Estes métodos foram desenvolvidos por EEL durante uma licença de pesquisa no laboratório de Apoio JT foi fornecido pela Universidade DePaul Research Council e um NIH / NIDCR R01 conceder ao JT (DE016678). Agradecemos os esforços de Hunter Caroline, técnico de cuidados de animais nas instalações do núcleo zebrafish CMRC e Pawluczuk Paulina, a nossa assistente de laboratório de graduação.

Zebrafish criação Peixe-zebra são alojados e criados de acordo com métodos padronizados 1. Passado o período tardio larval, o estágio de desenvolvimento de um peixe-zebra pode ser medido pelo seu comprimento padrão (SL), ou a distância em linha reta em milímetros do ponto anteriormost do lábio superior para a base da nadadeira caudal (placa hypural posteriormost) 2. Em aproximadamente um mês após a fertilização (10-12 mm SL), o barbos nasal e maxilar aparecer como transparente brotos epiteliais perto do pits olfativa e nos cantos posterior da maxila, respectivamente. Como o peixe-zebra amadurece, a estender-se barbos estreito, whisker-como apêndices. Porque o barbo maxilar é maior (2-3 mm) e mais fácil de manipular, nosso protocolo aplica-se somente a este apêndice particular; técnicas semelhantes, no entanto, poderia ser adaptada para o menor nasal barbos. Clipping Barbel <ol><li> Anestesiar zebrafish adulto na fase desejada (por exemplo., 1,5-2,5 cm SL, ~ 3-6 meses pós-fertilização) por imersão em 0,015% MS-222 (3-aminobenzoato de etilo metanossulfonato) tamponada a 7,0 pH em água do sistema. Observe os movimentos até parar de nadar e ventilação branquial torna-se lenta e regular. Dependendo do tamanho do peixe, anestesia completa demora cerca de 05/02 minutos. </li><li> Usando um arrastão aquário, peixes de transferência de 1-3 em um momento de um pedaço dobrado de papel toalha molhada em uma placa de Petri. Usando uma espátula sem corte, orientar o peixe assim que são paralelos uns aos outro lado e lateral esquerdo para cima. Parte dobra da toalha de papel molhado sobre a parte caudal do peixe, cobrindo todo o corpo até o opérculo (guelra cobre) para manter a pele e as guelras úmidas durante o procedimento. </li><li> Ver a placa de Petri sob estereomicroscópio, utilizando-se de baixo ângulo de luz incidente para iluminar a região da cabeça. Foco na base do barbo maxilar esquerdo, que se projeta a partir do canto posterior ventral da maxila (Fig. 1). <img src="/files/ftp_upload/1558/1558fig1.jpg" alt="Figura 1" /> Figura 1. </li><li> Firmemente segure o eixo do barbo ligeiramente para a extremidade distal da maxila. Elevar o eixo barbo e inserir as mandíbulas de uma tesoura de ponta fina de primavera apenas proximal ao fórceps. A tesoura pode ser tocado com a pinça para a estabilidade. Deslize as mandíbulas da tesoura ao longo do eixo do barbo até que a ponta se aproxima da borda da maxila. Fechar a tesoura para cortar através do eixo barbos. O barbo amputada, ainda agarrado na pinça, pode ser removido para a fixação ou observação posterior. </li><li> Transferir imediatamente o peixe para um pequeno tanque de água sistema limpo (~ 500 mL) contendo uma gota de azul de metileno para controlar a infecção fúngica superficial. Permitir que o peixe se recuperar durante a noite. Na manhã seguinte, devolver o peixe para o sistema de criação. Barbel regeneração é máxima após 2 semanas. </li></ol> Incorporação de Agar Pares Barbel <ol><li> Coletar peixes pela técnica apropriada a eutanásia e fixar em um tubo de 50 mL de paraformaldeído 4% tampão fosfato (PBS) com agitação a 4 ° C durante a noite. O volume de fixador deve ser pelo menos dez vezes o volume do tecido. Após a fixação, descarte de resíduos paraformaldeído em um recipiente aprovado e lavar o tecido completamente em diversas mudanças de PBS. </li><li> Prepare em um mL de vidro 250 ml frasco 150 de 2% agarose (T m ~ 37 ° C) em água destilada. Calor com um microondas ou chapa quente, agitando periodicamente até que esteja