Name: dissection of human retina and rpe-choroid for proteomic analysis
Uploaded: 2017-11-12T14:00:00
Description: Watch this Scientific Journal Video about Dissection of Human Retina and RPE-Choroid for Proteomic Analysis at JoVE.com

VBM is supported by NIH grants [K08EY020530, R01EY024665, R01EY025225, R01EY024698 and R21AG050437], Doris Duke Charitable Foundation Grant #: 2013103, and Research to Prevent Blindness (RPB), New York, NY. MT and GV are supported by NIH grant T32GM007337.

This study was approved by the University of Iowa&#39;s Institutional Review Board and adheres to the tenets set forth in the Declaration of Helsinki.
1. Foveal and Macular Biopsy Punch
<ol>
	<li>Open and butterfly the human eye, such that it consists of 4 separate flaps of tissue, as described in a previous publication.5</li>
	<li>Beginning with a butterflied human eye placed in a Petri dish, center a 4-mm punch biopsy tool over the fovea, press down, and roll gently...

<ol>
	<li>Chirco, K. R., Sohn, E. H., Stone, E. M., Tucker, B. A., Mullins, R. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Structural+and+molecular+changes+in+the+aging+choroid:+implications+for+age-related+macular+degeneration.">Structural and molecular changes in the aging choroid: implications for age-related macular degeneration.</a> Eye (Lond). , (2016).</li><li>Zhang, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Defining+the+proteome+of+human+iris,+ciliary+body,+retinal+pigment+epithelium,+and+choroid.">Defining the proteome of human iris, ciliary body, retinal pigment epithelium, and choroid.</a> Proteomics. 16 (7), 1146-1153 (2016).</li><li>Funke, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Glaucoma+related+Proteomic+Alterations+in+Human+Retina+Samples.">Glaucoma related Proteomic Alterations in Human Retina Samples.</a> Sci Rep. 6, 29759 (2016).</li><li>Decanini, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Human+retinal+pigment+epithelium+proteome+changes+in+early+diabetes.">Human retinal pigment epithelium proteome changes in early diabetes.</a> Diabetologia. 51 (6), 1051-1061 (2008).</li><li>Skeie, J. M., Mahajan, V. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dissection+of+human+vitreous+body+elements+for+proteomic+analysis.">Dissection of human vitreous body elements for proteomic analysis.</a> J Vis Exp. (47), (2011).</li><li>Skeie, J. M., Mahajan, V. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Proteomic+landscape+of+the+human+choroid-retinal+pigment+epithelial+complex.">Proteomic landscape of the human choroid-retinal pigment epithelial complex.</a> JAMA Ophthalmol. 132 (11), 1271-1281 (2014).</li><li>Skeie, J. M., Tsang, S. H., Mahajan, V. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evisceration+of+mouse+vitreous+and+retina+for+proteomic+analyses.">Evisceration of mouse vitreous and retina for proteomic analyses.</a> J Vis Exp. (50), (2011).</li><li>Skeie, J. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Proteomic+analysis+of+vitreous+biopsy+techniques.">Proteomic analysis of vitreous biopsy techniques.</a> Retina. 32 (10), 2141-2149 (2012).</li><li>Skeie, J. M., Mahajan, V. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Proteomic+interactions+in+the+mouse+vitreous-retina+complex.">Proteomic interactions in the mouse vitreous-retina complex.</a> PLoS One. 8 (11), e82140 (2013).</li><li>Mahajan, V. B., Skeie, 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=Translational+vitreous+proteomics.">Translational vitreous proteomics.</a> Proteomics Clin Appl. 8 (3-4), 204-208 (2014).</li><li>Skeie, J. M., Roybal, C. N., Mahajan, V. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Proteomic+insight+into+the+molecular+function+of+the+vitreous.">Proteomic insight into the molecular function of the vitreous.</a> PLoS One. 10 (5), e0127567 (2015).</li><li>Velez, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Precision+Medicine:+Personalized+Proteomics+for+the+Diagnosis+and+Treatment+of+Idiopathic+Inflammatory+Disease.">Precision Medicine: Personalized Proteomics for the Diagnosis and Treatment of Idiopathic Inflammatory Disease.</a> JAMA Ophthalmol. 134 (4), 444-448 (2016).</li><li>Velez, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Proteomic+analysis+of+elevated+intraocular+pressure+with+retinal+detachment.">Proteomic analysis of elevated intraocular pressure with retinal detachment.</a> Am J Ophthalmol Case Rep. 5, 107-110 (2017).</li><li>Skeie, J. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+biorepository+for+ophthalmic+surgical+specimens.">A biorepository for ophthalmic surgical specimens.</a> Proteomics Clin Appl. 8 (3-4), 209-217 (2014).</li><li>Ferrer, I., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Brain+protein+preservation+largely+depends+on+the+postmortem+storage+temperature:+implications+for+study+of+proteins+in+human+neurologic+diseases+and+management+of+brain+banks:+a+BrainNet+Europe+Study.">Brain protein preservation largely depends on the postmortem storage temperature: implications for study of proteins in human neurologic diseases and management of brain banks: a BrainNet Europe Study.</a> J Neuropathol Exp Neurol. 66 (1), 35-46 (2007).</li><li>Ahmed, M. M., Gardiner, K. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Preserving+protein+profiles+in+tissue+samples:+differing+outcomes+with+and+without+heat+stabilization.">Preserving protein profiles in tissue samples: differing outcomes with and without heat stabilization.</a> J Neurosci Methods. 196 (1), 99-106 (2011).</li><li>Kanshin, E., Tyers, M., Thibault, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sample+Collection+Method+Bias+Effects+in+Quantitative+Phosphoproteomics.">Sample Collection Method Bias Effects in Quantitative Phosphoproteomics.</a> J Proteome Res. 14 (7), 2998-3004 (2015).</li><li>Crecelius, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Assessing+quantitative+post-mortem+changes+in+the+gray+matter+of+the+human+frontal+cortex+proteome+by+2-D+DIGE.">Assessing quantitative post-mortem changes in the gray matter of the human frontal cortex proteome by 2-D DIGE.</a> Proteomics. 8 (6), 1276-1291 (2008).</li><li>Oka, T., Tagawa, K., Ito, H., Okazawa, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dynamic+changes+of+the+phosphoproteome+in+postmortem+mouse+brains.">Dynamic changes of the phosphoproteome in postmortem mouse brains.</a> PLoS One. 6 (6), e21405 (2011).</li><li>Nagy, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+postmortem+interval+on+biomolecule+integrity+in+the+brain.">Effects of postmortem interval on biomolecule integrity in the brain.</a> J Neuropathol Exp Neurol. 74 (5), 459-469 (2015).</li><li>Mukherjee, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Proteomic+analysis+of+frozen+tissue+samples+using+laser+capture+microdissection.">Proteomic analysis of frozen tissue samples using laser capture microdissection.</a> Methods Mol Biol. 1002, 71-83 (2013).</li></ol>

