Failed to mount partition of MAC OS Extended (HFS+)

please help me save me, as well as my External hard disk !! As a matter of fact, my 1TB External hard disk has three partition: MAC OS, NTFS and FAT32. All of the partitions work very well in the past. However, I just discovered that my MAC OS Extended (HFS+) format "MAC OS" partition could not be mounted, although my another two partitions were seemingly fine. I have tried to repair the partition with the Disk Utility but I failed. I have no ideas that why would this happen to my hard disk since I have not done anything to my hard disk and my MAC OS partition.

Please let me know if there is anyone know how to to solve the problem and recover my MAC OS partition. I just want to get back the data inside my MAC OS partition. Million Thanks!!

(P.S. I have only done two things before I discovered that my MAC OS partition was no longer working. 1) I have updated the Apple Security Update 2015-002 when my hard disk was plugged into my Macbook air. 2) I have tried to move some files from my "NTFS" partition to another external hard disk. But I failed because of unknown reason.)

This is what I got when I did the "diskutill info" on Terminal. This is what I got when I tried to repair my partition.