I would like to offer great thanks to David Carlson, Professor of English at Matsumoto Dental University, for his kind support in writing this report. I would also like to thank Tadafumi Adachi, a seminarist in our laboratory, for his compliance as a subject in this investigation.

1. Preparation of EMG electrodes
 <ol>
 <li>Begin by preparing nine electrodes. Eight of them are used for recording signals from sites over the muscle, and one is a reference electrode. </li>
 <li>After connecting the recording and reference electrodes to the amplifier, fill the discs with electric-conductance paste. Every type is OK, but a low fluid type is better.</li>
 <li>Before attaching the electrodes to the skin, have the subject down firmly, and determine the approximate location of the masseter muscle on the face. </li>
 <li>The superior tendon of the masseter muscle attaches to the zygomatic arch, and its inferior tendon to the angle of mandible.</li>
	<li>Place the eight recording electrodes onto a long piece of adhesive tape in equal inter-electrode distance, and attach the array to the skin surface. The first recording electrode is placed on the zygomatic arch, and the last one on the angle of mandible.</li>
 	<li>Finally, attach the reference electrode to the tip of the nose.</li>
</ol>
2. EMG recording
<ol>
	<li>To begin recording, first set the parameters of the multi-channel analogue amplifier (MEG6100). Set the gain to x 500, the low pass filter to 0.5 Hz, and the high pass filter to 10 kHz.</li>
 	<li>Connect the eight outputs of the analogue amplifier to an Analogue-Digital converter (PCI-MIO-16E-4). The digital signal is processed with LabView software with a sampling rate of 20kHz.</li>
 	<li>When everything is connected, record EMGs during quick chewing-gum clenching on the ipsilateral side.</li>
 	<li>The traces from the eight channels are presented on the LabView display immediately after the recording process has been completed.</li>
</ol>
3. EPP extraction and observation of its features
<ol>
	<li>To extract the EPP component, first remove the action potential component from the raw EMGs using a high-cut digital filter (Butterworth filter).</li>
 	<li>Begin applying the filter with a cut-off frequency of 10 Hz. A slow wave that deflects in the positive or negative direction should appear. This wave corresponds to the EPP, and the difference in polarity reflects the sink-source relation of the end plate current.</li>
 	<li>When recording from the masseter muscle, the most negative deflection of the wave is expected in the trace from the most inferior recording site, and the polarity should shift around 3 sites away from that site.</li>
 	<li>The magnitude of the EPP component can be measured as a peak point of the deflection or an area during the deflection.</li>
 	<li>The polarity change of the EPP component can be determined by plotting the EPP wave from each channel against a reference channel that showed the most negative deflection.</li>
 	<li>Now by increasing the cut-off frequency, the slow wave will become oscillatory. The oscillation will increase with increasing cut-off frequency and will generally become obvious at a cut-off frequency of 30 Hz.</li>
 	<li>The phase of the wave will reverse across the trace in which the polarity of the 10Hz filtered EPP wave showed a reversal.</li>
 <li>The phase shift of the oscillation can be checked with the same graphs that were applied to the 10Hz-filtered EPP wave.</li>
 <li>From the interval between neighboring positive and/or negative peaks of the oscillation, we can get an approximation of the frequency of the oscillation</li>
</ol>
4. EMG recording results
<img src="/files/ftp_upload/1653/1653Fig1a.jpg" alt="Figure 1 a" /> Figure 1a: Shown here is a schematic of the eight sites along the masseter muscle that were recorded from.
<img src="/files/ftp_upload/1653/1653Fig1b.jpg" alt="Figure 1 b" /> Figure 1b: We see a sample of the monopolar EMGs recorded simultaneously from the sites over the masseter muscle in response to quick gum clenching on the ipsilateral side. The EPP component was extracted using a high-cut digital filter with a cut-off frequency of 10Hz, which is superimposed on each raw EMG. In this trial, the most negative deflection was observed in traces-5 and -6 and the polarity changed across trace-3.
<img src="/files/ftp_upload/1653/1653Fig1c.jpg" alt="Figure 1c" /> Figure 1c: When the cut-off frequency of the high-cut digital filter was set to 30Hz, the slow wave exhibited an oscillation. Its phase also shifted across trace 3, where the polarity of the 10Hz-filtered EPP wave changed. The interval between neighboring positive peaks of the oscillation was measured. In this subject, the average inter-peak interval was 31.7 &plusmn; 6.5 msec over 16 recordings.

