Sperm motility in the horseshoe crab, Limulus polyphemus L: I. Sperm behavior near eggs and motility initiation by egg extracts☆

摘要: Abstract Limulus spermatozoa are nonmotile when spawned and become motile only after encountering a sperm motility initiating factor (SMI) exuded by the egg. SMI extracts (produced washing intact eggs with distilled water, lyophilizing supernatant to dryness, redissolving dried extract in artificial seawater, ASW) initiate absence of eggs. Utilizing such extracts, initiation was found be unaffected changes temperature from 16 30°C, pH 6.3 8.6, salinity 85 125% ASW. Within these ranges, an “all-or-nothing” response, greater than 99% becoming motile. Also, each swam apparently same speed (at given temperature) until spontaneously stopping within 10 min addition extracts. Evidence that may bind irreversibly receptor, which is inactivated few seconds or minutes, leading observed cessation motility. Observations behavior near showed no evidence chemotaxis. Spermatozoa swim toward progressed uniform were less 5 sec attaching The presence all-or-nothing response SMI, independence experimental parameters, several other characteristics animal its make potentially excellent model for examination control mechanisms.