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Weizmann Institute of Science

20 ARTICLES PUBLISHED IN JoVE

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Biology

Two-Photon-Based Photoactivation in Live Zebrafish Embryos
Niva Russek-Blum *1, Helit Nabel-Rosen *1, Gil Levkowitz 1
1Molecular Cell Biology, Weizmann Institute of Science

Multiphoton microscopy allows control of low energy photons with deep optical penetration and reduced phototoxicity. We describe the use of this technology for live cell labeling in zebrafish embryos. This protocol can be readily adapted for photo-induction of various light-responsive molecules.

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Biology

Analyzing Large Protein Complexes by Structural Mass Spectrometry
Noam Kirshenbaum 1, Izhak Michaelevski 1, Michal Sharon 1
1Department of Biological Chemistry, Weizmann Institute of Science

Mass spectrometry has proven to be a valuable tool for analyzing large protein complexes. This method enables insights into the composition, stoichiometry and overall architecture of multi-subunit assemblies. Here, we describe, step-by-step, how to perform a structural mass spectrometry analysis, and characterize macromolecular structures.

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Biology

T-wave Ion Mobility-mass Spectrometry: Basic Experimental Procedures for Protein Complex Analysis
Izhak Michaelevski 1, Noam Kirshenbaum 1, Michal Sharon 1
1Department of Biological Chemistry, Weizmann Institute of Science

Ion mobility-mass spectrometry is an emerging gas-phase technology that separates ions, based on their collision cross-section and mass. The method provides three-dimensional information on the overall topology and shape of protein complexes. Here, we outline a basic procedure for instrument setting and optimization, calibration of drift times, and data interpretation.

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Neuroscience

Axoplasm Isolation from Rat Sciatic Nerve
Ida Rishal 1, Meir Rozenbaum 1, Mike Fainzilber 1
1Department of Biological Chemistry, Weizmann Institute of Science

We demonstrate a protocol for axoplasm isolation from adult rat sciatic nerve based on dissection of nerve fascicles and incubation in hypotonic medium to release myelin and lyse non-axonal structures, followed by extraction of the remaining axon-enriched material.

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Biology

Dissection and Staining of Drosophila Larval Ovaries
Iris Maimon 1, Lilach Gilboa 1
1Department of Biological Regulation, Weizmann Institute of Science

How niches and stem cells form during development is an important question with practical implications. In the Drosophila ovary, germ line stem cells and their somatic niches form during larval development. This video demonstrates how to dissect, stain and mount female gonads from late third instar (LL3) Drosophila larvae.

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Bioengineering

High Resolution 3D Imaging of Ex-Vivo Biological Samples by Micro CT
Amnon Sharir 1, Gregory Ramniceanu 2, Vlad Brumfeld 3
1Department of Molecular Genetics, Weizmann Institute of Science, 2Department of Biological Regulation, Weizmann Institute of Science, 3Department of Chemical Infrastructure, Weizmann Institute of Science

Non-destructive volume visualization can be achieved only by tomographic techniques, of which the most efficient is the x-ray micro computerized tomography ( CT).

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Engineering

Bringing the Visible Universe into Focus with Robo-AO
Christoph Baranec 1,2, Reed Riddle 1, Nicholas M. Law 3, A.N. Ramaprakash 4, Shriharsh P. Tendulkar 2, Khanh Bui 1, Mahesh P. Burse 4, Pravin Chordia 4, Hillol K. Das 4, Jack T.C. Davis 1, Richard G. Dekany 1, Mansi M. Kasliwal 5, Shrinivas R. Kulkarni 1,2, Timothy D. Morton 2, Eran O. Ofek 6, Sujit Punnadi 4
1Caltech Optical Observatories, California Institute of Technology, 2Department of Astronomy, California Institute of Technology, 3Dunlap Institute for Astronomy and Astrophysics, University of Toronto, 4Inter-University Centre for Astronomy & Astrophysics, 5Observatories of the Carnegie Institution for Science, 6Benoziyo Center for Astrophysics, Weizmann Institute of Science

Light from astronomical objects must travel through the earth's turbulent atmosphere before it can be imaged by ground-based telescopes. To enable direct imaging at maximum theoretical angular resolution, advanced techniques such as those employed by the Robo-AO adaptive-optics system must be used.

