单词

apotosis 细胞凋亡
necrosis 细胞坏死
endonucleases 内切酶
electrophoretic 电泳的
embryonic 胚胎的

apotosis&necrosis

apotosis

定义-autonomous and orderly cell death controlled by genes to maintain internal environmental stability为维持内环境稳定，由基因控制的细胞自主的有序的死亡
occurs by a programmed sequence of molecular events
is an active process
cell shrinks,Chromatain condenses and breaks up into fragments,finally form apotosis bodies(membrane-enclosed fragments)
no damaging inflammatory responses

necrosis

细胞被动死亡，没有细胞膜包裹，细胞内容物释放到细胞外
产生炎症反应

detection of apotosis

1.Morphological observation 形态学观察

Trypan blue staining-stain dead cells
Giemsa staining-stain chromatin
DAPI-bind to DNA

2.Electrophoretic DNA analysis 电泳分析

细胞凋亡会产生许多endonucleases,会把DNA切断成fragments,所以电泳时DNA会分成很多条带

3.Terminal deoxynucleotidyl transferase(TdT) dUTP nick end labeling(TUNEL) 末端脱氧核苷酸转移酶(TdT)dUTP缺口末端标记

4.Annexin V(AV) and propidium iodide(PI) staining by flow cytometry 流式细胞术

活细胞 AV-/PI-
凋亡前期细胞 AV+/PI-
凋亡末期细胞 AV+/PI+

the purpose of apoptotic cell death

cell death help sculpt hands and feet during embryonic development

在胚胎时期帮助形成手脚

cell die when the structure they form is no longer needed

比如青蛙长大失去尾巴

cell death help to adjust the number of cells to satisfy certain needs

比如神经细胞凋亡使一个轴突对着一个目标细胞

cell death functions as a quality control process in development,eliminating cells that are abnormal,misplaced,nonfunctional,or potentially dagerous to the animals

either excessive or insufficient apoptosis can contribute to disease

细胞凋亡太少或太多都会导致疾病

caspases

作用

apoptosis depends on an intracellular Proteolytic cascade that is mediated by caspases
凋亡依赖于胱天蛋白酶介导的细胞内蛋白水解级联反应

结构

caspase是cysteine aspartic acid specific proteases半胱氨酸天冬氨酸特异性蛋白酶
have a cysteine at the active site活性部位有半胱氨酸
cleave their taeget proteins at specific aspartic acid在特定的天冬氨酸上切割它们的taeget蛋白