Cortical response

Reaction cortex - a process called. Slow block against polyspermia, the main purpose of which is to protect the resulting zygote against the penetration of other spermatozoa. Egg-sperm mating with the sperm leads to a combination of cortical grains placed in the cytoplasm of the ovum with its cell membrane which results in the release of their contents between the cell membrane and the yolk sac. Cereal grains contain a mixture of enzymes which include: tyrosine peroxidase and numerous proteases, which aim to prevent the penetration of other sperm into the cytoplasm of the fertilized egg. In addition, bubbles contain hyaline, which is a glycoprotein that has many functions in the further development of the body. In addition, the presence of mucopolysaccharides under the yolk casing increases the osmotic potential of this area, which results in the absorption of water and the formation of the so- fertilization sleeve. The cortical response is induced by the release of calcium ions from the endoplasmic reticulum of the egg at the site of penetration of the sperm. Sperm binding leads to activation of a signaling cascade associated with inositol trisphosphate (IP3). As the endoplasmic reticulum membranes contain IP3-dependent calcium channels, increasing the concentration of this receptor causes the activation of channels and the influx of calcium cations into the cytoplasm. This process is autocatalytic because calcium alone can bind to and activate these channels, so that the cortical response can rapidly spread throughout the cytoplasm. Although the cortical response was primarily studied in ectomycorrhagia, it is also present in mammals, but for these animals no conidia are produced: fertilization and halibut. Bibliography

wiki