Supported by Funda&#231;&atilde;o de Amparo a Pesquisa do Estado do Rio de Janeiro (FAPERJ) and Conselho Nacional de Desenvolvimento Cient&iacute;fico e Tecnol&oacute;gico (CNPq). We are grateful to anonymous referees whose comments helped us improve both the manuscript and video.

All chemicals stored in solid form, such as 6-OHDA and apomorphine, were diluted in sterile injection water and filtered inside a laminar flow hood, to avoid contamination. In addition, neurotoxins and neuroactive substances were stored, prepared, handled and disposed according to regulations set by international guidelines6 and the local Biosafety Committee. 
1 - Anesthesia and surgery
Adult male Swiss mice (25-30g) are premedicated with Atropine (0.2 mg/Kg, s.c.) to reduce vagal tone and then anesthetized with an intraperitoneal injection of Ketamine (90-120 mg/Kg) and Xylazine (10 mg/Kg). The animal is placed on an electronically controlled heating pad (Insight) to ensure body temperature is maintained at 37&deg;C, as induction of sedation takes some minutes. The anesthesia level is checked throughout the procedure by testing the absence of withdrawal reflex. Anesthetic dosage should be ajusted for each strain/colony. Depending on the animal and duration of the surgery, additional doses of Ketamine may be necessary. After that, saline (NaCl 0,9%) is applied on both eyes to protect the corneas from drying out and test the absence of the blink reflex in this first moment. The fur over the entire head is shaved with a trimmer to ensure the minimum contact with unsterile areas. Local anesthetic (Xylocaine) is applied to the ear bars to prevent discomfort. Only once withdrawal and blink reflex have vanished, indicating the level of anesthesia is deep enough for surgery (stage 3), the animal is positioned on the stereotaxic frame using mouth-piece and ear bars specially designed for this species (Insight). Once positionated, an ophthalmologic ointment (MARCA) is applied to protect the animal eyes throughout all surgery. Only after be sure that the eyes are correctly protected, the procedure continue with the disinfection of the skin of the surgical region by repeating three applications of povidone iodine followed by 70% Ethanol, using sterile cottons swabs After, proper placement of the ear bars is ensured by testing for sideways movements of the head (the head must not move to ensure that the bars are securely fixed). Proper dorsoventral inclination of the head will be verified later when skull landmarks are revealed. A sagittal incision (1.5 cm) is made with a sterile scalpel (#15 blade). The periosteum over the area of interest is gently scraped away with a new blade, and the bone is wiped clean with sterile gaze and cotton swabs, to uncover skull landmarks: bregma is defined as the point of intersection of sagittal and coronal sutures, while lambda is the point of intersection of the sagittal suture and the best fit line passing through the left and right portions of the lambdoid suture. The tip of a vertically aligned reference needle is first zeroed at the bregma, under examination through the surgical microscope, and then moved as to touch the lambda point. If the head is properly positioned, lambda should be at the same dorso-ventral level as bregma, and both landmarks should be distant by 4.2 mm along the rostro-caudal axis. If not, the ears bars and nosepiece should be loosen and the head delicately tilted around the interaural axis, in order to achieve the desired position, which defines the "flat skull" reference for stereotaxical measures. The tip of the reference needle is then positioned at the desired coordinates: anterior-posterior (AP +0.5 mm) and lateral (L -2.0 mm, left). The location is marked on the skull and a small (1.2 mm diameter) hole is opened with a sterilized drill bit, using intermittent action to prevent heat the area. Bone fragments are carefully removed with a dental curette and washed with sterile warm 0.9% NaCl. The sterilized 5 &mu;l Hamilton syringe (26s gauge; 0.47 mm outer diameter) is loaded with the 6-OHDA solution (or vehicle for control animals) and vertically aligned in the stereotaxic apparatus. The tip of the needle (type 2 or 12&deg; bevel) is then inserted into the opened hole, until touch the pial surface, to determinate the reference point of the dorso-ventral coordinate. Once determinate this coordinate, the needle is slowly lowered to reach the coordinates of the striatum (AP: +0.5; L: -2.0 and DV: -3.0 mm, below pial surface7). The 6-OHDA solution (10 &mu;g 6-OHDA in 0.9% NaCl with 0.02% ascorbic acid), which was prepared and filtered inside a laminar flow hood, and must be protected from light by aluminum foil throughout the procedure, is then injected at a flow rate of 0.1&mu;L/min. For control animals, an equal volume of vehicle (0.02% ascorbic acid and 0.9% NaCl in sterile water) is injected. Once the entire 2.0 &mu;L has been injected, the syringe is kept in place for 5 min before being very slowly retracted from the brain, in no less than in 5 minutes. The skull is cleaned and the incision is closed using a #6-0 nylon suture (Shalon). To take a extra care against infection, a local antibiotic ointment, such as neomycin, may be applied to the sutured skin. Animals are removed from the frame, given 0.5 ml of saline (sc.) to prevent dehydration, and kept warm and under close observation until full recovery. They are then housed with food and water ad libitum. Analgesic is added to the drinking water bottle for the first two days after surgery (given an average daily water consumption of 5.5 ml, and a recommended dosage of 0.03 mg Ibuprofen/g of body weight/day; add 0,82 mL of 20 mg/mL Ibuprofen-Abbott suspension to 100 mL drinking water). Mice usually recover promptly from the procedure, wandering and reaching for water food pellets easily. In any case of apparent discomfort, or any sign of infection, animals should be euthanized according to local guidelines.
2 - Behavioral test
Although motor impairment can be observed after a week, a post-lesion interval of one month is allowed before reliable quantification with the rotation test. The animal receives a subcutaneous injection of DA agonist apomorphine (0.5 mg/Kg), and is placed in an opaque cylinder of 30 cm diameter, placed 45 cm below the recording camera. It is important to remove any residues and odors from previously tested animals before each test. After a 5 min habituation period, movements are recorded over a 5 min timeframe. Both contra- and ipsilateral full-body rotation are measured and compared with the control group (vehicle injected). If the procedure was correctly performed, control animals will not exhibit any rotation, whereas 6-OHDA lesioned animals will start turning to the contralateral side, since the agonist predominantly activates the supersensitive denervated striatum on the lesioned side. Animals scoring over 7 rpm (displaying at least 7 full-body contralateral rotations per minute) are considered as successfully lesioned. The animal can be safely returned to their housing 30 min after the test, which may be repeated weekly. In our hands, less than 5% of the lesioned mice displayed suboptimal rotation rates.

