Procedure for the preparation of the crude earthworm
extract
The live earthworms were rinsed 5 times with tap water to let
the internal dirt discharge as much as possible, and then rinsed
twice with deionized water. The clean earthworms (200 mL,measured with a graduated beaker) were homogenized with equal
volume ice-cold deionized water (200 mL). The homogenate was
centrifuged (RCF= 4250 g, for 5 min). The collected supernatants
were concentrated by dialysis against solid sucrose at 4uC. The
concentrate was placed in a tray and blown with an electric fan at
17–25uC until it turned into a paste. The paste was further dried
under vacuum, and then ground into powder with a porcelain
mortar to give a gray powder (52.1 g). The extract powder was
stored at 4uC for use.