Este projecto foi apoiado pela National Science Foundation Natural da China (NSFC): 31301950 e 31671288.

O método atual foi estabelecido e validado para colher e armazenar mais de 1.000 amostras de músculo para a coloração histológica em nosso laboratório. Todos os procedimentos envolvendo cuidados com os animais e uso seguiu as diretrizes estabelecidas pelo Ministério da Agricultura da China. 1. Equipamentos para Coleta de Amostras <ol><li> Rotular a identidade da amostra em cada frasco criogénico. Nota: O criotubo foi especialmente concebido para congelar amostras de tecido fresco para o procedimento criocorte (Figura 1A). Os frascos para injectáveis são feitas de polipropileno numa fábrica de molde (Figura 1C). </li><li> Obter o seguinte equipamento: azoto líquido em um tanque de azoto líquido apropriado, óculos de segurança ou uma viseira, luvas congeladores, 10 cm fórceps, 25 pinças cm, uma caixa de isopor (dimensões internas: 20 cm de comprimento x 12 cm de largura x 13,5 cm de altura ; dimensões externas: 24 cm de comprimento x 16 cm de largura x 15 cm de altura), película de plástico (2,5 cm de comprimento x 0,8 cm de largura x 0,1 mm de espessura),um bisturi, e as tampas de ligação A4 PVC (21 cm x 29,5 centímetros) (Figura 1B). </li></ol> 2. Preparação de amostras de músculo <ol><li> Encher a caixa de isopor com azoto líquido 5 min antes da recolha da amostra. NOTA: O grande coluna de azoto líquido é essencial porque parte do azoto líquido evapora e se transforma em gás quando amostras frescas tocá-lo. A fim de reduzir a frequência de transferência de azoto líquido para repor a perda, uma caixa de isopor dimensionado apropriadamente deve ser adquirida antecipadamente de acordo com o número de amostras. </li><li> Uma vez que uma amostra é obtida, gentilmente colocá-lo sobre uma peça de cobertura de ligação A4 PVC e observar o sentido das fibras musculares. NOTA: Aqui, usamos o corte transversal do músculo longissimus doris da primeira para a última vértebra lombar em porcos. Os espécimes são cerca de 12 cm de comprimento, 8 cm de largura e 5 cm de altura. </li><li> Use um bisturi para fazer duas incisões paralelas através do i espécimen a direcção das fibras musculares, aproximadamente 3 cm de comprimento e 0,6 cm de distância. Aparar a incisão do músculo num rectângulo de aproximadamente 0,6 cm de largura x 0,6 cm de altura x 1,5 cm de comprimento. NOTA: A fiabilidade da medição da área da secção transversal das fibras musculares depende principalmente da orientação das fibras do músculo incisa. </li><li> Usar 10 cm fórceps para colocar suavemente a amostra sobre uma peça de película de plástico, com o eixo longitudinal do músculo paralelo incisão ao longo do bordo do filme (Figura 2A). NOTA: O filme plástico tem duas funções: uma função de exploração, que ajuda na fixação da orientação das fibras musculares e uma função de adesão que impede fissuras na amostra devido a congelação rápida. </li><li> Usando fórceps, colocar o tecido muscular em parte inferior central de um criotubo marcado, apenas entre os orifícios de entrada de ar, e, em seguida, tapar bem o frasco (Figura 2B). </li></ol> 3. Congelamento e Armazenamento de amostra de músculos <ol><li> Usando pinças 25 cm, rapidamente submergir todo o frasco criogénico em azoto líquido na caixa de isopor pré-arrefecida, espera até que o azoto líquido não ferva (aproximadamente 10-20 s). NOTA: O criotubo irá flutuar quando o azoto líquido está em ebulição, então cuidadosamente imergir o frasco em azoto líquido em ebulição durante 10-20 s. </li><li> Transferir as amostras de músculo a um tanque de armazenamento de azoto líquido ou uma -80 ° C congelador para armazenamento a longo prazo. </li></ol> 4. Preparação corrediça <ol><li> Precool um criostato a entre -20 ° C e -22 ° C. </li><li> Remover e descartar o velho lâmina micrótomo, limpar o suporte da faca e a placa de anti-rolo no criostato, instalar uma nova lâmina micrótomo no criostato, e definir a espessura de corte de 8? M. </li><li> Transfira a amostra muscular no frasco criogico a partir do tanque de armazenamento de azoto líquido ou a -80 ° C para o congelador criostato, transportando-o em azoto líquido ou em gelo seco. </li&gt; <li> Esperar 30 min para o espécime para equilibrar com a temperatura do criostato. NOTA: Qualquer equipamento que possa tocar o espécime tem de ser pré-arrefecido, porque uma temperatura elevada pode provocar a formação de cristais de gelo na amostra. </li><li> Montar a amostra no suporte da amostra, sob a formulação temperatura de corte óptima de glicóis e resinas solúveis em água (PTU). Cortar as secções 8 mícrons. NOTA: Ajustar o ângulo de corte de forma perpendicular à orientação das fibras musculares, porque o CSAF é a área da secção transversal das fibras musculares. </li><li> Montar as secções em direcção ao centro de uma microlâmina à temperatura ambiente. colocar imediatamente a deslizar para uma caixa de corrediça numa -80 ° C congelador. Não permita que o slide para secar em temperatura ambiente. </li></ol>

