This procedure follows to a large extent the transplantation technique developed for cave fish by the lab of Bill Jeffrey.

Part 1: Preparing the embryos
In this protocol, we will use the jjxy symbol to denote a hypothetical zebrafish lens mutant.
<ol>
<li>Zebrafish strains are maintained in standard fish facility conditions at 28.5 C on a 14h light/10h dark cycle.</li>
<li>In the evening, place males and females of the zebrafish strain jjxy:AB/TU; tg(mGFP) in a tank with a divider to separate them from each other. The progeny of this cross will express the GFP transgene in all tissues, and will be used as donors. In parallel, use the same procedure to set up crosses between non-transgenic wild-type animals. Depending on the purpose of this experiment, one can cross animals wild-type at the jjxy locus as donors or hosts.</li>
<li>Within one hour after the light turns on in the morning, remove the dividers to allow the fish to mate.</li>
<li>After 15-30 minutes collect embryos in 100 x 15 mm Petri dishes, clean them, and change the medium (egg water).</li>
<li>Keep the embryos in a 28.5 C incubator until desired time.</li>
<li>When ready for transplantation, remove the chorion manually with two pairs of sharp forceps, and incubate the embryos in 0.2%EDTA in calcium-free ZFR for 30 minutes.</li>
</ol>
Part 2: Preparation of dissection needles
<ol>
<li>The transplantation procedure requires two types of needles: a sharpened one, which is used to cut tissues surrounding the lens, remove the chorion, and release embryos from agarose; and a blunt needle used to move the donor lens and insert it into the host. Here we will show you how to make these needles.</li>
<li>First, the tip of a Pasteur pipette must be cut off using a diamond knife. Then insert a glass capillary into the Pasteur pipette tip so that about half of its length is inside it. This will make it easier to immobilize the tungsten wire by melting it into the glass in the next step.</li>
<li>Then insert a thin tungsten wire into the open end of the capillary. Melt the glass over the wire with a Bunsen burner. Using forceps, hold steady the glass end with the metal wire while twisting the other end of the needle with your hand. The softened glass should spiral around the metal gripping it in place.</li>
<li>If you are making a blunt tip needle, then this is the end of the procedure. To create a sharpened needle, hold the tungsten wire over a Bunsen burner for 1-1.5 minutes, burning off the metal so a very fine tip is created. Check the quality of tip by microscropy.It is a good idea to sterilize both needles in the flame for a few seconds immediately before transplantation. </li>
</ol>
Part 3: Preparation of reagents
<ol>
<li>Calcium-free Zebrafish Ringer&#x2019;s (ZFR) Solutions (116 mM NaCl, 2.9 mM KCl, 5 mM HEPES, pH 7.2)</li>
<li>0.2%EDTA in calcium-free Zebrafish Ringer&#x2019;s Solutions (pH 7.2)</li>
<li>1.2% agarose (low melting point) in calcium-free ZFR</li>
<li>0.2% agarose (low melting point) in calcium-free ZFR</li>
<li>Embryo medium (pH 7.0, per liter contains: 10 ml Hanks Solution #1, 1ml Hanks Solution #2, 10ml Hanks Solution #4, 10ml Hanks Solution #5, 0.35 g sodium bicarbonate, 300 uL of 2M HCl, penicillin-streptomycin 500,000U) As in The Zebrafish Book (University of Oregon Press, 2000).</li>
<li>Tungsten wire, gold plated, 0.1mm diameter, Alfa Aesar</li>
<li>Capillary tube, 1.0mm diameter, World Precision Instruments</li>
</ol>
Part 4: Transplantation procedure
<ol>
<li>In a plastic centrifuge tube, prepare 1.2% low melting point agarose in calcium-free ZFR preheated to 40 C in a water bath.</li>
<li>At the desired stage (30 hpf, for example), take up the embryos in a Pasteur pipette, slowly expel them into the centrifuge tube, and slowly expel them into the centrifuge tube and incubate for about 5 seconds. The donors and hosts should be incubated separately.</li>
<li>With a pipette, take up the embryos in 1.2% agarose from the centrifuge tube and arrange them in two parallel rows in a 100mm polystyrene Petri dish, keeping hosts and donors separate. By pipetting them out slowly and carefully, most embryos will lie on their sides in the agarose. You will need to reorient those that do not lie in this position using the blunt needle so that the eye is facing up before the agarose solidifies.</li>
<li>Wait for the 1.2% agarose to solidify, and then overlay it with 0.2% low melting point agarose solution.</li>
<li>Using the sharpened needle, remove any agarose around the eyes, and very carefully cut the lens out from the host and donor embryos using small strokes. Make sure to cut just close enough to the lens so as not to tear it, but also so you do not remove too much tissue from the rest of the host eye.</li>
<li>Once free, lenses will float in the medium. Using the blunt needle, carefully push the donor lens to just above the location of where the host lens would be normally, and then push it down into the eye with the blunt needle. The host lens may be discarded.</li>
<li>Leave donor and host embryos in 1.2% agarose for 30-60 minutes, then release them from the agarose using the sharp needle, and transfer them into a 24-well plate with embryo medium. Each embryo should occupy a separate well. Make sure to label the wells properly so that it is clear which host corresponds to which donor.</li>
<li>Incubate at 28.5 C. The donor-derived lens can be distinguished from the host lens on the unoperated side of the same animal based on GFP fluorescence. Sections can also be made to measure lens size and to determine whether it differentiates properly. </li>
</ol>
<img src="/files/ftp_upload/1258/1258fig1.jpg" alt="figure 1" /> Fig. 1 Low magnification image of a sharpened needle used for lens transplantation. A glass capillary (B) is inserted into the Pasteur pipette (A), and a thin tungsten wire (C) is inserted into the open end of the capillary. The glass over the wire is softened with a Bunsen burner. Using forceps, hold steady the glass end with the metal wire while twisting the other end of the Pasteur pipette with your hand. The softened glass should spiral around the metal, gripping it in place.
 <img src="/files/ftp_upload/1258/fig2 1258.png" alt="" width="600" height="204" /> Fig. 2 The tips of the two kinds of needles used for lens transplantation.
 <img src="/files/ftp_upload/1258/1258fig3.jpg" alt="figure 3" /> Fig. 3 Embryos underwent lens transplantation at 30hpf. Shown are a donor embryo (A, B), a host eye on with transplanted lens (C, D), and the control side of the host embryo (E, F). Each eye is shown in both transmitted light and UV illumination as indicated. Photographs were taken at 48 hpf. The Q01[9] transgenic line was used in this experiment.