<ol>
	<li>Eccles, J. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> The physiology of synapses. , (1964).</li><li>Mitzdorf, U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Current+source-density+method+and+application+in+cat+cerebral+cortex:+investigation+of+evoked+potentials+and+EEG+phenomena.">Current source-density method and application in cat cerebral cortex: investigation of evoked potentials and EEG phenomena.</a> Physiol. Rev. 65, 37-100 (1985).</li><li>Rall, W., Shepherd, G. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Theoretical+reconstruction+of+field+potentials+and+dendrodendritic+synaptic+interactions+in+olfactory+bulb.">Theoretical reconstruction of field potentials and dendrodendritic synaptic interactions in olfactory bulb.</a> J. Neurophysiol. 31, 884-915 (1968).</li><li>Richardson, T. L., Turner, R. W., Miller, J. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Action-potential+discharge+in+hippocampal+CA1+pyramidal+neurons:+current+source+density+analysis.">Action-potential discharge in hippocampal CA1 pyramidal neurons: current source density analysis.</a> J. Neurophysiol. 58, 981-996 (1987).</li><li>Kumai, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Location+of+the+neuromuscular+junction+of+the+human+masseter+muscle+estimated+from+the+low+frequency+component+of+the+surface+electromyogram.">Location of the neuromuscular junction of the human masseter muscle estimated from the low frequency component of the surface electromyogram.</a> J. Jpn. Physiol. 55, 61-68 (2005).</li><li>Mito, K., Sakamoto, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Distribution+of+muscle+fiber+conduction+velocity+of+m.+masseter+during+voluntary+isometric+contraction.">Distribution of muscle fiber conduction velocity of m. masseter during voluntary isometric contraction.</a> Electroencephalogr. Clin. Neurophysiol. 40, 275-285 (2000).</li><li>Tokunaga, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Two-dimensional+configuration+of+the+myoneural+junctions+of+human+masticatory+muscle+detected+with+matrix+electrode.">Two-dimensional configuration of the myoneural junctions of human masticatory muscle detected with matrix electrode.</a> J. Oral Rehabili. 25, 329-334 (1998).</li><li>Rohen, J. H., Yokochi, C., L&#x0171;tjen-Drecoll, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Color atlas of anatomy. , (2006).</li><li>Wichmann, T., DeLong, M. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Oscillation+in+the+basal+ganglia.">Oscillation in the basal ganglia.</a> Nature. 400, 621-622 (1999).</li></ol>

<ol><li>As the negative potential is considered to be formed by a flow-in of the endplate current, and the positive deflection, by its flow-out [1,2,3,4], the trace showing the most negative deflection must correspond to the site locating the neuromuscular junction [5]. Figure 1b indicates the neuromuscular junction of the masseter muscle locate in its inferior portion close to the angle of mandible, which is approximately the same as results obtained by another method utilizing the conduction manner of the motor unit action potential [6,7].</l...

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		<div>
		<table border="1">
		<thead>
		<tr>
		<th>Material Name</th>
		<th>Type</th>
		<th>Company</th>
		<th>Catalogue Number</th>
		<th>Comment</th>
		</tr>
		</thead>
		<tbody>
		
<tr>
<td>Analogue filter</td>
<td>&nbsp;</td>
<td>Nihon Kohden</td>
<td>MEG6100</td>
<td>pre-,main-amplifier</td>
</tr>
<tr>
<td>A/D converter</td>
<td>&nbsp;</td>
<td>National Instruments</td>
<td>PCI-MIO-16E-4</td>
<td>PCI board for computer</td>
</tr>
<tr>
<td>Connection interface</td>
<td>&nbsp;</td>
<td>National Instruments</td>
<td>BNC-2090</td>
<td>8ch BNC adaptor</td>
</tr>
<tr>
<td>Disc electrodes</td>
<td>&nbsp;</td>
<td>Nihon Kohden</td>
<td>NS-11</td>
<td>Ag/AgCl (&Phi;8mm)</td>
</tr>
<tr>
<td>Electrode past</td>
<td>&nbsp;</td>
<td>Sanshin</td>
<td>SA-5</td>
<td>Semi-fluid carbon past</td>
</tr>
<tr>
<td>LabVIEW (Digital filter)</td>
<td>&nbsp;</td>
<td>National Instruments</td>
<td>V. 8.5</td>
<td>Programming language</td>
</tr>
<tr>
<td>Chewing gum</td>
<td>&nbsp;</td>
<td>Lotte</td>
<td>Green gum</td>
<td>Test food in clenching</td>
</tr>		</tbody>
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extraction of the epp component from the surface emg

