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中华鳖病毒及组织病理简报 总被引：2，自引：0，他引：2
于1994年广东斗门县一中华鳖（Trionyxsinensis）养殖场患红脖子病中华鳖和1996年广东东莞市一中华鳖养殖场患红底板和白底板病中华鳖中检测到3种病毒．红脖子病中华鳖检测到的病毒粒子吴杆状，具囊膜，大小103nm×（293～330）um，核衣壳大小69nm×（241～270）nm，于肠肌细胞质中复制、装配和成熟．在白底板中华鳖检测到的病毒粒子圆球形，无囊膜，直径70～75nm，于脾、肾和胃组织细胞质和细胞核中复制、装配和成熟．在红底板中华鳖肠细胞，检测到的病毒粒子直径85～90um，于肠细胞核中复制、装配和成熟． 相似文献
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养殖斑节对虾红体病病原及组织病理研究 总被引：3，自引：0，他引：3
养殖班节对虾红体病病原经组织病理、电镜观察和白斑杆状病毒PCR检测，初步证实是一种枝原体．枝原体高度多态性，主要以球状体和分枝丝状体形式存在．球状体直径60～108um，分枝丝状体膨大部直径达150um，丝状部为25um．枝原体主要寄生在斑节对虾肝胰腺上皮细胞、造血组织细胞、鳃上皮细胞、甲壳表皮细胞等，致肝胰腺萎缩糜烂．受感染细胞细胞质空泡变性，细胞核固缩解体，内质网、高尔基体和溶酶体消失．对红体带白斑斑节对虾、白斑（无红体特征）斑节对虾和红体（无白斑特征）斑节对虾组织病理、电镜和白斑杆状病毒PCR检测，证实斑节对虾红体病不是由白斑杆状病毒引起，红体斑节对虾具有白斑杆状病毒是病毒继发感染所致． 相似文献
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斑节对虾白斑综合症杆状病毒致病性及组织细胞特异性研究 总被引：7，自引：0，他引：7
班节对虾白斑综合症杆状病毒（Whitespotsyndromebaculoviruses，WSSBV）感染胃上皮细胞，胃环肌和纵肌细胞，海绵结缔组织细胞；鳃下皮细胞；触角腺分泌型和非分泌型上皮细胞，触角腺体胶囊上皮细胞；造血组织细胞；心脏心肌细胞，随体细胞，结统组织细胞；神经系统胶质细胞，神经膜细胞，神经细胞和球形细胞；甲壳表皮细胞、肌细胞．WSSBV对中肠和中肠育囊上皮细胞，肝胰腺上皮细胞，雄性生殖系统精原细胞，输精管上皮细胞等不敏感．人工肌注感染，WSBV有3d内可致斑节对虾90％，甚至100％死亡．感染斑节对虾鳃经电镜观察发现了3种杆状病毒，2种为无包涵体细胞核杆状病毒，其中一种大小为（119～136）um×（289～306）um，核农壳（98～105）nm×（265～272）um，另一种大小为（101～112）um×（391～420）um，核衣壳（78～85）nm×（276～298）um；1种为细胞质杆状病毒，大小为（102～112）nm×（326～340）um，核衣壳（71～78）nm×（306～308）um． 相似文献
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<正>为什么核移植时常用去核的MⅡ中期卵母细胞?1问题[网友AX]在人教版高中生物教科书《现代生物科技专题》P.48的体细胞核移植过程流程图中,为什么用的是处于MⅡ中期次级卵母细胞作为受体细胞?教科书中说,由于MⅡ期卵母细胞核位置靠近第一极体,用微型吸管可以一并吸出细胞核与第一极体。中期不是核消失了吗?吸的时候极体和卵母细胞还在一个细胞中吗?图上的一个小红点是什么?2讨论李雪峰[华南师范大学生命科学学院(510631)]细胞核移植常用受体细胞是处于MⅡ中期的卵母细胞,这是由于第一极体与中期染色体位置很近,可以通过去除极体附近的部分细胞质的方法把中期染色体去掉。正如您提到的,这个时候没有细胞核只有中期染色体,一般将去除中期染色体的过程称为去核, 相似文献
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生物的性状受基因控制，而控制性状的基因，有的分布在细胞质内的细胞器中，有的分布在细胞核内的染色体上，通常把细胞核内同源染色体上与相对性状有关的基因组成称核基因型。每种真核生物的体细胞核内有一定数量的染色体，根据染色体形态、结构、来源等的不同可分为若干染色体组。再根据个体的发育起点及其体细胞内所含染色体组数的不同分别把生物分为单倍体、二倍体和多倍体。为探讨染色体组数与细胞核基因型之间的对应关系，我们先研究一个选择题： 相似文献
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采用复合腔结构，把Cr^4＋：YAG既作为Nd：YAG激光器的调Q器件，又作为增益介质，实现被动调Q和增益调Q同时进行的双调Q运转，得到1．06um和1．44um双波长输出的短脉冲． 相似文献
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质疑是创新教育的重要环节，只有当学生能质疑、会质疑，才能培养他们的创新精神和能力。爱因斯坦说过：若不让错误发生，便不会有真理降世。因此，我们教师应在生物教学中适时点拨，让学生想问、敢问和善问，以达到培养学生创新思维能力的目的。 例如，在讲“细胞”一节中的细胞核时，我就这样讲述：细胞近似球形，内含遗传物质，决定生物的主要性状，所谓“种瓜得瓜，种豆得豆”就是因为细胞中的细胞核起着主要作用。讲到这里，我举起手中的洋葱表皮细胞模型，说：“假如这是一个洋葱的体细胞，并在电子显微镜下将它的细胞核移出，而… 相似文献
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《海外英语》2007,(5):10-11
Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help? 相似文献
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罗艳萍 《读与写:教育教学刊》2008,5(6)
The communication of people partially is the communication of cultures. Culture has a direct effect on international commercial activities in all aspects. Different conceptions about time, space, equality, law and the like, lead people to deal with things in different ways. So to know cultures of the counterpart is to facil-itate our enterprises so as to have a smooth and successful communication in commercial activity. 相似文献
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《海外英语》2007,(4):36
There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love. 相似文献
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Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject. 相似文献
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Richard Denner 《海外英语》2007,(4):14-15
Rosco and I wait for the fishermen to return.I sit at a wooden bench near the store at Mt.Baker Resort and watch the clouds change shape. Rosco has my belt around his neck and an eight foot tow chain hooked to a tree. Dogs must be on a leash. Ducks and rabbits are loose. 相似文献
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Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities. 相似文献
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RUZBEHANI Mohsen 《重庆大学学报(英文版)》2004,3(1):20-25
1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec… 相似文献