Fertilization Fertilization – fusion of egg and sperm into a single diploid cell, the zygote. External Internal

External Fertilization Sperm spread over egg cells Requires water Most aquatic animals Examples: most fish, corals, starfish Inefficient Spermatophore – sperm packaged into capsule Some terrestrial animals Examples: salamanders, scorpions, octopus

Internal Fertilization Requires copulation Most common method for terrestrial animals Less sperm and eggs needed

The Process - sperm capacitation hyperactivation zona binding acrosome reaction zona penetration sperm-oocyte membrane fusion decondensation of sperm nucleus formation of male pronucleus

The Process - Egg Ovulation Sperm-egg membrane fusion Egg activation increase in Ca++ cortical reaction - zona block completion of meiosis (2nd PB) formation of female pronucleus Syngamy - fusion of both pronuclei

Capacitation process of sperm becoming fertile occurs in uterus must be removed from seminal fluid in vitro, wash sperm capacitated sperm have the ability to fertilize the egg

Hyperactivation facilitates sperm-oocyte contact occurs in oviduct motility pattern becomes frenzied

Zona Binding Zona proteins: ZP1, ZP2, ZP3 Sperm bind ZP3 specifically Initiates acrosome reaction

Acrosome Reaction Fusion of two membranes Acrosin released spermatazoal plasma membrane outer acrosomal membrane Acrosin released allows sperm to penetrate zona Exposes equatorial segment for fusion with egg

Sperm-Egg Fusion Equatorial segment of sperm Plasma membrane of egg Initiates egg activation

Egg Activation Cortical Reaction Zona block exocytosis of cortical granules Zona block biochemical changes eliminates sperm binding

PHASES OF FERTLIZATION Passage of sperm through the corona radiata of the oocytes by the use of hyaluronidase which is released by the acrosome of the sperm and movement of the tail Penetration of Zona Pellucida- helped by the enzymes esterase, acrosin, and neuraminidase Once penetration occurs there is a biochemical zona reaction that causes the egg to become impermeable to other sperm.

PHASES OF FERTLIZATION 3. Fusion of the plasma membranes of the oocyte and sperm 4. Completion of second meiotic division of the oocyte and formation of the female pronucleus 5. Formation of the male pronucleus

PHASES OF FERTLIZATION 6. Breakdown of pronuclear membranes, condensation of chromosomes, and arrangement of chromosomes for mitotic cell division

Recognition of egg and sperm; 1. Chemoattraction of the sperm to the egg by soluble molecules 2. The exocytosis of the acrosomal vesicle to release its enzyme 3. The binding of the sperm to the extracellular envelop of the egg 4. The passage of the sperm through this envelop 5. Fusion of egg and sperm cell membrane Figures\Chapter07\DevBio7e07081.jpg Figure 7.8(1) Events Leading to the Fusion of Egg and Sperm Plasma Membranes

The Entry of Sperm into Sea Urchin Eggs Gamete fusion The Entry of Sperm into Sea Urchin Eggs Figures\Chapter07\DevBio7e07191.jpg Entry of Sperm into Golden Hamster Egg

Entry of Sperm into Golden Hamster Egg Figures\Chapter07\DevBio7e07203.jpg

Fertilization  The prevention of polyspermy Acrosome discharges enzymes to digest zona pellucida Once single sperm enters egg Egg releases enzymes that harden zona pellucida preventing other sperm from entering Sperm nucleus enters egg and fuses with egg nucleus

The prevention of polyspermy A fast reaction / Zona block biochemical changes eliminates sperm binding The slow block to polyspermy / Cortical Reaction  Cortical granule fuse with egg cell membrane exocytosis of cortical granules

Entry of Sperm

Abnormal Sperm Motility

JUST RIGHT! With just the right number of sperm all of the eggs get fertilized and development occurs normally.

NORMAL FERTILIZATION The sperm enters and binds to the egg surface. This induces a calcium wave that causes the cortical granules, white, to fuse with the plasma membrane, releasing their contents and causing the fertilization membrane to rise. The sperm is then pulled into the egg where it moves to the egg nucleus and fuses. DNA synthesis occurs along with duplication of the centrosome, black. Nuclear envelope breakdown and chromosome condensation leads to the metaphase plate. Anaphase leads to telophase and cell division. The process is repeated.

NUCLEAR MIGRATION This time-lapse video shows the female pronucleus moving to the center of the embryo where it will fuse with the male pronucleus. The numbers in the lower left corner are minutes after fertilization. Species is Lytichinus pictus at about 18C. Red arrow points to the nucleus.

TOO FEW! Too few and the eggs will not be fertilized

TOO MANY! Too many and the embryos will be polyspermic and die.

POLYSPERMY If two or more sperm make it into the egg polyspermy occurs. In this case some of the genetic material condensed into chromosome is attracted to the extra sperm causing abnormal development and ultimately the death of the embryo. Too many sperm and toxic conditions can lead to polyspermy.

From single cell to 4 cell

Pembelahan 4 sel - Morula

Landak Laut (Sea Urchin) Fertilisasi Landak Laut (Sea Urchin)

Landak Laut / Sea Urchin

Struktur Anatomi Landak Laut

Notice how the needle goes into the soft part between the teeth and shell, on the opposite side from the syringe. This "squirts" the potassium chloride onto the gonads causing them to contract and expel the gametes.

A milliliter of 3.7% potassium chloride is injected into each side of the sea urchin. (Smaller amounts for smaller sea urchins. A Lytichinus pictus would only need a tenth of a milliliter per side.) Smaller gauge, 25-30, needles work best.

