Movies/Pics

Drosophila Oogenesis

• The Drosophila Egg Chamber is composed of 1 oocyte connected to 15 Nurse Cells. The Nurse Cells provide the oocyte with many molecules and organelles. Egg Chamber

• This animation depicts the synthesis of mRNAs by the Nurse Cells in a Drosophila egg chamber and passage of those mRNAs into the oocyte. Drosophila Egg Chamber

Xenopus laevis Oogenesis

• Take a look at a female Xenopus laevis.

• Stage I oocytes start their growth in the ovary as an unpigmented cell approximately 100 um in diameter. The oocyte increases in volume due to the deposition of yolk into the oocyte cytoplasm. The animal hemisphere becomes heavily pigmented, while the vegetal hemisphere is only slightly pigmented. The full-grown stage VI oocyte is approximately 1200 um in diameter.
  • Stages I-->VI of Xenopus Oogenesis Picture
    
    
  • Stages I-->VI of Xenopus Oogenesis (.mov)
    
    
  • Most of the Oocyte yolk is made in the liver. Xenopus Vitellogenesis
    
    
  • Lampbrush Chromosomes form during the Diplotene Stage of meiotic prophase.

Xenopus Oocyte Meiotic Maturation

• Xenopus laevis oocytes treated with progesterone. Xenopus oocytes.

• In response to progesterone stimulation Xenopus laevis oocytes undergo meiotic maturation. A number of physiological and morphological changes take place within the stimulated oocyte.
  • Protein Kinase Cascade Activation

  • An increase in Oocyte pHi.

  • MPF Activation

Meiosis in Human Oocytes

• Both germ cell lineages must undergo meiosis before fertilization. Meiosis in Human oocytes.

• Meiosis Animation

Mammalian Oocyte, Egg and Ovulation

• In a sexually-mature human female, there is a highly coordinated and interdependent series of cycles. These cycles repeat approximately every 28-29 days, however they stop if a successful pregnancy takes place. Reproductive Cycles

• The full-grown mammalian oocyte is surrounded by granulosa cells and a fluid-filled antrum. Graffian Follicle.

• The mammalian egg is surrounded by the Zona Pellucida and the somatic Corona Radiata (Granulosa Cells). Mammalian Egg.

• In response to LH stimulation, the full-grown mammalian egg is ovulated into the ampulla of the oviduct. Egg Ovulation.

Spermatogenesis Within the Mammalian Testis

• The central medulla region of the testis contains numerous seminiferous tubules. Spermatogenesis takes place in close association with the Sertoli cells (somatic) within the tubules. Spermatogenesis

• The round haploid spermatid undergoes cytodifferentiation forming a streamlined spermatozoa. Most of the cytoplasm is lost and a flagellum polymerizes from the basal body/centriole. Spermiogenesis
  
  
  

Sea Urchin Egg Fertilization

• Take a look at what a sea urchin looks like. Sea urchin.

• Take a look at an animation of sperm motility. Sperm Movement

• The sperm undergoes the acrosome reaction when it comes in contact with the jelly layer. Acrosome Reaction.

• Look at an animation of the sea urchin sperm acrosome reaction. Acrosome Animation

• When a sperm fertilizes a sea urchin egg, it first binds to a receptor on the egg plasma membrane. This causes a signal transduction pathway to be activated within the egg. Fertilization Signal Transduction

• Many sperm are trying to fertilize one sea urchin egg. Sperm S.E.M.

• Fertilized sea urchin eggs undergo a rapid membrane depolarization due to the influx of Na+. This results in a fast electrical block to prevent extra sperm from entering the egg. Fast Electrical Block to Polyspermy

Mammalian Egg Fertilization

• This diagram shows a comparision between an ovulated mouse egg and an ovulated sea urchin egg being fertilized. Mouse versus Sea Urchin Egg Fertilization

• Mammalian sperm approach with the side of the head of the sperm parallel to the egg surface. Mammalian Sperm Approach

Egg Activation

• When an egg is fertilized, calcium ions are released through an IP3 gated channel in the endoplasmic reticulum. This animation shows an egg that is fertilized at approximately the 2 o'clock position. The calcium increase spreads as a wave across to the opposite side of the egg cytoplasm at the 8 o'clock position. Animation

• A color movie of the calcium wave during sea urchin egg activation. Calcium levels are shown in false color (red= high calcium, blue= low calcium). Ca++ Increase During Egg Activation (.mov).

