Sperm transfer

Dean, S. R. and Meola, R. W. (2002). Effect of diet composition on weight gain, sperm transfer, and insemination in the cat flea (Siphonaptera Pulicidae). J Med Entomol, 39(2), 370-375. 

The relevant literature has been reviewed by Williams McVicar (959), Nollen (599), Oshmarin Prokhova (609) and Smyth (802). Although the mechanical processes involved in insemination are well known, almost nothing is known regarding the physiology of this process or the fertilisation which results. There is no information as to whether in cestodes sexual maturation is co-ordinated by an internal, sexual endocrine system or whether external chemotactic attraction between worms takes place. Three types of sperm transfer are known (a) self-insemination (b) crossinsemination and (c) hypodermic insemination. 

Williams, H. H. McVicar, A. (1968). Sperm transfer in Tetraphyllidea (Platyhelminthes Cestoda). Nytt Magasin for Zoologi, 16 61-71. 

Bauer RT (1991) Sperm transfer and storage structures in penaeoid shrimps a functional and phylogenetic perspective. In Bauer RT, Martin JW (eds) Crustacean sexual biology. Columbia University Press, New York, pp 183-207... 

At 1500 h, wash the eggs three times in pregassed M16 medium to remove excess sperm. Transfer the eggs to the M16 microdrops and culture overnight. 

Cattle Organic versus conventional fodder Reduced sperm motility in bulls transferred from organic to conventional fodder sperm motility restored when returned to organic fodder (Aehnelt and Hahn, 1978)... 

Chromosomal disorders can also be caused by changes in chromosome structure. These changes are caused by the breakage and reunion of chromosome segments when an egg or sperm cell is formed or in early fetal development. Pieces of DNA can be rearranged within one chromosome, or transferred between two or more chromosomes. The effects of structural changes depend on their size and location. Many different structural changes are possible some cause medical problems, while others may have no effect on a person s health. 

Electron transfer to the protein metal center is monitored spectroscopically. In the case of a heme (FeP), a fast increase in absorbance due to direct reduction of Fe(III)P by Ru(bpy)f is followed by a slower increase in absorbance due to reduction of Fe(III)P by the Ru(II) on the protein surface. Control flash experiments with unmodified proteins show only the fast initial increase in absorbance due to Fe(III)P reduction by Ru(bpy)3. Such control experiments demonstrate for horse heart cytochrome c [21], azurin [28], and sperm whale myoglobin [14] that slow reduction of the heme by the EDTA radical produced in the scavenging step does not occur in competition with intramolecular ET. However, for Candida krusei cytochrome c, the control experiment shows evidence for slow EDTA radical reduction of the heme after initial fast reduetion by Ru(bpy)i+ [19]. 

In spermatozoa, the phosphocreatine shuttle is present to transfer energy from the mitochondria to the flagellum, which is essential for swimming of the sperm (Figure 9.21) (see also Chapter 19). 

Figure 9.21 The creatine/phosphocreatine shuttle in spermatozoa. This shuttle may not be present in all sperm it will depend upon the distance between the mitochondria and the flagellum. Mitochondria are present in the midpiece just below the head. ATP is required for movement of the flagellum which enables the sperm to swim. Dynein ATPase is the specific motor ATPase, similar to myosin ATPase, that transfers energy from ATP to the flagellum. A deficiency of creatine may explain low sperm motility in some infertile men. CK - creatine kinase. Deficiences of enzymes in the pathway for synthesis of creatine are known to occur (see Appendix 8.3).

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