completamente dissolvido. Equilibrar a solução fundida em um banho de água 50-60 ° C. </li><li> Montar um equipamento de eletroforese em gel padrão, colocando um molde de gel vedado pequena (10 x 10 cm; ~ 100 mL de volume gel) firmemente contra os lados da câmara de buffer. Adicionar 2-4 pequena amostra pentes de dentes (4 x 1,5 mm). </li><li> Sobre uma superfície plana, coloque a agarose derretida no molde para cobrir apenas a base dos favos, formando poços muito superficial. Imediatamente coloque a agarose sobra volta para o banho de água morna, que será usado posteriormente para incorporar o tecido (Passos 9-12). Coloque um copo longo Pasteur pipeta no frasco para manter a pipeta para a mesma temperatura que a agarose. </li><li> Permita que o gel para endurecer por 20-30 minutos. Remover os favos, em seguida, retire o molde gel contendo o gel endurecido da câmara de buffer. Firmemente a fita lados abertos do molde gel com fita de laboratório para que o gel não deslize para fora. Esta fita deve se estender vários milímetros sobre a superfície do agarose para que agarose adicionais podem ser adicionados mais tarde (Passo 13). </li><li> Posicione o molde de gel no palco de um estereomicroscópio. Ampliar um poço vazio e trazer as bordas em foco. </li><li> Sobre a superfície do agarose ao lado do bem, pipetar uma gota de água ou tampão contendo os espécimes fixos barbo (por exemplo, regenerar, e controle). Using dobrados pinos de insetos, arraste as amostras úmidas para dentro do poço e empurrá-los para o fundo. Orientar o barbo eixos paralelos um ao outro e alinhados contra oposto bordas longas do poço. Tensão superficial vai ajudar a segurar o tecido na posição. </li><li> Quando estiver pronto para incorporar, use uma ponteira fina ou o canto de um tecido de laboratório para remover o excesso de fluido do poço. Trabalhar rapidamente para não deixar o tecido secar. </li><li> Usando a pipeta Pasteur de vidro aquecido, gentilmente pipeta fresco agarose derretida e em torno da espécimes para selar o tecido barbo no lugar. Não encha demais. Antes da agarose endurece, fazer adaptações de última hora com os pinos de insetos. </li><li> Coloque uma etiqueta numerada exemplar de papel ao lado do bem e prenda-o com uma pequena gota de agarose. </li><li> Repita os passos 6 a 10 para cada poço de espécimes. </li><li> Se desejar para a calibração da imagem, inserir um pedaço de papel com uma escala micrométrica impressos (por exemplo, <a href="http://incompetech.com/graphpaper/multiwidth/">http://incompetech.com/graphpaper/multiwidth/</a> ) no fundo de um poço vazio. Achatar o papel para o fundo do poço e cobri-lo com agarose quente. </li><li> Depois de todos os espécimes são incorporados, a superfície do gel será irregular, com gotas de agarose endurecido. Coloque o gel sobre uma superfície plana e gentilmente despeje adicionais agarose derretida até a superfície superior é uniforme. Use a menor quantidade de agarose necessário para obter uma superfície lisa; muito agarose vai obscura de luz de transmissão fotografia. Permitir que esta camada superior para endurecer. </li><li> O gel pode agora ser fotografado no palco de um estereomicroscópio para registrar morfologia bruta para cada par de barbo. Calibração da imagem é obtida por fotografar a escala micrométrica incorporado. </li><li> O gel inteiro pode ser armazenado envolto em toalhas de papel molhado e selado em um saco plástico a 4 ° por várias semanas. </li><li> Para posterior análise, blocos de ágar contendo par casado de barbos podem ser cortadas do gel com uma lâmina de bisturi ou navalha e processados ​​para exame histológico de parafina ou cryosectioning por métodos padrão 3,4. Alternativamente, barbos individuais podem ser dissecados fora da agarose com agulhas finas, lavadas em água, e processados ​​para outras aplicações a jusante (por exemplo, imuno-histoquímica todo-mount ou microscopia confocal). </li></ol>