After tissue collection, sample handling and treatment are crucial considerations14. Preservation in liquid nitrogen is preferred over chemical fixation, as the latter may result in damage to protein structure, which could skew downstream analysis. Additionally, liquid nitrogen preservation is preferred to methods which do not involve freezing of samples. Notably, Ferrer et al. showed significant differences in protein levels between brain samples preserved at 4 &#176;C or room temperatur...

The retina, RPE, and choroid are complex tissues that demonstrate important regional differences in protein expression, physiological function, and pathological susceptibilities1,2. For example, diseases such as Age-Related Macular Degeneration (AMD), retinitis pigmentosa, and central serous retinopathy each demonstrate characteristic localization within the fovea, macula, or retina periphery1,3,4,6. Here, we present a method demonstrating how distinct retinal regions can be independently sampled. The overall goal of this method is to provide a reliable guide for collection of tissue samples from the foveal, macular, and peripheral regions of the human retina and RPE-choroid for proteomic analysis. The rationale for the development and use of this technique is that through proteomic analysis of these specific retinal regions, important molecular insights may be gained into the physiological and pathophysiological functions of these regions.
This approach promises to reveal the proteomic basis for relative regional disease susceptibilities, and to facilitate the identification of new specific therapeutic targets. Indeed, proteomic investigations of the vitreous and its interactions with the retina have provided key insights into the molecular composition and function of healthy and diseased tissue5,7,8,9,10,11,12,13. However, clear comparative proteomic analyses of distinct retinal regions are lacking. The technique will help to support these much-needed studies, providing advantages over other methods by demonstrating a reliable and reproducible tissue collection approach. More so, the approach is very accessible, taking advantage of standard-sized and readily available tissue punch biopsy tools. Our technique emphasizes the appropriate collection and storage of tissues for proteomic processing, making important considerations for protein stability and degradation. Thus, this method is most appropriate for investigators considering downstream molecular analysis of proteomic factors.

