Now, a new study in mice shows how a hormone secreted by active muscle cells triggers bone remodeling.

现在，一项在老鼠身上进行的新研究揭示了活跃肌肉细胞分泌的激素是如何触发骨骼重塑的。

The problem starts when they germinate into active cells, at which point they begin to produce seven different toxins, four of which are deadly to humans.

真正的麻烦是从孢子复苏成活跃细菌开始。一旦活化，它开始产生七种毒素，其中四种对人类极度危险，足以致命。