<ol>
	<li>Joo, S. T., Kim, G. D., Hwang, Y. H., Ryu, Y. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Control+of+fresh+meat+quality+through+manipulation+of+muscle+fiber+characteristics.">Control of fresh meat quality through manipulation of muscle fiber characteristics.</a> Meat Sci. 95 (4), 828-836 (2013).</li><li>Lefaucheur, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+second+look+into+fibre+typing--relation+to+meat+quality.">A second look into fibre typing--relation to meat quality.</a> Meat Sci. 84 (2), 257-270 (2010).</li><li>Fiems, L. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Double+Muscling+in+Cattle:+Genes,+Husbandry,+Carcasses+and+Meat.">Double Muscling in Cattle: Genes, Husbandry, Carcasses and Meat.</a> Animals (Basel). 2 (3), 472-506 (2012).</li><li>Cockett, N. E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+callipyge+mutation+and+other+genes+that+affect+muscle+hypertrophy+in+sheep.">The callipyge mutation and other genes that affect muscle hypertrophy in sheep.</a> Genet Sel Evol. 37, 65-81 (2005).</li><li>Stinckens, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+RYR1+g.1843C&gt;T+mutation+is+associated+with+the+effect+of+the+IGF2+intron3-g.3072G&gt;A+mutation+on+muscle+hypertrophy.">The RYR1 g.1843C&gt;T mutation is associated with the effect of the IGF2 intron3-g.3072G&gt;A mutation on muscle hypertrophy.</a> Anim Genet. 38 (1), 67-71 (2007).</li><li>Brameld, J. M., Buttery, P. J., Dawson, J. M., Harper, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nutritional+and+hormonal+control+of+skeletal-muscle+cell+growth+and+differentiation.">Nutritional and hormonal control of skeletal-muscle cell growth and differentiation.</a> Proc Nutr Soc. 57 (2), 207-217 (1998).</li><li>Reinoso, R. F., Telfer, B. A., Rowland, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tissue+water+content+in+rats+measured+by+desiccation.">Tissue water content in rats measured by desiccation.</a> J Pharmacol Toxicol Methods. 38 (2), 87-92 (1997).</li><li>Meng, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tissue+triage+and+freezing+for+models+of+skeletal+muscle+disease.">Tissue triage and freezing for models of skeletal muscle disease.</a> J Vis Exp. (89), (2014).</li><li>Kumar, A., Accorsi, A., Rhee, Y., Girgenrath, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Do's+and+don'ts+in+the+preparation+of+muscle+cryosections+for+histological+analysis.">Do's and don'ts in the preparation of muscle cryosections for histological analysis.</a> J Vis Exp. (99), e52793 (2015).</li><li>Meijer, A. E., Vloedman, A. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+histochemical+characterization+of+the+coupling+state+of+skeletal+muscle+mitochondria.">The histochemical characterization of the coupling state of skeletal muscle mitochondria.</a> Histochemistry. 69 (3), 217-232 (1980).</li><li>Harnkarnsujarit, N., Kawai, K., Suzuki, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+Freezing+Temperature+and+Water+Activity+on+Microstructure,+Color,+and+Protein+Conformation+of+Freeze-Dried+Bluefin+Tuna+(Thunnus+orientalis).">Effects of Freezing Temperature and Water Activity on Microstructure, Color, and Protein Conformation of Freeze-Dried Bluefin Tuna (Thunnus orientalis).</a> Food Bioprocess Technol. 8 (4), 916-925 (2015).</li><li>Dubowitz, V., Sewry, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Muscle Biopsy: A Practical Approach. , 407-422 (2007).</li><li>Suvarna, S. K., Layton, C., Bancroft, J. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Bancroft's Theory and Practice of Histological Techniques: Expert Consult: Online and Print, 7e. , (2008).</li><li>Sulaiman, S. A., Kamarudin, N. A. Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bubbles+Size+Estimation+in+Liquid+Flow+Through+a+Vertical+Pipe.">Bubbles Size Estimation in Liquid Flow Through a Vertical Pipe.</a> J Appl Sci. 12 (23), 2464-2468 (2012).</li><li>Fukutomi, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Study+of+A+Flow+through+Small+Apertures+:+2nd+Report,+Experiments+on+The+Velocity+Field.">A Study of A Flow through Small Apertures : 2nd Report, Experiments on The Velocity Field.</a> Nihon Kikai Gakkai Ronbunshu B Hen/transactions of the Japan Society of Mechanical Engineers Part B. 53 (496), 3516-3521 (1987).</li><li>Shah, M. S., Joshi, J. B., Kalsi, A. S., Prasad, C. S. R., Shukla, D. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Analysis+of+flow+through+an+orifice+meter:+CFD+simulation.">Analysis of flow through an orifice meter: CFD simulation.</a> Chem Eng Sci. 71 (9), 300-309 (2012).</li></ol>

