Gostaríamos de agradecer o espírito cooperativo de todos os membros Caldwell Lab. Pesquisa distúrbios do movimento no laboratório tem sido apoiado pela distonia Bachmann-Strauss &amp; Parkinson Foundation, Parkinson United Foundation, Parkinson Disease Association americana, doença de Parkinson Associação de Alabama, a Michael J. Fox Foundation for Research de Parkinson, e um de Iniciação Científica

A. Construção Expressão Plasmid Dois plasmídeos são necessários: um para expressão tecido específico do gene de interesse e um segundo como marcador de transformação selecionável (embora o marcador plasmídeo é geralmente disponível a partir de dentro da comunidade de pesquisa). Experimental Plasmid <ol><li> Selecione um promotor que se expressa no tipo de tecido / células de interesse, neste caso, o transportador de DA (PDAt-1) promotor é usado. Esta expressão plasmídeo foi criado como um gateway Invitrogen sistema compatível com vector de destino (pDEST-DAT-1) para permitir a inserção de qualquer gene de interesse a jusante do promotor por clonagem recombinational 1. </li><li> O cDNA do gene de interesse é amplificado PCR usando primers que contêm o Gateway att seqüência B recombinational. O cDNA amplificado é primeiro recombinados no vetor doador pDONR201 para criar o vetor de entrada e depois transformado em E. coli estirpe DH5α. Após a selecção de recombinantes de sucesso e mini-prep isolamento de DNA, o vetor de entrada é recombinado na pDEST-DAT-1 vector de destino para criar a expressão plasmídeo. Detalhes sobre a clonagem recombinational estão disponíveis a partir de qualquer manual de gateway da Invitrogen ou em Caldwell et al. 5. </li></ol> Marcador selecionável Plasmid Um marcador de transgênicos plasmídeo consiste de um vetor com um promotor dirigindo a expressão de uma proteína fluorescente em um tecido óbvio. Neste procedimento, o promotor unc-54 drives expressão da proteína cereja no músculo do corpo de parede (pon-54:: cereja). B. A geração de transgênicos C. elegans através de microinjeção Ver artigo relacionado JOVE: <a href="https://www.jove.com/index/details.stp?ID=833">https://www.jove.com/index/details.stp?ID=833</a> C. Genética cruzes para DA Análise de neurodegeneração <ol><li> Worms são cultivadas utilizando procedimentos padrão 6. </li><li> Coloque 10 PDAt-1:: α-syn; PDAt-1:: machos GFP 1, 2 em uma placa de acasalamento com 04/03 L4 hermafroditas estágio transgênicos (expressando PDAt-1:: gene X e punção-54:: cereja) . Esta deve ser realizada individualmente para cada uma das três linhas separadas estável criado. Depois de dois dias, retire os machos. </li><li> Inspecionar a geração F1, se há descendência masculina diversas, o acasalamento foi bem sucedida. </li><li> Clone com 5 hermafrodita L4 animais de cada cruz que apresentam ambos os PDAt-1:: GFP marcador fluorescente (herdadas do pai do sexo masculino) e os pon-54:: cereja fluorescentes corpo marcador músculo da parede (herdadas do pai hermafrodita). Os animais precisam ser clonado no estágio L4 para garantir que eles ainda não tenham acasalado com animais machos presentes na placa. Permitir-lhes a auto-cross e produzir progênie F2. </li><li> Animais F2 produzidos no passo 3 são clonados para fora. Especificamente, a transferência ~ 5-10 animais que apresentam ambos os marcadores fluorescentes para os seus próprios pratos individuais. Tela da geração F3 para placas onde 100% dos animais expressam GFP em DA neurônios e alguns dos animais são expressas cereja em células do corpo muscular da parede. Estes animais serão homozigotos para o PDAt-1:: α-syn; PDAt-1:: gene GFP estavelmente enquanto transmitindo o transgene recém-criado (gene X). </li></ol> D. dopaminérgicos Neuron Análise <ol><li> Prepare um prato de doce para cada uma das três linhas criadas acima, bem como a PDAt-1:: α-syn; PDAt-1:: GFP sozinho tensão. Permitir-lhes a crescer até a idade adulta. </li><li> Transferência de 30-40 adultos transgênicos de cada linha em um prato doce. Lhes permitem colocar os embriões durante 4 horas a 20 º C. </li><li> Remove os adultos. Permitir que os embriões a desenvolver por 3-4 dias a 20 º C até atingirem o estágio L4. </li><li> Escolha ~ 100 transgênicos L4 animais a uma placa contendo 0,04 mg / ml 5-fluoro-2&#39;-deoxiuridina (FUDR). Este nucleotídeo desenvolvimento blocos analógicos de próxima geração através da inibição da síntese de DNA, impedindo assim a descendência de esmagadora dos animais experimentais 7. Proteger as placas FUDR da luz, uma vez que é sensível à luz. </li><li> Animais adultos serão analisados ​​em vários dias seguintes postura de ovos. Os dias apropriados de análise são determinados empiricamente. Por exemplo, nós determinamos que 77%, 87% e 90% do PDAt-1:: α-syn; PDAt-1:: GFP animais apresentam neurônios degenerados DA nos dias 6, 7 e 10 pós-desenvolvimento, respectivamente. Portanto, se nós prevemos que o transgene de interesse pode aumentar neurodegeneração, vamos analisar no dia 6 e / ou 7. Da mesma forma, transgenes que poderia suprimir neurodegeneração serão analisados ​​nos dias 7 e 10. </li><li> Fazer 4 almofadas frescas agarose (ao contrário do agar microinjeção almofadas, elas são usadas frescas e não estão autorizados a secar). Definiu dois lâminas de microscópio que possuem um pedaço de fita entre eles; a fita serve como espaçador para blocos equivalente de espessura. Lay terzodeslize entre eles no banco (eles estão posicionados lado a lado três). Coloque uma gota de agarose derretida no slide centro e rapidamente estava outro slide em cima do agarose, perpendicular e em todos os três slides. Fazer várias almofadas adicionais, deixando os dois slides juntos até o bloco está pronto para uso. </li><li> Para analisar os neurônios verme DA, coloque uma gota 6 mL de 3 mM levamisole (um anestésico) em uma tampa de vidro 22 x 30 mm. Escolha 40 animais adultos (10 extras além da 30 a ser marcado) para a queda, então inverter a tampa de vidro sobre o bloco de agarose. Repita o procedimento para cada uma das outras linhas. </li><li> Pontuação 30 animais por linha para a presença de cada CEP e neurônio ADE usando um microscópio composto com epifluorescência e um cubo de filtro que permite a visualização de FITC ou GFP. Usamos um Dotar GFP HYQ filtro cubo (Tecnologia Chroma). Registro de dados na folha de pontuação em anexo. Do tipo selvagem animais reterá a fluorescência da GFP completa em todos os CEP 4 e 2 neurônios ADE. Animais individuais apresentando perda de neurônios DA são marcados como não-WT ou &quot;degenerando&quot;. Da mesma forma, o grau de degeneração pode ser marcado pela contagem do total de neurônios perdidos em cada animal, bem como da população. </li><li> Repetir a análise mais 2 vezes (30 animais a mais por linha por julgamento). O número total de vermes exibindo neurônios do tipo selvagem DA das três rodadas de análises é média. Análise estatística para a neuroproteção é então realizada usando o teste t de Student (p &lt;0,05) para comparar worms controle (PDAt-1:: α-syn; PDAt-1:: GFP) com cepas que o excesso de expressar genes candidatos em neurônios DA . </li></ol>