• Animation of cortical vesicle (cortical granule) exocytosis in response to the calcium increase. Cortical Vesicle Exocytosis

• The transient increase in calcium in a newly fertilized egg, causes the exocytosis of the cortical vesicles. The released contents of the cortical vesicles into the perivitelline space causes the elevation of the vitelline membrane, now called the fertilization membrane, away from the surface of the egg. This biochemically hardened membrane now acts as a slow physical block to polyspermy. I think the sperm enters the sea urchin egg at the 7 o'clock position? Sea Urchin Fertilization Membrane Elevation (.mov a big movie file, long download time!).

• Within 8-10 minutes post-fertilization, there is a dramatic increase in protein synthesis. This increase is caused by an increase in intracellular pH (pHi) from 6.9 to 7.2 Protein Synthesis Activation

Cytoplasmic Rearrangements

• Fertilization can initiate rearrangements of the egg cytoplasm containing morphogenetic determinants. Cytoplasm Movements

• Animation showing the shifting of the deeper cytoplasm relative to the cortical cytoplasm in a fertilized amphibian egg. Viewed from the SEP (Sperm Entry Point). Cytoplasmic rotation (mov.)

Cleavage Symmetry

• In some embryos (example, echinoderms)the mitotic apparatus is either parallel with or at right angles to the animal-vegetal pole axis. The cleavage furrows are either equatorial or meridional respectively. The daughter blastomeres are either above or to the side of each other. This is said to be radial-type symmetry. In some embryos (example, molluscs) the mitotic apparatus is tilted on a 45 degree angle to the animal-vegetal pole axis. In this case the daughter blastomeres are not direclty over or beside each other. They are tilted to the left or right 45 degrees. This latter cleavage symmetry is said to be spiral.
  • Radial versus Spiral Cleavage Animated Picture (.gif)

  • Radial versus Spiral Cleavage Movie (.mov)

Drosophila Embryo Cleavage

• In insects such as Drosophila, the early embryo undergoes nuclear division without cytoplasmic division. Drosophila Early Embryo

Sea Urchin Embryonic Cleavage

• This diagram shows stages of sea urchin development from fertilization through to the Blastula Stage. Sea Urchin Development

• This time-lapse movie courtesy of Chris Patton, Stanford University shows the development of a sea urchin embryo from the 1-cell to 4-cell stages. 1-4 Cell

• A series of pictures showing early Sea Urchin development. 1-Cell to Late Blastula

Amphibian Embryo Cleavage

• Diagrams showing various stages of amphibian embryonic development. Stages.

• Amphibian embryos cleave rapidly at first and then slow down. Rapid cleavage is the result of an abbreviated cell cycle when compared to somatic cells. Cleavage rates and cycle

• This is a time lapse movie of the early cleavage stages in an amphibian embryo from the one-cell stage to the neural fold stage. Amphibian Cleavage Movie

Axolotl Development

• A slide showing Axolotl development from the 8-cell stage through to the tadpole stage. Axolotl Development

C. elegans Embryonic Cleavage

• This movie is courtesy of Dr. Ahna Skop and Dr. John G. White, University of Wisconsin - Madison It is a time lapse movie of C. elegans early development taken through Nomarski optics. The large circles are the nuclei.
  • Time-lapse series of pictures made from the movie. First cleavage cycle (Note Less time to download)

  • C. elegans cleavage (Note This is a big movie file!)

  
  

• Dr. Bob Goldstein's C. elegans Movies Page (The University of North Carolina at Chapel Hill)

Fish Embryonic Development

• Pictures showing various stages of Zebra Fish development. Zebra Fish.

• Movie courtesy Dr. M. Cooper, Univ. of Washington showing a Zebrafish embryo undergoing cleavage from the 2-cell to the 8-cell stage. Note. This is meroblastic type cleavage. The yolk mass shown at the top of the movie does not cleave. 2-cell to 8-cell movie (.mov)

• Movie courtesy Dr. P. Myers, Temple Univ. showing a Zebrafish embryo undergoing meroblastic cleavage from the 1-cell to the 100% epiboly stage (11 hrs.). Zebrafish Movie (.mov big movie file to download, but well worth the wait!)