<ol>
	<li>Thut, C. J., Rountree, R. B., Hwa, M., Kingsley, D. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+large-scale+in+situ+screen+provides+molecular+evidence+for+the+induction+of+eye+anterior+segment+structures+by+the+developing+lens.">A large-scale in situ screen provides molecular evidence for the induction of eye anterior segment structures by the developing lens.</a> Dev Biol. 231, 63-76 (2001).</li><li>Yamamoto, Y., Jeffery, W. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Central+role+for+the+lens+in+cave+fish+eye+degeneration.">Central role for the lens in cave fish eye degeneration.</a> Science. 289, 631-633 (2000).</li><li>Easter, S. S., Nicola, G. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+development+of+vision+in+the+zebrafish(Danio+rerio).">The development of vision in the zebrafish(Danio rerio).</a> Dev Biol. 180, 646-663 (1996).</li><li>Schmitt, E., Dowling, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Early+eye+morphogenesis+in+the+zebrafish.+Brachydanio+rerio.">Early eye morphogenesis in the zebrafish. Brachydanio rerio.</a> J.comp. Neuro. 344 (4), 532-542 (1994).</li><li>Malicki, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Harnessing+the+power+of+forward+genetics--analysis+of+neuronal+diversity+and+patterning+in+the+zebrafish+retina.">Harnessing the power of forward genetics--analysis of neuronal diversity and patterning in the zebrafish retina.</a> Trends Neurosci. 23 (11), 531-541 (2000).</li><li>Malicki, J., Pujic, Z., Thisse, C., Thisse, B., Wei, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Forward+and+reverse+genetic+approaches+to+the+analysis+of+eye+development+in+zebrafish.">Forward and reverse genetic approaches to the analysis of eye development in zebrafish.</a> Vision Res. 42 (4), 527-533 (2002).</li><li>Avanesov, A., Malicki, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Approaches+to+study+neurogenesis+in+the+zebrafish+retina.">Approaches to study neurogenesis in the zebrafish retina.</a> Methods Cell Biol. 76, 333-384 (2004).</li><li>Vihtelic, T. S., Hyde, D. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Zebrafish+mutagenesis+yields+eye+morphological+mutants+with+retinal+and+lens+defects.">Zebrafish mutagenesis yields eye morphological mutants with retinal and lens defects.</a> Vision Res. 42, 535-540 (2002).</li><li>Godinho, L., Mumm, J. S., Williams, P. R., Schroeter, E. H., Koerber, A., Park, S. W., Leach, S. D., Wong, R. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Targeting+of+amacrine+cell+neurites+to+appropriate+synaptic+laminae+in+the+developing+zebrafish+retina.">Targeting of amacrine cell neurites to appropriate synaptic laminae in the developing zebrafish retina.</a> Development. Nov 132, 5069-5079 (2005).</li></ol>

