222 resultados para 321.7
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The authors thank the anonymous reviewer for helpful comments on the early version of the manuscript. This work was financially supported by the earmarked fund for Modern Agro-industry Technology Research System, the Science Fund for Young Scholars in Sichuan Province (Grant No: ZQ 026-017), and the National 863 Project of China (No. 2008AA101001).
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This research is focused on the contribution of area 7 to the short-term visual spatial memory. Three rhesus monkeys (Macaca mulatta) were trained in the direct delayed response task in which 5 delay intervals were used in each session. When each monkey reached the criterion of 90% correct responses in 5 successive sessions, two monkeys underwent a surgery while the other one received a sham operation as a control. In the first stage of the surgery, bilateral areas 7a, 7b and 7ip of the parietal cortex of two monkeys were precisely lesioned. After 7 days of recuperation, the monkeys were required to do the same task. The average percentage of correct responses in the lesioned animals decreased from 94.7% to 89.3% and 93.3% to 82.0% respectively (no significance, P > 0.05, n = 2). In addition, the monkeys' complex movements were mildly impaired. The lesioned monkeys were found to have difficulty picking up food from the wells. In the second stage, bilateral area 7m was lesioned. In the 5 postoperative sessions, the average percentage of correct responses in one monkey, with a relatively precise 7m lesion, decreased from 94.7% to 92.2% (no significance, P > 0.05), while the other monkey, with widely spread necrosis of lateral parietal cortex, showed an. obvious decline in performance, but still over the chance level. After 240 trials this monkey reattained the normal criterion. The results of this research suggest that the lesions of area 7 of the parietal cortex did not significantly affect the short-term visual spatial memory, which has been shown to be sensitive to lesions of the prefrontal cortex; they also support the notion of dissociation of spatial functions in the prefrontal and parietal cortices.
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2003年5月,在广西壮族自治区都安县高岭乡红水河水系采集到一批条鳅标本.经鉴定,为云南鳅属(Yunnanilius)一未经发表的新种.新种长须云南鳅(Yunnanilus longibarbatus sp. nov.) 属于黑斑云南鳅种组(Yunnanilus nigromaculatus group),并与黑斑云南鳅[Y.nigromaculatus (Regan)]、钝吻云南鳅(Y.obtusirostris Yang)、长背云南鳅(Y.longidorsalis Li, Tao et Lu)和巴江云南鳅(Y.bajingensis Li)等4种最为相似.长背云南鳅背鳍分枝鳍条11根,颌须短,仅达眼中部,背鳍起点距吻端较距尾鳍基为近,可与包括本种在内的其余4种相区别(背鳍分枝鳍条8-9根,颌须达到或超过眼后缘,背鳍起点距吻端较距尾鳍基为远).本种和钝吻云南鳅上颌中央无齿状突、下颌中央无缺刻,可与黑斑云南鳅和巴江云南鳅相区别.本种在鳍条数、上下颌、背鳍起点的位置、尾鳍形状、鳞片、头部侧线管孔、体侧纵纹等方面与钝吻云南鳅最为相似,但本种可藉多个特征与后者相区别:颌须伸过眼后缘至鳃盖后缘的中点至鳃盖后缘,是已知云南鳅中须最长的;背鳍不分枝鳍条下1/3处具一不显著黑色斑点 (vs. 无斑);体侧纵纹,其宽窄于眼径,较大个体背鳍之前的纵纹被虫状纹取代 (vs. 体侧纵纹始终存在,其宽约等于眼径);头背具斑点 (vs. 无斑);尾柄较细长,体长/尾柄长=5.3-6.1 (vs. 7.4-9.0,尾柄长/尾柄高=1.3-1.8 vs. 0.8-1.1).
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目的 检测7 种从蛇毒分离的小肽是否对临床分离的耐药性结核分枝杆菌菌株具有活性。方法 放射性方法检测蛇毒 小肽对结核分枝杆菌的最小抑制浓度,细菌存活计数确证放射性方法的结果。结果 7 种蛇毒小肽对耐药性结核分枝杆菌菌 株都有活性。其MIC 值分别为(μg·mL - 1) : Opiophagus hannah 5. 4 , Naja at ra 8. 6 , B ungarus f asciatus 6. 4 , Trimeresurus ste2 jnegri 12. 6 , Protobothrops mucrosquamatus 11. 8 , Protobothrops jerdonii 7 , A gksist rodon halys 4. 2 。结论 这些结果是首次报 道,为进一步设计和开发新来源的抗结核病新药提供了依据。
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以小鼠骨髓细胞染色体畸变试验、小鼠睾丸减数分裂染色体畸变及小鼠致畸试验为指标,研究金不换鲜三七液的安全性。结果:小鼠骨髓细胞染色体畸变试验;低、中、高3个剂量组小鼠骨髓细胞染色体畸变率分别为0.7%、0.2%和0.9%,与对照组相比无显著差异。阳性对照组染色体畸变率大大增高。小鼠睾丸减数分裂细胞染色体畸变:在该实验条件下,小鼠睾丸细胞染色体畸变率[包括性染色体单价体(X-YU),常染色体单价体(AU)]在各实验组和对照组之间无显著差异。小鼠致畸试验:小鼠口服金不换鲜三七液的累积剂量达15g/kg体重的1/10、1/5和1/2,小鼠致畸试验也无显著差异。
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以野外收集的水华蓝藻为原料,经过75%甲醇溶液浸提,快速色谱分离和半制备色谱纯化,从滇池水华蓝藻中分离纯化出1种微囊藻毒素变体.电喷雾质谱、紫外分光光度计和HPLC检测结果表明,所得毒素为[Dha7]MCRR,是MCRR的1种去甲基化变体,其纯度大于95%.该毒素的分子组成为环(Ala-Arg-MeAsp-Arg-Adda-Glu-Dha),分子量为1 023,其紫外扫描光谱(200~300 nm)在239 nm处有特征吸收.[Dha7]MCRR在滇池水华蓝藻中普遍存在,有时会成为MC的主要种类.
