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Distribution of intramembranous particles and filipin‐sterol complexes in the spermatid and spermatozoon of Culex quinquefasciatus (Culicidae)
Author(s) -
Báo Sônia N.,
Souza Wanderley
Publication year - 1992
Publication title -
biology of the cell
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.543
H-Index - 85
eISSN - 1768-322X
pISSN - 0248-4900
DOI - 10.1016/0248-4900(92)90122-h
Subject(s) - spermatozoon , filipin , biology , spermatid , membrane , microbiology and biotechnology , biophysics , intramembranous ossification , caveolae , anatomy , ultrastructure , biochemistry , botany , sperm
Summary— A freeze‐fracture study was carried out on spermatid and spermatozoon of the mosquito Culex quinquefasciatus . In the spermatid plasma membrane few and randomly distributed intramembranous particles were observed. In the spermatozoon the density of intramembranous particles was higher on the P‐ than on the E‐fracture face of the plasma membrane. Two populations of particles were observed. Large particles (about 15 nm in diameter) are regularly arranged in double rows as a zipper‐line, longitudinally oriented in relation to the main cell axis. These strands of particles were observed in the posterior head region, mainly associated with the E‐fracture face. Filipin was used to analyse the presence and distribution of cholesterol in thin sections and freeze‐fracture replicas. Filipin‐sterol complexes were not homogeneously distributed throughout the spermatozoon plasma membrane. They were more abundant on the P‐fracture face of the membrane lining the nuclear region. The results obtained show that Culex spermatozoon differs from those of other species in that its plasma membrane exhibits only a membrane domain, the zipper‐line, localized in the postacrosomal region.