<ol>
	<li>Cao, S., Gelwix, C. C., Caldwell, K. A., Caldwell, G. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Torsin-mediated+neuroprotection+from+cellular+stresses+to+dopaminergic+neurons+of+C.+elegans.">Torsin-mediated neuroprotection from cellular stresses to dopaminergic neurons of C. elegans.</a> J Neurosci. 25, 3801-3812 (2005).</li><li>Hamamichi, S., Rivas, R. N., Knight, A. L., Cao, S., Caldwell, K. A., Caldwell, G. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hypothesis-based+RNAi+screening+identifies+neuroprotective+genes+in+a+Parkinson&#x2019;s+disease+model.">Hypothesis-based RNAi screening identifies neuroprotective genes in a Parkinson&#x2019;s disease model.</a> PNAS. 105, 728-733 (2008).</li><li>Cooper, A. A., Gitler, A. D., Cashikar, A., Haynes, C. M., Hill, K. J., Bhullar, B., Liu, K., Xu, K., Strathearn, K. E., Liu, F., Cao, S., Caldwell, K. A., Caldwell, G. A., Marsischky, G., Kolodner, R. D., Labaer, J., Rochet, J. C., Bonini, N. M., Lindquist, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=alpha-synuclein+blocks+ER-golgi+traffic+and+Rab1+rescues+neuron+loss+in+Parkinson's+models.">alpha-synuclein blocks ER-golgi traffic and Rab1 rescues neuron loss in Parkinson's models.</a> Science. 313, 324-328 (2006).</li><li>Gitler, A. D., Bevis, B. J., Shorter, J., Strathearn, K. E., Hamamichi, S., Su, L. J., Caldwell, K. A., Caldwell, G. A., Rochet, J. -. C., McCaffery, J. M., Barlowe, C., Lindquist, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Parkinson's+disease+protein+alpha-synuclein+disrupts+cellular+Rab+homeostasis.">The Parkinson's disease protein alpha-synuclein disrupts cellular Rab homeostasis.</a> PNAS. 105, 145-150 (2008).</li><li>Caldwell, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Integrated+Genomics:+A+Discovery-Based+Laboratory+Course.">Integrated Genomics: A Discovery-Based Laboratory Course.</a> , (2006).</li><li>Brenner, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+genetics+of+Caenorhabditis+elegans.">The genetics of Caenorhabditis elegans.</a> Genetics. 77, 71-94 (1974).</li><li>Gandhi, S., Santelli, J., Mitchell, J. D. H., Stiles, J. W., Sanadi, 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=A+simple+method+for+maintaining+large,+aging+populations+of+Caenorhabditis+elegans.">A simple method for maintaining large, aging populations of Caenorhabditis elegans.</a> Mechanisms of Ageing and Development. 12, 137-150 (1980).</li></ol>