<ol>
	<li>Westerfield, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chapter+1+General+Methods+for+Zebrafish+Care.">Chapter 1 General Methods for Zebrafish Care.</a> The zebrafish book. A guide for the laboratory use of zebrafish (Danio rerio). , (2000).</li><li>Howe, J. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Standard+length:+Not+quite+so+standard.">Standard length: Not quite so standard.</a> Fisheries Research (Amsterdam). 56, 1-7 (2002).</li><li>Fischer, A. H., Jacobson, K. A., Rose, J., Zeller, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Paraffin+Embedding+Tissue+Samples+for+Sectioning.">Paraffin Embedding Tissue Samples for Sectioning.</a> Cold Spring Harbor Protocols. 6, (2008).</li><li>Westerfield, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ch+8.3+Agar+Embedding+for+Cryostat+Sectioning+of+Embryos+or+Larvae.">Ch 8.3 Agar Embedding for Cryostat Sectioning of Embryos or Larvae.</a> The zebrafish book. A guide for the laboratory use of zebrafish (Danio rerio). , (2000).</li><li>Hansen, A., Reutter, K., Zeiske, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Taste+bud+development+in+the+zebrafish,+Danio+rerio.">Taste bud development in the zebrafish, Danio rerio.</a> Dev Dyn. 223, 483-496 (2002).</li></ol>

O peixe-zebra maxilar barbo é um sistema de tecido subutilizados para estudar o crescimento, manutenção e regeneração de vários tipos de células no zebrafish. Embora o apêndice barbel não tem analógico humanos, os tipos de células que contém são altamente conservadas, tornando possível o estudo da pele, glândulas, vasos melanócitos, circulatório e os nervos em uma estrutura opticamente clara e anatomicamente simples cilíndrico. Semelhante ao fin bem estudado caudal, tecido barbel podem ser induzidas a regenerar pela amputação. Usando a fronteira da maxila como um marco anatômico, o plano de amputação pode ser colocado com precisão, facilitando a medição de barbo rebrota. Para um operador experiente, cada cirurgia leva apenas alguns segundos. A recuperação é rápida, e nós temos até agora não detectaram efeitos a curto ou a longo prazo sobre o comportamento dos peixes. Peixe-zebra com um mergulho barbel maxilar, comer e raça de forma tão eficaz como controles não-cirúrgico, e têm a sobrevivência comparável ao momento da coleta de tecido, até 6 meses após a cirurgia. O impacto fisiológico da cirurgia prevista para ser mínimo, porque 1) o paladar extraoral transportados no barbo também são encontrados em muitas outras partes do epitélio de peixes, incluindo lábios, bochechas e cabeça 5, e 2) papilas gustativas diferenciar aparecem no o barbo regeneração dentro de 72 horas (LeClair et al., dados não publicados). Isso torna o barbo maxilar um sistema minimamente invasivo para estudar a cicatrização de feridas, a revascularização e reinervação no contexto de um vertebrado adulto. Após a indução cirúrgica de regeneração, barbos podem ser coletados em intervalos de medição morfométricas e / ou análise microscópica do tecido fixo. Convenientemente, o barbo maxilar é aproximadamente o comprimento (2-3 mm) e diâmetro (100-200 mm) de um embrião de peixe-zebra, facilitando a aplicação de muitos protocolos padrão, incluindo histologia de parafina, cryosectioning, todo-mount imuno-histoquímica, e in situ hibridização. Em conjunto, estas características tornam o barbo maxilar altamente viável em modelo in vivo para estudar reparo e regeneração tecidual.

Equipamentos microscópio Um microscópio estéreo dissecando com transmitida e iluminação incidente de fibra óptica é necessário para barbel clipping e incorporação de agar. Clipping Barbel <ul><li> Água do sistema de peixe </li><li> 2 tanques de peixe-zebra cruzamento </li><li> MS-222 (3-aminobenzoato de etilo metanossulfonato; Sigma Chemical # E10521-10G) </li><li> estéril de 120 mm placa de Petri </li><li> toalhas de papel molhado </li><li> espátula de metal sem corte </li><li> Dumont # 55 Bio Inox Pinça (Ferramentas Ciência Belas # 11255-20) </li><li> Mini-Vannas primavera tesouras (Ferramentas Ciência Belas # 15000-00) </li><li> metileno agente antifúngico azul (Drs. Foster &amp; Smith # CD-905781) </li><li> pequeno aquário fishnet </li></ul> Coleta de tecido e incorporação de agar <ul><li> 4% paraformaldeído em 1x tampão fosfato (PBS-PF), até aliquotado em tubos cônicos de 50 mL e armazenadas congeladas a -20 ° C use </li><li> 1x tampão fosfato (pH 7,27-6) </li><li> 250 mL frasco de vidro </li><li> Agarose 2% em água destilada </li><li> padrão pequena plataforma eletroforese em gel de agarose (gel tamanho = ~ 10 cm quadrado) </li><li> pequeno pente de dentes amostra de eletroforese (tamanho pente 4 x 1,5 mm) </li><li> banho de água morna (50-60 ° C) </li><li> fita de laboratório </li><li> preto esmaltado pinos de insetos, o tamanho 000 (Ferramentas Ciência Belas # 26000-25) </li><li> 02/01 retentores de pinos (ferramentas de Ciência Belas # 26016-12) </li><li> De 9 polegadas de vidro Pasteur pipeta </li><li> pipeta lâmpada ou bomba </li><li> tecidos de laboratório </li><li> pequenas etiquetas de papel </li><li> (Opcional) escala de calibração impressa </li><li> toalhas de papel molhado </li><li> zip encerramento saco plástico </li><li> bisturi / lâmina de barbear (para cortar blocos de agar) </li></ul>