Several steps require special attention during lens transplantations.
<ol>
<li>Sharpened needles: It&rsquo;s better to prepare several needles before carrying out lens transplantation, and the tip of the needles should be as thin as possible. A thicker needle will tear more tissue because of its wider diameter, causing a failure in the eye to heal.</li>
<li>Arranging the embryos: Right before transplantation you must position the embryos so they are lying on their sides. When positioning, the 1.2% agarose can ...

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">	
		
		<div>
		<table border="1">
		<thead>
		<tr>
		<th>Material Name</th>
		<th>Type</th>
		<th>Company</th>
		<th>Catalogue Number</th>
		<th>Comment</th>
		</tr>
		</thead>
		<tbody>
		
<tr>
<td>0.1mm diameter tungsten wire</td>
<td>&nbsp;</td>
<td>A Johnson Matthey</td>
<td>45086</td>
<td>&nbsp;</td>
<tr>
<td>Agarose(low melting point)</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>39346</td>
<td>&nbsp;</td>
<tr>
<td>Borosilicate glass capillaries</td>
<td>&nbsp;</td>
<td>World Precision Instruments</td>
<td>TW 100-4</td>
<td>&nbsp;</td>
<tr>
<td>Forceps</td>
<td>&nbsp;</td>
<td>Dumont #5</td>
<td>11252-30</td>
<td>&nbsp;</td>
<tr>
<td>Pasteur pipette</td>
<td>&nbsp;</td>
<td>Fisher</td>
<td>13-678-20C</td>
<td>&nbsp;</td>
<tr>
<td>Pipette pump</td>
<td>&nbsp;</td>
<td>Fisher</td>
<td>13-683C</td>
<td>&nbsp;</td>
<tr>
<td>Petri Dish</td>
<td>&nbsp;</td>
<td>CardinalHealth</td>
<td>D1906</td>
<td>&nbsp;</td>
<tr>
<td>Penicillin-streptomycin</td>
<td>&nbsp;</td>
<td>GIBCO</td>
<td>15140-122</td>
<td>&nbsp;</td>		</tbody>
		</table>
		</div>

lens transplantation in zebrafish and its application in the analysis of eye mutants