<table border="0" cellpadding="0" cellspacing="0" width="691">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">4-mm skin punch biopsy tool</td>
			<td style="width:189px;">Miltex</td>
			<td style="width:119px;">REF 33-34</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">8-mm skin punch biopsy tool</td>
			<td style="width:189px;">Miltex</td>
			<td style="width:119px;">REF 33-37</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">0.12 Colibri Forceps</td>
			<td style="width:189px;">Stephens Instruments</td>
			<td style="width:119px;">S5-1145</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Wescott Scissors</td>
			<td style="width:189px;">Sklar Surgical Instruments</td>
			<td style="width:119px;">64-3146</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Microfuge tubes</td>
			<td style="width:189px;">Eppendorf</td>
			<td style="width:119px;">#022364111</td>
			<td>1.5 mL</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Liquid Nitrogen</td>
			<td style="width:189px;">Praxair, Inc.</td>
			<td style="width:119px;">7727-37-9 [R]</td>
			<td></td>
		</tr>
	</tbody>
</table>

dissection of human retina and rpe-choroid for proteomic analysis

The human retina is composed of the sensory neuroretina and the underlying retinal pigmented epithelium (RPE), which is firmly complexed to the vascular choroid layer. Different regions of the retina are anatomically and molecularly distinct, facilitating unique functions and demonstrating differential susceptibility to disease. Proteomic analysis of each of these regions and layers can provide vital insights into the molecular process of many diseases, including Age-Related Macular Degeneration (AMD), diabetes mellitus, and glaucoma. However, separation of retinal regions and layers is essential before quantitative proteomic analysis can be accomplished. Here, we describe a method for dissection and collection of the foveal, macular, and peripheral retinal regions and underlying RPE-choroid complex, involving regional punch biopsies and manual removal of tissue layers from a human eye.One-dimensional SDS-PAGE as well as downstream proteomic analysis, such as liquid chromatography-tandem mass spectrometry (LC-MS/MS), can be used to identify proteins in each dissected retinal layer, revealing molecular biomarkers for retinal disease.

Retinal and RPE-choroid tissue can be processed in various ways to suit an individual investigation. After collection, the researcher will possess samples of retinal and RPE-choroid tissue from the foveal region, outer macula, and peripheral retina (Figure 1). Specifically, the foveal region punch will include the fovea, the parafovea, and a small amount of the adjacent perifovea. The macular punch includes the remainder of the perifoveal region as well as a ...

Watch this Scientific Journal Video about Dissection of Human Retina and RPE-Choroid for Proteomic Analysis at JoVE.com

Dissection of Human Retina and RPE-Choroid for Proteomic Analysis

The human retina is composed of functionally and molecularly distinct regions, including the fovea, macula, and peripheral retina. Here, we describe a method using punch biopsies and manual removal of tissue layers from a human eye to dissect and collect these distinct retinal regions for downstream proteomic analysis.

The human retina is composed of the sensory neuroretina and the underlying retinal pigmented epithelium (RPE), which is firmly complexed to the vascular ...