methods for the study of the zebrafish maxillary barbel

Barbos são apêndices sensoriais da pele encontrados em peixes, répteis e anfíbios. O peixe-zebra, Danio rerio, desenvolve dois pares de barbos-um par de curto nasal e um par mais maxilar. Barbel tecido contém células de origem ectodérmica, mesodérmica e origem da crista neural, incluindo as células da pele, glândulas, papilas gustativas, os melanócitos, vasos circulatórios e nervos sensoriais. Diferentemente da maioria dos tecidos adultos, o barbo maxilar é opticamente clara, o que nos permite visualizar o desenvolvimento ea manutenção destes tipos de tecidos em todo o ciclo de vida. Este vídeo mostra o desenvolvimento inicial do barbo maxilar (início cerca de um mês pós-fertilização) e demonstra um protocolo cirúrgico para induzir a regeneração no apêndice adultos (&gt; 3 meses pós-fertilização). Resumidamente, o barbo maxilar esquerdo de um peixe é elevado anestesiados com pinças esterilizadas imediatamente distal à borda caudal da maxila. Uma multa, tesoura primavera estéril é posicionado contra a pinça para cortar o eixo do barbo, a este nível, estabelecendo um marco anatômico para o plano de amputação. Crescimento regenerativa pode ser medida com relação a este plano, e em comparação com o barbo contralateral. Barbel tecido se regenera rapidamente, atingindo regrowth máxima dentro de 2 semanas da lesão. Técnicas de análise do barbo regeneradas incluem dissecar e incorporação de pares de barbos (regenerar e controle) nos poços de um gel de eletroforese de DNA padrão. Espécimes incorporados são convenientemente fotografados em um estereomicroscópio para a morfologia e morfometria bruta, e pode ser armazenado durante semanas antes de aplicações a jusante como histologia parafina, cryosectioning, e / ou imuno-histoquímica montar todo. Estes métodos estabelecer o barbo maxilar como um romance no sistema de tecido vivo para estudar a capacidade de regeneração dos vários tipos de células dentro do contexto genético de peixe-zebra.

Watch this Scientific Journal Video about Methods for the Study of the Zebrafish Maxillary Barbel at JoVE.com

Methods for the Study of the Zebrafish Maxillary Barbel

O peixe-zebra maxilar barbo é um órgão do sentido tegumentar contendo ectodérmica, mesodérmica e derivados da crista neural. Importante, o barbo adulta consegue regenerar após a amputação proximal. Este vídeo apresenta o desenvolvimento barbel maxilar e demonstra um protocolo cirúrgico para induzir a regeneração, seguido por incorporação de coleta, ea jusante de imagens de espécimes barbos.

Métodos para o Estudo do maxilar Zebrafish Barbel

Barbels are skin sensory appendages found in fishes, reptiles and amphibians.  The zebrafish, Danio rerio, develops two pairs of barbels- a short nasal ...

methods-for-the-study-of-the-zebrafish-maxillary-barbel

Research

JoVE Journal

Biology

12.4K visualizações.  DePaul University. O peixe-zebra maxilar barbo é um órgão do sentido tegumentar contendo ectodérmica, mesodérmica e derivados da crista neural. Importante, o barbo adulta consegue regenerar após a amputação proximal. Este vídeo apresenta o desenvolvimento barbel maxilar e demonstra um protocolo cirúrgico para induzir a regeneração, seguido por incorporação de coleta, ea jusante de imagens de espécimes barbos.

