Sodium and Calcium on the Sperm Motility and Acrosome Reaction 5
THEEFFECT OF SODIUM AND CALCIUM ON THE SPERM MOTILITY AND ACROSOMEREACTION OF THE POLYCHAETE, GALEOLARIA CAESPITOSA,
Eventsof sperm motility development
Spermmotility refers to process and the capability of male gametes to bepropelled through the reproductive systems of females for internalfertilization or through fluids such as water to reach the egg inexternal fertilization (Severeyn, Villasmil, Severeyn, Morales, F.,&Montiel, 2013). In this case, external fertilization is the mainconcern since sea worms reproduce through egg fertilization in seawater. Ions such as calcium and sodium ions are crucial in spermmotility development. Sperm motility in Polychaete,Galeolariacaespitosa requires ATP energy just like in other organisms(Kupriyanova&Havenhand, 2005). ATP is transmitted from itsmitochondrion to the flagellum in a process that involves thediffusion of substances called phosphocreatine. Phosphocreatine isdiffused between the isozymes of creatine kinase that are located onboth ends of organism. Sodium ions reduce the PH of medium hostingspermatozoa. The result is an increased level of ATP energy thatpropels it through strong flagella(Havenhand, Dupont& Quinn,2010). However, when sodium ions are decreased, they cause anelevation of PH that alters ATP production.
Insidethe frontal tip of the sperm cell, there is the acrosome. Theacrosome is a storage structure enclosed in a membrane with specialenzymes that digest proteins and sugars. Acrosomal reaction takesplace when the sperm comes in contact with outer cover of the eggwhere the former erupts and lets the contents out. The process beginsthe fusion of outer membrane of acrosome with sperm’s cellmembrane. The enzymes in the contents of the acrosome that come incontact with the egg after the Acrosomal reaction digest the outercoating of the egg creating a leeway for sperm with the energeticpropulsion by the flagella. The process of Acrosomal reaction followsa protoelytic enzyme specific mechanism that ensures that enzymesfertilize only the right eggs. Thus, enzymatic action that followsthe Acrosomal reaction happen a manner that is overly specific todifferent species of sea worms. For example, the resactisa peptide enzyme is a chemo-attractant inside the egg jelly thatattracts sperm from only the right species of a sea worm.
Therole of calcium and sodium in sea-worm acrosome reaction
Theacrosome reaction uses adenosine triphosphate (ATP)energy(Kupriyanova, 2006). When a medium has a high concentration ofcalcium ions, it causes increased Acrosomal reaction. Calcium ionstrigger the process even when there is no egg jelly. Furthermore,sperm deletion occurs more rapidly after Acrosomal reaction. BeforeAcrosomal reaction takes place, the eggs usually must be active forfertilization. Increased concentration of Calcium ions inside the eggcauses this activation(Byrne et al, 2010). In sea worms the freecalcium ions originate from the medium around such as water and enterthe egg. Calcium ions, therefore, prepare the specific site throughwhich the sperm and the egg will fuse to facilitate Acrosomalreaction. After the egg and the sperm fuse, the vestment also causesan influx of Calcium ion concentrations because the Acrosomalreaction takes some time and the process requires a sustainedconcentration of the ions. Sodium ions maintain the required normalPH that induces the active uptake of calcium ions by the. The PH forAcrosomal reactions is between 8 and 8.5, which is only possiblethrough a high concentration of sodium ions(Mita& Nakamura,1998).A PH above 8.5 reduces the uptake of the calcium ions. Thus,introducing a solution of sodium ions plays a pivotal role intriggering Acrosomal reaction in situations where the egg jelly doesnot induce its occurrence.
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