Comparison and evaluation of capacitation and acrosomal reaction in freeze-thawed human ejaculated spermatozoa treated with L-carnitine and pentoxifylline

Andrologia ◽  
2017 ◽  
Vol 50 (2) ◽  
pp. e12845 ◽  
Author(s):  
E. Aliabadi ◽  
S. Jahanshahi ◽  
T. Talaei-Khozani ◽  
M. Banaei
Keyword(s):  
Acrosomal Reaction

The extracellular matrix of echinoderm and amphibian eggs: Visualization in quick-frozen, deep-etched, and rotary-shadowed specimens

1990 ◽  
Vol 48 (3) ◽  
pp. 60-61
Author(s):  
Barry Bonnell ◽  
Carolyn Larabell ◽  
Douglas Chandler
Keyword(s):  
Extracellular Matrix ◽  
Plasma Membrane ◽  
Sea Urchin ◽  
Crystalline Structure ◽  
Cortical Granule ◽  
Two Dimensional ◽  
Small Peptides ◽  
Deep Etching ◽  
Quick Freezing ◽  
Acrosomal Reaction

Eggs of many species including those of echinoderms, amphibians and mammals exhibit an extensive extracellular matrix (ECM) that is important both in the reception of sperm and in providing a block to polyspermy after fertilization.In sea urchin eggs there are two distinctive coats, the vitelline layer which contains glycoprotein sperm receptors and the jelly layer that contains fucose sulfate glycoconjugates which trigger the acrosomal reaction and small peptides which act as chemoattractants for sperm. The vitelline layer (VL), as visualized by quick-freezing, deep-etching, and rotary-shadowing (QFDE-RS), is a fishnet-like structure, anchored to the plasma membrane by short posts. Orbiting above the VL are horizontal filaments which are thought to anchor the thicker jelly layer to the egg. Upon fertilization, the VL elevates and is transformed by cortical granule secretions into the fertilization envelope (FE). The rounded casts of microvilli in the VL are transformed into angular peaks and the envelope becomes coated inside and out with sheets of paracrystalline protein having a quasi-two dimensional crystalline structure.

scholarly journals Human spermatozoa possess a calcium-dependent chloride channel that may participate in the acrosomal reaction

2012 ◽  
Vol 590 (11) ◽  
pp. 2659-2675 ◽  
Author(s):  
Gerardo Orta ◽  
Gonzalo Ferreira ◽  
Omar José ◽  
Claudia L. Treviño ◽  
Carmen Beltrán ◽  
...  
Keyword(s):  
Chloride Channel ◽  
Human Spermatozoa ◽  
Calcium Dependent ◽  
Acrosomal Reaction

Test for the acrosomal reaction of goat spermatozoa treated with heparin

1997 ◽  
Vol 26 (1-2) ◽  
pp. 163-166 ◽  
Author(s):  
R.K. Malik ◽  
I.S. Lohan ◽  
O.P. Dhanda ◽  
R.K. Tuli
Keyword(s):  
Acrosomal Reaction

scholarly journals Membrane events in the acrosomal reaction of Limulus sperm. Membrane fusion, filament-membrane particle attachment, and the source and formation of new membrane surface.

1979 ◽  
Vol 81 (1) ◽  
pp. 229-253 ◽  
Author(s):  
L G Tilney ◽  
J G Clain ◽  
M S Tilney
Keyword(s):  
Plasma Membrane ◽  
Membrane Surface ◽  
Membrane Particles ◽  
Free Zone ◽  
Cytoplasmic Filaments ◽  
Thin Sectioning ◽  
Acrosomal Reaction ◽  
Sperm Membrane ◽  
Membrane Particle ◽  
Surface Fusion

The membranes of Limulus (horseshoe crab) sperm were examined before and during the acrosomal reaction by using the technique of freeze-fracturing and thin sectioning. We focused on three areas. First, we examined stages in the fusion of the acrosomal vacuole with the cell surface. Fusion takes place in a particle-free zone which is surrounded by a circlet of particles on the P face of the plasma membrane and an underlying circlet of particles on the P face of the acrosomal vauole membrane. These circlets of particles are present before induction. Up to nine focal points of fusion occur within the particle-free zone. Second, we describe a system of fine filaments, each 30 A in diameter, which lies between the acrosomal vacuole and the plasma membrane. These filaments change their orientation as the vacuole opens, a process that takes place in less than 50 ms. Membrane particles seen on the P face of the acrosomal vacuole membrane change their orientation at the same time and in the same way as do the filaments, thus indicating that the membrane particles and filaments are probably connected. Third, we examined the source and the point of fusion of new membrane needed to cover the acrosomal process. This new membrane is almost certainly derived from the outer nuclear envelope and appears to insert into the plasma membrane in a particle-free area adjacent to an area rich in particles. The latter is the region where the particles are probably connected to the cytoplasmic filaments. The relevance of these observations in relation to the process of fertilization of this fantastic sperm is discussed.