The lens plays an important role in the development of the optic cup[1,2]. Using the zebrafish as a model organism, questions regarding lens development can be addressed. The zebrafish is useful for genetic studies due to several advantageous characteristics, including small size, high fecundity, short lifecycle, and ease of care. Lens development occurs rapidly in zebrafish. By 72 hpf, the zebrafish lens is functionally mature [3]. Abundant genetic and molecular resources are available to support research in zebrafish. In addition, the similarity of the zebrafish eye to those of other vertebrates provides basis for its use as an excellent animal model of human defects[4-7]. Several zebrafish mutants exhibit lens abnormalities, including high levels of cell death, which in some cases leads to a complete degeneration of lens tissues [8]. To determine whether lens abnormalities are due to intrinsic causes or to defective interactions with the surrounding tissues, transplantation of a mutant lens into a wild-type eye is performed. Using fire-polished metal needles, mutant or wild-type lenses are carefully dissected from the donor animal, and transferred into the host. To distinguish wild-type and mutant tissues, a transgenic line is used as the donor. This line expresses membrane-bound GFP in all tissues, including the lens. This transplantation technique is an essential tool in the studies of zebrafish lens mutants.

Watch this Scientific Journal Video about Lens Transplantation in Zebrafish and its Application in the Analysis of Eye Mutants at JoVE.com

Lens Transplantation in Zebrafish and its Application in the Analysis of Eye Mutants

Lens development involves interactions with other tissues. Several zebrafish eye mutants are characterized by an abnormally small lens size. Here we demonstrate a lens transplantation experiment to determine whether this phenotype is due to intrinsic causes or defective interactions with tissues that surround the lens.

The lens plays an important role in the development of the optic cup[1,2]. Using the zebrafish as a model organism, questions regarding lens development ...

lens-transplantation-zebrafish-its-application-analysis-eye

Research

JoVE Journal

Biology

11.0K Views.  The Second Teaching Hospital of Jilin University. Lens development involves interactions with other tissues. Several zebrafish eye mutants are characterized by an abnormally small lens size. Here we demonstrate a lens transplantation experiment to determine whether this phenotype is due to intrinsic causes or defective interactions with tissues that surround the lens. 

Video: Lens Transplantation in Zebrafish and its Application in the Analysis of Eye Mutants

Transplantation of Whole Kidney Marrow in Adult Zebrafish

Hematopoietic stem cells (HSC) are a rare population of pluripotent cells that maintain all the differentiated blood lineages throughout the life of an organism. The functional definition of a HSC is a transplanted cell that has the ability to reconstitute all the blood lineages of an irradiated recipient long term. This designation was established by decades of seminal work in mammalian systems. Using hematopoietic cell transplantation (HCT) and reverse genetic manipulations in the mouse, the underlying regulatory factors of HSC biology are beginning to be unveiled, but are still largely under-explored. Recently, the zebrafish has emerged as a powerful genetic model to study vertebrate hematopoiesis. Establishing HCT in zebrafish will allow scientists to utilize the large-scale genetic and chemical screening methodologies available in zebrafish to reveal novel mechanisms underlying HSC regulation. In this article, we demonstrate a method to perform HCT in adult zebrafish. We show the dissection and preparation of zebrafish whole kidney marrow, the site of adult hematopoiesis in the zebrafish, and the introduction of these donor cells into the circulation of irradiated recipient fish via intracardiac injection. Additionally, we describe the post-transplant care of fish in an "ICU" to increase their long-term health. In general, gentle care of the fish before, during, and after the transplant is critical to increase the number of fish that will survive more than one month following the procedure, which is essential for assessment of long term (&lt;3 month) engraftment. The experimental data used to establish this protocol will be published elsewhere. The establishment of this protocol will allow for the merger of large-scale zebrafish genetics and transplant biology.

In this article, we demonstrate a method to perform HCT in adult zebrafish.

Hematopoietic stem cells (HSC) are a rare population of pluripotent cells that maintain all the differentiated blood lineages throughout the life of an ...