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利用14C标记1,2,7,8-四氯代二苯并二噁英(1,2,7,8Tetrachloro[U—14C]dibenzodioxin,14C1,2,7,8TCDD)初步研究了其在鲤体内的分布和代谢规律。14C1,2,7,8-TCDD溶解于丙酮/植物油中,腹腔暴露。暴露1、2、4、8、12d后取样,肝脏、胆汁、腹腔脂肪等消化制样后用液闪仪测量放射性活度。肝脏和胆汁内的放射性活度同步变化,都是第8d达到峰值后下降。腹腔脂肪内1—2d放射性明显高于随后取样的样品。肝和腹腔脂肪的分布量之比呈现“S”型变化趋势。暴露4d
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通过测定原代培养鲫鱼(Carassius auratus)肝细胞中雌激素受体所介导的卵黄蛋白原(Vtg)生成以及芳香烃受体所介导的CYP1A1基因转录水平的变化, 建立了一种类雌激素体外实验模型. 实验结果表明, Vtg和Vtg mRNA的表达与己烯雌酚(DES)之间均有很好的剂量-效应关系, Vtg和Vtg mRNA均可作为指示类雌激素毒性的生物标志物. TCDD, B[a]P可显著抑制鱼肝细胞中DES诱导的Vtg和Vtg mRNA的表达, 呈明显的抗雌激素效应, 并同时激活了CYP1A1 基因的表达;
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为探讨华鳊属鱼类种间和种内居群间的形态差异及其物种有效性 ,采用多变量形态度量 ,结合传统分类方法 ,获得该属鱼类不同地理居群共 2 2 4尾标本的 32个测量性状和 7个可数性状数据 ,并做主成分分析。在可数性状上 ,海南华鳊各居群间无差异 ,但明显不同于其他种类 ;四川华鳊与大眼华鳊差别明显 ,与伍氏华鳊之间也存在较大程度的差异 ;大眼华鳊的乌江和珠江居群之间存在显著差异 ,而伍氏华鳊各地理居群差异不明显。在可量性状上 ,四川华鳊和大眼华鳊的乌江居群都明显区别于其他种或居群 ,而大眼华鳊的珠江居群与伍
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采用腹腔注射人工雌激素 1 7α 乙炔基雌二醇 (1 7α ethinyloestradiol,EE2 )的方法 ,在鲤幼鱼和团头鲂幼鱼体内诱导生成卵黄蛋白原 ;并结合利用阴离子交换介质DEAE SephraroseCL 6B和液相层析技术分离纯化了诱导后的鲤幼鱼和团头鲂幼鱼血浆中的卵黄蛋白原 ;SDS PAGE电泳结果表明所分离的两种鲤科鱼类卵黄蛋白原其亚基的分子量分别为 1 70KD和1 5 0KD。
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为阐明鲟形目鱼类的系统发育关系,采用随机扩增多态性DNA(RAPD)技术对中华鲟、达氏鲟、史氏鲟、意大利鲟、短吻鲟、长江白鲟和匙吻鲟的基因组进行了研究。13个引物在每个种共产生127个信息座位。按UPGMA聚类法构建这7种鲟形目鱼类的分子系统树。分子系统树首先分成两大支,即长江白鲟和匙吻鲟为一支,其他5种鲟科鱼类为对应的另一支。在5种鲟科鱼类中,我国3种鲟科鱼类中华鲟、达氏鲟和史氏鲟聚在一起,与意大利鲟和短吻鲟分开。我国3种鲟科鱼类又可分成两小支,中华鲟和达氏鲟为一支与史氏鲟相对应。由分子系统树得到的各个
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国家自然科学基金29607004
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A liquid chromatography electrospray mass spectrometry (LC/ESI/MS) method working in multiple reactions monitoring mode for the determination of trace amounts of microcystin variants (MC-LR and [Dha(7)] MC-LR) in waters was developed. The limit of quantification was 0.05 mu g/L and the limit of detection was 0.015 mu g/L for MC-LR and [Dha(7)] MC-LR, respectively. Recoveries for MCs were in the range of 68%-81%. MC-LR and [Dha(7)] MC-LR were chemically stable with similar physiochemical behavior.