A surface electromyogram (EMG), especially when recorded near the neuromuscular junction, is expected to contain the endplate potential (EPP) component which can be extracted with an appropriate signal filter. Two factors are important: the EMG must be recorded in monopolar fashion, and the recording must be done so the low frequency signal corresponding the EPP is not eliminated. This report explains how to extract the EPP component from the EMG of the masseter muscle in a human subject. The surface EMG is recorded from eight sites using traditional disc electrodes aligned along over the muscle, with equal inter-electrode distance from the zygomatic arch to the angle of mandible in response to quick gum clenching. A reference electrode is placed on the tip of the nose. The EPP component is extracted from the raw EMGs by applying a high-cut digital filter (2nd dimension Butterworth filter) with a range of 10-35 Hz. When the filter is set to 10 Hz, the extracted EPP wave deflects either negative or positive depending on the recording site. The difference in the polarity reflects the sink-source relation of the end plate current, with the site showing the most negative deflection corresponding to the neuromuscular junction. In the case of the masseter muscle, the neuromuscular junction is estimated to be located in the inferior portion close to the angle of mandible. The EPP component exhibits an interesting oscillation when the cut-off frequency of the high-cut digital filter is set to 30 Hz. The EPP oscillation indicates that muscle contraction is adjusted in an intermittent manner. Abnormal tremors accompanying various sorts of diseases may be substantially due to this EPP oscillation, which becomes slower and is difficult to cease.

Watch this Scientific Journal Video about Extraction of the EPP Component from the Surface EMG at JoVE.com

Extraction of the EPP Component from the Surface EMG

The endplate potential (EPP) component can be extracted from the surface EMG using a digital filter. The extracted EPP shows oscillation with a frequency of about 30 Hz.

A surface electromyogram (EMG), especially when recorded near the neuromuscular junction, is expected to contain the endplate potential (EPP) component ...

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12.5K Views.  Matsumoto Dental University. The endplate potential (EPP) component can be extracted from the surface EMG using a digital filter. The extracted EPP shows oscillation with a frequency of about 30 Hz.

Video: Extraction of the EPP Component from the Surface EMG

Micro-dissection of Rat Brain for RNA or Protein Extraction from Specific Brain Region

Micro-dissection of rat brain into various regions is extremely important for the study of different neurodegenerative diseases. This video demonstrates micro-dissection of four major brain regions include olfactory bulb, frontal cortex, striatum and hippocampus in fresh rat brain tissue. Useful tips for quick removal of respective regions to avoid RNA and protein degradation of the tissue are given.

Micro-dissection of rat brain into various regions is extremely important for the study of different neurodegenerative diseases. This video demonstrates micro-dissection of four major brain regions include olfactory bulb, frontal cortex, striatum and hippocampus in fresh rat brain tissue. Useful tips for quick removal of respective regions to avoid RNA and protein degradation of the tissue are given.

Micro-dissection of rat brain into various regions is extremely important for the study of different neurodegenerative diseases. This video demonstrates ...