Não há conflitos de interesse, financeiro ou outro, são declarados pelos autores.

Aqui, descrevemos um novo, cryovial multi-buraco para congelar e armazenar os tecidos musculares para realizar avaliações histológicas da função muscular. O passo crítico modificado neste protocolo é que a amostra no criotubo multi-furo é directamente imerso em azoto líquido. Para o nosso conhecimento, esta é a maneira mais simples e rapidest obter excelentes amostras congeladas para cryosectioning muscular entre os métodos de congelação existentes (ver os resultados representativos). <p class="jove_con...

O músculo esquelético é o componente mais valioso de um animal produtor de carne a partir do ponto de vista nutricional e processamento. Na indústria da carne, há dois aspectos especialmente críticos: a eficiência de crescimento muscular e a qualidade da carne resultante. Como um componente principal do músculo, as fibras musculares estão directamente relacionadas com o desempenho do crescimento e qualidade da carne fresca em animais 1. Por exemplo, o número total de fibras (TNF) e a área da secção transversal das fibras (CSAF) principalmente determinar a massa muscular e a qualidade da carne; Também, Tipo de fibra Composição (FTC) afeta fortemente a qualidade da carne fresca 2. Portanto, a manipulação de características da fibra muscular em animais é um método altamente eficaz para aumentar a rentabilidade do núcleo e da competitividade de quintas 1. Até à data, vários factores intrínsecos e extrínsecos têm sido identificados para manipular characterist fibra muscularics 1. Esta manipulação pode ser obtida através da escolha adequada dos animais com genes específicos, tais como o gene da miostatina em gado 3, o gene Callipyge em ovelhas 4, e o RYR1 e genes IGF2 em porcos 5. Além disso, o controle da dieta e tratamentos com hormônios específicos desempenham um papel importante em características da fibra muscular 6. Assim, uma abordagem que combina fatores genéticos e nutricionais pode ser capaz de melhorar o teor de carne magra e qualidade da carne. No entanto, os estudos sobre fibras musculares estão limitados na indústria da carne, porque a elucidação da estrutura de fibras musculares é ainda um desafio. propriedades da fibra muscular são identificados utilizando métodos histoquímicos, tais como o ensaio de miosina adenosina trifosfatase (ATPase). Este método baseia-se no facto de enzimas localizadas em secções finas (6-8? M) congelados defibras musculares pode ser feito reagir quimicamente com determinados produtos. No entanto, o teor de água de músculos é maior do que 75% em porcos, coelhos, ratos e seres humanos, independentemente da posição (isto é, costas, abdómen, ou dos membros posteriores) 7. Tal teor de humidade elevado em músculos provoca um problema vulgarmente encontrado - congelação artefactos - durante a preparação dos criocortes, como anteriormente descrito 8, 9. Na maioria dos casos, é quase impossível para congelar adequadamente tecidos musculares em uma linha de produção matadouro, de acordo com a nossa experiência. O protocolo aqui apresentado descreve um método simples e eficiente utilizado no nosso laboratório para congelar tecidos musculares para cryosectioning de um modo de elevado rendimento. O destaque do presente método é um novo frasco de congelação que é concebido para tecidos musculares de flash-congelação em azoto líquido. O fluxo de trabalho de corrente pode simultaneamente facilitar tecidoscongelamento e processamento para uma excelente criocorte muscular, com um compartimento citoplasmático claramente visível e a aposição apertada de miofibras para o tecido circundante. Além disso, este protocolo pode ser aplicado a uma grande variedade de opções para a análise de tecido por causa de azoto líquido não se mistura com os tecidos.