Preparation and Culture of Rat Lens Epithelial Explants for Studying Terminal Differentiation

The anterior surface of the ocular lens is covered by a monolayer of epithelial cells, which proliferate in an annular zone underlying the ciliary body.  Following division, these cells migrate posteriorly, where FGF diffusing from the retina induces them to differentiate into a posterior array of elongated lens fiber cells, which compose the bulk of the lens.  Differentiation of lens epithelial cells into lens fibers can be induced in vitro by culturing explants of the central region of the anterior epithelium in the presence of FGF-2.  Explants are prepared from lenses of neonatal rats by removing the lens from the eye and grasping the lens capsule on the posterior side with dissecting tweezers.  The posterior capsule is then gently torn open and pressed down into the plastic bottom of a tissue culture dish. The peripheral regions of the explant are removed with a scalpel and the central area is then cultured in the presence of 100ng/ml FGF-2 for as long as 2-3 weeks, depending on the parameters to be studied.  Since epithelial cells in cultured explants differentiate in approximate synchrony over a period of days to weeks, the time course of signaling and gene expression can be determined using molecular, biochemical, and pharmacological techniques.  Immunofluorescence microscopy is a powerful adjunct to these methods as it demonstrates the subcellular localization of proteins of interest and can reveal the physiological consequences of experimental manipulations of signaling pathways.

Explants of the central region of rat lens epithelia differentiate synchronously when cultured in the presence of FGF-2. Immunofluorescence microscopy of such cultures can provides novel information about gene expression and signaling events associated with terminal differentiation.

The anterior surface of the ocular lens is covered by a monolayer of epithelial cells, which proliferate in an annular zone underlying the ciliary body.  ...

Primary Culture and Plasmid Electroporation of the Murine Organ of Corti. 

In all mammals, the sensory epithelium for audition is located along the spiraling organ of Corti that resides within the conch shaped cochlea of the inner ear (fig 1). Hair cells in the developing cochlea, which are the mechanosensory cells of the auditory system, are aligned in one row of inner hair cells and three (in the base and mid-turns) to four (in the apical turn) rows of outer hair cells that span the length of the organ of Corti. Hair cells transduce sound-induced mechanical vibrations of the basilar membrane into neural impulses that the brain can interpret. Most cases of sensorineural hearing loss are caused by death or dysfunction of cochlear hair cells.
An increasingly essential tool in auditory research is the isolation and in vitro culture of the organ explant 1,2,9. Once isolated, the explants may be utilized in several ways to provide information regarding normative, anomalous, or therapeutic physiology. Gene expression, stereocilia motility, cell and molecular biology, as well as biological approaches for hair cell regeneration are examples of experimental applications of organ of Corti explants.
This protocol describes a method for the isolation and culture of the organ of Corti from neonatal mice. The accompanying video includes stepwise directions for the isolation of the temporal bone from mouse pups, and subsequent isolation of the cochlea, spiral ligament, and organ of Corti. Once isolated, the sensory epithelium can be plated and cultured in vitro in its entirety, or as a further dissected micro-isolate that lacks the spiral limbus and spiral ganglion neurons. Using this method, primary explants can be maintained for 7-10 days. As an example of the utility of this procedure, organ of Corti explants will be electroporated with an exogenous DsRed reporter gene. This method provides an improvement over other published methods because it provides reproducible, unambiguous, and stepwise directions for the isolation, microdissection, and primary culture of the organ of Corti.

Primary Culture and Plasmid Electroporation of the Murine Organ of Corti.

This procedure describes a method for the isolation and culture of the murine organ of Corti with or without the spiral limbus and spiral ganglion neurons. We also demonstrate a method for the expression of an exogenous reporter gene in the organ of Corti explant by electroporation.

In all mammals, the sensory epithelium for audition is located along the spiraling organ of Corti that resides within the conch shaped cochlea of the ...