Vídeo: Methods for the Study of the Zebrafish Maxillary Barbel

Testing Visual Sensitivity to the Speed and Direction of Motion in Lizards

Testing visual sensitivity in any species provides basic information regarding behaviour, evolution, and ecology. However, testing specific features of the visual system provide more empirical evidence for functional applications. Investigation into the sensory system provides information about the sensory capacity, learning and memory ability, and establishes known baseline behaviour in which to gauge deviations (Burghardt, 1977). However, unlike mammalian or avian systems, testing for learning and memory in a reptile species is difficult. Furthermore, using an operant paradigm as a psychophysical measure of sensory ability is likewise as difficult. Historically, reptilian species have responded poorly to conditioning trials because of issues related to motivation, physiology, metabolism, and basic biological characteristics. Here, I demonstrate an operant paradigm used a novel model lizard species, the Jacky dragon (Amphibolurus muricatus) and describe how to test peripheral sensitivity to salient speed and motion characteristics. This method uses an innovative approach to assessing learning and sensory capacity in lizards. I employ the use of random-dot kinematograms (RDKs) to measure sensitivity to speed, and manipulate the level of signal strength by changing the proportion of dots moving in a coherent direction. RDKs do not represent a biologically meaningful stimulus, engages the visual system, and is a classic psychophysical tool used to measure sensitivity in humans and other animals. Here, RDKs are displayed to lizards using three video playback systems. Lizards are to select the direction (left or right) in which they perceive dots to be moving. Selection of the appropriate direction is reinforced by biologically important prey stimuli, simulated by computer-animated invertebrates.

Testing visual sensitivity in lizards using an operant conditioning paradigm that employs video playback of random-dot kinematograms and computer-generated invertebrates.

Teste de sensibilidade visual para a velocidade e direção do movimento em Lagartos

Testing visual sensitivity in any species provides basic information regarding behaviour, evolution, and ecology. However, testing specific features of ...

Biologia

Computer-Generated Animal Model Stimuli

Communication between animals is diverse and complex. Animals may communicate using auditory, seismic, chemosensory, electrical, or visual signals. In particular, understanding the constraints on visual signal design for communication has been of great interest. Traditional methods for investigating animal interactions have used basic observational techniques, staged encounters, or physical manipulation of morphology. Less intrusive methods have tried to simulate conspecifics using crude playback tools, such as mirrors, still images, or models. As technology has become more advanced, video playback has emerged as another tool in which to examine visual communication (Rosenthal, 2000). However, to move one step further, the application of computer-animation now allows researchers to specifically isolate critical components necessary to elicit social responses from conspecifics, and manipulate these features to control interactions. Here, I provide detail on how to create an animation using the Jacky dragon as a model, but this process may be adaptable for other species. In building the animation, I elected to use Lightwave  3D to alter object morphology, add texture, install bones, and provide comparable weight shading that prevents exaggerated movement. The animation is then matched to select motor patterns to replicate critical movement features. Finally, the sequence must rendered into an individual clip for presentation. Although there are other adaptable techniques, this particular method had been demonstrated to be effective in eliciting both conspicuous and social responses in staged interactions.

Computer-generated stimuli using the Jacky dragon as a model.

Gerados por computador Modelo Estímulos animal

Communication between animals is diverse and complex. Animals may communicate using auditory, seismic, chemosensory, electrical, or visual signals. In ...

Using the optokinetic response to study visual function of zebrafish

Optokinetic response (OKR) is a behavior that an animal vibrates its eyes to follow a rotating grating around it. It has been widely used to assess the visual functions of larval zebrafish1-5. Nevertheless, the standard protocol for larval fish is not yet readily applicable in adult zabrafish. Here, we introduce how to measure the OKR of adult zebrafish with our simple custom-built apparatus using a new protocol which is established in our lab. Both our apparatus and step-by-step procedure of OKR in adult zebrafish are illustrated in this video. In addition, the measurements of the larval OKR, as well as the optomotor response (OMR) test of adult zebrafish, are also demonstrated in this video. This OKR assay of adult zebrafish in our experiment may last for up to 4 hours. Such OKR test applied in adult fish will benefit to visual function investigation more efficiently when the adult fish vision system is manipulated.
Su-Qi Zou and Wu Yin contributed equally to this paper.

