Egg Development After Insemination in Japanese Quail ().

fertilization has been widely used to produce offspring in several mammalian species. We previously successfully produced Japanese quail chicks using intracytoplasmic sperm injection (ICSI), whereas insemination was not successful. This may be due to the difficulties associated with mimicking the sperm-egg fusion process and subsequent events in physiological polyspermic fertilization .

Possible involvement of annexin A6 in preferential sperm penetration in the germinal disk region.

Abstract: During fertilization, avian sperm preferentially penetrate into the perivitelline membrane that covers the germinal disk region where the female nucleus is present. This phenomenon has been observed not only in domestic birds but also in wild birds; however, the mechanisms controlling sperm preference are still unclear. In this study, we investigated the possible involvement of annexin family protein in sperm-egg interaction in Japanese quail.

Accelerated invagination of vacuoles as a stress response in chronically heat-stressed yeasts.

When exposed to sublethal high temperatures, budding yeast cells can survive for a period of time; however, a sufficient amount of ubiquitin is necessary for this survival. To understand the nature of the stress, we examined the morphological changes in yeast cells, focusing on the vacuoles. Changes in vacuolar morphology were notable, and ruffled vacuolar membranes, accelerated invaginations of vacuolar membranes, and vesicle-like formations were observed.

Egg Envelope Glycoproteins ZP1 and ZP3 Mediate Sperm-Egg Interaction in the Japanese Quail.

Fertilization is indispensable for zygotic formation leading to the birth of animals and the species-specific sperm-egg binding thought to be the initial step in this important process. In birds, the oocyte, which encounters the spermatozoa at the time of fertilization, is enclosed in a perivitelline membrane (pvm) constructed of several zona pellucida glycoproteins (ZP proteins: ZP1, ZP2, ZP3, ZP4 and ZPD). The aim of this study was to determine the ZP protein in the pvm responsible for sperm-pvm binding in Japanese quail.

Significance of structural variation in thylakoid membranes in maintaining functional photosystems during reproductive growth.

Structural variation in the stroma-grana (SG) arrangement of the thylakoid membranes, such as changes in the thickness of the grana stacks and in the ratio between grana and inter-grana thylakoid, is often observed. Broadly, such alterations are considered acclimation to changes in growth and the environment. However, the relation of thylakoid morphology to plant growth and photosynthesis remains obscure.

Sperm-Egg Interaction during Fertilization in Birds.

Fertilization in animals that employ sexual reproduction is an indispensable event for the production of the next generation. A significant advancement in our understanding of the molecular mechanisms of sperm-egg interaction in mammalian species was achieved in the last few decades. However, the same level of knowledge has not been accumulated for birds because of egg size and the difficulty in mimicking the physiological polyspermy that takes place during normal fertilization.

Expression of Prolactin Receptor on the Surface of Quail Spermatozoa.

Prolactin receptor (PRLR) is expressed in a wide variety of tissues and mediates diverse biological actions of prolactin (PRL). In mammals, PRL signaling is thought to be involved not only in the process of spermatogenesis and steroidogenesis in the testis, but also in the survival of ejaculated sperm. In avian species, although the expression of PRLR with several variants in the testis was reported, the role of PRL in testicular function is still unclear.

Lactic acid is a sperm motility inactivation factor in the sperm storage tubules.

Although successful fertilization depends on timely encounters between sperm and egg, the decoupling of mating and fertilization often confers reproductive advantages to internally fertilizing animals. In several vertebrate groups, postcopulatory sperm viability is prolonged by storage in specialized organs within the female reproductive tract. In birds, ejaculated sperm can be stored in a quiescent state within oviductal sperm storage tubules (SSTs), thereby retaining fertilizability for up to 15 weeks at body temperature (41°C); however, the mechanism by which motile sperm become quiescent within SSTs is unknown.