A morphological and functional study of fusibility in round-headed spermatozoa in the human.
OBJECTIVE
To study the molecular origin and functionality of the plasma membrane of round-head spermatozoa in the human.


METHODS
Clinical and laboratory study.


METHODS
Patients in a clinical and academic environment.


METHODS
Men with round-head spermatozoa.


RESULTS
Pisum sativum lectin homogeneously stains the surface of round sperm; however, the staining pattern and transmission electron microscopy show that the plasma membrane does not alter after exposure to the calcium ionophore A23187. In a clinical program, round-head spermatozoa injected subzonally into metaphase II oocytes with or without pretreatment with the fusogen polyethylene glycol did not bind or fuse to the oocyte surface.


CONCLUSIONS
The data suggests that plasma membrane fusion in human gametes is regulated by specific surface molecules and that exposure of these molecules on the sperm surface cannot be triggered by elevating intracellular calcium alone.
Dale
B
B
Stazione Zoologica, Naples, Italy.
Iaccarino
M
M
Fortunato
A
A
Gragnaniello
G
G
Kyozuka
K
K
Tosti
E
E
D000328:Adult; D000001:Calcimycin / Q000494:pharmacology; D002462:Cell Membrane / Q000187:drug effects / Q000502:physiology; D006801:Humans; D007248:Infertility, Male / Q000473:pathology* / Q000503:physiopathology; D037102:Lectins; D008297:Male; D008561:Membrane Fusion; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D037121:Plant Lectins; D011092:Polyethylene Glycols / Q000494:pharmacology; D013081:Sperm Motility; D013094:Spermatozoa / Q000002:abnormalities* / Q000648:ultrastructure
D037102:Lectins; D037121:Plant Lectins; C036292:pea lectin; D000001:Calcimycin; D011092:Polyethylene Glycols