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流式细胞术(英文flow cytometry)是一种生物学技术,用于对悬浮于流体中的微小颗粒进行计数和分选。这种技术可以用来对流过光学或电子检测器的一个个细胞进行连续的多种参数分析。
目录
[隐藏]
* 1 原理
* 2 流式细胞仪(flow cytometer)。
* 3 应用
* 4 参见
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原理
一束单色光(通常是激光)照到流体力学聚焦的一股流体上。若干个检测器瞄向流束和激光相交的这个点,其中一个和激光在同一直在线(称作前散射(FSC)),其它几个和激光垂直(旁散射(SSC)和一个或几个荧光监测器)。当每个悬浮颗粒通过光束时会按某种方式把光散射,同时所带有的荧光化合物被激发并发射出频率低于激发光的荧光。这些散射光和荧光的组合数据被检测器记录,根据各检测器亮度的波动(每个细胞会显出一个散射或荧光的峰)就能够推算出每个颗粒的物理和化学性质。前散射与细胞体积相关,而旁散射取决于颗粒的内部复杂程度(比如核的形状、胞质内颗粒的种类或者末的粗糙程度)。
可以检测的参数有:
* 细胞的体积和形态复杂程度。
* 细胞中的色素
* DNA(细胞周期分析、细胞动力学、细胞增殖等)
* RNA
* 染色体分析和分选(文库构建、染色体涂染)
* 蛋白质
* 细胞表面抗原(CD标记)
* 胞内抗原(各种细胞因子(cytokine)、次级媒介等)
* 核抗原
* 酶活性
* pH,胞内离子化的钙、镁,膜电势。
* 膜流动性
* 细胞凋亡(apoptosis)(定量检测DNA降解、线粒体膜电位、通透性变化)
* 细胞存活能力
* 监测细胞电通透性
* 氧爆作用(oxidative burst)。
* 研究癌细胞中的多重耐药性(multi-drug resistance, MDR)。
* 谷胱甘肽
* 各种组合(DNA/表面抗原等等)
这个列表非常长,而且在不断地扩展。
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流式细胞仪(flow cytometer)。
流式细胞仪又称荧光激活细胞分选器、荧光活化细胞分类计(FACS,Fluorescence Activated Cell Sorter)。
现代的流式细胞仪每秒可以实时检测几千个颗粒,并且可以主动分离具有不同特性的颗粒。
流式细胞仪和显微镜比较像,但能够对大量的单个细胞利用一组参数进行高通量的自动量化。固体组织需要在检测前制备成单细胞的悬浮液。
一个流式细胞仪包括五个组成部分:
* 细胞流动系统:液流(鞘液(sheath fluid))携带细胞,使颗粒以串流形式通过光束。
* 光源:有通常的灯(汞或氙)、高功率水冷的激光源(氩、氪、染料激光)、低功率气冷激光(氩(488nm),红氦氖(633nm),绿氦氖,氦镉(紫外))、偶极激光(蓝、绿、红、紫)。
* 检测和模数转换(analogue-to-digital conversion, ADC)系统:产生前散射、旁散射光和荧光的信号。
* 放大系统,线性或对数放大。
* 计算机,用于分析信号。
早期的流式细胞仪主要是实验设备,但目前仪器和相关的试剂有了很广的市场。不同厂商的仪器特性也不同,主要的厂商和品牌如下:
* Beckman-Coulter (ex-Coulter): Epics XL/XL-MCL; Epics Altra (Hypersort) (IBM-PC compatible platforms)。
* Becton, Dickinson: (FACS's): FACSCAlibur, FACScan, FACSort, FASCSVantage (Mac OS platform) FACS Canto, LSRII, Aria, DiVa (PC PLatform)。
* Cytomation: MoFlo, Cyan (IBM-PC platform)。
* Partec/Dako: Galaxy; PAS; CCA; PA (IBM-PC compatible platforms)。
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应用
流式细胞术在很多领域中都有应用,包括分子生物学、病理学、免疫学和海洋生物学等。在分子生物学中,它主要用于荧光标记的抗体。特异性的抗体与靶细胞上的抗原结合,能够通过流式细胞仪研究这些细胞的特别信息。这在医学(尤其是器官移植、血液学、肿瘤免疫学和化疗、遗传学)中具有很广泛的应用。
现代的流式细胞仪具有多个激光和荧光检测器(目前商业用仪器的记录是4个激光和14个检测器),可以用于多个抗体标记,以便在表现型中更准确地区别某个靶群体。
流式细胞仪也是很有用的分选仪器。当细胞/颗粒通过时,可以被选择性地加上某种电荷,并在通过电磁场后偏转,从不同出口流出。这样就可以从一个混合物中高速(理论上可达到每秒大约9万个细胞)准确地分离开四类细胞。
由流式细胞仪得到的数据可以画成一维的柱状图或者二位或者三维的散点图。
The data coming from flow-cytometers can be plotted in 1-D to produce histograms or seen in 2D as dot plots or in 3D with newer software. The regions on these plots can be sequentially separated by a series of subset extractions which are termed gates. Specific gating protocols exist for diagnostic and clinical purposes especially in relation to haematology. The plots are often made on logarithmic scales. Because of overlaping fluorescent dyes, emission spectrum generated interfering signals by detectors signals have to be compensated electronically.。
海洋中主要的光合生物之一——占海洋浮游生物总细胞数将近1/3的原绿球藻(Prochlorococcus)就是通过流式细胞术发现的。因为其细胞小,叶绿素含量少,在通常的荧光观察中被迅速漂白(bleach),但由于在流式细胞术中细胞通过光束的时间极短,胞内叶绿素的荧光可被观察到。
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参见
* 荧光显微镜
* 荧光活化细胞分选
取自"http://wikipedia.cnblog.org/wiki/%E6%B5%81%E5%BC%8F%E7%B4%B0%E8%83%9E%E8%A1%93"。
页面分类: 待翻译文章 | 细胞生物学 | 实验室技术 | 解剖病理学 | 血液学 | 医学检验。