RNA Extraction from Neuroprecursor Cells Using the Bio-Rad Total RNA Kit

Retrograde Labeling of Retinal Ganglion Cells by Application of Fluoro-Gold on the Surface of Superior Colliculus

Retinal ganglion cell (RGC) counting is essential to evaluate retinal degeneration especially in glaucoma. Reliable RGC labeling is fundamental for evaluating the effects of any treatment. In rat, about 98% of RGCs is known to project to the contralateral superior colliculus (SC) (Forrester and Peters, 1967). Applying fluoro-gold (FG) on the surface of SC can label almost all the RGCs, so that we can focus on this most vulnerable retinal neuron in glaucoma. FG is taken up by the axon terminals of retinal ganglion cells and bilaterally transported retrogradely to its somas in the retina. Compare with retrograde labeling of RGC by putting FG at stump of transected optic nerve for 2 days, the interference of RGC survival is minimized. Compare with cresyl violet staining that stains RGCs, amacrine cells and endothelium of the blood vessel in the retinal ganglion cell layer, this labeling method is more specific to the RGC. This video describes the method of retrograde labeling of RGC by applying FG on the surface of SC. The surgical procedures include drilling the skull; aspirating the cortex to expose the SC and applying gelatin sponge over entire dorsal surface of SC are shown. Useful tips for avoiding massive intracranial bleeding and aspiration of the SC have been given.

This video describes the method of retrograde labeling of RGC by applying fluoro-gold (FG) on the surface of superior colliculus (SC). Technique involves drilling the skull, aspirating the cortex, and applying gelatin sponge over entire dorsal surface of SC.

Retinal ganglion cell (RGC) counting is essential to evaluate retinal degeneration especially in glaucoma. Reliable RGC labeling is fundamental for ...

Avidity-based Extracellular Interaction Screening (AVEXIS) for the Scalable Detection of Low-affinity Extracellular Receptor-Ligand Interactions

Extracellular protein:protein interactions between secreted or membrane-tethered proteins are critical for both initiating intercellular communication and ensuring cohesion within multicellular organisms. Proteins predicted to form extracellular interactions are encoded by approximately a quarter of human genes1, but despite their importance and abundance, the majority of these proteins have no documented binding partner. Primarily, this is due to their biochemical intractability: membrane-embedded proteins are difficult to solubilise in their native conformation and contain structurally-important posttranslational modifications. Also, the interaction affinities between receptor proteins are often characterised by extremely low interaction strengths (half-lives &lt; 1 second) precluding their detection with many commonly-used high throughput methods2. 
Here, we describe an assay, AVEXIS (AVidity-based EXtracellular Interaction Screen) that overcomes these technical challenges enabling the detection of very weak protein interactions (t1/2 &le; 0.1 sec) with a low false positive rate3. The assay is usually implemented in a high throughput format to enable the systematic screening of many thousands of interactions in a convenient microtitre plate format (Fig. 1). It relies on the production of soluble recombinant protein libraries that contain the ectodomain fragments of cell surface receptors or secreted proteins within which to screen for interactions; therefore, this approach is suitable for type I, type II, GPI-linked cell surface receptors and secreted proteins but not for multipass membrane proteins such as ion channels or transporters.
The recombinant protein libraries are produced using a convenient and high-level mammalian expression system4, to ensure that important posttranslational modifications such as glycosylation and disulphide bonds are added. Expressed recombinant proteins are secreted into the medium and produced in two forms: a biotinylated bait which can be captured on a streptavidin-coated solid phase suitable for screening, and a pentamerised enzyme-tagged (&beta;-lactamase) prey. The bait and prey proteins are presented to each other in a binary fashion to detect direct interactions between them, similar to a conventional ELISA (Fig. 1). The pentamerisation of the proteins in the prey is achieved through a peptide sequence from the cartilage oligomeric matrix protein (COMP) and increases the local concentration of the ectodomains thereby providing significant avidity gains to enable even very transient interactions to be detected. By normalising the activities of both the bait and prey to predetermined levels prior to screening, we have shown that interactions having monomeric half-lives of 0.1 sec can be detected with low false positive rates3.

Avidity-based Extracellular Interaction Screening AVEXIS for the Scalable Detection of Low-affinity Extracellular Receptor-Ligand Interactions

AVEXIS is a high throughput protein interaction assay developed to systematically screen for novel extracellular receptor-ligand pairs involved in cellular recognition processes. It is specifically designed to detect transient protein interactions that are difficult to identify using other high throughput approaches.

Extracellular protein:protein interactions between secreted or membrane-tethered proteins are critical for both initiating intercellular communication and ...