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Biology

Assessing the Secretory Capacity of Pancreatic Acinar Cells
Erez Geron 1, Eyal D. Schejter 1, Ben-Zion Shilo 1
1Department of Molecular Genetics, Weizmann Institute of Science

Isolated pancreatic acini retain their in vivo morphology and activity and offer powerful ways for monitoring and manipulating secretion. This work demonstrates how acini can be isolated from the mouse pancreas, and how their secretory capacities can be assessed.

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Medicine

Tracking the Mammary Architectural Features and Detecting Breast Cancer with Magnetic Resonance Diffusion Tensor Imaging
Noam Nissan 1, Edna Furman-Haran 2, Myra Feinberg-Shapiro 3, Dov Grobgeld 1, Erez Eyal 1, Tania Zehavi 4, Hadassa Degani 1
1Department of Biological Regulation, Weizmann Institute of Science, 2Unit of Biological Services, Weizmann Institute of Science, 3Department of Diagnostic Imaging, Meir Medical Center, 4Pathology Department, Meir Medical Center

We describe how to obtain parametric and vector maps of the diffusion tensor of the breast using magnetic resonance imaging. The protocol and final output following imaging processing are tailored for tracking breast architectural features and detecting breast malignancy.

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JoVE Core

Water in Oil Emulsions: A New System for Assembling Water-soluble Chlorophyll-binding Proteins with Hydrophobic Pigments
Dominika Bednarczyk 1, Dror Noy 2
1Department of Biological Chemistry, Weizmann Institute of Science, 2Migal-Galilee Research Institute

This manuscript describes a simple and high-throughput method for assembling water-soluble proteins with hydrophobic pigments that is based on water-in-oil emulsions. We demonstrate the effectiveness of the method in the assembly of native chlorophylls with four variants of recombinant water-soluble-chlorophyll binding proteins (WSCPs) of Brassica plants expressed in E. coli.

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Environment

Air-sampled Filter Analysis for Endotoxins and DNA Content
Naama Lang-Yona 1,2, Yinon Mazar 1, Michal Pardo 1, Yinon Rudich 1
1Department of Earth and Planetary Sciences, Weizmann Institute of Science, 2Multiphase Chemistry Department, Max Planck Institute

Two complementary analyses of atmospheric biological particles from air sampled filters are described herein: the extraction and detection of endotoxin, and of DNA.

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JoVE Core

Studying the Supramolecular Organization of Photosynthetic Membranes within Freeze-fractured Leaf Tissues by Cryo-scanning Electron Microscopy
Dana Charuvi 1,3, Reinat Nevo 1, Ifat Kaplan-Ashiri 2, Eyal Shimoni 2, Ziv Reich 1
1Department of Biological Chemistry, Weizmann Institute of Science, 2Department of Chemical Research Support, Weizmann Institute of Science, 3Institute of Plant Sciences, Agricultural Research Organization, Volcani Center

Here we describe a procedure for studying freeze-fractured plant tissues. High-pressure frozen leaf samples are freeze-fractured and double-layer coated, yielding well preserved frozen-hydrated samples that are imaged using the cryo-scanning electron microscope at high magnifications with minimal beam damage.

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Education

External Excitation of Neurons Using Electric and Magnetic Fields in One- and Two-dimensional Cultures
Shani Stern 1, Assaf Rotem 2, Yuri Burnishev 3, Eyal Weinreb 3, Elisha Moses 3
1Laboratory of Genetics, The Salk Institute for Biological Studies, 2Department of Physics and SEAS, Harvard University, 3Department of Physics of Complex Systems, Weizmann Institute of Science

Neuronal cultures are a good model for studying emerging brain stimulation techniques via their effect on single neurons or a population of neurons. Presented here are different methods for stimulation of patterned neuronal cultures by an electric field produced directly by bath electrodes or induced by a time-varying magnetic field.