A perda idade-dependentes de neurônios de dopamina é um marco clínico da doença de Parkinson e tem sido associada com a acumulação ou misfolding de uma proteína chamada alfa-sinucleína. Aqui demonstramos como rótulo, através de um transgene fluorescente, a neurônios dopaminérgicos da C. elegans e imitar a neurodegeneração visto na doença de Parkinson por coexpressing humana alfa-sinucleína nestas células. Este vídeo mostra a metodologia para a travessia de crescimento, genética, montagem e pontuação de ...

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application of a c. elegans dopamine neuron degeneration assay for the validation of potential parkinson's disease genes

Melhorias para o diagnóstico e tratamento da doença de Parkinson (DP) são dependentes de conhecimentos sobre os fatores que tornam a susceptibilidade populações em risco. No processo de tentar identificar novos fatores genéticos associados com a DP, os cientistas têm gerado muitas listas de genes candidatos, polimorfismos, e proteínas, que representam avanços importantes, mas estas ligações permanecem mecanicamente indefinido. Nosso trabalho estará voltado para a redução significativa tais listas, explorando as vantagens de um sistema simples de animais modelo. Enquanto os seres humanos têm bilhões de neurônios, a lombriga microscópica Caenorhabditis elegans tem precisamente 302, dos quais apenas oito produzir dopamina (DA) em hemaphrodites. Expressão de um gene humano que codifica a proteína PD-associados, alfa-sinucleína, em C. elegans resultados DA neurônios na dose e idade-dependente neurodegeneração. Worms expressar humana alfa-sinucleína em neurônios DA são isogênicos e expressar tanto GFP e humano alfa-sinucleína sob o promotor transportador DA (PDAt-1). A presença de GFP serve como um marcador facilmente visualizado por seguir neurodegeneração DA nesses animais. Inicialmente demonstrou que alfa-sinucleína neurodegeneração induzida DA poderia ser resgatado nestes animais por torsinA, uma proteína com atividade chaperone molecular 1. Além disso, o candidato relacionados com a DP genes identificados em nosso laboratório através de esforços em larga escala de triagem RNAi usando um ensaio misfolding alfa-sinucleína foram, então, sobre-expressa em C. elegans DA neurônios. Determinou-se que cinco dos sete genes testados representada moduladores candidato significativa de PD como eles resgatados alfa-sinucleína neurodegeneração induzida DA 2. Além disso, o Lab Lindquist (esta questão de Jove) realizou telas de fermento em que a alfa-sinucleína dependentes de toxicidade é usado como uma leitura de genes que podem aumentar ou suprimir citotoxicidade. Nós posteriormente examinou os genes candidatos fermento em nossa C. elegans ensaio neurodegeneração alfa-sinucleína induzida e validado com sucesso muitos destes três metas, 4. Nossa metodologia envolve a geração de um elegans DA C. vetor de expressão neurônio-específicos usando a clonagem de cDNAs recombinational gene candidato sob o controle do PDAt-1 promotor. Estes plasmídeos são então microinjeção no tipo selvagem (N2) worms, juntamente com um marcador selecionável para transformação de sucesso. Múltiplas estáveis ​​linhagens transgênicas de produzir a proteína nos neurônios DA candidato são obtidas de forma independente e depois cruzou para a cepa alfa-sinucleína degenerativas e avaliados quanto à neurodegeneração, tanto o animal eo nível de neurônio individual, ao longo do envelhecimento.