Budding Yeast Protein Extraction and Purification for the Study of Function, Interactions, and Post-translational Modifications

Homogenization by bead beating is a fast and efficient way to release DNA, RNA, proteins, and metabolites from budding yeast cells, which are notoriously hard to disrupt. Here we describe the use of a bead mill homogenizer for the extraction of proteins into buffers optimized to maintain the functions, interactions and post-translational modifications of proteins. Logarithmically growing cells expressing the protein of interest are grown in a liquid growth media of choice. The growth media may be supplemented with reagents to induce protein expression from inducible promoters (e.g. galactose), synchronize cell cycle stage (e.g. nocodazole), or inhibit proteasome function (e.g. MG132). Cells are then pelleted and resuspended in a suitable buffer containing protease and/or phosphatase inhibitors and are either processed immediately or frozen in liquid nitrogen for later use. Homogenization is accomplished by six cycles of 20 sec&#160;bead-beating (5.5 m/sec), each followed by one minute incubation on ice. The resulting homogenate is cleared by centrifugation and small particulates can be removed by filtration. The resulting cleared whole cell extract (WCE) is precipitated using 20% TCA for direct analysis of total proteins by SDS-PAGE followed by Western blotting. Extracts are also suitable for affinity purification of specific proteins, the detection of post-translational modifications, or the analysis of co-purifying proteins. As is the case for most protein purification protocols, some enzymes and proteins may require unique conditions or buffer compositions for their purification and others may be unstable or insoluble under the conditions stated. In the latter case, the protocol presented may provide a useful starting point to empirically determine the best bead-beating strategy for protein extraction and purification. We show the extraction and purification of an epitope-tagged SUMO E3 ligase, Siz1, a cell cycle regulated protein that becomes both sumoylated and phosphorylated, as well as a SUMO-targeted ubiquitin ligase subunit, Slx5.

The preparation of high quality yeast cell extracts is a necessary first step in the analysis of individual proteins or entire proteomes. Here we describe a fast, efficient, and reliable homogenization protocol for budding yeast cells that has been optimized to preserve protein functions, interactions, and post-translational modifications.

Homogenization by bead beating is a fast and efficient way to release DNA, RNA, proteins, and metabolites from budding yeast cells, which are notoriously ...

Real Time Measurements of Membrane Protein:Receptor Interactions Using Surface Plasmon Resonance (SPR)

Protein-protein interactions are pivotal to most, if not all, physiological processes, and understanding the nature of such interactions is a central step in biological research. Surface Plasmon Resonance (SPR) is a sensitive detection technique for label-free study of bio-molecular interactions in real time. In a typical SPR experiment, one component (usually a protein, termed 'ligand') is immobilized onto a sensor chip surface, while the other (the 'analyte') is free in solution and is injected over the surface. Association and dissociation of the analyte from the ligand are measured and plotted in real time on a graph called a sensogram, from which pre-equilibrium and equilibrium data is derived. Being label-free, consuming low amounts of material, and providing pre-equilibrium kinetic data, often makes SPR the method of choice when studying dynamics of protein interactions. However, one has to keep in mind that due to the method's high sensitivity, the data obtained needs to be carefully analyzed, and supported by other biochemical methods. 
SPR is particularly suitable for studying membrane proteins since it consumes small amounts of purified material, and is compatible with lipids and detergents. This protocol describes an SPR experiment characterizing the kinetic properties of the interaction between a membrane protein (an ABC transporter) and a soluble protein (the transporter's cognate substrate binding protein).

Real Time Measurements of Membrane Protein:Receptor Interactions Using Surface Plasmon Resonance SPR

Surface Plasmon Resonance (SPR) is a label-free method for detecting bio-molecular interactions in real time. Herein, a protocol for a membrane protein:receptor interaction experiment is described, while discussing the pros and cons of the technique.