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		<col />
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	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:140px;">Cryostat Microtome</td>
			<td style="width:111px;">&#160;Leica</td>
			<td style="width:111px;">Leica CM1950</td>
			<td style="width:148px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Digital Microscope&#160;</td>
			<td>Nikon</td>
			<td>Nikon DS-U3</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:140px;">&#160;Cryogenic Vial&#160;&#160; Plastic film</td>
			<td></td>
			<td></td>
			<td>Designed by ourself</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Liquid Nitrogen</td>
			<td></td>
			<td></td>
			<td>Commomly-used</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Scalpel</td>
			<td></td>
			<td></td>
			<td>Commomly-used</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">10cm-forcep</td>
			<td></td>
			<td></td>
			<td>Commomly-used</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">25cm-tweezer</td>
			<td></td>
			<td></td>
			<td>Commomly-used</td>
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		<tr height="20">
			<td height="20" style="height:20px;">Safety glass</td>
			<td></td>
			<td></td>
			<td>Commomly-used</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Freezer gloves</td>
			<td></td>
			<td></td>
			<td>Commomly-used</td>
		</tr>
	</tbody>
</table>

a multi-hole cryovial eliminates freezing artifacts when muscle tissues are directly immersed in liquid nitrogen

Estudos sobre a fisiologia do músculo esquelético enfrentar o desafio técnico de processar adequadamente as amostras para obtenção de cortes com compartimentos citoplasmáticos claramente visíveis. Outro obstáculo é a aposição apertada de miofibras para os tecidos circundantes. Uma vez que o processo de fixação do tecido e parafina leva ao encolhimento das fibras musculares, congelamento é um meio óptimas de endurecimento tecido muscular para seccionamento. No entanto, um problema vulgarmente encontrado, a formação de cristais de gelo, ocorre durante a preparação de secções congeladas por causa do elevado teor de água de músculo. O protocolo aqui apresentado descreve um primeiro método simples e eficiente para a congelação de tecidos musculares adequadamente por imersão em azoto líquido. O problema com o uso de azoto líquido sozinho é que ele provoca a formação de uma barreira de gás de azoto ao lado do tecido, que actua como um isolador e inibe o arrefecimento dos tecidos. Para evitar este efeito &quot;cobertor de vapor&quot;, a new criotubo foi concebido para aumentar a velocidade do fluxo de líquido em torno da superfície do tecido. Isto foi conseguido por perfuração de um total de 14 orifícios de entrada na parede do frasco. De acordo com a dinâmica de bolha, uma taxa mais elevada de resultados de escoamento de líquido em bolhas mais pequenas e menos possibilidades de formar uma barreira ao gás. Quando azoto líquido flui para dentro do frasco de congelação através dos orifícios de entrada de ar, a velocidade do fluxo em torno do tecido é suficientemente rápido para eliminar a barreira de gás. Em comparação com o método de congelação dos tecidos musculares usando isopentano pré-arrefecido, este protocolo é mais simples e mais eficiente e pode ser usada para congelar músculo de um modo de transferência. Além disso, este método é ideal para instituições que não têm acesso a isopentano, que é extremamente inflamável à temperatura ambiente.

