论文部分内容阅读
婴儿出生时,他们与胎盘食物供应的联系就被切断了。新的研究表明,他们能分解掉自己的部分细胞,可能是用来维持能量,直到母亲为他们哺乳。多种生物的细胞都能通过一个名为“自我吞噬”(自己吃掉自己)的过程来分解糖类、脂肪和蛋白质,以此来重复利用自身的组成部分。研究人员迄今只发现了一个哺乳动物的自我吞噬基因:Atg5。为此,他们繁育出Atg5基因缺失的小鼠。新生小鼠看上去相对比较健康,但如果不开始吃奶,它们的死亡速度就会比挨饿的正常新生小鼠快一倍,这说明它们缺少某些正常小鼠拥有的营养成分。研究小组还向小鼠体内插入了一种能发绿光的蛋白质,这种蛋白质在细胞进行自我吞噬的过程中可使其变亮。随后,对出生3小时至2.5天的正常小鼠的各种组织进行了检查,发现心脏、横膈膜和肺细胞的自我吞噬作用活跃。而Atg5基因缺失的小鼠并无这种活动,证明该基因在新生儿自我吞噬过程中扮演了关键的角色。
When the baby was born, their connection with the placenta food was cut off. New research shows that they can break down parts of their cells, probably to sustain energy until the mother breast-feeds them. Cells of many organisms can recycle their own components by breaking down sugars, fats and proteins through a process called “self-eating” (eating themselves). Researchers have so far only discovered a mammalian self-phagocytosis gene: Atg5. To this end, they breed Atg5-deficient mice. Newborn mice appear to be relatively healthy, but they die more quickly than starved normal newborn babies unless they start eating, suggesting that they lack the nutrients that some normal mice have. The team also inserted a green-emitting protein into mice that brightened cells as they swallow themselves. Subsequently, various tissues of normal mice born between 3 hours and 2.5 days were examined and found that the autophagy of the heart, diaphragm and lung cells was active. This activity was absent in Atg5-deficient mice, demonstrating that the gene plays a key role in neonatal self-phagocytosis.