Fertilization Fertilization – fusion of egg and sperm into a single diploid cell, the zygote. External Internal.
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Presentasi berjudul: "Fertilization Fertilization – fusion of egg and sperm into a single diploid cell, the zygote. External Internal."— Transcript presentasi:
1FertilizationFertilization – fusion of egg and sperm into a single diploid cell, the zygote.ExternalInternal
2External Fertilization Sperm spread over egg cellsRequires waterMost aquatic animalsExamples: most fish, corals, starfishInefficientSpermatophore – sperm packaged into capsuleSome terrestrial animalsExamples: salamanders, scorpions, octopus
3Internal Fertilization Requires copulationMost common method for terrestrial animalsLess sperm and eggs needed
4The Process - sperm capacitation hyperactivation zona binding acrosome reactionzona penetrationsperm-oocyte membrane fusiondecondensation of sperm nucleusformation of male pronucleus
5The Process - Egg Ovulation Sperm-egg membrane fusion Egg activation increase in Ca++cortical reaction - zona blockcompletion of meiosis (2nd PB)formation of female pronucleusSyngamy - fusion of both pronuclei
6Capacitation process of sperm becoming fertile occurs in uterus must be removed from seminal fluidin vitro, wash spermcapacitated sperm have the ability to fertilize the egg
9Acrosome Reaction Fusion of two membranes Acrosin released spermatazoal plasma membraneouter acrosomal membraneAcrosin releasedallows sperm to penetrate zonaExposes equatorial segmentfor fusion with egg
10Sperm-Egg Fusion Equatorial segment of sperm Plasma membrane of egg Initiates egg activation
11Egg Activation Cortical Reaction Zona block exocytosis of cortical granulesZona blockbiochemical changes eliminates sperm binding
12PHASES 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 tailPenetration of Zona Pellucida- helped by the enzymes esterase, acrosin, and neuraminidaseOnce penetration occurs there is a biochemical zona reaction that causes the egg to become impermeable to other sperm.
13PHASES OF FERTLIZATION 3. Fusion of the plasma membranes of the oocyte and sperm4. Completion of second meiotic division of the oocyte and formation of the female pronucleus5. Formation of the male pronucleus
14PHASES OF FERTLIZATION 6. Breakdown of pronuclear membranes, condensation of chromosomes, and arrangement of chromosomes for mitotic cell division
17Recognition of egg and sperm; 1. Chemoattraction of the sperm to the egg by soluble molecules2. The exocytosis of the acrosomal vesicle to release its enzyme3. The binding of the sperm to the extracellular envelop of the egg4. The passage of the sperm through this envelop5. Fusion of egg and sperm cell membraneFigures\Chapter07\DevBio7e07081.jpgFigure 7.8(1) Events Leading to the Fusion of Egg and Sperm Plasma Membranes
19The Entry of Sperm into Sea Urchin Eggs Gamete fusionThe Entry of Sperm into Sea Urchin EggsFigures\Chapter07\DevBio7e07191.jpgEntry of Sperm into Golden Hamster Egg
20Entry of Sperm into Golden Hamster Egg Figures\Chapter07\DevBio7e07203.jpg
21Fertilization The prevention of polyspermy Acrosome discharges enzymes to digest zona pellucidaOnce single sperm enters eggEgg releases enzymes that harden zona pellucida preventing other sperm from enteringSperm nucleus enters egg and fuses with egg nucleus
22The prevention of polyspermy A fast reaction / Zona blockbiochemical changes eliminates sperm bindingThe slow block to polyspermy / Cortical Reaction Cortical granule fuse with egg cell membraneexocytosis of cortical granules
28JUST RIGHT!With just the right number of sperm all of the eggs get fertilized and development occurs normally.
29NORMAL FERTILIZATIONThe 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.
30NUCLEAR MIGRATIONThis 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.
32TOO FEW!Too few and the eggs will not be fertilized
33TOO MANY!Too many and the embryos will be polyspermic and die.