Induction of acrosomal reaction and calcium uptake in ram spermatozoa by ionophores

1988 ◽  
Vol 939 (2) ◽  
pp. 214-222 ◽  
Author(s):  
Pazit Ben-Av ◽  
Sara Rubinstein ◽  
Haim Breitbart
Keyword(s):  
Calcium Uptake ◽  
Acrosomal Reaction

scholarly journals Polymerization of actin. IV. Role of Ca++ and H+ in the assembly of actin and in membrane fusion in the acrosomal reaction of echinoderm sperm

1978 ◽  
Vol 77 (2) ◽  
pp. 536-550 ◽  
Author(s):  
LG Tilney ◽  
DP Kiehart ◽  
C Sardet ◽  
M Tilney
Keyword(s):  
Cell Surface ◽  
Membrane Fusion ◽  
Intracellular Ph ◽  
Actin Filaments ◽  
External Medium ◽  
Ionophore A23187 ◽  
Natural Stimulus ◽  
High Affinity ◽  
Acrosomal Reaction

When Pisaster, Asterias, or Thyone sperm are treated with the ionophore A23187 or X537A, an acrosomal reaction similar but not identical to a normal acrosomal reaction is induced in all the sperm. Based upon the response of the sperm, the acrosomal reaction consists of a series of temporally related steps. These include the fusion of the acrosomal vacuole with the cell surface, the polymerization of the actin, the alignment of the actin filaments, an increase in volume, an increase in the limiting membrane, and changes in the shape of the nucleus. In this report, we have concentrated on the first two steps in this sequence. Although fusion of the acrosomal vacuole with the cell surface requires Ca++, we found that the polymerization of actin instead appears to be dependent upon an increase in intracellular pH. This conclusion was reached by applying to sperm A23187, X537A, or nigericin, ionophores which all carry H+ at high affinity, yet vary in their affinity for other cations. When sperm are suspended in isotonic NaCl, isotonic KCl, calcium-free seawater, or seawater, all at pH 8.0, and the ionophore is added, the actin polymerizes explosively and an efflux of H+ from the cell occurs. However, if the pH, of the external medium is maintained at 6.5, the presumed intracellular pH, no effect is observed. And, finally, if egg jelly is added to sperm (the natural stimulus for the acrosomal reaction) at pH 8.0, H+ is also released. On the basis of these observations and those presented in earlier papers in this series, we conclude that a rise in intracellular pH induces the actin to disassociate from its binding proteins. Now it can polymerize.

scholarly journals Zona pellucida in the process of fertilization and mammal embryonal development

2022 ◽  
Vol 78 (03) ◽  
pp. 6626-2022
Author(s):  
JADWIGA JAWORSKA-ADAMU ◽  
ALEKSANDRA KRAWCZYK ◽  
KAROL RYCERZ
Keyword(s):  
Zona Pellucida ◽  
Male Gamete ◽  
External Factors ◽  
Structure And Properties ◽  
Cortical Reaction ◽  
Embryonal Development ◽  
Acrosomal Reaction ◽  
Primary Attachment ◽  
Reproductive Rates ◽  
Internal And External Factors

In mammals, oocytes, fertilized eggs and pre-implantation embryos are surrounded by an acellular zona pellucida (zona pellucida – ZP). This structure has a fibro-spongy character but it undergoes constant modifications throughout its existence depending on many internal and external factors. ZP consists of glycoproteins marked as ZP1, ZP2, ZP3 and ZP4, the presence of which is species different. ZP1 and probably ZP4 molecules stabilize the fibrillary skeleton of the zona pellucida formed of ZP2 and ZP3 protein polymers which are ligands for specific spermatozoid receptors. The oligosaccharide chains of ZP3 are responsible for the primary attachment of the male gamete which induces the acrosomal reaction. ZP2 enhances this connection by secondary binding to an acrosome-free spermatozoid. Additionally, oviductal specific glycoprotein 1 which plays a role in interspecific oocyte-sperm interactions, appears around the postovulatory oocyte surrounded by ZP. In addition, this protein modifies the resistance of ZP to the action of proteases released as a result of the cortical reaction during polyspermia block. After fertilization, ZP not only protects the egg and then the embryo until implantation, but also has an embryotrophic effect. Understanding the molecular basics of the structure and properties of ZP can significantly improve animal fertility as well as reproductive rates.

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