Watch this Scientific Journal Video about Application of a C. elegans Dopamine Neuron Degeneration Assay for the Validation of Potential Parkinson's Disease Genes at JoVE.com

Application of a C. elegans Dopamine Neuron Degeneration Assay for the Validation of Potential Parkinson&#039;s Disease Genes

Este vídeo demonstra como usar C. elegans para avaliar neurônio dopaminérgico neurodegeneração como um modelo para a doença de Parkinson. Além disso, as telas genéticos são usados ​​para identificar os fatores que quer aumentar a degeneração ou neuroprotetor.

Aplicação de um elegans dopamina C. Ensaio degeneração dos neurônios de Validação do Potencial Doença de Parkinson Genes

Improvements to the diagnosis and treatment of Parkinson's disease (PD) are dependent upon knowledge about susceptibility factors that render populations ...

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Biology

Application of a C. elegans Dopamine Neuron Degeneration Assay for the Validation of Potential Parkinson's Disease Genes

15.9K visualizações.  University of Alabama. Este vídeo demonstra como usar C. elegans para avaliar neurônio dopaminérgico neurodegeneração como um modelo para a doença de Parkinson. Além disso, as telas genéticos são usados ​​para identificar os fatores que quer aumentar a degeneração ou neuroprotetor.

Vídeo: Application of a C. elegans Dopamine Neuron Degeneration Assay for the Validation of Potential Parkinson's Disease Genes

Ole Isacson: Development of New Therapies for Parkinson's Disease

Ole Isacson: Development of New Therapies for Parkinson&#039;s Disease

Ole Isacson gives a concise overview of Parkinsons's disease, its causes, therapeutic strategies, and advances in Parkinson's research.

Ole Isacson: desenvolvimento de novas terapias para a doença de Parkinson

Biologia

Generation of Stable Transgenic C. elegans Using Microinjection

Transgenic Caenorhabditis elegans can be readily created via microinjection of a DNA plasmid solution into the gonad 1. The plasmid DNA rearranges to form extrachromosomal concatamers that are stably inherited, though not with the same efficiency as actual chromosomes 2. A gene of interest is co-injected with an obvious phenotypic marker, such as rol-6 or GFP, to allow selection of transgenic animals under a dissecting microscope. The exogenous gene may be expressed from its native promoter for cellular localization studies. Alternatively, the transgene can be driven by a different tissue-specific promoter to assess the role of the gene product in that particular cell or tissue. This technique efficiently drives gene expression in all tissues of C. elegans except for the germline or early embryo 3. Creation of transgenic animals is widely utilized for a range of experimental paradigms. This video demonstrates the microinjection procedure to generate transgenic worms. Furthermore, selection and maintenance of stable transgenic C. elegans lines is described.

This video demonstrates the technique of microinjection into the gonad of C. elegans to create transgenic animals.

Geração de transgênicos Estável C. elegans Usando microinjeção

Transgenic Caenorhabditis elegans can be readily created via microinjection of a DNA plasmid solution into the gonad 1.  The plasmid DNA rearranges to ...

