Lectin binding sites on the plasma membranes of Orthoptera Tettigonioidea spermatodesms

2020 ◽  
Vol 83 (11) ◽  
pp. 1321-1329
Author(s):  
Roberta Pecoraro ◽  
Maria Elena Scalisi ◽  
Maria Violetta Brundo
1975 ◽  
Vol 66 (2) ◽  
pp. 263-274 ◽  
Author(s):  
G L Nicolson ◽  
R Yanagimachi ◽  
H Yanagimachi

Receptors for Ricinus communis agglutinin I (RCAI), concanavalin A (Con A), and wheat germ agglutinin (WGA) were localized on the zonae pellucidae and plasma membranes of hamster, mouse, and rat eggs with ferritin-lectin conjugates. Intact eggs labeled with the ferritin conjugates showed dense concentrations of RCAI and WGA receptors in the outermost regions of their zonae pellucidae and sparse distributions of Con A receptors throughout the zonae. Ferritin-lectin labeling was specific, since inhibitory saccharides effectively blocked labeling. The asymmetric density of RCAI receptors across the zona was confirmed by ferritin-RCAI and fluorescein-RCAI labeling of mechanically isolated zonae pellucidae, indicating that the RCAI-binding sites are more densely distributed in the exterior zona regions. Plasma membranes of rodent eggs contained RCAI, WGA, and Con A receptors. These receptors were found to be more or less randomly distributed on surfaces of aldehyde-fixed eggs or on eggs labeled near 0 degrees C. However, eggs incubated at 25 degrees C showed aggregated WGA- and Con A-binding site distributions on their plasma membranes. This indicates that lectin-induced receptor redistribution occurs at this temperature. The possibility that plasma membrane receptor mobility is a requirement for sperm-egg fusion is discussed.


1977 ◽  
Vol 74 (3) ◽  
pp. 950-962 ◽  
Author(s):  
GL Nicolson ◽  
N Usui ◽  
R Yanagimachi ◽  
H Yanagimachi ◽  
Smith JR

Modifications in rabbit sperm plasma membranes during epididymal passage and after ejaculation were investigated by used of three lectins: concanavalin A (Con A); Ricinus communis I (RCA(I)); and wheat germ agglutinin (WGA). During sperm passage from caput to cauda epididymis, agglutination by WGA drastically decreased, and agglutination by RCA(I) slightly decreased, although agglutination by Con A remained approximately unchanged. After ejaculation, spermatozoa were agglutinated to a similar degree or slightly less by Con A, WGA, and RCA(I), compared to cauda epididymal spermatozoa. Ultrastructural examination of sperm lectin-binding sites with ferritin- lectin conjugates revealed differences in the densities of lectin receptors in various sperm regions, and changes in the same regions during epididymal passage and after ejaculation. Ferritin-RCA(I) showed abrupt changes in lectin site densities between acrosomal and postacrosomal regions of sperm heads. The relative amounts of ferritin-RCA(I) bound to heads of caput epididymal or ejaculated spermatozoa. Tail regions were labeled by ferritin RCA(I) almost equally on caput and cauda epididymal spermatozoa, but the middle-piece region of ejaculated spermatozoa was slightly more densely labeled than the principal-piece region, and these two regions on ejaculated spermatozoa were labeled less than on caput and cuada epididymal spermatozoa. Ferritin-WGA densely labeled the acrosomal region of caput epididymal spermatozoa, although labeling of cauda epidiymal spermatozoa was relatively sparse except in the apical area of the acrosomal region. Ejaculated spermatozoa bound only a few molecules of ferritin-WGA, even at the highest conjugate concentrations used. Caput epididymal, but not cauda epididymal or ejaculated spermatozoa, bound ferritin-WGA in the tail regions. Dramatic differences in labeling densities during epididymal passage and after ejaculation were not found with ferritin-Con A.


1989 ◽  
Vol 27 ◽  
pp. 82
Author(s):  
M. Narita ◽  
K. Yamashita ◽  
M. Yasuda

1988 ◽  
Vol 89 (2) ◽  
pp. 177-184 ◽  
Author(s):  
A. Velasco ◽  
J. Hidalgo ◽  
M. M�ller ◽  
G. Garcia-Herdugo

1984 ◽  
Vol 80 (6) ◽  
pp. 527-533 ◽  
Author(s):  
T. -C. Wu ◽  
M. -C. Lee ◽  
Y. -J. Wan ◽  
I. Damjanov

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