<a href="https://www.jove.com/video/4003">Generation of Mice Derived from Induced Pluripotent Stem Cells</a>
Michael J. Boland1, Jennifer L. Hazen1, Kristopher L. Nazor1, Alberto R. Rodriguez2, Greg Martin2, Sergey Kupriyanov2, Kristin K. Baldwin1 
1Dorris Neuroscience Center &amp; Department of Cell Biology, The Scripps Research Institute , 2Mouse Genetics Core Facility, The Scripps Research Institute 
Generating induced pluripotent stem cell (iPSC) lines produces lines of differing developmental potential even when they pass standard tests for pluripotency. Here we describe a protocol to produce mice derived entirely from iPSCs, which defines the iPSC lines as possessing full pluripotency1.
<a href="https://www.jove.com/video/50016">Analyzing Murine Schwann Cell Development Along Growing Axons</a>
Stephan Heermann1, 2, Kerstin Krieglstein1, 3 
1Department of Molecular Embryology, Institute of Anatomy and Cell Biology, University of Freiburg , 2Department of Neuroanatomy, University of Heidelberg, 3FRIAS, University of Freiburg 
Here we describe a Schwann cell (SC) migration assay in which SCs are able to develop along extending axons.
<a href="https://www.jove.com/video/50027">A Lightweight, Headphones-based System for Manipulating Auditory Feedback in Songbirds</a>
Lukas A. Hoffmann1, 2, Conor W. Kelly1, 3, David A. Nicholson1, 2, Samuel J. Sober1 
1Department of Biology, Emory University, 2Neuroscience Graduate Program, Emory University, 3Program in Neuroscience and Behavioral Biology, Emory University
We describe the design and assembly of miniaturized headphones suitable for replacing a songbird's natural auditory feedback with a manipulated acoustic signal. Online sound processing hardware is used to manipulate song output, introduce real-time errors in auditory feedback via the headphones, and drive vocal motor learning.
<a href="https://www.jove.com/video/50086">Screening for Melanoma Modifiers using a Zebrafish Autochthonous Tumor Model</a>
Sharanya Iyengar1, Yariv Houvras2, 3, Craig J. Ceol1 
1Program in Molecular Medicine and Department of Cancer Biology, University of Massachusetts Medical School, 2Departments of Surgery and Medicine, Weill Cornell Medical College , 3Departments of Surgery and Medicine, New York Presbyterian Hospital
A rapid way to screen for melanoma modifiers using a zebrafish autochthonous tumor model is presented. It takes advantage of the miniCoopR vector which allows for expression of candidate melanoma genes in melanocytes. A method to obtain melanoma-free survival curves, an invasion assay, a protocol for antibody staining of scale melanocytes and a melanoma transplantation assay are described.
<a href="https://www.jove.com/video/50117">Flexural Rigidity Measurements of Biopolymers Using Gliding Assays</a>
Douglas S. Martin, Lu Yu, Brian L. Van Hoozen 
Department of Physics, Lawrence University
A method to measure the persistence length or flexural rigidity of biopolymers is described. The method uses a kinesin-driven microtubule gliding assay to experimentally determine the persistence length of individual microtubules and is adaptable to actin-based gliding assays.
<a href="https://www.jove.com/video/50123">Collection, Isolation and Enrichment of Naturally Occurring Magnetotactic Bacteria from the Environment</a>
Zachery Oestreicher1, Steven K. Lower1, 2, Wei Lin3, Brian H. Lower2 
1School of Earth Sciences, The Ohio State University, 2School of Environment &amp; Natural Resources, The Ohio State University, 3Institute of Geology and Geophysics, Chinese Academy of Sciences 
We demonstrate a method to collect magnetotactic bacteria (MTB) that can be applied to natural waters. MTB can be isolated and enriched from sediment samples using a relatively simple setup that takes advantage of the bacteria's natural magnetism. Isolated MTB can then be examined in detail using both light and electron microscopy.
<a href="https://www.jove.com/video/2168">Transnuclear Mice with Pre-defined T Cell Receptor Specificities Against Toxoplasma gondii Obtained Via SCNT</a>
Oktay Kirak1, Eva-Maria Frickel1, Gijsbert M. Grotenbreg1, 2, Heikyung Suh1, Rudolf Jaenisch1, 3, Hidde L. Ploegh1, 3 
1 , Whitehead Institute for Biomedical Research, 2Departments of Microbiology and Biological Sciences, National University of Singapore, 3Department of Biology, Massachusetts Institute of Technology
We demonstrate here that epigenetic reprogramming via Somatic Cell Nuclear Transfer (SCNT) can be used as a tool to generate mouse models with pre-defined T cell receptor (TCR) specificities. These transnuclear mice express the corresponding TCR from their endogenous locus under the control of the endogenous promoter.