Murine Model for Parkinson's Disease: from 6-OH Dopamine Lesion to Behavioral Test

Parkinson's disease (PD) affects at least 6.5 million people worldwide, irrespective of gender, social, ethnic, economic, or geographic boundaries. Key symptoms, such as tremor, rigidity and bradikinesia, develop when about 3/4 of dopaminergic cells are lost in the substantia nigra, and fail to provide for the smooth, coordinated regulation of striatal motor circuits. Depression and hallucinations are common, and dementia eventually occurs in 20% of patients. At this time, there is no treatment to delay or stop the progression of PD. Rather, the medications currently available aim more towards the alleviation of these symptoms. New surgical strategies may reversibly switch on the functionally damaged circuits through the electrical stimulation of deep brain structures, but although deep brain stimulation is a major advance, it is not suitable for all patients. It remains therefore necessary to test new cell therapy approaches in preclinical models.
Selective neurotoxic disruption of dopaminergic pathways can be reproduced by injection of 6-hydroxydopamine (6-OHDA) or MPTP (1-methyl-4-phenyl-1,2,3,6-tertahydropyridine) whereas depleting drugs and oxidative-damaging chemicals may also reproduce specific features of PD in rodents. Unlike MPTP, 6-OHDA lesions cause massive irreversible neuronal loss, and can be uni- or bilateral. The 6-OHDA lesion model is reliable, leads to robust motor deficits, and is the most widely used after 40 years of research in rats1. As interactions between grafted cells and host can now be studied more thoroughly in mice rather than in rats, the model has been transposed to mice2,3, where it has been recently characterized4.
In this video, we demonstrate how to lesion the left nigro-striatal pathway of anesthetized mice by slowly delivering 2.0 &mu;L of 6-OHDA through a stereotaxically inserted micro-syringe needle. The loss of dopaminergic input occurs within days, and the functional impairments can be monitored over post-operative weeks and months by rating animal rotations induced by dopaminergic agents5. Here, we show full-body contralateral rotations occurring 10 minutes after a single subcutaneous administration of apomorphine, measured one month after the lesion. Outcomes and drawbacks are discussed below.

Murine Model for Parkinson&#039;s Disease: from 6-OH Dopamine Lesion to Behavioral Test

Parkinson disease is caused by loss of dopaminergic innervation to the striatum, which can be experimentally induced by 6-OH-dopamine. We describe how to perform a stereotaxic lesion and to monitor apomorphine-induced rotational behavior in mice. This model is useful and reliable for testing new therapies for Parkinson disease.

Modelo murino para a doença de Parkinson: a partir de 6-OH lesão dopamina para teste comportamental

Parkinson's disease (PD) affects at least 6.5 million people worldwide, irrespective of gender, social, ethnic, economic, or geographic boundaries. Key ...

Generation of Transgenic C. elegans by Biolistic Transformation

The number of laboratories using the free living nematode C. elegans is rapidly growing. The popularity of this biological model is attributed to a rapid generation time and short life span, easy and inexpensive maintenance, fully sequenced genome, and array of RNAi resources and mutant animals. Additionally, analysis of the C. elegans genome revealed a great similarity between worms and higher vertebrates, which suggests that research in worms could be an important adjunct to studies performed in whole mice or cultured cells. A powerful and important part of worm research is the ability to use transgenic animals to study gene localization and function. Transgenic animals can be created either via microinjection of the worm germline or through the use of biolistic bombardment. Bombardment is a newer technique and is less familiar to a number of labs. Here we describe a simple protocol to generate transgenic worms by biolistic bombardment with gold particles using the Bio-Rad PDS-1000 system. Compared with DNA microinjection into hermaphrodite germline, this protocol has the advantage of not requiring special skills from the operator with regards to identifying worm anatomy or performing microinjection. Further multiple transgenic lines are usually obtained from a single bombardment. Also in contrast to microinjection, biolistic bombardment produces transgenic animals with both extrachromosomal arrays and integrated transgenes. The ability to obtain integrated transgenic lines can avoid the use of mutagenic protocols to integrate foreign DNA. In conclusion, biolistic bombardment can be an attractive method for the generation of transgenic animals, especially for investigators not interested in investing the time and effort needed to become skilled at microinjection.

Generation of Transgenic C. elegans by Biolistic Transformation

Transgenic worms are commonly used in C. elegans research. Described is a simple, yet effective, protocol to introduce transgenes into worms using biolistic bombardment with DNA-coated gold particles. The effort involved and results of bombardment compare favorably with microinjection for the generation of transgenic animals.