A ilustração criotubo e o equipamento laboratorial comum para a congelação de músculos durante a preparação de secções congeladas são mostrados na Figura 1. Os criotubos são feitos de polipropileno num molde fábrica. Cada frasco tem um total de 14 orifícios de entrada: um está no tampão; outra está na parte inferior; e os restantes 12 formam quatro linhas paralelas, cada uma com quatro orifícios a 90 ° um do outro. Estes orifícios de entrada de ar pode...

Watch this Scientific Journal Video about A Multi-hole Cryovial Eliminates Freezing Artifacts when Muscle Tissues are Directly Immersed in Liquid Nitrogen at JoVE.com

A Multi-hole Cryovial Eliminates Freezing Artifacts when Muscle Tissues are Directly Immersed in Liquid Nitrogen

Este protocolo descreve um processo para congelar os tecidos musculares, mergulhando-os directamente em azoto líquido. Este protocolo também realça um novo frasco de congelação que pode evitar o &quot;efeito manta&quot; de gás de azoto quando os contactos de azoto líquido da superfície do tecido de um espécime.

Um multi-furo criotubo Elimina congelação Artifacts quando tecidos musculares são directamente Imerso em azoto líquido

Studies on skeletal muscle physiology face the technical challenge of appropriately processing the specimens to obtain sections with clearly visible ...

a-multi-hole-cryovial-eliminates-freezing-artifacts-when-muscle

Research

JoVE Journal

Biology

11.2K visualizações.  Jiangxi Agricultural University.  Este protocolo descreve um processo para congelar os tecidos musculares, mergulhando-os directamente em azoto líquido. Este protocolo também realça um novo frasco de congelação que pode evitar o "efeito manta" de gás de azoto quando os contactos de azoto líquido da superfície do tecido de um espécime. 

Vídeo: A Multi-hole Cryovial Eliminates Freezing Artifacts when Muscle Tissues are Directly Immersed in Liquid Nitrogen

Freezing Human ES Cells

Here we demonstrate how our lab freezes HuES human embryonic stem cell lines.  A healthy, exponentially expanding culture is washed with PBS to remove residual media that could otherwise quench the Trypsin reaction.  Warmed 0.05% Trypsin-EDTA is then added to cover the cells, and the plate allowed to incubate for up to 5 mins at room temperature.  During this time cells can be observed rounding, and colonies lifting off the plate surface.  Gentle repeated pipetting will remove cells and colonies from the plate surface.  Trypsinized cells are placed in a standard conical tube containing pre-warmed hES cell media to quench remaining trypsin, and then spun.  Cells are resuspended growth media at a concentration of approximately one million cells in one mL of media, a concentration such that one frozen aliquot is sufficient to resurrect a culture on a 10cm plate.  After cells are adequately resuspended, ice cold freezing media is added at equal volume.  Cell suspensions are mixed thoroughly, aliquoted into freezing vials, and allowed to slowly freeze to -80C over 24 hours.  Frozen cells can then moved to the vapor phase of liquid nitrogen for long term storage, or remain at -80 for approximately six months.

Here we demonstrate how our lab freezes HuES human embryonic stem cell lines.

Congelamento células ES

Here we demonstrate how our lab freezes HuES human embryonic stem cell lines.  A healthy, exponentially expanding culture is washed with PBS to remove ...

Biologia

Flash Freezing and Cryosectioning E12.5 Mouse Brain

Demonstrated in this video are the techniques for flash freezing and sectioning embryonic brain tissue from mouse. Useful tips for using the cryostat are given, including troubleshooting methods that can be used while cutting to ensure that the resultant tissues sections are free of cracks and other distortions.

Flash Freezing e Cryosectioning E12.5 cérebro de camundongo

Freezing, Thawing, and Packaging Cells for Transport

Cultured mammalian cells are used extensively in cell biology studies. It requires a number of special skills in order to be able to preserve the structure, function, behavior, and biology of the cells in culture. This video describes the basic skills required to freeze and store cells and how to recover frozen stocks. 

Cultured mammalian cells are used extensively in cell biology studies. This video describes the basic skills required to freeze and store cells and how to recover frozen stocks.