<ol>
	<li>Ungerstedt, U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=6-hydroxy-dopamine+induced+degeneration+of+central+monoamine+neurons.">6-hydroxy-dopamine induced degeneration of central monoamine neurons.</a> Eur. J. Pharmacol. 5, 107-110 (1968).</li><li>Akerud, P., Canals, J. M., Snyder, E. Y., Arenas, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neuroprotection+through+delivery+of+glial+cell+line-derived+neurotrophic+factor+by+neural+stem+cells+in+a+mouse+model+of+Parkinson's+Disease.">Neuroprotection through delivery of glial cell line-derived neurotrophic factor by neural stem cells in a mouse model of Parkinson's Disease.</a> J. Neurosci. 21, 8108-8118 (2001).</li><li>Ghosh, A., Roy, A., Liu, X., Kordower, J. H., Mufson, E. J., Hartley, D. M., Ghosh, S., Mosley, R. L., Gendelman, H. E., Pahan, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Selective+inhibition+of+NF-kappaB+activation+prevents+dopaminergic+neuronal+loss+in+a+mouse+model+of+Parkinson's+Disease.">Selective inhibition of NF-kappaB activation prevents dopaminergic neuronal loss in a mouse model of Parkinson's Disease.</a> Proc. Natl. Acad. Sci. USA. 104, 18754-18759 (2007).</li><li>Alvarez-Fischer, D., Henze, C., Strenzke, C., Westrich, J., Ferger, B., H&#246;glinger, G. U., Oertel, W. H., Hartmann, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+of+the+striatal+6-OHDA+model+of+Parkinson's+disease+in+wild+type+and+a-synuclein-deleted+mice.">Characterization of the striatal 6-OHDA model of Parkinson's disease in wild type and a-synuclein-deleted mice.</a> Exp. Neurol. 210, 182-193 (2008).</li><li>Ungerstedt, U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=6-Hydroxydopamine-induced+degeneration+of+the+nigrostriatal+dopamine+pathway:+The+turning+syndrome.">6-Hydroxydopamine-induced degeneration of the nigrostriatal dopamine pathway: The turning syndrome.</a> Pharmacology and Therapeutics Part B: General and Systematic Pharmacology. 2, 37-40 (1976).</li><li>. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Guidelines for the Care and Use of Mammals in Neuroscience and Behaviour Research. , 209 (2003).</li><li>Franklin, K. B. J., Paxinos, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> The Mouse Brain in Stereotaxic Coordinates. , (1997).</li><li>Hudson, J. L., Horne, C. G. v. a. n., Str&#246;mberg, I., Brock, S., Clayton, J., Masserano, J., Hoffer, B. J., Gerhardt, 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=Correlation+of+apomorphine-+and+amphetamine-induced+turning+with+nigrostriatal+dopamine+content+in+unilateral+6-hydroxydopamine+lesioned+rats.+Brain+Res.">Correlation of apomorphine- and amphetamine-induced turning with nigrostriatal dopamine content in unilateral 6-hydroxydopamine lesioned rats. Brain Res.</a> , 626-6167 (1993).</li><li>Truong, L., Allbutt, H., Kassiou, M., Henderson, 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=Developing+a+preclinical+model+of+Parkinson's+disease:+A+study+of+behaviour+in+rats+with+graded+6-OHDA+lesions.">Developing a preclinical model of Parkinson's disease: A study of behaviour in rats with graded 6-OHDA lesions.</a> Behav. Brain Res. 169, 1-9 (2006).</li><li>Harvey, B. K., Wang, Y., Hoffer, B. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transgenic+rodent+models+of+Parkinson's+disease.">Transgenic rodent models of Parkinson's disease.</a> Acta Neurochir. (Wien.). 101, 89-92 (2008).</li><li>Isacson, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ole+Isacson:+Development+of+New+Therapies+for+Parkinson's+Disease.">Ole Isacson: Development of New Therapies for Parkinson's Disease.</a> JoVE. 3, (2007).</li></ol>

