Different ways to die: cell death modes of the unicellular chlorophyte Dunaliella viridis exposed to various environmental stresses are mediated by the caspase-like activity DEVDase.
Different ways to die: cell death modes of the unicellular chlorophyte Dunaliella viridis exposed to various environmental stresses are mediated by the caspase-like activity DEVDase.
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DOI：
10.1093/jxb/ern330
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发表时间：
2009
影响因子：
6.9
通讯作者：
Segovia M
中科院分区：
文献类型：
--
作者：
Jiménez C;Capasso JM;Edelstein CL;Rivard CJ;Lucia S;Breusegem S;Berl T;Segovia M
程序性细胞死亡是多细胞生物体内稳态所必需的，也被广泛认为发生在单细胞生物体中。然而，它在单细胞中发生的机制以及参与最终反应的酶仍然是激烈辩论的主题。这表明，单细胞微藻绿色杜氏藻暴露在几种环境胁迫下，根据所收到的刺激，诱导了不同的细胞死亡形态。衰老细胞表现出典型的、明确的凋亡样特征，如染色质凝集、DNA断裂、细胞器完整和细胞膜起泡。急性热休克引起全身肿胀和质膜改变，但染色质簇和DNA链断裂的存在暗示了坏死样事件。紫外线照射的细胞呈现典型的坏死改变，伴随着类似于一种中间细胞死亡表型的凋亡特征，称为脱发坏死样。受高渗休克的细胞可见染色质斑点，无DNA片段化，胞浆广泛肿胀和空泡化，类似于类细胞死亡表型。氮饥饿的细胞表现为固缩、起泡和细胞质消耗，表明类似于自噬/空泡样细胞死亡。用荧光底物Ac-DEVD-AMC和抗人caspase-3活性酶的抗体与条带交叉反应，其强度与活性平行。所有测试的环境压力都使DEVDase活性和蛋白质水平大幅增加。不可逆的caspase-3抑制剂Z-DEVD-FMK完全抑制该酶的活性，而丝氨酸和天冬氨酸蛋白酶抑制剂则不能。这些结果表明，绿色假丝酵母的细胞死亡不符合单一的模式，环境刺激可能会产生不同类型的细胞死亡，这一切都有助于理解caspase样蛋白的细胞死亡依赖和细胞死亡非依赖功能。因此，这些数据支持这样的理论，即替代的、非凋亡性的程序性细胞死亡(PCD)与凋亡平行或以独立的方式存在，并且已经存在于大约12-16亿年前进化的单细胞生物体中。
Programmed cell death is necessary for homeostasis in multicellular organisms and it is also widely recognized to occur in unicellular organisms. However, the mechanisms through which it occurs in unicells, and the enzymes involved within the final response is still the subject of heated debate. It is shown here that exposure of the unicellular microalga Dunaliella viridis to several environmental stresses, induced different cell death morphotypes, depending on the stimulus received. Senescent cells demonstrated classical and unambiguous apoptotic-like characteristics such as chromatin condensation, DNA fragmentation, intact organelles, and blebbing of the cell membrane. Acute heat shock caused general swelling and altered plasma membrane, but the presence of chromatin clusters and DNA strand breaks suggested a necrotic-like event. UV irradiated cells presented changes typical for necrosis, together with apoptotic characteristics resembling an intermediate cell-death phenotype termed aponecrosis-like. Cells subjected to hyperosmotic shock revealed chromatin spotting without DNA fragmentation, and extensive cytoplasmic swelling and vacuolization, comparable to a paraptotic-like cell death phenotype. Nitrogen-starved cells showed pyknosis, blebbing, and cytoplasmic consumption, indicating a similarity to autophagic/vacuolar-like cell death. The caspase-like activity DEVDase was measured by using the fluorescent substrate Ac-DEVD-AMC and antibodies against the human caspase-3 active enzyme cross-reacted with bands, the intensity of which paralleled the activity. All the environmental stresses tested produced a substantial increase in both DEVDase activity and protein levels. The irreversible caspase-3 inhibitor Z-DEVD-FMK completely inhibited the enzymatic activity whereas serine and aspartyl proteases inhibitors did not. These results show that cell death in D. viridis does not conform to a single pattern and that environmental stimuli may produce different types of cell death depending on the type and intensity of the stimulus, all of which help to understand the cell death-dependent and cell death-independent functions of caspase-like proteins. Hence, these data support the theory that alternative, non-apoptotic programmed cell death (PCDs), exist either in parallel or in an independent manner with apoptosis and were already present in single-celled organisms that evolved some 1.2-1.6 billion years ago.
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影响因子：
2.6
作者：
BOROWITZKA, LJ
通讯作者：
BOROWITZKA, LJ
DOI：
10.1083/jcb.119.3.493
发表时间：
1992-11
期刊：
The Journal of cell biology
影响因子：
--
作者：
Gavrieli Y;Sherman Y;Ben-Sasson SA
通讯作者：
Ben-Sasson SA
影响因子：
4.5
作者：
Berman-Frank, I;Bidle, KD;Falkowski, PG
通讯作者：
Falkowski, PG
DOI：
10.1016/s0022-0981(02)00036-9
发表时间：
2002-06-10
影响因子：
2
作者：
Dunn, SR;Bythell, JC;Thomason, JC
通讯作者：
Thomason, JC
DOI：
10.1098/rspb.2004.2810
发表时间：
2004-10-22
影响因子：
4.7
作者：
Franklin, DJ;Berges, JA
通讯作者：
Berges, JA