Congelamento, descongelamento e Células de embalagem para transporte

Cultured mammalian cells are used extensively in cell biology studies. It requires a number of special skills in order to be able to preserve the ...

Freezing and Thawing Human Embryonic Stem Cells

Since James Thomson et al developed a technique in 1998 to isolate and grow hES in culture, freezing cells for later use and thawing and expanding cells from a frozen stock have become important procedures performed in routine hES cell culture. Since hES cells are very sensitive to the stresses of freezing and thawing, special care must taken. Here we demonstrate the proper technique for rapidly thawing hES cells from liquid nitrogen stocks, plating them on mouse embryonic feeder cells, and slowly freezing them for long-term storage.

Since James Thomson et al developed a technique in 1998 to isolate and grow hES in culture, freezing cells for later use and thawing and expanding cells from a frozen stock have become important procedures performed in routine hES cell culture. Since hES cells are very sensitive to the stresses of freezing and thawing, special care must taken. Here we demonstrate the proper technique for rapidly thawing hES cells from liquid nitrogen stocks, plating them on mouse embryonic feeder cells, and slowly freezing them for long-term storage.

Congelamento e descongelamento, células estaminais embrionárias humanas

Since James Thomson et al developed a technique in 1998 to isolate and grow hES in culture, freezing cells for later use and thawing and expanding cells ...

Culturing of Human Nasal Epithelial Cells at the Air Liquid Interface

In vitro models using human primary epithelial cells are essential in understanding key functions of the respiratory epithelium in the context of microbial infections or inhaled agents. Direct comparisons of cells obtained from diseased populations allow us to characterize different phenotypes and dissect the underlying mechanisms mediating changes in epithelial cell function. Culturing epithelial cells from the human tracheobronchial region has been well documented, but is limited by the availability of human lung tissue or invasiveness associated with obtaining the bronchial brushes biopsies. Nasal epithelial cells are obtained through much less invasive superficial nasal scrape biopsies and subjects can be biopsied multiple times with no significant side effects. Additionally, the nose is the entry point to the respiratory system and therefore one of the first sites to be exposed to any kind of air-borne stressor, such as microbial agents, pollutants, or allergens. 
Briefly, nasal epithelial cells obtained from human volunteers are expanded on coated tissue culture plates, and then transferred onto cell culture inserts. Upon reaching confluency, cells continue to be cultured at the air-liquid interface (ALI), for several weeks, which creates more physiologically relevant conditions. The ALI culture condition uses defined media leading to a differentiated epithelium that exhibits morphological and functional characteristics similar to the human nasal epithelium, with both ciliated and mucus producing cells. Tissue culture inserts with differentiated nasal epithelial cells can be manipulated in a variety of ways depending on the research questions (treatment with pharmacological agents, transduction with lentiviral vectors, exposure to gases, or infection with microbial agents) and analyzed for numerous different endpoints ranging from cellular and molecular pathways, functional changes, morphology, etc. 
In vitro models of differentiated human nasal epithelial cells will enable investigators to address novel and important research questions by using organotypic experimental models that largely mimic the nasal epithelium in vivo.

Nasal epithelial cells, obtained through superficial scrape biopsy of human volunteers, are expanded and transferred onto tissue culture inserts. Upon reaching confluency, cells are grown at air liquid interface, yielding cultures of ciliated and non-ciliated cells. Differentiated nasal epithelial cell cultures provide viable experimental models for studying the respiratory mucosa.

A cultura de células epiteliais nasais Humano na interface ar líquido

In vitro models using human primary  epithelial cells are essential in understanding key functions of the respiratory  epithelium in the context of ...