Experiments were performed in accordance with the international Guidelines for the Care and Use of Mammals in Neuroscience and Behavior Research6, after approval by the Institutional Animal Care and Use Committee (Comiss&atilde;o de Avalia&#231;&atilde;o de Uso de Animais em Pesquisa: UFRJ/CAUAP protocol #DAHEICB 027). Adequate measures were taken to minimize the pain and discomfort of the experimental animals.

Extensive unilateral lesion of the nigro-striatal pathway can be achieved reliably in mice by a single stereotaxic injection of 6-OHDA into the striatum. The extent of the lesion can be verified post-mortem by immunohistochemistry for Tyrosine Hydroxylase (which catalyses the rate limiting stage of the synthesis of DA, i.e. the conversion of L-Tyrosine to dihydroxyphenylalanine), as illustrated in the video.
In vivo, contralateral rotations induced by apomorphine are a better predictor of max...

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		<th>Material Name</th>
		<th>Type</th>
		<th>Company</th>
		<th>Catalogue Number</th>
		<th>Comment</th>
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<tr>
<td>Ketamine hydrochloride</td>
<td>&nbsp;</td>
<td>K&ouml;nig</td>
<td>&nbsp;</td>
<td>90-120 mg/Kg</td>
</tr>
<tr>
<td>Xylazine hydrochloride</td>
<td>&nbsp;</td>
<td>K&ouml;nig</td>
<td>&nbsp;</td>
<td>10 mg/Kg</td>
</tr>
<tr>
<td>Atropine Sulfate</td>
<td>&nbsp;</td>
<td>Isofarma</td>
<td>&nbsp;</td>
<td>Isofarma</td>
</tr>
<tr>
<td>6 &#x2013; Hydroxydopamine Hydrochloride</td>
<td>&nbsp;</td>
<td>Sigma-Aldrich</td>
<td>&nbsp;</td>
<td>5 &mu;g/&mu;L</td>
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<td>L - Ascorbic Acid</td>
<td>&nbsp;</td>
<td>USB Corporation</td>
<td>&nbsp;</td>
<td>0.2%</td>
</tr>
<tr>
<td>Xylocaine (Lidocaine Chloridrate)</td>
<td>&nbsp;</td>
<td>ASTRA Chemistry</td>
<td>&nbsp;</td>
<td>5% 50 mg</td>
</tr>
<tr>
<td>Nebacetin (Neomycin Sulfate + Bacitracin)</td>
<td>&nbsp;</td>
<td>Altana Pharma</td>
<td>&nbsp;</td>
<td>5 mg/g + 250 Ul/g</td>
</tr>
<tr>
<td>R-(-)-Apomorphine hydrochloride</td>
<td>&nbsp;</td>
<td>Sigma-Aldrich</td>
<td>&nbsp;</td>
<td>0.5 mg/Kg</td>
</tr>
<tr>
<td>GenTeal lOphthalmic ointment Hypromellose</td>
<td>&nbsp;</td>
<td>NOVARTIS</td>
<td>&nbsp;</td>
<td> 0.33%</td>
</tr>
<tr>
<td>Ibuprofen</td>
<td>&nbsp;</td>
<td>Abbott</td>
<td>&nbsp;</td>
<td>4 mg/ 100 ml drinking water</td>
</tr>
<tr>
<td>Povidine</td>
<td>&nbsp;</td>
<td>JohnsonDiversey</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>R-(-)-Apomorphine hydrochloride</td>
<td>&nbsp;</td>
<td>Sigma-Aldrich</td>
<td>&nbsp;</td>
<td>0.5 mg/Kg</td>
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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.