In vivo Electroporation of Morpholinos into the Adult Zebrafish Retina

Many devastating inherited eye diseases result in progressive and irreversible blindness because humans cannot regenerate dying or diseased retinal neurons. In contrast, the adult zebrafish retina possesses the robust ability to spontaneously regenerate any neuronal class that is lost in a variety of different retinal damage models, including retinal puncture, chemical ablation, concentrated high temperature, and intense light treatment 1-8. Our lab extensively characterized regeneration of photoreceptors following constant intense light treatment and inner retinal neurons after intravitreal ouabain injection 2, 5, 9. In all cases, resident M&uuml;ller glia re-enter the cell cycle to produce neuronal progenitors, which continue to proliferate and migrate to the proper retinal layer, where they differentiate into the deficient neurons. 
	We characterized five different stages during regeneration of the light-damaged retina that were highlighted by specific cellular responses. We identified several differentially expressed genes at each stage of retinal regeneration by mRNA microarray analysis 10. Many of these genes are also critical for ocular development. To test the role of each candidate gene/protein during retinal regeneration, we needed to develop a method to conditionally limit the expression of a candidate protein only at times during regeneration of the adult retina. 
	Morpholino oligos are widely used to study loss of function of specific proteins during the development of zebrafish, Xenopus, chick, mouse, and tumors in human xenografts 11-14. These modified oligos basepair with complementary RNA sequence to either block the splicing or translation of the target RNA. Morpholinos are stable in the cell and can eliminate or "knockdown" protein expression for three to five days 12. 
	Here, we describe a method to efficiently knockdown target protein expression in the adult zebrafish retina. This method employs lissamine-tagged antisense morpholinos that are injected into the vitreous of the adult zebrafish eye. Using electrode forceps, the morpholino is then electroporated into all the cell types of the dorsal and central retina. Lissamine provides the charge on the morpholino for electroporation and can be visualized to assess the presence of the morpholino in the retinal cells. 
	Conditional knockdown in the retina can be used to examine the role of specific proteins at different times during regeneration. Additionally, this approach can be used to study the role of specific proteins in the undamaged retina, in such processes as visual transduction and visual processing in second order neurons.

In vivo Electroporation of Morpholinos into the Adult Zebrafish Retina

A method to conditionally knockdown a target protein&#x2019;s expression in the adult zebrafish retina is described, which involves intravitreally injecting antisense morpholinos and electroporating them into the retina. The resulting protein is knocked down for several days, which allows testing the protein&#x2019;s role in the regenerating or intact retina.

Many devastating inherited eye diseases result in progressive and irreversible blindness because humans cannot regenerate dying or diseased retinal ...

Gavaging Adult Zebrafish

The zebrafish has become an important in vivo model in biomedical research. Effective methods must be developed and utilized to deliver compounds or agents in solutions for scientific research. Current methods for administering compounds orally to adult zebrafish are inaccurate due to variability in voluntary consumption by the fish. A gavage procedure was developed to deliver precise quantities of infectious agents to zebrafish for study in biomedical research. Adult zebrafish over 6 months of age were anesthetized with 150 mg/L of buffered MS-222 and gavaged with 5 &mu;l of solution using flexible catheter implantation tubing attached to a cut 22-G needle tip. The flexible tubing was lowered into the oral cavity of the zebrafish until the tip of the tubing extended past the gills (approximately 1 cm). The solution was then injected slowly into the intestinal tract. This method was effective 88% of the time, with fish recovering uneventfully. This procedure is also efficient as one person can gavage 20-30 fish in one hour. This method can be used to precisely administer agents for infectious diseases studies, or studies of other compounds in adult zebrafish.

The increasing use of zebrafish as an animal model requires the development of effective methods for the delivery of known quantities of compounds and solutions. The gavage procedure described below allows for the oral delivery of precise volumes of solution reliably, safely and efficiently to adult zebrafish.

The zebrafish has become an important in vivo model in biomedical research. Effective methods must be developed and utilized to deliver compounds or ...

Design and Analysis of Temperature Preference Behavior and its Circadian Rhythm in Drosophila

The circadian clock regulates many aspects of life, including sleep, locomotor activity, and body temperature (BTR) rhythms1,2. We recently identified a novel Drosophila circadian output, called the temperature preference rhythm (TPR), in which the preferred temperature in flies rises during the day and falls during the night 3. Surprisingly, the TPR and locomotor activity are controlled through distinct circadian neurons3. Drosophila locomotor activity is a well&#160;known circadian behavioral output and has provided strong contributions to the discovery of many conserved mammalian circadian clock genes and mechanisms4. Therefore, understanding TPR will lead to the identification of hitherto unknown molecular and cellular circadian mechanisms. Here, we describe how to perform and analyze the TPR assay. This technique not only allows for dissecting the molecular and neural mechanisms of TPR, but also provides new insights into the fundamental mechanisms of the brain functions that integrate different environmental signals and regulate animal behaviors. Furthermore, our recently published data suggest that the fly TPR shares features with the mammalian BTR3. Drosophila are ectotherms, in which the body temperature is typically behaviorally regulated. Therefore, TPR is a strategy used to generate a rhythmic body temperature in these flies5-8. We believe that further exploration of Drosophila TPR will facilitate the characterization of the mechanisms underlying body temperature control in animals.