Aip1p Dynamics Are Altered by the R256H Mutation in Actin

Mutations in actin cause a range of human diseases due to specific molecular changes that often alter cytoskeletal function. In this study, imaging of fluorescently tagged proteins using total internal fluorescence (TIRF) microscopy is used to visualize and quantify changes in cytoskeletal dynamics. TIRF microscopy and the use of fluorescent tags also allows for quantification of the changes in cytoskeletal dynamics caused by mutations in actin. Using this technique, quantification of cytoskeletal function in live cells valuably complements in vitro studies of protein function. As an example, missense mutations affecting the actin residue R256 have been identified in three human actin isoforms suggesting this amino acid plays an important role in regulatory interactions. The effects of the actin mutation R256H on cytoskeletal movements were studied using the yeast model. The protein, Aip1, which is known to assist cofilin in actin depolymerization, was tagged with green fluorescent protein (GFP) at the N-terminus and tracked in vivo using TIRF microscopy. The rate of Aip1p movement in both wild type and mutant strains was quantified. In cells expressing R256H mutant actin, Aip1p motion is restricted and the rate of movement is nearly half the speed measured in wild type cells (0.88 &#177; 0.30 &#956;m/sec in R256H cells compared to 1.60 &#177; 0.42 &#956;m/sec in wild type cells, p &#60; 0.005).

Disease-causing mutations in actin can alter cytoskeletal function. Cytoskeletal dynamics are quantified through imaging of fluorescently tagged proteins using total internal fluorescence microscopy. As an example, the cytoskeletal protein, Aip1p, has altered localization and movement in cells expressing the mutant actin isoform, R256H.

Aip1p Dynamics são alteradas pela R256H Mutação em actina

Mutations in actin cause a range of human diseases due to specific molecular changes that often alter cytoskeletal function. In this study, imaging of ...

Tissue Triage and Freezing for Models of Skeletal Muscle Disease

Skeletal muscle is a unique tissue because of its structure and function, which requires specific protocols for tissue collection to obtain optimal results from functional, cellular, molecular, and pathological evaluations. Due to the subtlety of some pathological abnormalities seen in congenital muscle disorders and the potential for fixation to interfere with the recognition of these features, pathological evaluation of frozen muscle is preferable to fixed muscle when evaluating skeletal muscle for congenital muscle disease. Additionally, the potential to produce severe freezing artifacts in muscle requires specific precautions when freezing skeletal muscle for histological examination that are not commonly used when freezing other tissues. This manuscript describes a protocol for rapid freezing of skeletal muscle using isopentane (2-methylbutane) cooled with liquid nitrogen to preserve optimal skeletal muscle morphology. This procedure is also effective for freezing tissue intended for genetic or protein expression studies. Furthermore, we have integrated our freezing protocol into a broader procedure that also describes preferred methods for the short term triage of tissue for (1) single fiber functional studies and (2) myoblast cell culture, with a focus on the minimum effort necessary to collect tissue and transport it to specialized research or reference labs to complete these studies. Overall, this manuscript provides an outline of how fresh tissue can be effectively distributed for a variety of phenotypic studies and thereby provides standard operating procedures (SOPs) for pathological studies related to congenital muscle disease.

The analysis of skeletal muscle tissues to determine structural, functional, and biochemical properties is greatly facilitated by appropriate preparation. This protocol describes appropriate methods to prepare skeletal muscle tissue for a broad range of phenotyping studies.

Triagem de Tecidos e Congelamento de modelos de doença do músculo esquelético

Skeletal muscle is a unique tissue because of its structure and function, which requires specific protocols for tissue collection to obtain optimal ...

Tandem High-pressure Freezing and Quick Freeze Substitution of Plant Tissues for Transmission Electron Microscopy

Since the 1940s transmission electron microscopy (TEM) has been providing biologists with ultra-high resolution images of biological materials. Yet, because of laborious and time-consuming protocols that also demand experience in preparation of artifact-free samples, TEM is not considered a user-friendly technique. Traditional sample preparation for TEM used chemical fixatives to preserve cellular structures. High-pressure freezing is the cryofixation of biological samples under high pressures to produce very fast cooling rates, thereby restricting ice formation, which is detrimental to the integrity of cellular ultrastructure. High-pressure freezing and freeze substitution are currently the methods of choice for producing the highest quality morphology in resin sections for TEM. These methods minimize the artifacts normally associated with conventional processing for TEM of thin sections. After cryofixation the frozen water in the sample is replaced with liquid organic solvent at low temperatures, a process called freeze substitution. Freeze substitution is typically carried out over several days in dedicated, costly equipment. A recent innovation allows the process to be completed in three hours, instead of the usual two days. This is typically followed by several more days of sample preparation that includes infiltration and embedding in epoxy resins before sectioning. Here we present a protocol combining high-pressure freezing and quick freeze substitution that enables plant sample fixation to be accomplished within hours. The protocol can readily be adapted for working with other tissues or organisms. Plant tissues are of special concern because of the presence of aerated spaces and water-filled vacuoles that impede ice-free freezing of water. In addition, the process of chemical fixation is especially long in plants due to cell walls impeding the penetration of the chemicals to deep within the tissues. Plant tissues are therefore particularly challenging, but this protocol is reliable and produces samples of the highest quality.