Watch this Scientific Journal Video about Murine Model for Parkinson's Disease: from 6-OH Dopamine Lesion to Behavioral Test at JoVE.com

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.

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 ...

murine-model-for-parkinson-s-disease-from-6-oh-dopamine-lesion-to

Research

JoVE Journal

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31.5K Views.  Universidade Federal do Rio de Janeiro, Brasil. 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.

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

Gibberella zeae Ascospore Production and Collection for Microarray Experiments.

Fusarium graminearum Schwabe (teleomorph Gibberella zeae) is a plant pathogen causing scab disease on wheat and barley that reduces crop yield and grain quality. F. graminearum also causes stalk and ear rots of maize and is a producer of mycotoxins such as the trichothecenes that contaminate grain and are harmful to humans and livestock (Goswami and Kistler, 2004).

The fungus produces two types of spores. Ascospores, the propagules resulting from sexual reproduction, are the main source of primary infection.  These spores are forcibly discharged from mature perithecia and dispersed by wind (Francl et al 1999). Secondary infections are mainly caused by macroconidia which are produced by asexual means on the plant surface. To study the developmental processes of ascospores in this fungus, a procedure for their collection in large quantity under sterile conditions was required. Our protocol was filmed in order to generate the highest level of information for understanding and reproducibility; crucial aspects when full genome gene expression profiles are generated and interpreted. In particular, the variability of ascospore germination and biological activity are dependent on the prior manipulation of the material. The use of video for documenting every step in ascospore production is proposed in order to increase standardization, complying with the increasingly stringent requirements for microarray analysis. The procedure requires only standard laboratory equipment. Steps are shown to prevent contamination and favor time synchronization of ascospores.

To study the developmental processes of ascospores in Gibberella zeae, a procedure for collection under sterile conditions is filmed in order to generate the highest level of information for protocol description. This should facilitate the reproducibility of the experiment, a crucial aspect when full genome expression profile tests are implemented.

Gibberella zeae Produkcja Ascospore i Kolekcja dla Eksperymenty mikromacierzy.

Fusarium graminearum Schwabe (teleomorph Gibberella zeae) is a plant pathogen causing scab disease on wheat and barley that reduces crop yield and grain ...

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

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

Primary Dissociated Midbrain Dopamine Cell Cultures from Rodent Neonates

The ability to create primary cell cultures of dopamine neurons allows for the study of the presynaptic characteristics of dopamine neurons in isolation from systemic input from elsewhere in the brain. In our lab, we use these neurons to assess dopamine release kinetics using carbon fiber amperometry, as well as expression levels of dopamine related genes and proteins using quantitative PCR and immunocytochemistry. In this video, we show you how we generate these cultures from rodent neonates.
The process involves several steps, including the plating of cortical glial astrocytes, the conditioning of neuronal cell culture media by the glial substrate, the dissection of the midbrain in neonates, the digestion, extraction and plating of dopamine neurons and the addition of neurotrophic factors to ensure cell survival.
The applications suitable for such a preparation include electrophysiology, immunocytochemistry, quantitative PCR, video microscopy (i.e., of real-time vesicular fusion with the plasma membrane), cell viability assays and other toxicological screens.