This video will illustrate how to capture tissue biopsies from the fovea, macula and peripheral retina for proteomic research. In several steps we'll use a four millimeter skin punch biopsy tool. The human eye is placed in a petri dish after it has been butterflied.The punch biopsy tool is centered right over the fovea, press down, rolled slightly until an incision is made around the fovea. Center and press an eight millimeter punch biopsy within the arcades of the macula with gentle pressure and rolling. Again, use the four millimeter punch biopsy to make a series or punches in the peripheral retina just outside the arcade.We get two punches for each flap. After all the punches are made, the eye will look something like this. And we are ready to begin the tissue collection process.We use a curved 0.12 colibri forcep to grab the edges of the tissue. Here we grasp the edge of the foveal retina. The same forcep is used to grasp the ring of macular tissue.In this case, it appears to stuck to the disc. Using a pair of westcott scissors, you can trim the edge, so to capture just the retina. Next we turn our attention to the peripheral retinal punches we use a colibri forcep to gently lift and separate them from the underlying RPE and choroid.In some cases there can be some residual vitreous gel. Try to use the forceps and separate this away before capturing the tissue. This is another specimen with a lot of vitreous gel.It's just lifted away from separated using the forceps and then the retina is captured. Once the retina has been removed, the RPE-choroid remains. We use the same forceps to grasp the edges of this pigmented tissue and carefully separate it from the sclera.This tissue represents the RPE-choroid underlying the fovea. Here's the ring of underlying RPE-choroid of the macula. A second instrument in the left hand can be useful for manipulating the tissue.Similar to the retina, the RPE-choroid complex is fused to the disc and westcott scissors again are useful to separate this tissue from the eye. 12 colibri forceps are used to peel away the RPE-choroid in the peripheral punch area. If the punch biopsy blade was dull, or you didn't push hard enough, there may not be a clean cut surrounding the tissue.In these cases, pull the tissue away as much as possible and then use westcott scissors to trim and separate. Tissue samples were trypsin digested and analyzed using one dimensional STS page to visualize protein content. The results of this analysis suggested distinct proteins among the different sampled regions of the retina.The follow up experiment using liquid chromatography tandem mass spectrometry properly identified peptides from rhodopsin, a highly abundant and unique retina protein. In panel B, the representative rhodopsin spectrum obtained from the macular region is shown. Further analysis of the protein content will provide insights into the molecular functions of the anatomically distinct regions of the retina.The retina and RPE-choroid are complex tissues that demonstrate important regional differences in protein expression and pathological susceptibilities. Here we described the novel method for reliably removing tissue samples from distinct regions of the retina for proteomic analysis. Important considerations for this technique include, proper handling, treatment and storage of samples after collection.Post-mortem timing of tissue harvesting, considering the use of different skin size punch biopsy tools to adjust the amount and degree of regional specificity of tissue harvested. In considering the use of visual aids, such as a dissecting scope or magnifying glass to aid in the tissue collection process. Particularly in cases of smaller globe sizes.

dissection-of-human-retina-and-rpe-choroid-for-proteomic-analysis

Research

JoVE Journal

Biochemistry

Resolving Affinity Purified Protein Complexes by Blue Native PAGE and Protein Correlation Profiling

Most proteins act in association with others; hence, it is crucial to characterize these functional units in order to fully understand biological processes. Affinity purification coupled to mass spectrometry (AP-MS) has become the method of choice for identifying protein-protein interactions. However, conventional AP-MS studies provide information on protein interactions, but the organizational information is lost. To address this issue, we developed a strategy to unravel the distinct functional assemblies a protein might be involved in, by resolving affinity-purified protein complexes prior to their characterization by mass spectrometry. Protein complexes isolated through affinity purification of a bait protein using an epitope tag and competitive elution are separated through blue native electrophoresis. Comparison of protein migration profiles through correlation profiling using quantitative mass spectrometry allows assignment of interacting proteins to distinct molecular entities. This method is able to resolve protein complexes of close molecular weights that might not be resolved by traditional chromatographic techniques such as gel filtration. With little more work than conventional AP-geLC-MS/MS, we demonstrate this strategy may in many cases be adequate for obtaining protein complex topological information concomitantly to identifying protein interactions.

Here we present protocols for affinity purification of protein complexes and their separation by blue native PAGE, followed by protein correlation profiling using label free quantitative mass spectrometry. This method is useful to resolve interactomes into distinct protein complexes.

Most proteins act in association with others; hence, it is crucial to characterize these functional units in order to fully understand biological ...

Fractionation for Resolution of Soluble and Insoluble Huntingtin Species

The accumulation of misfolded proteins is central to pathology in Huntington's disease (HD) and many other neurodegenerative disorders. Specifically, a key pathological feature of HD is the aberrant accumulation of mutant HTT (mHTT) protein into high molecular weight complexes and intracellular inclusion bodies composed of fragments and other proteins. Conventional methods to measure and understand the contributions of various forms of mHTT-containing aggregates include fluorescence microscopy, western blot analysis, and filter trap assays. 
However, most of these methods are conformation specific, and therefore may not resolve the full state of mHTT protein flux due to the complex nature of aggregate solubility and resolution.
For the identification of aggregated mHTT and various modified forms and complexes, separation and solubilization of the cellular aggregates and fragments is mandatory. Here we describe a method to isolate and visualize soluble mHTT, monomers, oligomers, fragments, and an insoluble high molecular weight (HMW) accumulated mHTT species. HMW mHTT tracks with disease progression, corresponds with mouse behavior readouts, and has been beneficially modulated by certain therapeutic interventions1. This approach can be used with mouse brain, peripheral tissues, and cell culture but may be adapted to other model systems or disease contexts.

