FEMALE REPRODUCTIVE SYSTEM - OVARY (First of Three Laboratory Sessions)
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In Hardening of the Zona Pellucida K
Disulfide formation in bovine zona pellucida glycoproteins during fertilization: evidence for the involvement of cystine cross-linkages in hardening of the zona pellucida K. Kwamoto, K. Ikeda, N. Yonezawa, S. Noguchi, K. Kudo, S. Hamano, M. Kuwayama and M. Nakano department ofChemistry, Faculty ofScience and 2Graduate School ofScience and Technology, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan; and3Animal Bio-Technology Center, Livestock Improvement Association, Tokyo, Japan The time for solubilization of the bovine zona pellucida in a hypotonic buffer containing 5% (v/v) \g=b\-mercaptoethanoland 7 mol urea l\m=-\1 increased by 10% after fertilization. Coupling with a specific fluorescent thiol probe, monobromobimane (mBBr), was markedly greater in the zona pellucida of ovarian eggs compared with fertilized eggs, indicating that the cysteine residues in the zona pellucida of unfertilized eggs are oxidized to cystines during fertilization. After endo-\g=b\-galactosidasedigestion to remove N-acetyllactosamine repeats of the carbohydrate chains, three zona pellucida glycoproteins (ZPA, ZPB and ZPC) coupled with the fluorescent bimane groups were fractionated efficiently by reverse-phase HPLC. Estimation of bimane groups in the three components and SDS-PAGE revealed that intramolecular disulfide bonds in ZPA and intra- and intermolecular disulfide bonds in ZPB were formed during fertilization, but oxidation of cysteine residues in ZPC was low. Specific proteolysis of ZPA during fertilization was also observed. These results indicate that the formation of disulfide linkages together with specific proteolysis result in the construction of a rigid zona pellucida structure, which is responsible for hardening of the zona pellucida. Introduction cross-linkages between tyrosine residues of the zona pellucida proteins formed by ovoperoxidase caused the The zona is one of the two sites at which pellucida In contrast to sea urchins (Foerder and is blocked and hardening. -
Chapter 28 *Lecture Powepoint
Chapter 28 *Lecture PowePoint The Female Reproductive System *See separate FlexArt PowerPoint slides for all figures and tables preinserted into PowerPoint without notes. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Introduction • The female reproductive system is more complex than the male system because it serves more purposes – Produces and delivers gametes – Provides nutrition and safe harbor for fetal development – Gives birth – Nourishes infant • Female system is more cyclic, and the hormones are secreted in a more complex sequence than the relatively steady secretion in the male 28-2 Sexual Differentiation • The two sexes indistinguishable for first 8 to 10 weeks of development • Female reproductive tract develops from the paramesonephric ducts – Not because of the positive action of any hormone – Because of the absence of testosterone and müllerian-inhibiting factor (MIF) 28-3 Reproductive Anatomy • Expected Learning Outcomes – Describe the structure of the ovary – Trace the female reproductive tract and describe the gross anatomy and histology of each organ – Identify the ligaments that support the female reproductive organs – Describe the blood supply to the female reproductive tract – Identify the external genitalia of the female – Describe the structure of the nonlactating breast 28-4 Sexual Differentiation • Without testosterone: – Causes mesonephric ducts to degenerate – Genital tubercle becomes the glans clitoris – Urogenital folds become the labia minora – Labioscrotal folds -
Chapter 24 Primary Sex Organs = Gonads Produce Gametes Secrete Hormones That Control Reproduction Secondary Sex Organs = Accessory Structures
Anatomy Lecture Notes Chapter 24 primary sex organs = gonads produce gametes secrete hormones that control reproduction secondary sex organs = accessory structures Development and Differentiation A. gonads develop from mesoderm starting at week 5 gonadal ridges medial to kidneys germ cells migrate to gonadal ridges from yolk sac at week 7, if an XY embryo secretes SRY protein, the gonadal ridges begin developing into testes with seminiferous tubules the testes secrete androgens, which cause the mesonephric ducts to develop the testes secrete a hormone that causes the paramesonephric ducts to regress by week 8, in any fetus (XX or XY), if SRY protein has not been produced, the gondal ridges begin to develop into ovaries with ovarian follicles the lack of androgens causes the paramesonephric ducts to develop and the mesonephric ducts to regress B. accessory organs develop from embryonic duct systems mesonephric ducts / Wolffian ducts eventually become male accessory organs: epididymis, ductus deferens, ejaculatory duct paramesonephric ducts / Mullerian ducts eventually become female accessory organs: oviducts, uterus, superior vagina C. external genitalia are indeterminate until week 8 male female genital tubercle penis (glans, corpora cavernosa, clitoris (glans, corpora corpus spongiosum) cavernosa), vestibular bulb) urethral folds fuse to form penile urethra labia minora labioscrotal swellings fuse to form scrotum labia majora urogenital sinus urinary bladder, urethra, prostate, urinary bladder, urethra, seminal vesicles, bulbourethral inferior vagina, vestibular glands glands Strong/Fall 2008 Anatomy Lecture Notes Chapter 24 Male A. gonads = testes (singular = testis) located in scrotum 1. outer coverings a. tunica vaginalis =double layer of serous membrane that partially surrounds each testis; (figure 24.29) b. -
Oogenesis in Mammals
OOGENESIS IN MAMMALS In contrast to most other vertebrates , mammals do not replenish the stores of oocytes present in the ovary at birth. At birth the human ovaries contain about 1 million oocytes ( many of which are already degenerating) that have been arrested in the diplotene stage of the first meiotic division . These oocytes are already surrounded by a layer of follicular cells or granulosa cells , and the complex of ovum and its surrounding cellular investments is known as a follicle . Of all the germ cells present in the ovary ,only about 400 (one per menstrual cycle) will reach maturity and become ovulated. The remainder develop to varying degrees and then undergo atresia (degeneration). Oocytes first become associated with follicular cells in the late fetal period , when they are going through early prophase of the first meiotic division . The primary oocyte (so called because it is undergoing the first meiotic division ) plus its incomplete covering of flattened follicular cells is called a primordial follicle . According to Gougeon (1993) a follicle passes through three major phases on its way to ovulation. The first phase is characterized by a large pool of nongrowing follicles , approximately 500,000 per ovary at birth. In this pool are primordial follicles, which develop into primary follicles by surrounding themselves with a complete single layer of cuboidal follicular cells . By this time , the oocytes have entered the first period of meiotic arrest , the diplotene stage . In human , essentially all oocytes , unless Page 1 of 5 : SEM-2 (GEN ) , Unit#6 : OOGENESIS : Pritha Mondal they degenerate ,remain arrested in the diplotene stage until puberty ; some will not progress past the diplotene stage until the woman’s last reproductive cycle (age 45 to 55 years). -