Primary dissociated midbrain dopamine cell cultures allow for the study of presynaptic characteristics of dopamine neurons. They can be used to monitor real-time dopamine release kinetics and protein/mRNA levels of regulators of dopamine exocytosis. Here, we show you how to generate these cultures from rodent neonates.

The ability to create primary cell cultures of dopamine neurons allows for the study of the presynaptic characteristics of dopamine neurons in isolation ...

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

Improvements to the diagnosis and treatment of Parkinson's disease (PD) are dependent upon knowledge about susceptibility factors that render populations at risk. In the process of attempting to identify novel genetic factors associated with PD, scientists have generated many lists of candidate genes, polymorphisms, and proteins that represent important advances, but these leads remain mechanistically undefined. Our work is aimed toward significantly narrowing such lists by exploiting the advantages of a simple animal model system. While humans have billions of neurons, the microscopic roundworm Caenorhabditis elegans has precisely 302, of which only eight produce dopamine (DA) in hemaphrodites. Expression of a human gene encoding the PD-associated protein, alpha-synuclein, in C. elegans DA neurons results in dosage and age-dependent neurodegeneration.
Worms expressing human alpha-synuclein in DA neurons are isogenic and express both GFP and human alpha-synuclein under the DA transporter promoter (Pdat-1). The presence of GFP serves as a readily visualized marker for following DA neurodegeneration in these animals. We initially demonstrated that alpha-synuclein-induced DA neurodegeneration could be rescued in these animals by torsinA, a protein with molecular chaperone activity 1. Further, candidate PD-related genes identified in our lab via large-scale RNAi screening efforts using an alpha-synuclein misfolding assay were then over-expressed in C. elegans DA neurons. We determined that five of seven genes tested represented significant candidate modulators of PD as they rescued alpha-synuclein-induced DA neurodegeneration 2. Additionally, the Lindquist Lab (this issue of JoVE) has performed yeast screens whereby alpha-synuclein-dependent toxicity is used as a readout for genes that can enhance or suppress cytotoxicity. We subsequently examined the yeast candidate genes in our C. elegans alpha-synuclein-induced neurodegeneration assay and successfully validated many of these targets 3, 4.
Our methodology involves generation of a C. elegans DA neuron-specific expression vector using recombinational cloning of candidate gene cDNAs under control of the Pdat-1 promoter. These plasmids are then microinjected in wild-type (N2) worms, along with a selectable marker for successful transformation. Multiple stable transgenic lines producing the candidate protein in DA neurons are obtained and then independently crossed into the alpha-synuclein degenerative strain and assessed for neurodegeneration, at both the animal and individual neuron level, over the course of aging.

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

This video demonstrates how to use C. elegans to assess dopaminergic neuron neurodegeneration as a model for Parkinson's disease. Furthermore, genetic screens are used to identify factors that either enhance degeneration or are neuroprotective.

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

Murine Model of Hindlimb Ischemia 

In the United States, peripheral arterial disease (PAD) affects about 10 million individuals, and is also prevalent worldwide. Medical therapies for symptomatic relief are limited. Surgical or endovascular interventions are useful for some individuals, but long-term results are often disappointing. As a result, there is a need for developing new therapies to treat PAD. The murine hindlimb ischemia preparation is a model of PAD, and is useful for testing new therapies. When compared to other models of tissue ischemia such as coronary or cerebral artery ligation, femoral artery ligation provides for a simpler model of ischemic tissue. Other advantages of this model are the ease of access to the femoral artery and low mortality rate. 
In this video, we demonstrate the methodology for the murine model of unilateral hindimb ischemia. The specific materials and procedures for creating and evaluating the model will be described, including the assessment of limb perfusion by laser Doppler imaging. This protocol can also be utilized for the transplantation and non-invasive tracking of cells, which is demonstrated by Huang et al.1.

Murine Model of Hindlimb Ischemia

The surgical procedure for induction of unilateral hindlimb ischemia is demonstrated, with confirmation of ischemia by laser Doppler perfusion imaging.

In the United States, peripheral arterial disease (PAD) affects about 10 million individuals, and is also prevalent worldwide.  Medical therapies for ...