Optokinetic response has been widely used to assess the visual functions of larval zebrafish. Nevertheless, the standard protocol for larval fish is not yet readily applicable in adults1-5. Here, we introduce how to measure the OKR of adult zebrafish using a new protocol which is established in our lab.

Usando a resposta optocinético para estudar a função visual de zebrafish

Optokinetic response (OKR) is a behavior that an animal vibrates its eyes to follow a rotating grating around it. It has been widely used to assess the ...

Intraperitoneal Injection into Adult Zebrafish

A convenient method for chemically treating zebrafish is to introduce the reagent into the tank water, where it will be taken up by the fish. However, this method makes it difficult to know how much reagent is absorbed or taken up per fish. Some experimental questions, particularly those related to metabolic studies, may be better addressed by delivering a defined quantity to each fish, based on weight. Here we present a method for intraperitoneal (IP) injection into adult zebrafish. Injection is into the abdominal cavity, posterior to the pelvic girdle. This procedure is adapted from veterinary methods used for larger fish. It is safe, as we have observed zero mortality. Additionally, we have seen bleeding at the injection site in only 5 out of 127 injections, and in each of those cases the bleeding was brief, lasting several seconds, and the quantity of blood lost was small. Success with this procedure requires gentle handling of the fish through several steps including fasting, weighing, anesthetizing, injection, and recovery. Precautions are required to minimize stress throughout the procedure. Our precautions include using a small injection volume and a 35G needle. We use Cortland salt solution as the vehicle, which is osmotically balanced for freshwater fish. Aeration of the gills is maintained during the injection procedure by first bringing the fish into a surgical plane of anesthesia, which allows slow operculum movements, and second, by holding the fish in a trough within a water-saturated sponge during the injection itself. We demonstrate the utility of IP injection by injecting glucose and monitoring the rise in blood glucose level and its subsequent return to normal. As stress is known to increase blood glucose in teleost fish, we compare blood glucose levels in vehicle-injected and non-injected adults and show that the procedure does not cause a significant rise in blood glucose.

We demonstrate intraperitoneal injection into adult zebrafish. We use a 10 &mu;l NanoFil microsyringe controlled by a Micro4 controller and UltraMicroPump III. This demonstration includes the use of cold water as an anesthetic.

Injeção intraperitoneal em Zebrafish Adulto

A convenient method for chemically treating zebrafish is to introduce the reagent into the tank water, where it will be taken up by the fish. However, ...

Laser Ablation of the Zebrafish Pronephros to Study Renal Epithelial Regeneration

Acute kidney injury (AKI) is characterized by high mortality rates from deterioration of renal function over a period of hours or days that culminates in renal failure1. AKI can be caused by a number of factors including ischemia, drug-based toxicity, or obstructive injury1. This results in an inability to maintain fluid and electrolyte homeostasis. While AKI has been observed for decades, effective clinical therapies have yet to be developed. Intriguingly, some patients with AKI recover renal functions over time, a mysterious phenomenon that has been only rudimentally characterized1,2. Research using mammalian models of AKI has shown that ischemic or nephrotoxin-injured kidneys experience epithelial cell death in nephron tubules1,2, the functional units of the kidney that are made up of a series of specialized regions (segments) of epithelial cell types3. Within nephrons, epithelial cell death is highest in proximal tubule cells. There is evidence that suggests cell destruction is followed by dedifferentiation, proliferation, and migration of surrounding epithelial cells, which can regenerate the nephron entirely1,2. However, there are many unanswered questions about the mechanisms of renal epithelial regeneration, ranging from the signals that modulate these events to reasons for the wide variation of abilities among humans to regenerate injured kidneys.
The larval zebrafish provides an excellent model to study kidney epithelial regeneration as its pronephric kidney is comprised of nephrons that are conserved with higher vertebrates including mammals4,5. The nephrons of zebrafish larvae can be visualized with fluorescence techniques because of the relative transparency of the young zebrafish6. This provides a unique opportunity to image cell and molecular changes in real-time, in contrast to mammalian models where nephrons are inaccessible because the kidneys are structurally complex systems internalized within the animal. Recent studies have employed the aminoglycoside gentamicin as a toxic causative agent for study of AKI and subsequent renal failure: gentamicin and other antibiotics have been shown to cause AKI in humans, and researchers have formulated methods to use this agent to trigger kidney damage in zebrafish7,8. However, the effects of aminoglycoside toxicity in zebrafish larvae are catastrophic and lethal, which presents a difficulty when studying epithelial regeneration and function over time. Our method presents the use of targeted cell ablation as a novel tool for the study of epithelial injury in zebrafish. Laser ablation gives researchers the ability to induce cell death in a limited population of cells. Varying areas of cells can be targeted based on morphological location, function, or even expression of a particular cellular phenotype. Thus, laser ablation will increase the specificity of what researchers can study, and can be a powerful new approach to shed light on the mechanisms of renal epithelial regeneration. This protocol can be broadly applied to target cell populations in other organs in the zebrafish embryo to study injury and regeneration in any number of contexts of interest.