Design and Analysis of Temperature Preference Behavior and its Circadian Rhythm in Drosophila

We recently identified a novel Drosophila circadian output, temperature preference rhythm (TPR), in which the preferred temperature in flies rises during the day and falls during the night. TPR is regulated independently from another circadian output, locomotor activity. Here&#160;we describe the design and analysis of TPR in Drosophila.

The circadian clock regulates many aspects of life, including sleep, locomotor activity, and body temperature (BTR) rhythms1,2. We recently identified a ...

Analysis of Nephron Composition and Function in the Adult Zebrafish Kidney

The zebrafish model has emerged as a relevant system to study kidney development, regeneration and disease. Both the embryonic and adult zebrafish kidneys are composed of functional units known as nephrons, which are highly conserved with other vertebrates, including mammals. Research in zebrafish has recently demonstrated that two distinctive phenomena transpire after adult nephrons incur damage: first, there is robust regeneration within existing nephrons that replaces the destroyed tubule epithelial cells; second, entirely new nephrons are produced from renal progenitors in a process known as neonephrogenesis. In contrast, humans and other mammals seem to have only a limited ability for nephron epithelial regeneration. To date, the mechanisms responsible for these kidney regeneration phenomena remain poorly understood. Since adult zebrafish kidneys undergo both nephron epithelial regeneration and neonephrogenesis, they provide an outstanding experimental paradigm to study these events. Further, there is a wide range of genetic and pharmacological tools available in the zebrafish model that can be used to delineate the cellular and molecular mechanisms that regulate renal regeneration. One essential aspect of such research is the evaluation of nephron structure and function. This protocol describes a set of labeling techniques that can be used to gauge renal composition and test nephron functionality in the adult zebrafish kidney. Thus, these methods are widely applicable to the future phenotypic characterization of adult zebrafish kidney injury paradigms, which include but are not limited to, nephrotoxicant exposure regimes or genetic methods of targeted cell death such as the nitroreductase mediated cell ablation technique. Further, these methods could be used to study genetic perturbations in adult kidney formation and could also be applied to assess renal status during chronic disease modeling.

The zebrafish adult kidney is an excellent system for renal regeneration and disease studies. An essential aspect of such research is the assessment of nephron structure and function. This protocol describes several methodologies that can be implemented to assess nephron tubule composition and to evaluate renal reabsorption.

The zebrafish model has emerged as a relevant system to study kidney development, regeneration and disease. Both the embryonic and adult zebrafish kidneys ...

Sequential Application of Glass Coverslips to Assess the Compressive Stiffness of the Mouse Lens: Strain and Morphometric Analyses

The eye lens is a transparent organ that refracts and focuses light to form a clear image on the retina. In humans, ciliary muscles contract to deform the lens, leading to an increase in the lens&#39; optical power to focus on nearby objects, a process known as accommodation. Age-related changes in lens stiffness have been linked to presbyopia, a reduction in the lens&#39; ability to accommodate, and, by extension, the need for reading glasses. Even though mouse lenses do not accommodate or develop presbyopia, mouse models can provide an invaluable genetic tool for understanding lens pathologies, and the accelerated aging observed in mice enables the study of age-related changes in the lens. This protocol demonstrates a simple, precise, and cost-effective method for determining mouse lens stiffness, using glass coverslips to apply sequentially increasing compressive loads onto the lens. Representative data confirm that mouse lenses become stiffer with age, like human lenses. This method is highly reproducible and can potentially be scaled up to mechanically test lenses from larger animals.