Using SecM Arrest Sequence as a Tool to Isolate Ribosome Bound Polypeptides

Extensive research has provided ample evidences suggesting that protein folding in the cell is a co-translational process1-5. However, the exact pathway that polypeptide chain follows during co-translational folding to achieve its functional form is still an enigma. In order to understand this process and to determine the exact conformation of the co-translational folding intermediates, it is essential to develop techniques that allow the isolation of RNCs carrying nascent chains of predetermined sizes to allow their further structural analysis.
SecM (secretion monitor) is a 170 amino acid E. coli protein that regulates expression of the downstream SecA (secretion driving) ATPase in the secM-secA operon6. Nakatogawa and Ito originally found that a 17 amino acid long sequence (150-FSTPVWISQAQGIRAGP-166) in the C-terminal region of the SecM protein is sufficient and necessary to cause stalling of SecM elongation at Gly165, thereby producing peptidyl-glycyl-tRNA stably bound to the ribosomal P-site7-9. More importantly, it was found that this 17 amino acid long sequence can be fused to the C-terminus of virtually any full-length and/or truncated protein thus allowing the production of RNCs carrying nascent chains of predetermined sizes7. Thus, when fused or inserted into the target protein, SecM stalling sequence produces arrest of the polypeptide chain elongation and generates stable RNCs both in vivo in E. coli cells and in vitro in a cell-free system. Sucrose gradient centrifugation is further utilized to isolate RNCs.
The isolated RNCs can be used to analyze structural and functional features of the co-translational folding intermediates. Recently, this technique has been successfully used to gain insights into the structure of several ribosome bound nascent chains10,11. Here we describe the isolation of bovine Gamma-B Crystallin RNCs fused to SecM and generated in an in vitro translation system.

We describe here a technique that is now routinely used to isolate stably bound ribosome nascent chain complexes (RNCs). This technique takes advantage of the discovery that a 17 amino acid long SecM "arrest sequence" can halt translation elongation in a prokaryotic (E. coli) system, when inserted into (or fused to the C-terminus) of virtually any protein.

Extensive research has provided ample evidences suggesting that protein folding in the cell is a co-translational process1-5. However, the exact pathway ...

Xenopus laevis as a Model to Identify Translation Impairment

Protein synthesis is a fundamental process to gene expression impacting diverse biological processes notably adaptation to environmental conditions. The initiation step, which involves the assembly of the ribosomal subunits at the mRNA initiation codon, involved initiation factor including eIF4G1. Defects in this rate limiting step of translation are linked to diverse disorders. To study the potential consequences of such deregulations, Xenopus laevis oocytes constitute an attractive model with high degrees of conservation of essential cellular and molecular mechanisms with human. In addition, during meiotic maturation, oocytes are transcriptionally repressed and all necessary proteins are translated from preexisting, maternally derived mRNAs. This inexpensive model enables exogenous mRNA to become perfectly integrated with an effective translation. Here is described a protocol for assessing translation with a factor of interest (here eIF4G1) using stored maternal mRNA that are the first to be polyadenylated and translated during oocyte maturation as a physiological readout. At first, mRNA synthetized by in vitro transcription of plasmids of interest (here eIF4G1) are injected in oocytes and kinetics of oocyte maturation by Germinal Vesicle Breakdown detection is determined. The studied maternal mRNA target is the serine/threonine-protein-kinase mos. Its polyadenylation and its subsequent translation are investigated together with the expression and phosphorylation of proteins of the mos signaling cascade involved in oocyte maturation. Variations of the current protocol to put forward translational defects are also proposed to emphasize its general applicability. In light of emerging evidence that aberrant protein synthesis may be involved in the pathogenesis of neurological disorders, such a model provides the opportunity to easily assess this impairment and identify new targets.

Xenopus laevis as a Model to Identify Translation Impairment

Protein synthesis control occurs mainly at the translation initiation step, deficiencies in which are linked to diverse disorders. To better understand their etiology, we described here a protocol using Xenopus laevis oocytes assessing the translation of mos transcript in the presence of a mutant of translation initiation factor eIF4G1.

Protein synthesis is a fundamental process to gene expression impacting diverse biological processes notably adaptation to environmental conditions. The ...

