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October, 2006
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Fertilization: The fusion of a spermatozoon (Spermatozoa) with an Ovum thus resulting in the formation of a Zygote.

Zebrafish Reproduction and Development

JoVE 5151

The zebrafish (Danio rerio) has become a popular model for studying genetics and developmental biology. The transparency of these animals at early developmental stages permits the direct visualization of tissue morphogenesis at the cellular level. Furthermore, zebrafish are amenable to genetic manipulation, allowing researchers to determine the effect of gene expression on the development of a vertebrate with a high degree of genetic similarity to humans. This video provides a brief overview of the major phases of zebrafish development, with particular focus on the first 24 hours post fertilization (hpf). The discussion begins with a zygote consisting of a single cell, or blastomere, atop a large ball of yolk. Cleavage of the blastomere is then shown to produce an embryo containing thousands of cells within a matter of hours. Next, the dramatic cellular movements known as epiboly and gastrulation are explained, revealing how they contribute to reshaping a mass of cells into a moving embryo with a beating heart in just 1 day. The presentation follows embryo development through the hatching phase, when they become swimming, feeding larvae. Important considerations for caring for larvae are incorporated, including a brief review of how fish are raised to adulthood in a dedicated facility known as the nursery. Finally, the video concludes with some commo

 Biology II

C. elegans Development and Reproduction

JoVE 5110

Ceanorhabditis elegans is a powerful tool to help understand how organisms develop from a single cell into a vast interconnected array of functioning tissues. Early work in C. elegans traced the complete cell lineage and structure at the electron microscopy level, allowing researchers unprecedented insight into the connection between genes, development and disease. Appreciating the stereotyped development and reproductive program of C. elegans is essential to using this model organism to its experimental fullest. This video will give you a peek into the development of a worm from fertilization to hatching, and walk you though the life stages of the newly hatched larvae on its journey to reproductive maturity. The video will detail how the major axes are established, which founder cells give rise to what tissues in the developing embryo and how to discriminate between the four larval stages. Finally, you will learn how to set up a genetic cross and we"ll visit a few applications that manipulate the development and reproduction of C. elegans to experimental benefit.

 Biology I

An Introduction to the Zebrafish: Danio rerio

JoVE 5128

Zebrafish (Danio rerio) are small freshwater fish that are used as model organisms for biomedical research. The many strengths of these fish include their high degree of genetic conservation with humans and their simple, inexpensive maintenance. Additionally, gene expression can be easily manipulated in zebrafish embryos, and their transparency allows for observation of developmental processes. This overview video first introduces basic zebrafish biology, including their phylogeny, life cycle, and natural environment, before presenting the features that make them so useful in the lab. A brief history of zebrafish research is also provided through a review of major discoveries made in fish, ranging from the early establishment of methods for efficient genetic screening to the discovery of novel therapeutics for human diseases such as cancer. Finally, some of the many avenues of experimentation performed in zebrafish are discussed, including immunological and developmental studies.

 Biology II

Development and Reproduction of the Laboratory Mouse

JoVE 5159

Successful breeding of the laboratory mouse (Mus musculus) is critical to the establishment and maintenance of a productive animal colony. Additionally, mouse embryos are frequently studied to answer questions about developmental processes. A wide variety of genetic tools now exist for regulating gene expression during mouse embryonic and postnatal development, which can help scientists to understand more about heritable diseases affecting human development. This video provides an introduction to the reproduction and development of mice. In addition to clarifying the terminology used to describe developmental progression, the presentation reviews key stages of the mouse life cycle. First, major development events that take place in utero are described, with special attention given to the unique layout of early rodent embryos. Next, husbandry protocols are provided for postnatal mice, or pups, including the process of weaning, or removal of pups from their mother's cage. Since males and females must be separated at this stage to prevent unscheduled mating, the demonstration also reveals how to determine mouse sex. Subsequently, instructions are given for carrying out controlled mouse breeding, including screening for the copulatory plug, which is useful for precisely timed embryonic development. Finally, the video highlights strategies used to in

 Biology II

Development of the Chick

JoVE 5155

The chicken embryo (Gallus gallus domesticus) provides an economical and accessible model for developmental biology research. Chicks develop rapidly and are amenable to genetic and physiological manipulations, allowing researchers to investigate developmental pathways down to the cell and molecular levels.