Acute kidney injury (AKI) in humans is a common clinical problem caused by damage to the epithelial cells that comprise kidney nephrons, and AKI is associated with high mortality rates of 50-70%1. Following epithelial cell destruction, nephrons have a limited ability to regenerate, though the mechanisms and limitations that guide this phenomenon remain poorly understood. In this video article, we describe our technique for targeted laser ablation of kidney nephron cells in the zebrafish embryo kidney, or pronephros. Our new method can be used to complement nephrotoxicity-induced models of AKI and gain a high-resolution understanding of the cell and molecular alterations that are associated with epithelial regeneration in the kidney nephron.

Ablação a laser da Pronephros Zebrafish para estudo da regeneração epitelial renal

Acute kidney injury (AKI) is characterized by high mortality rates from deterioration of renal function over a period of hours or days that culminates in ...

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.

Em Eletroporação vivo de Morpholinos na Retina Zebrafish Adulto

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

In vivo Electroporation of Morpholinos into the Regenerating Adult Zebrafish Tail Fin

Certain species of urodeles and teleost fish can regenerate their tissues. Zebrafish have become a widely used model to study the spontaneous regeneration of adult tissues, such as the heart1, retina2, spinal cord3, optic nerve4, sensory hair cells5, and fins6.
The zebrafish fin is a relatively simple appendage that is easily manipulated to study multiple stages in epimorphic regeneration. Classically, fin regeneration was characterized by three distinct stages: wound healing, blastema formation, and fin outgrowth. After amputating part of the fin, the surrounding epithelium proliferates and migrates over the wound. At 33 &deg;C, this process occurs within six hours post-amputation (hpa, Figure 1B)6,7. Next, underlying cells from different lineages (ex. bone, blood, glia, fibroblast) re-enter the cell cycle to form a proliferative blastema, while the overlying epidermis continues to proliferate (Figure 1D)8. Outgrowth occurs as cells proximal to the blastema re-differentiate into their respective lineages to form new tissue (Figure 1E)8. Depending on the level of the amputation, full regeneration is completed in a week to a month.
The expression of a large number of gene families, including wnt, hox, fgf, msx, retinoic acid, shh, notch, bmp, and activin-betaA genes, is up-regulated during specific stages of fin regeneration9-16. However, the roles of these genes and their encoded proteins during regeneration have been difficult to assess, unless a specific inhibitor for the protein exists13, a temperature-sensitive mutant exists or a transgenic animal (either overexpressing the wild-type protein or a dominant-negative protein) was generated7,12. We developed a reverse genetic technique to quickly and easily test the function of any gene during fin regeneration.
Morpholino oligonucleotides are widely used to study loss of specific proteins during zebrafish, Xenopus, chick, and mouse development17-19. Morpholinos basepair with a complementary RNA sequence to either block pre-mRNA splicing or mRNA translation. We describe a method to efficiently introduce fluorescein-tagged antisense morpholinos into regenerating zebrafish fins to knockdown expression of the target protein. The morpholino is micro-injected into each blastema of the regenerating zebrafish tail fin and electroporated into the surrounding cells. Fluorescein provides the charge to electroporate the morpholino and to visualize the morpholino in the fin tissue.
This protocol permits conditional protein knockdown to examine the role of specific proteins during regenerative fin outgrowth. In the Discussion, we describe how this approach can be adapted to study the role of specific proteins during wound healing or blastema formation, as well as a potential marker of cell migration during blastema formation.

In vivo Electroporation of Morpholinos into the Regenerating Adult Zebrafish Tail Fin

We describe a method to conditionally knockdown the expression of a target protein during adult zebrafish fin regeneration. This technique involves micro-injecting and electroporating antisense oligonucleotide morpholinos into fin tissue, which allows testing the protein&#x2019;s role in various stages of fin regeneration, including wound healing, blastema formation, and regenerative outgrowth.