雨果: Victor-Marie Hugo (26 February 1802-May 1885) was a French poet, novelist, playwright, essayist, visual artist, statesman and human rights campaigner, perhaps the most influential exponent of the Romantic movement in France. Although in France his literary reputation rests on his poetic and dramatic output, in the Anglophone world his best-known works are the novels Les Misérables and Notre-Dame de Paris (often translated as The Hunchback of Notre-Dame in the English-speaking world). Among many volumes of poetry, Les Contemplations and La Légende des siècles stand particularly high in critical esteem, and Hugo is sometimes identified as the greatest French poet. Though extremely conservative in his youth, Hugo moved to the political left as the decades passed; he became a passionate supporter of republicanism, and his work touches upon most of the political and social issues and artistic trends of his time.。
Movie review: 'Harry Potter and the Deathly Hallows — Part 1'。
Much of the plot of "Harry Potter and the Deathly Hallows" involves the attempt to find and destroy a series of Horcruxes, and if you haven't a clue about what they are or why they're important, you might as well stay home.。
There is something different, however, about this Potter movie, and that is the words "Part 1" that end the title. Understandably distraught about "Hallows" being the last of the phenomenally popular J.K. Rowling novels, Warner Bros. has split the final effort into two films and is likely kicking itself for not having thought of that with the earlier books.。
You don't make $5.7 billion in theatrical revenue, however, by being cavalier about your source material and the watchword for the "Potter" series in general, and this film in particular, is making the audience feel like it's in safe hands.。
Though adventurous filmmakers like Alfonso Cuarón have made "Potter" films, David Yates, who directed the two previous epics as well as both installments of "Deathly Hallows," is not one of them.。
Capable and dependable, he can be counted on to make solid albeit unsurprising films that believe in connecting the dots rather than creating risky excitement. When studio president Alan Horn said his priority for the series was treating the books "respectfully," he wasn't kidding.。
Being respectful also means making sure you have quality people behind the camera (Steve Kloves has written almost all the screenplays and the new cinematographer is Oscar-nominated "Girl With a Pearl Earring" veteran Eduardo Serra) as well as top acting talent in front of it. Even if you don't always have enough for them to do.。
In fact, the Potter films are so loaded down with the best of British performers that Bill Nighy, who was added to the cast this time along with Rhys Ifans, wasn't really kidding when he commented, "For a while, I thought I would be the only English actor of a certain age who wasn't in a 'Harry Potter' film."哈利波特的 你删删改改就行了。
Aristotle
Greek philosopher. A pupil of Plato, the tutor of Alexander, the Great, and the author of works on logic, metaphysics, ethics, natural sciences, politics, and poetics, he profoundly influenced Western thought. In his philosophical system theory follows empirical observation and logic, based on the syllogism, is the essential method of rational inquiry.。
Einstein Albert 1879--1955 。