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Biochemistry

Mimicking the Function of Signaling Proteins: Toward Artificial Signal Transduction Therapy
Ronny Peri-Naor 1, Leila Motiei 1, David Margulies 1
1Department of Organic Chemistry, Weizmann Institute of Science

We present guidelines for developing synthetic 'chemical transducers' that can induce communication between naturally unrelated proteins. In addition, detailed protocols are presented for synthesizing and testing a specific 'transducer' that enables a growth factor to activate a detoxifying enzyme and consequently, to regulate the cleavage of an anticancer prodrug.

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Genetics

Novel RNA-Binding Proteins Isolation by the RaPID Methodology
Nitzan Samra 1,2, Yoav Arava 1
1Faculty of Biology, Technion - Israel Institute of Technology, 2Department of Biomolecular Sciences, Weizmann Institute of Science

RNA-protein interactions lie at the heart of many cellular processes. Here, we describe an in vivo method to isolate specific RNA and identify novel proteins that are associated with it. This could shed new light on how RNAs are regulated in the cell.

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Immunology and Infection

Methodologies for Studying B. subtilis Biofilms as a Model for Characterizing Small Molecule Biofilm Inhibitors
Tabitha Bucher 1, Elena Kartvelishvily 2, Ilana Kolodkin-Gal 1
1Department of Molecular Genetics, Weizmann Institute of Science, 2Electron Microscopy Unit, Weizmann Institute of Science

This study presents the development of reproducible methodologies to study biofilm inhibitors and their effects on Bacillus subtilis multicellularity.

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Biology

Method for Labeling Transcripts in Individual Escherichia coli Cells for Single-molecule Fluorescence In Situ Hybridization Experiments
Rinat Arbel-Goren 1, Yonatan Shapira 1, Joel Stavans 1
1Department of Physics of Complex Systems, Weizmann Institute of Science

This manuscript describes a method for labeling individual messenger RNA (mRNA) transcripts with fluorescently-labeled DNA probes, for use in single-molecule fluorescence in situ hybridization (smFISH) experiments in E. coli. smFISH is a visualization method that allows the simultaneous detection, localization, and quantification of single mRNA molecules in fixed individual cells.

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Developmental Biology

Generation of Human Primordial Germ Cell-like Cells at the Surface of Embryoid Bodies from Primed-pluripotency Induced Pluripotent Stem Cells
Shino Mitsunaga 1, Keiko Shioda 1, Kurt J. Isselbacher 1, Jacob H. Hanna 2, Toshi Shioda 1
1Center for Cancer Research, Massachusetts General Hospital, 2Department of Molecular Genetics, Weizmann Institute of Science

Primordial germ cells (PGCs) are common precursors of both sperm and eggs. Human embryonic PGCs are specified from pluripotent epiblast cells through interactions of cytokines. Here, we describe a 13-day protocol of inducing human cells transcriptomally resembling PGCs at the surface of embryoid bodies from primed-pluripotency induced pluripotent stem cells.

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Behavior

Longitudinal Two-Photon Imaging of Dorsal Hippocampal CA1 in Live Mice
Alessandro F. Ulivi 1, Tim P. Castello-Waldow 1, Ghabiba Weston 1,2, Long Yan 3, Ryohei Yasuda 3, Alon Chen 1,4, Alessio Attardo 1
1Dept. of Stress Neurobiology and Neurogenetics, Max Planck Institute of Psychiatry, 2Graduate School of Systemic Neurosciences, Ludwig Maximilians University, 3Max Planck Florida Institute for Neuroscience, 4Dept. of Neurobiology, Weizmann Institute of Science

This method describes a chronic preparation that allows optical access to the hippocampus of living mice. This preparation can be used to perform longitudinal optical imaging of neuronal structural plasticity and activity-evoked cellular plasticity over a period of several weeks.

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Developmental Biology

Ex Utero Culture of Mouse Embryos from Pregastrulation to Advanced Organogenesis
Alejandro Aguilera-Castrejon 1, Jacob H. Hanna 1
1Department of Molecular Genetics, Weizmann Institute of Science

An enhanced platform for whole-embryo culture allows continuous and robust ex utero development of postimplantation mouse embryos for up to six days, from pregastrulation stages until advanced organogenesis. In this protocol, we detail the standard procedure for successful embryo culture using static plates and rotating bottle systems.

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