Na eletroporação in vivo de Morpholinos no Adulto Regeneração Zebrafish Cauda Fin

Certain species of urodeles and teleost fish can regenerate their tissues. Zebrafish have become a widely used model to study the spontaneous regeneration ...

Do-It-Yourself Device for Recovery of Cryopreserved Samples Accidentally Dropped into Cryogenic Storage Tanks

Liquid nitrogen is colorless, odorless, extremely cold (-196 &deg;C) liquid kept under pressure. It is commonly used as a cryogenic fluid for long term storage of biological materials such as blood, cells and tissues 1,2. The cryogenic nature of liquid nitrogen, while ideal for sample preservation, can cause rapid freezing of live tissues on contact - known as 'cryogenic burn'2, which may lead to severe frostbite in persons closely involved in storage and retrieval of samples from Dewars. Additionally, as liquid nitrogen evaporates it reduces the oxygen concentration in the air and might cause asphyxia, especially in confined spaces2.
In laboratories, biological samples are often stored in cryovials or cryoboxes stacked in stainless steel racks within the Dewar tanks1. These storage racks are provided with a long shaft to prevent boxes from slipping out from the racks and into the bottom of Dewars during routine handling. All too often, however, boxes or vials with precious samples slip out and sink to the bottom of liquid nitrogen filled tank. In such cases, samples could be tediously retrieved after transferring the liquid nitrogen into a spare container or discarding it. The boxes and vials can then be relatively safely recovered from emptied Dewar. However, the cryogenic nature of liquid nitrogen and its expansion rate makes sunken sample retrieval hazardous. It is commonly recommended by Safety Offices that sample retrieval be never carried out by a single person. Another alternative is to use commercially available cool grabbers or tongs to pull out the vials3. However, limited visibility within the dark liquid filled Dewars poses a major limitation in their use.
In this article, we describe the construction of a Cryotolerant DIY retrieval device, which makes sample retrieval from Dewar containing cryogenic fluids both safe and easy.

Here we present a low cost, durable cryotolerant device for sample retrieval from Dewar tanks filled with liquid nitrogen. The ease of construction and modular design of the device makes the process of sample retrieval from cryogenic tanks safe and easy.

Do-It-Yourself Dispositivo de Recuperação de amostras criopreservadas cair acidentalmente em Tanques de armazenamento criogênico

Liquid nitrogen is colorless, odorless, extremely cold (-196 &deg;C) liquid kept under pressure. It is commonly used as a cryogenic fluid for long term ...

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.

Gavaging Zebrafish Adulto

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

Methods for the Extraction of Endosymbionts from the Whitefly Bemisia tabaci

Bacterial symbionts form an intimate relationship with their hosts and confer advantages to the hosts in most cases. Genomic information is critical to study the functions and evolution of bacterial symbionts in their host. As most symbionts cannot be cultured in vitro, methods to isolate an adequate quantity of bacteria for genome sequencing are very important. In the whitefly Bemisia tabaci, a number of endosymbionts have been identified and are predicted to be of importance in the development and reproduction of the pests through multiple approaches. However, the mechanism underpinning the associations remains largely unknown. The obstacle partially comes from the fact that the endosymbionts in whitefly, mostly restrained in bacteriocytes, are hard to separate from the host cells. Here we report a step-by-step protocol for the identification, extraction and purification of endosymbionts from the whitefly B. tabaci mainly by dissection and filtration. Endosymbiont samples prepared by this method, although still a mixture of different endosymbiont species, are suitable for subsequent genome sequencing and analysis of the possible roles of endosymbionts in B. tabaci. This method may also be used to isolate endosymbionts from other insects.

Methods for the Extraction of Endosymbionts from the Whitefly Bemisia tabaci

Here, we present a protocol to isolate endosymbionts from the whitefly Bemisia tabaci through dissection and filtration. After amplification, the DNA samples are suitable for subsequent sequencing and study of the mutualism between endosymbionts and whitefly.

Métodos para a extração de endossimbiontes da mosca branca<em&gt; Bemisia tabaci</em

Bacterial symbionts form an intimate relationship with their hosts and confer advantages to the hosts in most cases. Genomic information is critical to ...