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The Infiltration-centrifugation Technique for Extraction of Apoplastic Fluid from Plant Leaves Using Phaseolus vulgaris as an Example

The apoplast is a distinct extracellular compartment in plant tissues that lies outside the plasma membrane and includes the cell wall. The apoplastic compartment of plant leaves is the site of several important biological processes, including cell wall formation, cellular nutrient and water uptake and export, plant-endophyte interactions and defence responses to pathogens. The infiltration-centrifugation method is well established as a robust technique for the analysis of the soluble apoplast composition of various plant species. The fluid obtained by this method is commonly known as apoplast washing fluid (AWF). The following protocol describes an optimized vacuum infiltration and centrifugation method for AWF extraction from Phaseolus vulgaris (French bean) cv. Tendergreen leaves. The limitations of this method and the optimization of the protocol for other plant species are discussed. Recovered AWF can be used in a wide range of downstream experiments that seek to characterize the composition of the apoplast and how it varies in response to plant species and genotype, plant development and environmental conditions, or to determine how microorganisms grow in apoplast fluid and respond to changes in its composition.

The Infiltration-centrifugation Technique for Extraction of Apoplastic Fluid from Plant Leaves Using Phaseolus vulgaris as an Example

This protocol details the optimized extraction of apoplast washing fluid from plant leaves, using French bean plants (Phaseolus vulgaris) as a model example.

The apoplast is a distinct extracellular compartment in plant tissues that lies outside the plasma membrane and includes the cell wall. The apoplastic ...

Real-time Imaging of Plant Cell Surface Dynamics with Variable-angle Epifluorescence Microscopy

A plant&#8217;s cell surface is its interface for perceiving environmental cues; it responds with cell biological changes such as membrane trafficking and cytoskeletal rearrangement. Real-time and high-resolution image analysis of such intracellular events will increase the understanding of plant cell biology at the molecular level. Variable angle epifluorescence microscopy (VAEM) is an emerging technique that provides high-quality, time-lapse images of fluorescently-labeled proteins on the plant cell surface. In this article, practical procedures are described for VAEM specimen preparation, adjustment of the VAEM optical system, movie capturing and image analysis. As an example of VAEM observation, representative results are presented on the dynamics of PATROL1. This is a protein essential for stomatal movement, thought to be involved in proton pump delivery to plasma membranes in the stomatal complex of Arabidopsis thaliana. VAEM real-time observation of guard cells and subsidiary cells in A. thaliana cotyledons showed that fluorescently-tagged PATROL1 appeared as dot-like structures on plasma membranes for several seconds and then disappeared. Kymograph analysis of VAEM movie data determined the time distribution of the presence (termed &#8216;residence time&#8217;) of the dot-like structures. The use of VAEM is discussed in the context of this example.

The goal of this protocol is to demonstrate how to monitor fluorescently-tagged protein dynamics on plant cell surfaces with variable-angle epifluorescence microscopy, showing blinking dots of GFP-tagged PATROL1, a membrane trafficking protein, in the cell cortex of the stomatal complex in Arabidopsis thaliana.

A plant&#8217;s cell surface is its interface for perceiving environmental cues; it responds with cell biological changes such as membrane trafficking and ...

Methods for the Extraction of Endosymbionts from the Whitefly Bemisia tabaci

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

Methods for the Extraction of Endosymbionts from the Whitefly Bemisia tabaci

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

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

In Vivo Surface Electrocardiography for Adult Zebrafish

The electrocardiogram waveforms of adult zebrafish and those of humans are remarkably similar. These electrocardiogram similarities enhance the value of zebrafish not only as a research model for human cardiac electrophysiology and myopathies but also as a surrogate model in high throughput pharmaceutical screening for potential cardiotoxicities to humans, such as QT prolongation. As such, in vivo electrocardiography for adult zebrafish is an electrical phenotyping tool that is necessary, if not indispensable, for cross-sectional or longitudinal in vivo electrophysiological characterizations. However, too often, the lack of a reliable, practical, and cost-effective recording method remains a major challenge preventing this in vivo diagnostic tool from becoming more readily accessible. Here, we describe a practical, straightforward approach to in vivo electrocardiography for adult zebrafish using a low-maintenance, cost-effective, and comprehensive system that yields consistent, reliable recordings. We illustrate our protocol using healthy adult male zebrafish of 12-18 months of age. We also introduce a rapid real-time interpretation strategy for quality validation to ensure data accuracy and robustness early in the electrocardiogram recording process.

Here, we present a reliable, minimally invasive, and cost-effective method to record and interpret electrocardiograms in live anesthetized adult zebrafish.

The electrocardiogram waveforms of adult zebrafish and those of humans are remarkably similar. These electrocardiogram similarities enhance the value of ...