HOW TO SPAWN AN URCHIN A 2cc syringe filled with 0.5M potassium chloride is inserted into the sea urchin between the teeth and the hard outer shell. A small amount of potassium chloride is injected into the urchin on each side (amount varies with size of urchin, 0.1cc/inch/side). This induces the urchin to spawn IF it has any eggs or sperm left.

Female S. purpuratus Orange indicates a female in most species (can be redish in others). Invert the sea urchin over a beaker of seawater and fill to the rim with seawater by pouring seawater over the sea urchin. Let the eggs drop to the bottom of the beaker. .

HOW TO COLLECT EGGS The injected female urchin is placed mouth side up over a beaker filled with sea water. The eggs will then be shed into the sea water and settle down to the bottom of the beaker. Store the eggs at the same temperature as would be best for development in this urchin.

Males can be collected "dry" by sucking up the sperm from the top of the sea urchin (white) with a pipette and collecting the sperm into a small centrifuge tube or test tube. Sperm may be stored at 4C in a refrigerator for up to a week.

HOW TO COLLECT SPERM The injected male urchin is placed on a dry surface mouth side down. The sperm are collected with a glass or plastic pipet and stored in a test tube at 4C for later use.

Terima Kasih Sukses selalu

PROSES FERTILISASI TERDIRI DARI 2 ASPEK: EMBRIOLOGIS GENETIS PENGAKTIFAN SEL TELUR GENETIS PENURUNAN UNSUR KEBAKAAN (DNA) DARI PEJANTAN UNSUR-UNSUR YANG BERPERAN: SEL TELUR YANG MATANG SPERMA DEWASA

SEL TELUR TERDIRI DARI: INTI. TEMPAT : KAUDA AMPULA (1/3 TF) WAKTU : TERGANTUNG SPESIES SEL TELUR TERDIRI DARI: INTI. SITOPLASMA (PROTEIN, BUTIR-BUTIR LEMAK, ENZIM). MEMBRAN PLASMA (MENGATUR ALIRAN ION-ION, TERUTAMA WAKTU FERTILISASI).

SPERMATOZOA : KEPALA  INTI, AKROSOM LEHER  CENTRIOLE EKOR KAPASITASI : SERANGKAIAN PERUBAHAN YANG TERJADI GUNA MEMPERSIAPKAN SPERMA UNTUK BERTEMU DAN BERINTERAKSI DENGAN OVUM PADA SAAT FERTILISASI. TEMPAT : DI BAGIAN BAWAH ISMUS

KAPASITASI PENTING, KARENA : MENGEMBANGKAN MOTILITAS YG HIPERAKTIF MENGANTARKAN PENETRASI SPERMA KE CUMULUS OOPHORUS MEMPERSIAPKAN SPERMA MENJALANI REAKSI AKROSOME REAKSI AKROSOME : TERJADI PERUBAHAN MEMBRAN KEPALA SPERMA  STRUKTUR LIPID ALBUMIN  COATING FACTOR

ASPEK-ASPEK DALAM PROSES KAPASITASI : MORFOLOGIS FISIOLOGIS BIOKIMIA PERUBAHAN LIPID PERUBAHAN PROTEIN REGULASI ION-ION  Ca2+ >>

JALUR JELAJAH SPERMATOZOA DALAM SALURAN KELAMIN JANTAN : TUB. SEM (SPERMA INMOTIL)  RETE TESTIS DUKT. EFEREN EPIDIDIMIS (KAPUT, KORPUS, KAUDA (PENDEWASAAN) : - [ ] - MENGKERUT DUKT. DEF - AKROSOM < - MOTIL URETRA EJAKULASI  SEMEN (SPERMA + PLASMA SEMEN)

DALAM SALURAN KELAMIN BETINA VAGINA : MAMALIA SERVIK : BABI UTERUS : KUDA TRANSPOR : 1. AKTIF  GERAKAN SPERMA 2. PASIF  KONTRAKSI OTOT UTERUS UTJ BARRIER  MENGHALANGI PERJALANAN SPERMA KE TEMPAT FERTILISASI

LAPISAN SEL TELUR YANG HARUS DILEWATI SPERMA : 1. SEL-SEL KUMULUS  EZM. HYALORONIDASE 2. ZONA PELUSIDA  ZONA LIZIN 3. SELAPUT VITELIN

2. PENETRASI SPERMA KE DALAM SEL TELUR AKTIVITAS UTAMA YANG TERJADI PADA PROSES FERTILISASI : 1. PENGENALAN SPERMA DAN SEL TELUR TERJADI PERLEKATAN KEPALA SPERMA DAN SEL TELUR  RESEPTOR Z. P. MENCEGAH PERLEKATAN  ANTIBODI ANTI ZONA / TRYPSIN SPERMA : ANTIBODI ANTI SPERMA 2. PENETRASI SPERMA KE DALAM SEL TELUR - KAPASITASI  REAKSI AKROSOME : -ZONALYSIN / AKROSIN -MOTILITAS SPERMA

3. FUSI GAMET SPERMA  MENEMBUS Z. P. KEPALA KONTAK M. VITELIN ROTASI FUSI MEMBRAN M. PLASMA SPERMA LEPAS INTI : DEKONDENSASI  PRONUKLEUS JANTAN

SPERMA M. VITELIN REDUKSI II  PB II 1. POLY SPERMA BLOCK : PERUBAHAN RESEPTOR ZONA PELUSIDA SPERMA MENEMBUS Z. P.  RESEPTOR MODIFIKASI  Z. P. BERUBAH TIDAK DIKENALI SPERMA LAIN 2. SLOW BLOCK POLYSPERMA/REAKSI KORTEKS M. VITELIN  BUTIR KORTEK  LEPAS  RONGGA PERIVITELIN