatibility was varied by using response keys with varying labelling of the keys (colours or words). The results show--contrary to traditional expectations--the usual pattern of interference in spite of the response key conditions. The existence of response delays of different magnitude indicates separate sources of interference. Encoding interference is found under conditions of high-compatible colour determining by coloured response keys (colour-colour key), recoding interference under conditions of low-compatible reading (word-colour key), both presented here in an isolated form. Both modes of interference should therefore contribute to the interference under conditions of low-compatible colour determining which is the traditional Stroop condition. In an attempt to predict this complete interference encoding interference was shown to be the more stable predictor. The same was true of interference as measured here in a list version.     

Word reading practice reduces Stroop interference in children

Stroop interference is thought to index reading automaticity and is expected to increase with reading practice and to decrease with improved color naming. We investigated the effects of practice in word reading and color naming on interference in 92 adults and 109 children in Grades 4–5. For children, interference was reduced after reading practice with color words. In neither group was interference affected by practice in color naming of neutral stimuli. These findings are consistent with a direct negative relationship between reading ability and interference and challenge the automaticity account in favor of a blocking mechanism whereby interference is determined by the delay to inhibit the reading response rather than by the efficiency of color naming.     

Levels of selective attention revealed through analyses of response time distributions

The present research examines the nature of the interference effects in a number of selective attention tasks. All of these tasks result in interference in performance by presenting information that is irrelevant to task performance but competes for selection. The interference from this competing information slows the response time (RT) of participants relative to a condition where the competition is minimized. The authors use a convolution of an exponential and a Gaussian (ex-Gaussian) distribution to examine the influence of interference on the characteristics of RT distributions. Consistent with previous research, the authors show that interference in the Stroop task is reflected by both the Gaussian and exponential portions of the ex-Gaussian. In contrast, in 4 experiments they show that several other interference tasks evidence interference that is reflected only in the Gaussian portion of the ex-Gaussian distribution. The authors suggest that these differences reflect the operation of different selection mechanisms, and they examine how sequential sampling models accommodate these effects.     

提取干扰对不同类型内隐记忆的影响

以往研究关于提取阶段的干扰是否会影响内隐记忆存在着异义, 其中一个重要因素可能源于所采用的内隐记忆测验类型的差异。本研究采用学习-测验范式, 通过4个实验, 分别考察了提取干扰对识别式知觉内隐测验、识别式概念内隐测验、产生式知觉内隐测验和产生式概念内隐测验的影响, 以期对提取干扰和内隐记忆之间的关系有着更全面的了解。结果表明: (1)词汇判断任务(识别式知觉)和语义分类任务(识别式概念)的启动效应在提取干扰下消失了, (2)而产生式词汇判断任务(产生式知觉)和产生式语义分类任务(产生式概念)在提取干扰下仍发现了明显的启动效应, 但与无干扰条件相比, 启动效应量也有着明显的减少。由此可见, 不同类型的内隐记忆都会受到提取干扰的影响, 相比于产生式启动, 识别式启动更容易受到提取干扰的破坏。     

Multiple levels of control in the Stroop task

Multiple levels of control may be used in service of reducing Stroop interference. One is list-wide, whereby interference is reduced strategically in lists that include disproportionately more incongruent trials. A second, item-specific control is observed when proportion congruence is manipulated at the level of items. Item-specific control reduces interference for mostly incongruent relative to mostly congruent items. First, we show that item-specific control may drive both list-wide and item-specific proportion congruence effects (Experiment 1). We then show that item-specific control affects Stroop interference similarly when a single feature (a word) as opposed to a feature combination (a word 1 font type) signals proportion congruence (Experiment 2). Although this suggests that font type offers little advantage for controlling Stroop interference beyond the word, a novel, font-specific proportion congruence effect is observed in Experiment 3, indicating that font type can be used to control interference. These findings support the idea that multiple levels of control are used in reducing Stroop interference.