Obtaining high-quality transmission electron microscopy images is challenging, especially in the case of plant cells, which have abundant large water-filled vacuoles and aerated spaces. Tandem high-pressure freezing and quick freeze substitution greatly reduce preparation time of plant samples for TEM while producing samples with excellent ultrastructural preservation.

Tandem congelamento de pressão alta e rápida substituição em congelamento dos tecidos vegetais por Microscopia Eletrônica de Transmissão

Since the 1940s transmission electron microscopy (TEM) has been providing biologists with ultra-high resolution images of biological materials. Yet, ...

Plunge Freezing: A Tool for the Ultrastructural and Immunolocalization Studies of Suspension Cells in Transmission Electron Microscopy

Transmission Electron Microscopy (TEM) is an extraordinary tool for studying cell ultrastructure, in order to localize proteins and visualize macromolecular complexes at very high resolution. However, to get as close as possible to the native state, perfect sample preservation is required. Conventional electron microscopy (EM) fixation with aldehydes, for instance, does not provide good ultrastructural preservation. The slow penetration of fixatives induces cell reorganization and loss of various cell components. Therefore, conventional EM fixation does not allow for an instantaneous stabilization and preservation of structures and antigenicity. The best choice for examining intracellular events is to use cryofixation followed by the freeze-substitution fixation method that keeps cells in their native state. High-pressure freezing/freeze-substitution, which preserves the integrity of cellular ultrastructure, is the most commonly used method, but requires expensive equipment. Here, an easy-to-use and low-cost freeze fixation method followed by freeze-substitution for suspension cell cultures is presented.

This manuscript describes an easy-to-use and low-cost cryofixation method for visualizing suspension cells by transmission electron microscopy.

Congelamento Plunge: Uma ferramenta para os estudos ultra-estruturais e de imunolocalização de células em suspensão em Microscopia Eletrônica de Transmissão

Transmission Electron Microscopy (TEM) is an extraordinary tool for studying cell ultrastructure, in order to localize proteins and visualize ...

The Ingestion of Fluorescent, Magnetic Nanoparticles for Determining Fluid-uptake Abilities in Insects

Fluid-feeding insects ingest a variety of liquids, which are present in the environment as pools, films, or confined to small pores. Studies of liquid acquisition require assessing mouthpart structure and function relationships; however, fluid uptake mechanisms are historically inferred from observations of structural architecture, sometimes unaccompanied with experimental evidence. Here, we report a novel method for assessing fluid-uptake abilities with butterflies (Lepidoptera) and flies (Diptera) using small amounts of liquids. Insects are fed with a 20% sucrose solution mixed with fluorescent, magnetic nanoparticles from filter papers of specific pore sizes. The crop (internal structure used for storing fluids) is removed from the insect and placed on a confocal microscope. A magnet is waved by the crop to determine the presence of nanoparticles, which indicate if the insects are able to ingest fluids. This methodology is used to reveal a widespread feeding mechanism (capillary action and liquid bridge formation) that is potentially shared among Lepidoptera and Diptera when feeding from porous surfaces. In addition, this method can be used for studies of feeding mechanisms among a variety of fluid-feeding insects, including those important in disease transmission and biomimetics, and potentially other studies that involve nano- or micro-sized conduits where liquid transport requires verification.

Fluid-feeding insects have the ability to acquire minute quantities of liquids from porous surfaces. This protocol describes a method to directly determine the ability for insects to ingest liquids from porous surfaces using feeding solutions with fluorescent, magnetic nanoparticles.

A ingestão de fluorescente, nanopartículas magnéticas para determinar as capacidades de absorção de fluido em insetos

Fluid-feeding insects ingest a variety of liquids, which are present in the environment as pools, films, or confined to small pores. Studies of liquid ...