Mammalian Embryonic Cleavage

• Scanning electron microscope pictures of 2-cell and morula stages of mouse development are shown on this page. Mammalian Embryonic Development.

• Color pictures of 2-cell, 4-cell, 16-cell and blastocyst stages of mammalian development. Mammalian Embryos

Mammalian Blastocyst Implantation

• Mammalian blastocyst showing the Inner Cell Mass and Trophoblast. Mammalian Blastocyst.

• This animation shows a mammalian blastocyst embryo approaching the uterine endometrium and then implanting into the wall of the uterus. Implantation (.mov)

Stages of Human Development

• A series of pictures showing human development from week 3 through week 8. Weeks 3-8

• Animation of human development from 1-cell zygote through week 6 of development. Animation

Sea Urchin Gastrulation

• This picture shows a sea urchin embryo in the the mid-gastrula stage where the Archenteron is forming. Archenteron formation.

• Here are some pictures of various stages of sea urchin gastrulation taken with light microscope. Gastrulation Pictures

Amphibian Gastrulation (External View)

• As surface cells invaginate and deeper cells involute during gastrulation, the outer ectoderm cells spread by epiboly to cover the surface of the embryo. As the blastopore becomes smaller in diameter, the yolk-laden vegetal cells forming the endoderm can be seen as the yolk plug.
  • Types of Embryonic Cell Movements

  • Scanning EM picture of the "Yolk Plug Stage"

  • An animated series of diagrams showing yolk plug closure at mid-gastrulation and ending in the early neural fold stage in an amphibian embryo. This animation was made by Dr. Steven Black (Reed College at Portland, OR) Yolk plug to neural fold (.mov)

  • Amphibian Gastrulation (External .mov)

Amphibian Gastrulation (Internal View)

• This is a film using confocal microscopy to "see" inside an opaque amphibian embryo. As cells invaginate or involute during gastrulation, the archenteron or primitive gut forms. The dorsal lip of the blastopore forms at the 5 o'clock position at the beginning of the film, while the future mouth opening will form at the 9 o'clock position at the end of the movie.
  • Amphibian Gastrulation Animated Picture (.gif)

  • Amphibian Gastrulation (Internal .mov)

Avian/Mammalian Gastrulation

• A cross-section diagram through an avian embryo undergoing gastrulation. Avian gastrulation

Ectoderm, Mesoderm and Endoderm

• During gastrulation, three primary cell lineages are being established. They are the Ectoderm, Mesoderm and Endoderm. This diagram shows the various cell derrivatives from these three primary cell lineages. Ectoderm, Mesoderm and Endoderm.

Neurulation and Neural Fold Closure

• Following gastrulation, the neural ectoderm is induced and the neural folds close. Neurulation

• Scanning Electron Microscope picture of Neural Tube closure in Frogs. Frog S.E.M.

• Scanning Electron Microscope picture of Neural Tube closure in Birds. Chick S.E.M.

Human Eye Development

• Optic Vesicle Stage

• Lens Vesicle Stage

• Mature Lens Stage

• This animation shows the sequence of events involved in lens induction and human eye formation. Lens Induction

Human Heart Development

• This page shows four major stages of early human heart development. An embryological timetable for early human heart development can also be found on this page. Heart Development

Epithelial-Mesenchymal Interactions

• This page depicts a humorous look at all of the possible epithelial-mesenchymal interactions (secondary inductions) in one "mammal-bird" creature. Epithelial-Mesenchymal

Limb Development and Limb Regeneration

• Chick Limb Development/Retinoic Acid

• Stages of Newt Limb Regeneration

• Newt Limb Regeneration Time-Lapse Pictures

• The role of the A.E.R. and FGF in Limb Formation/Regeneration

Animal Cloning

• The answer is yes! The cloning of tadpoles from an embryonic cell nucleus was done in 1952 by Briggs and King. Cloning a tadpole from a differentiated cell nucleus may have been done in 1962 by Gurdon. Frog Cloning

• The cloning of the sheep named Dolly was the first verified example of a mammal being cloned from an adult cell nucleus in 1995. Sheep Cloning

• A different technique was used to clone mice in 1998. Mouse Cloning