Age-related increases in eye lens stiffness are linked to presbyopia. This protocol describes a simple, cost-effective method for measuring mouse lens stiffness. Mouse lenses, like human lenses, become stiffer with age. This method is precise and can be adapted for lenses from larger animals.

The eye lens is a transparent organ that refracts and focuses light to form a clear image on the retina. In humans, ciliary muscles contract to deform the ...

High-resolution Time-lapse Imaging and Automated Analysis of Microtubule Dynamics in Living Human Umbilical Vein Endothelial Cells

The physiological process by which new vasculature forms from existing vasculature requires specific signaling events that trigger morphological changes within individual endothelial cells (ECs). These processes are critical for homeostatic maintenance such as wound healing, and are also crucial in promoting tumor growth and metastasis. EC morphology is defined by the organization of the cytoskeleton, a tightly regulated system of actin and microtubule (MT) dynamics that is known to control EC branching, polarity and directional migration, essential components of angiogenesis. To study MT dynamics, we used high-resolution fluorescence microscopy coupled with computational image analysis of fluorescently-labeled MT plus-ends to investigate MT growth dynamics and the regulation of EC branching morphology and directional migration. Time-lapse imaging of living Human Umbilical Vein Endothelial Cells (HUVECs) was performed following transfection with fluorescently-labeled MT End Binding protein 3 (EB3) and Mitotic Centromere Associated Kinesin (MCAK)-specific cDNA constructs to evaluate effects on MT dynamics. PlusTipTracker software was used to track EB3-labeled MT plus ends in order to measure MT growth speeds and MT growth lifetimes in time-lapse images. This methodology allows for the study of MT dynamics and the identification of how localized regulation of MT dynamics within sub-cellular regions contributes to the angiogenic processes of EC branching and migration.

Protocols for Human Umbilical Vein Endothelial Cell (HUVEC) culture, transient transfection of fluorescently-labeled markers of microtubule growth, live-cell imaging and automated analysis of interphase microtubule growth dynamics are detailed.

The physiological process by which new vasculature forms from existing vasculature requires specific signaling events that trigger morphological changes ...

The Assembly and Application of 'Shear Rings': A Novel Endothelial Model for Orbital, Unidirectional and Periodic Fluid Flow and Shear Stress

Deviations from normal levels and patterns of vascular fluid shear play important roles in vascular physiology and pathophysiology by inducing adaptive as well as pathological changes in endothelial phenotype and gene expression. In particular, maladaptive effects of periodic, unidirectional flow induced shear stress can trigger a variety of effects on several vascular cell types, particularly endothelial cells. While by now endothelial cells from diverse anatomic origins have been cultured, in-depth analyses of their responses to fluid shear have been hampered by the relative complexity of shear models (e.g., parallel plate flow chamber, cone and plate flow model). While these all represent excellent approaches, such models are technically complicated and suffer from drawbacks including relatively lengthy and complex setup time, low surface areas, requirements for pumps and pressurization often requiring sealants and gaskets, creating challenges to both maintenance of sterility and an inability to run multiple experiments. However, if higher throughput models of flow and shear were available, greater progress on vascular endothelial shear responses, particularly periodic shear research at the molecular level, might be more rapidly advanced. Here, we describe the construction and use of shear rings: a novel, simple-to-assemble, and inexpensive tissue culture model with a relatively large surface area that easily allows for a high number of experimental replicates in unidirectional, periodic shear stress studies on endothelial cells.

The Assembly and Application of &#039;Shear Rings&#039;: A Novel Endothelial Model for Orbital, Unidirectional and Periodic Fluid Flow and Shear Stress

Different levels and patterns of fluid shear are known to modulate endothelial gene expression, phenotype and susceptibility to disease. We discuss the assembly and use of 'shear rings': a model that produces unidirectional, periodic shear stress patterns. Shear rings are simple to assemble, economical and can produce high cell yields.

Deviations from normal levels and patterns of vascular fluid shear play important roles in vascular physiology and pathophysiology by inducing adaptive as ...