Geração de transgênicos C. elegans Por biobalística Transformação

The number of laboratories using the free living nematode C. elegans is rapidly growing. The popularity of this biological model is attributed to a rapid ...

The Production of C. elegans Transgenes via Recombineering with the galK Selectable Marker

The creation of transgenic animals is widely utilized in C. elegans research including the use of GFP fusion proteins to study the regulation and expression pattern of genes of interest or generation of tandem affinity purification (TAP) tagged versions of specific genes to facilitate their purification. Typically transgenes are generated by placing a promoter upstream of a GFP reporter gene or cDNA of interest, and this often produces a representative expression pattern. However, critical elements of gene regulation, such as control elements in the 3' untranslated region or alternative promoters, could be missed by this approach. Further only a single splice variant can be usually studied by this means. In contrast, the use of worm genomic DNA carried by fosmid DNA clones likely includes most if not all elements involved in gene regulation in vivo which permits the greater ability to capture the genuine expression pattern and timing. To facilitate the generation of transgenes using fosmid DNA, we describe an E. coli based recombineering procedure to insert GFP, a TAP-tag, or other sequences of interest into any location in the gene. The procedure uses the galK gene as the selection marker for both the positive and negative selection steps in recombineering which results in obtaining the desired modification with high efficiency. Further, plasmids containing the galK gene flanked by homology arms to commonly used GFP and TAP fusion genes are available which reduce the cost of oligos by 50% when generating a GFP or TAP fusion protein. These plasmids use the R6K replication origin which precludes the need for extensive PCR product purification. Finally, we also demonstrate a technique to integrate the unc-119 marker on to the fosmid backbone which allows the fosmid to be directly injected or bombarded into worms to generate transgenic animals. This video demonstrates the procedures involved in generating a transgene via recombineering using this method.

The Production of C. elegans Transgenes via Recombineering with the galK Selectable Marker

The ability to produce transgenes for Caenorhabditis elegans using genomic DNA carried by fosmids is particularly attractive as all of the native regulatory elements are retained. Described is a simple and robust procedure for the production of transgenes via recombineering with the galK selectable marker.

Produção de C. elegans Transgenes via Recombineering com o GalK Marcador selecionável

The creation of transgenic animals is widely utilized in C. elegans research including the use of GFP fusion proteins to study the regulation and ...

Chromosomics: Detection of Numerical and Structural Alterations in All 24 Human Chromosomes Simultaneously Using a Novel OctoChrome FISH Assay

Fluorescence in situ hybridization (FISH) is a technique that allows specific DNA sequences to be detected on metaphase or interphase chromosomes in cell nuclei1. The technique uses DNA probes with unique sequences that hybridize to whole chromosomes or specific chromosomal regions, and serves as a powerful adjunct to classic cytogenetics. For instance, many earlier studies reported the frequent detection of increased chromosome aberrations in leukemia patients related with benzene exposure, benzene-poisoning patients, and healthy workers exposed to benzene, using classic cytogenetic analysis2. Using FISH, leukemia-specific chromosomal alterations have been observed to be elevated in apparently healthy workers exposed to benzene3-6, indicating the critical roles of cytogentic changes in benzene-induced leukemogenesis. 
Generally, a single FISH assay examines only one or a few whole chromosomes or specific loci per slide, so multiple hybridizations need to be conducted on multiple slides to cover all of the human chromosomes. Spectral karyotyping (SKY) allows visualization of the whole genome simultaneously, but the requirement for special software and equipment limits its application7. Here, we describe a novel FISH assay, OctoChrome-FISH, which can be applied for Chromosomics, which we define here as the simultaneous analysis of all 24 human chromosomes on one slide in human studies, such as chromosome-wide aneuploidy study (CWAS)8. The basis of the method, marketed by Cytocell as the Chromoprobe Multiprobe System, is an OctoChrome device that is divided into 8 squares, each of which carries three different whole chromosome painting probes (Figure 1). Each of the three probes is directly labeled with a different colored fluorophore, green (FITC), red (Texas Red), and blue (Coumarin). The arrangement of chromosome combinations on the OctoChrome device has been designed to facilitate the identification of the non-random structural chromosome alterations (translocations) found in the most common leukemias and lymphomas, for instance t(9;22), t(15;17), t(8;21), t(14;18)9. Moreover, numerical changes (aneuploidy) in chromosomes can be detected concurrently. The corresponding template slide is also divided into 8 squares onto which metaphase spreads are bound (Figure 2), and is positioned over the OctoChrome device. The probes and target DNA are denatured at high-temperature and hybridized in a humid chamber, and then all 24 human chromosomes can be visualized simultaneously. 
OctoChrome FISH is a promising technique for the clinical diagnosis of leukemia and lymphoma and for detection of aneuploidies in all chromosomes. We have applied this new Chromosomic approach in a CWAS study of benzene-exposed Chinese workers8,10.