No conflicts of interest declared.

november 2012: this month in jove

In this issue, Oestreicher et al. show us how to isolate magnetotactic bacteria from freshwater samples, and concentrate the bacteria at one end of a glass capillary. The magnetotactic bacteria can then be visualized by light and transmission electron microscopy, and used for various other assays.
Also in the November 2012 issue, Boland et al. demonstrate how to reprogram fibroblasts into induced pluripotent stem cells (iPSCs), and how to isolate iPSC lines for injecting into tetraploid blastocysts, as demonstrated previously in <a href="http://www.jove.com/video/2168/transnuclear-mice-with-pre-defined-t-cell-receptor-specificities">JoVE</a>. While mouth pipetting is generally not recommended because it can have adverse effects, this protocol requires the technique, executed carefully, to manipulate the embryos. This is one of the rare occasions when it's actually OK to mouth pipet in the lab. If the induced cells are fully pluripotent, they can result in full-term mice derived completely from iPSCs.
In JoVE Neuroscience, Heermann and Krieglstein demonstrate a method for visualizing Schwann cell development along growing axons. To do this, our authors culture cervical ganglia explants onto collagen matrices, and treat the explants with nerve growth factor or other substances. The collagen gels can then be visualized using time-lapse imaging with fluorescence or bright-field microscopy, migrating along axons towards the periphery.
Also in JoVE Neuroscience, Hoffmann et al. put tiny headphones on songbirds to study how they use auditory feedback to adjust their singing. The authors demonstrate how to construct the headphones and attach them to the bird's head; then, by adjusting the acoustic signal, they can study the computational and neurophysiological basis of vocal learning in birds.
In JoVE Clinical &amp; Translational Medicine, Iyengar et al. use a zebrafish tumor model to study genes that can modify the pathogenesis of melanoma. This is done by first creating transgenic zebrafish that express a gene of interest. Various assays can then be performed to study how different genes affect melanoma, including onset, invasion, and transplantability.
In JoVE Bioengineering, Martin et al. demonstrate a gliding assay to measure the flexural rigidity of biopolymers (such as microtubules). By attaching motor proteins to a microscope slide, and adding fluorescently labeled microtubules, our authors can analyze the dynamics of cytoskeletal polymers.
This preview summarizes just a few notable video-articles in the November 2012 issue of JoVE. Stop by throughout the month of November to check out the full length versions of these articles and many more.

Watch this Scientific Journal Video about November 2012: This Month in JoVE at JoVE.com

November 2012: This Month in JoVE

In this issue, Oestreicher et al. show us how to isolate magnetotactic bacteria from freshwater samples, and concentrate the bacteria at one end of a glass capillary. The magnetotactic bacteria can then be visualized by light and transmission electron microscopy, and used for various other assays.

In this issue, Oestreicher et al. show us how to isolate magnetotactic bacteria from freshwater samples, and concentrate the bacteria at one end of a ...

Research

JoVE Journal

Biology

9.5K 조회수.  Massachusetts Eye and Ear. 이 문제를 Oestreicher에서 외. 민물 샘플 magnetotactic 박테리아를 분리하고, 모세관 유리의 한쪽 끝에서 박테리아를 집중하는 방법을 우리에게 보여줍니다. magnetotactic 박테리아는 빛과 전송 전자 현미경에 의해 보여 질 및 기타 다양한 assays에 사용하실 수 있습니다.