A method is described for fractionation of insoluble and soluble mutant huntingtin species from mouse brain and cell culture. The method described is useful for characterization and quantification of huntingtin protein flux and aids in analyzing protein homeostasis in disease pathogenesis and in the presence of perturbations

The accumulation of misfolded proteins is central to pathology in Huntington's disease (HD) and many other neurodegenerative disorders. Specifically, a ...

Split-BioID &#8212; Proteomic Analysis of Context-specific Protein Complexes in Their Native Cellular Environment

To complement existing affinity purification (AP) approaches for the identification of protein-protein interactions (PPI), enzymes have been introduced that allow the proximity-dependent labeling of proteins in living cells. One such enzyme, BirA* (used in the BioID approach), mediates the biotinylation of proteins within a range of approximately 10 nm. Hence, when fused to a protein of interest and expressed in cells, it allows the labeling of proximal proteins in their native environment. As opposed to AP that relies on the purification of assembled protein complexes, BioID detects proteins that have been marked within cells no matter whether they are still interacting with the protein of interest when they are isolated. Since it biotinylates proximal proteins, one can moreover capitalize on the exceptional affinity of streptavidin for biotin to very efficiently isolate them. While BioID performs better than AP for identifying transient or weak interactions, both AP- and BioID-mass spectrometry approaches provide an overview of all possible interactions a given protein may have. However, they do not provide information on the context of each identified PPI. Indeed, most proteins are typically part of several complexes, corresponding to distinct maturation steps or different functional units. To address this common limitation of both methods, we have engineered a protein-fragments complementation assay based on the BirA* enzyme. In this assay, two inactive fragments of BirA* can reassemble into an active enzyme when brought in close proximity by two interacting proteins to which they are fused. The resulting split-BioID assay thus allows the labeling of proteins that assemble around a pair of interacting proteins. Provided these two only interact in a given context, split-BioID then allows the analysis of specific context-dependent functional units in their native cellular environment. Here, we provide a step-by-step protocol to test and apply split-BioID to a pair of interacting proteins.

We provide a step-by-step protocol for split-BioID, a protein fragments-complementation assay based on the proximity-labeling technique BioID. Activated on the interaction of two given proteins, it allows the proteomics analysis of context-dependent protein complexes in their native cellular environment. The method is simple, cost-effective and only requires standard laboratory equipment.

To complement existing affinity purification (AP) approaches for the identification of protein-protein interactions (PPI), enzymes have been introduced ...

Sampling and Pretreatment of Tooth Enamel Carbonate for Stable Carbon and Oxygen Isotope Analysis

Stable carbon and oxygen isotope analysis of human and animal tooth enamel carbonate has been applied in paleodietary, paleoecological, and paleoenvironmental research from recent historical periods back to over 10 million years ago. Bulk approaches provide a representative sample for the period of enamel mineralization, while sequential samples within a tooth can track dietary and environmental changes during this period. While these methodologies have been widely applied and described in archaeology, ecology, and paleontology, there have been no explicit guidelines to aid in the selection of necessary lab equipment and to thoroughly describe detailed laboratory sampling and protocols. In this article, we document textually and visually, the entire process from sampling through pretreatment and diagenetic screening to make the methodology more widely available to researchers considering its application in a variety of laboratory settings.

Stable carbon and oxygen isotope analysis of human and animal tooth enamel carbonate has been used as a proxy for individual diet and environmental reconstruction. Here, we provide a detailed description and visual documentation of bulk and sequential tooth enamel sampling as well as pretreatment of archaeological and paleontological samples.

Stable carbon and oxygen isotope analysis of human and animal tooth enamel carbonate has been applied in paleodietary, paleoecological, and ...

Dynamic Proteomic and miRNA Analysis of Polysomes from Isolated Mouse Heart After Langendorff Perfusion

Studies in dynamic changes in protein translation require specialized methods. Here we examined changes in newly-synthesized proteins in response to ischemia and reperfusion using the isolated perfused mouse heart coupled with polysome profiling. To further understand the dynamic changes in protein translation, we characterized the mRNAs that were loaded with cytosolic ribosomes (polyribosomes or polysomes) and also recovered mitochondrial polysomes and compared mRNA and protein distribution in the high-efficiency fractions (numerous ribosomes attached to mRNA), low-efficiency (fewer ribosomes attached) which also included mitochondrial polysomes, and the non-translating fractions. miRNAs can also associate with mRNAs that are being translated, thereby reducing the efficiency of translation, we examined the distribution of miRNAs across the fractions. The distribution of mRNAs, miRNAs, and proteins was examined under basal perfused conditions, at the end of 30 min of global no-flow ischemia, and after 30 min of reperfusion. Here we present the methods used to accomplish this analysis&#8212;in particular, the approach to optimization of protein extraction from the sucrose gradient, as this has not been described before&#8212;and provide some representative results.