This video review of chick development begins by describing the process of egg fertilization and formation within the chicken reproductive tract. Next, the most commonly used chick staging nomenclature, the Hamburger Hamilton staging series, is introduced. Major events in chick development are then outlined, including the dramatic cellular movements known as gastrulation that form the three major cell layers: The ectoderm, mesoderm, and endoderm. Cells from these layers go on to generate all the tissues within the organism, as well as extraembryonic membranes, which are necessary for the transport of gases, nutrients, and wastes within the eggshell. To conclude the discussion, some exciting techniques will be presented as strategies for studying chick development in greater detail.

 Biology II

Detecting Reactive Oxygen Species

JoVE 5654

Reactive oxygen species are chemically active, oxygen-derived molecules capable of oxidizing other molecules. Because of their reactive nature, there are many deleterious effects associated with unchecked ROS production, including structural damage to DNA and other biological molecules. However, ROS can also be mediators of physiological signaling. There is accumulating evidence that ROS play significant roles in everything from activation of transcription factors to the mediation of inflammatory toxicity that kills foreign pathogens and defend the body.In this video we will delve into the associations between ROS, metabolism and disease. After establishing their significance, we will discuss the principles and a protocol of a commonly used methodology for measuring ROS levels in cells: the use of non-fluorescent probes that become fluorescent upon oxidation. Lastly, we will review some current applications of this technique in cell biology research.

 Cell Biology

An Introduction to Caenorhabditis elegans

JoVE 5103

Caenorhabditis elegans is a microscopic, soil-dwelling roundworm that has been powerfully used as a model organism since the early 1970’s. It was initially proposed as a model for developmental biology because of its invariant body plan, ease of genetic manipulation and low cost of maintenance. Since then C. elegans has rapidly grown in popularity and is now utilized in numerous research endeavors, from studying the forces at work during locomotion to studies of neural circuitry. This video provides an overview of basic C. elegans biology, a timeline of the many milestones in its short but storied history, and finally a few exciting applications using C. elegans as a model organism.

 Biology I

Drosophila Development and Reproduction

JoVE 5093

One of the many reasons that make Drosophila an extremely valuable organism is that the molecular, cellular, and genetic foundations of development are highly conserved between flies and higher eukaryotes such as humans. Drosophila progress through several developmental stages in a process known as the life cycle and each stage provides a unique platform for developmental research. This video introduces each stage of the Drosophila life cycle and details the physical characteristics and major developmental events that occur during each stage. Next, the video discusses the genetic regulation of pattern formation, which is important for establishing the body plan of the organism and specifying individual tissues and organs. In addition, this video gives an overview of Drosophila reproduction, and how to use the reproductive characteristics of Drosophila to set up a genetic cross. Finally, we discuss examples of how the principles of Drosophila development and reproduction can be applied to research. These applications include RNA interference, behavioral assays of mating behaviors, and live imaging techniques that allow us to visualize development as a dynamic process. Overall, this video highlights the importance of understanding development and reproduction in Drosophila, and how this knowledge can be use

 Biology I

Bottlenose Dolphin (Tursiops truncatus) Spermatozoa: Collection, Cryopreservation, and Heterologous In Vitro Fertilization

1Department of Animal Reproduction, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), 2Department of Animal Medicine and Surgery, School of Veterinary Medicine, Universidad Complutense de Madrid, 3Department of Physiology, Faculty of Veterinary Science, University of Murcia, Campus Mare Nostrum, 4Mundomar, Benidorm, 5Veterinary Services, L'Oceanográfic, Ciudad de las Artes y las Ciencias, Junta de Murs i Vals, s/n, 46013

JoVE 55237

 Developmental Biology

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