German-born American theoretical physicist whose special and general theories of relativity revolutionized modern thought on the nature of space and time and formed a theoretical base for the exploitation of atomic energy. He won a 1921 Nobel Prize for his explanation of the photoelectric effect.。
Shakespeare William 1564-1616 。
English playwright and poet whose body of works is considered the greatest in English literature. His plays, many of which were performed at the Globe Theatre in London, include historical works, such as Richard II, comedies, including Much Ado about Nothing and As You Like It, and tragedies, such as Hamlet, Othello, and King Lear. He also composed 154 sonnets.。
Roosevelt, Franklin Delano 1882-1945 。
The 32nd President of the United States (1933-1945). Governor of New York (1929-1932), he ran for President with the promise of a New Deal for the American people. His administration was marked by relief programs, measures to increase employment and assist industrial and agricultural recovery from the Depression, and World War II. He was the only U.S. President to be reelected three times (1936, 1940, and 1944). He died in office.。
Roosevelt and Adolph Hitler took different measures when facing the problems of big depression such examples can be used in the dealing with diverse attitudes on the problem of huge variation in society would lead to distinct results.。
Goethe, a great German writer , who lived in riches all his life, spent over 50 years on his two-part dramatic poem Faust which was considered as one of the greatest three epics. Another good example is Beethoven who was considered as the greatest composer of his day. 。
Mr. Gahli
Mr. Boutros Boutros Gahli, former UN Secretary General, appreciated French Promotion Programs sponsored by Ameson Educational & Cultural Exchange Foundation.。
Mr. Gahli appreciated the efforts Ameson Foundation made to promote French in China and encouraged that besides promoting French, Ameson Foundation should also promote Spanish, Russian, Arabic and other languages & cultures. He said studying foreign languages promote cultural understanding and peace.。
Van Gogh
Prodigies often could not receive contemporary appreciation and comprehension, Van Gogh is proper to be mentioned as a representative of the kind. He created the impressionism on painting, which was accepted many years after his death. Nevertheless he pursued his own ideals and faith till he was not able to pick up a pencil.。
Moby Dick is a novel by Herman Melville, a 19th century American novelist, published in 1851.。
The novel describes the story of Captain Ahab in order to chase and kill moby Dick, a white sperm whale, and eventually die with moby Dick.。
The story creates an atmosphere where people are exposed to all kinds of dangers and even death at any time. It is the author's representative work.。
The film Moby Dick, released on June 27, 1956, was adapted from this novel.。
《白鲸》是19世纪美国小说家赫尔曼·梅尔维尔于1851年发表的一篇海洋题材的长篇小说。
小说描写了亚哈船长为了追逐并杀死白鲸(实为白色抹香鲸)莫比·迪克,最终与白鲸同归于尽的故事。
故事营造了一种让人置身海上航行、随时遭遇各种危险甚至是死亡的氛围,是作者的代表作。
1956年06月27日发行的电影《白鲸记》,就是改编自这篇小说。
内容简介
捕鲸船“裴廊德”号船长亚哈,在一次捕鲸过程中,被凶残聪明的白鲸莫比·迪克咬掉了一条腿,因此他满怀复仇之念,一心想追捕这条白鲸,竟至失去理性,变成一个独断独行的偏执症狂。他的船几乎兜遍了全世界经历辗转,终于与莫比·迪克遭遇。
经过三天追踪,他用鱼叉击中白鲸,但船被白鲸撞破,亚哈被鱼叉上的绳子缠住,掉入海中。全船人落海,只有水手以实玛利(《圣经》中人名,意为被遗弃的人)一人得救。