A novel fluorescence in situ hybridization (FISH) method that simultaneously examines both numerical and structural chromosome alterations, particularly the specific chromosomal translocations associated with leukemia and lymphoma, of all 24 human chromosomes on a single device in one hybridization, is described.

Chromosomics: Detecção de alterações numéricas e estruturais em todos os 24 cromossomos humanos ao mesmo tempo usando um ensaio de FISH Novel OctoChrome

Fluorescence in situ hybridization (FISH) is a technique that allows specific DNA sequences to be detected on metaphase or interphase chromosomes in cell ...

Using RNA-mediated Interference Feeding Strategy to Screen for Genes Involved in Body Size Regulation in the Nematode C. elegans

Double-strand RNA-mediated interference (RNAi) is an effective strategy to knock down target gene expression1-3. It has been applied to many model systems including plants, invertebrates and vertebrates. There are various methods to achieve RNAi in vivo4,5. For example, the target gene may be transformed into an RNAi vector, and then either permanently or transiently transformed into cell lines or primary cells to achieve gene knockdown effects; alternatively synthesized double-strand oligonucleotides from specific target genes (RNAi oligos) may be transiently transformed into cell lines or primary cells to silence target genes; or synthesized double-strand RNA molecules may be microinjected into an organism. Since the nematode C. elegans uses bacteria as a food source, feeding the animals with bacteria expressing double-strand RNA against target genes provides a viable strategy6. Here we present an RNAi feeding method to score body size phenotype. Body size in C. elegans is regulated primarily by the TGF- &beta; - like ligand DBL-1, so this assay is appropriate for identification of TGF-&beta; signaling components7. We used different strains including two RNAi hypersensitive strains to repeat the RNAi feeding experiments. Our results showed that rrf-3 strain gave us the best expected RNAi phenotype. The method is easy to perform, reproducible, and easily quantified. Furthermore, our protocol minimizes the use of specialized equipment, so it is suitable for smaller laboratories or those at predominantly undergraduate institutions.

Using RNA-mediated Interference Feeding Strategy to Screen for Genes Involved in Body Size Regulation in the Nematode C. elegans

We demonstrate how to use the RNAi feeding technique to knock down target genes and score body size phenotype in C. elegans. This method could be used for a large scale screen to identify potential genetic components of interest, such as those involved in body size regulation by DBL-1/TGF-&beta; signaling.

Usando RNA mediada estratégia de alimentação Interferência em tela para genes envolvidos na regulação do tamanho corporal na Nemátodo<em&gt; C. elegans</em

Double-strand RNA-mediated interference (RNAi) is an effective strategy to knock down target gene expression1-3. It has been applied to many model systems ...

C. elegans Chemotaxis Assay

Many organisms use chemotaxis to seek out food sources, avoid noxious substances, and find mates. Caenorhabditis elegans has impressive chemotaxis behavior.
 The premise behind testing the response of the worms to an odorant is to place them in an area and observe the movement evoked in response to an odorant. Even with the many available assays, optimizing worm starting location relative to both the control and test areas, while minimizing the interaction of worms with each other, while maintaining a significant sample size remains a work in progress 1-10. The method described here aims to address these issues by modifying the assay developed by Bargmann et al.1. A Petri dish is divided into four quadrants, two opposite quadrants marked "Test" and two are designated "Control". Anesthetic is placed in all test and control sites. The worms are placed in the center of the plate with a circle marked around the origin to ensure that non-motile worms will be ignored. Utilizing a four-quadrant system rather than one 2 or two 1 eliminates bias in the movement of the worms, as they are equidistant from test and control samples, regardless of which side of the origin they began. This circumvents the problem of worms being forced to travel through a cluster of other worms to respond to an odorant, which can delay worms or force them to take a more circuitous route, yielding an incorrect interpretation of their intended path. This method also shows practical advantages by having a larger sample size and allowing the researcher to run the assay unattended and score the worms once the allotted time has expired.