Magnetic-Activated Cell Sorting Strategies to Isolate and Purify Synovial Fluid-Derived Mesenchymal Stem Cells from a Rabbit Model

Mesenchymal stem cells (MSCs) are the main cell source for cell-based therapy. MSCs from articular cavity synovial fluid could potentially be used for cartilage tissue engineering. MSCs from synovial fluid (SF-MSCs) have been considered promising candidates for articular regeneration, and their potential therapeutic benefit has made them an important research topic of late. SF-MSCs from the knee cavity of the New Zealand white rabbit can be employed as an optimized translational model to assess human regenerative medicine. By means of CD90-based magnetic activated cell sorting (MACS) technologies, this protocol successfully obtains rabbit SF-MSCs (rbSF-MSCs) from this rabbit model and further fully demonstrates the MSC phenotype of these cells by inducing them to differentiate to osteoblasts, adipocytes, and chondrocytes. Therefore, this approach can be applied in cell biology research and tissue engineering using simple equipment and procedures.

This article presents a simple and economic protocol for the straightforward isolation and purification of mesenchymal stem cells from New Zealand white rabbit synovial fluid.

Mesenchymal stem cells (MSCs) are the main cell source for cell-based therapy. MSCs from articular cavity synovial fluid could potentially be used for ...

Protocols for Testing the Toxicity of Novel Insecticidal Chemistries to Mosquitoes

New classes of insecticides with novel modes of action are needed to control insecticide resistant populations of mosquitoes that transmit diseases such as Zika, dengue and malaria. Assays for rapid, high-throughput analyses of unformulated novel chemistries against mosquito larvae and adults are presented. We describe protocols for single point-dose and dose response assays to evaluate the toxicity of small molecule chemistries to the Aedes aegypti vector of Zika, dengue and yellow fever,&#160;the malaria vector, Anopheles gambiae and the northern house mosquito, Culex quinquefasciatus, on contact and via ingestion. As an example, we evaluated the toxicity of amitriptyline, a small molecule antagonist of G protein-coupled receptors, via larval, adult topical and adult blood-feeding assay. The protocols provide a starting point to investigate insecticide potential. Results are discussed in the context of additional experiments to explore product applications and mechanisms for delivery.

Protocols are described for assessing the toxicity of chemistries to immature and adult mosquitoes for development as new classes of larvicides, adulticides and endectocides. The protocols enable high-throughput testing of multiple chemistries at single-point dose and subsequent evaluation via dose response assay to determine toxicity on contact or via ingestion.

New classes of insecticides with novel modes of action are needed to control insecticide resistant populations of mosquitoes that transmit diseases such ...

Noninvasive Monitoring of Lesion Size in a Heterologous Mouse Model of Endometriosis

Here, we describe a protocol for the implementation of a heterologous mouse model in which progression of endometriosis can be assessed in real time through noninvasive monitoring of fluorescence emitted by implanted ectopic human endometrial tissue. For this purpose, biopsies of human endometrium are obtained from donor women ongoing oocyte donation. Human endometrial fragments are cultured in the presence of adenoviruses engineered to express cDNA for the reporter fluorescent protein mCherry. Upon visualization, labeled tissues with an optimal rate of fluorescence after infection are subsequently chosen for the implantation in recipient mice. One week prior to the implantation surgery, recipient mice are oophorectomized, and estradiol pellets are placed subcutaneously to sustain the survival and growth of lesions. On the day of surgery mice are anesthetized, and peritoneal cavity accessed through a small (1.5 cm) incision by the linea-alba. Fluorescently labeled implants are tweezed, briefly soaked in glue and attached to the peritoneal layer. Incisions are sutured, and animals left to recover for a couple of days. Fluorescence emitted by endometriotic implants is usually non-invasively monitored every 3 days for 4 weeks with an in vivo imaging system. Variations in the size of endometriotic implants can be estimated in real time by quantification of the mCherry signal and normalization against the initial time-point showing maximal fluorescence intensity.
Traditional preclinical rodents of models of endometriosis do not allow non-invasive monitoring of lesion in real time but rather allow evaluation of the effects of drugs assayed at the end point. This protocol allows one to track lesions in real time and is more useful to explore the therapeutic potential of drugs in preclinical models of endometriosis. The main limitation of the model thus generated is that non-invasive monitoring is not possible over long periods of time due to the episomal expression of Ad-virus.

Here, we present a protocol for live-imaging of fluorescently labeled human endometrial fragments grafted in mice. The method allows studying the effects of drugs of choice on endometriotic lesion size through monitoring and quantification of fluorescence emitted by the fluorescent reporter on real time

Here, we describe a protocol for the implementation of a heterologous mouse model in which progression of endometriosis can be assessed in real time ...