34POLYSPERMYIf 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.
41Notice 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.
42A 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.
43HOW TO SPAWN AN URCHINA 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.
44Female S. purpuratusOrange 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..
45HOW TO COLLECT EGGSThe 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.
46Males 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.
47HOW TO COLLECT SPERMThe 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.
50PROSES FERTILISASI TERDIRI DARI 2 ASPEK: EMBRIOLOGIS GENETIS PENGAKTIFAN SEL TELURGENETISPENURUNAN UNSUR KEBAKAAN (DNA) DARI PEJANTANUNSUR-UNSUR YANG BERPERAN:SEL TELUR YANG MATANGSPERMA DEWASA
51SEL TELUR TERDIRI DARI: INTI. TEMPAT : KAUDA AMPULA (1/3 TF)WAKTU : TERGANTUNG SPESIESSEL TELUR TERDIRI DARI:INTI.SITOPLASMA (PROTEIN, BUTIR-BUTIR LEMAK, ENZIM).MEMBRAN PLASMA (MENGATUR ALIRAN ION-ION, TERUTAMA WAKTU FERTILISASI).
52SPERMATOZOA :KEPALA INTI, AKROSOMLEHER CENTRIOLEEKORKAPASITASI : SERANGKAIAN PERUBAHAN YANG TERJADI GUNA MEMPERSIAPKAN SPERMA UNTUK BERTEMU DAN BERINTERAKSI DENGAN OVUM PADA SAAT FERTILISASI.TEMPAT : DI BAGIAN BAWAH ISMUS
53KAPASITASI PENTING, KARENA : MENGEMBANGKAN MOTILITAS YG HIPERAKTIFMENGANTARKAN PENETRASI SPERMA KE CUMULUS OOPHORUSMEMPERSIAPKAN SPERMA MENJALANI REAKSI AKROSOMEREAKSI AKROSOME :TERJADI PERUBAHAN MEMBRAN KEPALA SPERMA STRUKTUR LIPIDALBUMIN COATING FACTOR
54ASPEK-ASPEK DALAM PROSES KAPASITASI : MORFOLOGIS FISIOLOGIS BIOKIMIA PERUBAHAN LIPIDPERUBAHAN PROTEINREGULASI ION-ION Ca2+ >>
56DALAM SALURAN KELAMIN BETINA VAGINA : MAMALIASERVIK : BABIUTERUS : KUDATRANSPOR :1. AKTIF GERAKAN SPERMA2. PASIF KONTRAKSI OTOT UTERUSUTJ BARRIER MENGHALANGI PERJALANAN SPERMA KE TEMPAT FERTILISASI
57LAPISAN SEL TELUR YANG HARUS DILEWATI SPERMA : 1. SEL-SEL KUMULUS EZM. HYALORONIDASE2. ZONA PELUSIDA ZONA LIZIN3. SELAPUT VITELIN
582. PENETRASI SPERMA KE DALAM SEL TELUR AKTIVITAS UTAMA YANG TERJADI PADA PROSES FERTILISASI :1. PENGENALAN SPERMA DAN SEL TELURTERJADI PERLEKATAN KEPALA SPERMA DAN SEL TELUR RESEPTOR Z. P.MENCEGAH PERLEKATAN ANTIBODI ANTI ZONA / TRYPSINSPERMA : ANTIBODI ANTI SPERMA2. PENETRASI SPERMA KE DALAM SEL TELUR- KAPASITASI REAKSI AKROSOME :-ZONALYSIN / AKROSIN-MOTILITAS SPERMA
593. FUSI GAMETSPERMA MENEMBUS Z. P.KEPALA KONTAK M. VITELINROTASIFUSI MEMBRANM. PLASMA SPERMA LEPASINTI : DEKONDENSASI PRONUKLEUS JANTAN
60SPERMA 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 LAIN2. SLOW BLOCK POLYSPERMA/REAKSI KORTEKSM. VITELIN BUTIR KORTEK LEPAS RONGGA PERIVITELIN