비디오: November 2012: This Month in JoVE

August 2012: This Month in JoVE

Traditional microscopy requires lens objectives to magnify specimens, and can involve numerous optical components like additional objectives, filters, and mirrors to refract and direct light to optical sensors. The August 2012 issue of JoVE (Journal of Visualized Experiments) is marked by the third publication from the Ozcan Lab (University of California, Los Angeles) on their lens free lens-free "on-chip" microscopy platform, which they have pioneered.
Back in 2009, the Ozcan lab published their first article, which demonstrated the use of a lens-free imaging platform that could image cells within whole blood. This imaging technique involves placing a sample directly on an optoelectric sensor array, like the CCD or CMOS chips found in the standard camcorder. Then, LED illumination from above the sample casts shadows on the chip, which are recorded as digital holograms that can be subjected to image processing. Not only does this lensless imaging system allow for an extremely large field of view (FOV of 0.6-8 cm2), the lack of bulky optical components makes it excellent for microfluidic applications. The Ozcan group demonstrates this in their follow-up 2011 JoVE article, in which fluorescently labeled white blood cells are imaged within a microfluidic chip.
This August in JoVE, the Ozcan group demonstrates further advancements to their lens-free microscopy platform by applying it to tomographic imaging of the nematode, C. elegans. By changing the angle of illumination, using a motorized rotation stage, the Ozcan group shows how multiple holographic slices may be generated for a sample-which, following processing, can be combined into tomograms. The Ozcan group confirms that their 3D reconstruction of the worm is successful by citing that the pharyngeal tube, a 5-micron-thick structure, is only visible in a single slice and in a 3D reconstructed cross section.
The compact and inexpensive nature of the lens-free imaging systems - designed and assembled by the Ozcan group - make them well suited for point-of-care diagnostic applications, or even cell phone based microscopy that can be performed in the field.
At the Ernest Gallo Clinic and Research Center at University of California, San Francisco JoVE learns how to visualize morphological changes in single cells using three-dimensional fluorescence microscopy and computer analysis. In this procedure, cells are given agonist, antagonist plus agonist, or no treatment, and prepared for immunofluorescence microscopy. Three-dimensional images are acquired with the help of a two-photon laser system, and the fluorescence data are processed on the computer using Imaris and Matlab.
To demonstrate the power of this technique, our authors quantify single-cell phenotypic changes in transfected HEK293 cells. Three-dimensional morphometric analysis shows dramatic changes in cells treated with agonist. These changes are not always apparent when using conventional 2D analysis. This technique allows morphological changes in single cells to be quantified and characterized in response to pharmacologic stimuli, offering a powerful new assessment tool to the arsenal of drug discovery research.
This month, in JoVE Applied Physics, we travel to South Carolina to visit the School of Materials Science and Engineering at Clemson University. Here, researchers show us how to construct lithium batteries for laboratory research.
The basic components of a lithium coin cell are the working electrode, the lithium electrolyte, and a lithium foil counter electrode. The different components of the coin cell are carefully assembled and sealed with a crimping machine. The finished coin cell can then be characterized in a battery tester. Using their homemade coin cells, our researchers can experiment with using different materials to make the cathodes of lithium coin cells.
This month in JoVE Immunology and Infection, we head to Basel, Switzerland to witness two techniques for diagnosing helminth infections. We also see how investigators perform the shuttle run test in children, in order to assess the effects of these infections on physical fitness.
Helminths are parasitic worms that can live inside humans and animals. Many species infect the intestinal tract, and may be transmitted through soil. Our authors demonstrate the Kato-Katz technique, which is used for diagnosing several common soil-transmitted helminths. They also demonstrate the Baermann technique, which uses light to stimulate the migration of certain types of phototactic helminths out of sample preparations. The various types of helminth species can subsequently be determined based on morphology.
Our authors then demonstrate how to set up and perform a 20-meter shuttle run test for children, and to measure the impact of helminth infections on physical fitness. This method can help determine the true burden of soil-transmitted helminth infections on overall health.
This brief summary highlights but a few notable video-articles that will be released in August. We'll also feature articles that demonstrate how to express genes in the midbrain of the chick embryo, study neutrophil transmigration in parallel flow chambers lined with endothelial cells, and precisely measure proteolytic degradation of the extracellular matrix.

Traditional microscopy requires lens objectives to magnify specimens, and can involve numerous optical components like additional objectives, filters, and mirrors to refract and direct light to optical sensors. The August 2012 issue of JoVE (Journal of Visualized Experiments) is marked by the third publication from the Ozcan Lab (University of California, Los Angeles) on their lens-free "on-chip" microscopy platform, which they have pioneered.

Traditional microscopy requires lens objectives to magnify specimens, and can involve numerous optical components like additional objectives, filters, and ...