C. elegans Chemotaxis Assay

A method of quantitatively evaluating the chemotactic response of Caenorhabditis elegans is described. A chemotactic index (CI) was employed as a way to precisely evaluate the response of worms to certain targets, and serve as a platform of comparison between strains and compounds of interest.

Many organisms use chemotaxis to seek out food sources, avoid noxious substances, and find mates.  Caenorhabditis elegans has impressive chemotaxis ...

A Method for Culturing Embryonic C. elegans Cells

C. elegans is a powerful model system, in which genetic and molecular techniques are easily applicable. Until recently though, techniques that require direct access to cells and isolation of specific cell types, could not be applied in C. elegans. This limitation was due to the fact that tissues are confined within a pressurized cuticle which is not easily digested by treatment with enzymes and/or detergents. Based on early pioneer work by Laird Bloom, Christensen and colleagues 1 developed a robust method for culturing C. elegans embryonic cells in large scale. Eggs are isolated from gravid adults by treatment with bleach/NaOH and subsequently treated with chitinase to remove the eggshells. Embryonic cells are then dissociated by manual pipetting and plated onto substrate-covered glass in serum-enriched media. Within 24 hr of isolation cells begin to differentiate by changing morphology and by expressing cell specific markers. C. elegans cells cultured using this method survive for up 2 weeks in vitro and have been used for electrophysiological, immunochemical, and imaging analyses as well as they have been sorted and used for microarray profiling.

A Method for Culturing Embryonic C. elegans Cells

We describe here a revised protocol for large-scale culture of embryonic C. elegans cells. Embryonic C. elegans cells cultured in vitro using this method, appear to differentiate and recapitulate the expression of genes in a cell specific manner. Techniques that require direct access to the cells or isolation of specific cell types from the other tissues can be applied on C. elegans cultured cells.

Um Método para o cultivo embrionário<em&gt; C. elegans</em&gt; Células

C. elegans is a powerful model system, in which genetic and molecular techniques are easily applicable. Until recently though, techniques that require ...

Measuring the Effects of Bacteria on C. Elegans Behavior Using an Egg Retention Assay

C. elegans egg-laying behavior is affected by environmental cues such as osmolarity1 and vibration2. In the total absence of food C. elegans also cease egg-laying and retain fertilized eggs in their uterus3. However, the effect of different sources of food, especially pathogenic bacteria and particularly Enterococcus faecalis, on egg-laying
	behavior is not well characterized. The egg-in-worm (EIW) assay is a useful tool to quantify the effects of different types of bacteria, in this case E. faecalis, on egg- laying behavior.
	
	EIW assays involve counting the number of eggs retained in the uterus of C. elegans4. The EIW assay involves bleaching staged, gravid adult C. elegans to remove the cuticle and separate the retained eggs from the animal. Prior to bleaching, worms are exposed to bacteria (or any type of environmental cue) for a fixed period of time. After bleaching, one is very easily able to count the number of eggs retained inside the uterus of the worms. In this assay, a quantifiable increase in egg retention after E. faecalis exposure can be easily measured. The EIW assay is a behavioral assay that may be used to screen for potentially pathogenic bacteria or the presence of environmental toxins. In addition, the EIW assay may be a tool to screen for drugs that affect neurotransmitter signaling since egg-laying behavior is modulated by neurotransmitters such as serotonin and acetylcholine5-9.

Measuring the Effects of Bacteria on C. Elegans Behavior Using an Egg Retention Assay

An egg-in-worm (EIW) assay is a useful method to quantify egg-laying behavior. Alterations in egg laying can be a behavioral response of the model organism Caenorhabditis elegans to potentially harmful environmental substances such as those produced by pathogenic bacteria.

Medição dos Efeitos de bactérias em<em&gt; C. Elegans</em&gt; Comportamento Usando um Retenção Ensaio Egg

C. elegans egg-laying behavior is  affected by environmental cues such as osmolarity1 and  vibration2. In the total absence of food C. elegans also cease ...