Abstract: Provided are Cas12i polypeptides, fusion proteins comprising such Cas12i polypeptides, CRISPR-Cas12i systems comprising such Cas12i polypeptides or fusion proteins, and methods of using the same.

Abstract: A drilling machine tool with a cooling liquid purifying and recycling mechanism. The drilling machine tool comprises a platform in which a blanking hole is formed, wherein air cylinders are fixedly mounted at the top of a transverse plate located above the platform, a lifting plate is mounted after the output shaft ends of the air cylinders penetrate through the transverse plate, an isolation cylinder is arranged below the lifting plate, an opening is formed in the bottom of the isolation cylinder, the bottom end of the vertical shaft slidably penetrates through the isolation cylinder and is fixedly provided with a drill bit, the isolation cylinder is connected with the lifting plate through pressing mechanisms, and a cooling liquid conveying mechanism communicating with the interior of the isolation cylinder is arranged on the platform; and a cooling liquid purifying and recycling mechanism is arranged at the bottom of the platform.