2012: A Year In Review

Here's a look at some of the milestones and highlights of the year 2012 in Journal of Visualized Experiments (JoVE).
At the start of 2012, JoVE reached a major milestone by publishing our 1500th article. In this publication, in JoVE Bioengineering, Yu et al. described a method for analyzing the free radical composition of cigarette smoke. This method simulated cigarette puffing with a single-port smoking device, and combined it with electron spin resonance (ESR) spectroscopy to measure the degree to which antioxidant compounds can scavenge free radicals in cigarette smoke. A possible outcome of this research is the creation of less harmful cigarettes.
JoVE Bioengineering also contained the most-viewed article of 2012. Owczarczak et al. described a method for hacking a standard inkjet printer, loading ink cartridges with a cell-suspension "bioink," and printing lines of live cells onto glass slides. The thermal inkjet printing process creates temporary pores in the cell membrane, visualized by the incorporation of fluorescently labeled actin monomers. This concept, called "bioprinting," has many potential applications in cell and tissue engineering.
Also in 2012, JoVE Bioengineering featured a protocol by Hsia et al. for isolating and purifying spider silk protein, spinning it into fibers, and assessing the fiber strength. This protocol for laboratory-scale production of spider silk, which is stronger than tensile steel, can potentially be extended to large-scale manufacturing.
In JoVE Clinical and Translational Medicine, we featured a number of articles related to stroke, one of which. In one article, M&ouml;bius-Winkler et al. demonstrated placement of the WATCHMAN left atrial appendage occlusion device from Boston Scientific. This device is designed to prevent strokes by trapping clots within the left atrial appendage of the heart before they exit. Our authors demonstrated how to insert the guide wire through the femoral artery into the heart, advance the device into the left atrium, and deploy the device in the left atrial appendage.
Another article focused on stroke, Hamel et al. described the use of a driving simulator to study how patients compensate for visual field defects following stroke. By analyzing the compensatory gaze behavior of patients as they navigated through virtual driving courses with varying degrees of complexity, our authors see great potential for the use of driving simulators in stroke rehabilitation.
In JoVE Immunology and Infection, we published an article by Keyel et al. describing the real-time kinetics of immune cell responses to bacterial toxins using live cell microscopy. Combined with high-speed 3D confocal microscopy, this technique can also visualize the cellular repair response.
Also in JoVE Immunology and Infection, we featured an article by Yap et al. describing methods for diagnosing helminth infections in children. Helminths are parasitic worms that can infect the intestinal tract of humans and animals, and may be distinguished based on their morphology. The same article demonstrated how to measure the impact of helminth infections on physical fitness in children, which is a measure of overall health.
In JoVE Neuroscience, we featured a method by Hoffmann et al., who used tiny headphones to alter the auditory feedback in songbirds, and analyzed the computational and neurophysiological basis of vocal learning in birds when they adjust their singing in response to altered acoustic signals.
Also in JoVE Neuroscience, we moved from birds to bees with a method that assesses associative and non-associative tactile learning in honeybees. This method, by Mujagi&#263; et al., allowed bees to scan different metal surfaces with their antennae, then conditioned them to expect sugar water when their antennae touched particular surfaces, and analyzed the corresponding changes in antennal movement.
In 2012, we launched a brand-new section: JoVE Applied Physics, which features articles on subjects ranging from plasma physics to material science. The Applied Physics section also contained JoVE's 2000th video article, filmed in a synchrotron radiation facility, where Borisenko et al. showed how to determine the electronic structure of complex materials using angle-resolved photoemission spectroscopy.
In the JoVE General section, we published an article by Artioli et al. demonstrating the use of a portable gas analyzer to measure oxygen consumption during complex exercise - such as judo. By analyzing oxygen consumption and collecting blood for measuring plasma lactate concentration, this method can determine the relative contributions of different energy systems to specific aspects of complex exercise.
Finally, JoVE followed Dolhi et al. to a permanently ice-covered saline lake in Antarctica. There, scientists drilled through the ice to study single-celled microorganisms called protists that live in the harsh conditions of Antarctica.
This Year in Review was just a brief glimpse of a few of over 600 video articles that JoVE offered in 2012. Browse the JoVE archives to see thousands of other videos, and stay tuned for what's coming up this year in JoVE: The Journal of Visualized Experiments.

Here's a look at some of the milestones and highlights of the year 2012 in Journal of Visualized Experiments (JoVE).

 
 
Here's a look at some of the milestones and highlights of the year 2012 in Journal of Visualized Experiments (JoVE).
At the start of 2012, JoVE ...