Here we present a protocol to perform polysome profiling on the isolated perfused mouse heart. We describe methods for heart perfusion, polysome profiling, and analysis of the polysome fractions with respect to mRNAs, miRNAs, and the polysome proteome.

Studies in dynamic changes in protein translation require specialized methods. Here we examined changes in newly-synthesized proteins in response to ...

Calibration-free In Vitro Quantification of Protein Homo-oligomerization Using Commercial Instrumentation and Free, Open Source Brightness Analysis Software

Number and brightness is a calibration-free fluorescence fluctuation spectroscopy (FFS) technique for detecting protein homo-oligomerization. It can be employed using a conventional confocal microscope equipped with digital detectors. A protocol for the use of the technique in vitro is shown by means of a use case where number and brightness can be seen to accurately quantify the oligomeric state of mVenus-labelled FKBP12F36V before and after the addition of the dimerizing drug AP20187. The importance of using the correct microscope acquisition parameters and the correct data preprocessing and analysis methods are discussed. In particular, the importance of the choice of photobleaching correction is stressed. This inexpensive method can be employed to study protein-protein interactions in many biological contexts.

Calibration-free In Vitro Quantification of Protein Homo-oligomerization Using Commercial Instrumentation and Free, Open Source Brightness Analysis Software

This protocol describes a calibration-free approach for quantifying protein homo-oligomerization in vitro based on fluorescence fluctuation spectroscopy using commercial light scanning microscopy. The correct acquisition settings and analysis methods are shown.

Number and brightness is a calibration-free fluorescence fluctuation spectroscopy (FFS) technique for detecting protein homo-oligomerization. It can be ...

Proteomic Analysis of Human Macrophage Polarization Under a Low Oxygen Environment

Macrophages are innate immune cells involved in a number of physiological functions ranging from responses to infectious pathogens to tissue homeostasis. The various functions of these cells are related to their activation states, which is also called polarization. The precise molecular description of these various polarizations is a priority in the field of macrophage biology. It is currently acknowledged that a multidimensional approach is necessary to describe how polarization is controlled by environmental signals. In this report, we describe a protocol designed to obtain the proteomic signature of various polarizations in human macrophages. This protocol is based on a label-free quantification of macrophage protein expression obtained from in-gel fractionated and Lys C/trypsin-digested cellular lysis content. We also provide a protocol based on in-solution digestion and isoelectric focusing fractionation to use as an alternative. Because oxygen concentration is a relevant environmental parameter in tissues, we use this protocol to explore how atmospheric composition or a low oxygen environment affects the classification of macrophage polarization.

We present a protocol to obtain proteomic signatures of human macrophages and apply this to determination of the impact of a low oxygen environment on macrophage polarization.

Macrophages are innate immune cells involved in a number of physiological functions ranging from responses to infectious pathogens to tissue homeostasis. ...

Analysis of Fucosylated Human Milk Trisaccharides in Biotechnological Context Using Genetically Encoded Biosensors

Human milk oligosaccharides (HMOs) are complex carbohydrate components of human breast milk that exhibit plentiful benefits on infant health. However, optimization of their biotechnological synthesis is limited by the relatively low throughput of detection and quantification of monosaccharide and linkages. Conventional techniques of glycan analysis include chromatographic/mass-spectrometric methods with throughput on the order of hundreds of samples per day without automation. We demonstrate here, a genetically encoded bacterial biosensor for the high-throughput, linkage-specific detection and quantification of the fucosylated HMO structures, 2&#8217;-fucosyllactose and 3-fucosyllactose, which we achieved via heterologous expression of fucosidases. As the presence of lactose in milk or in biotechnological processes could lead to false positives, we also demonstrate the reduction of signal from lactose using different strategies. Due to the high throughput of this technique, many reaction conditions or bioreactor parameters could be assayed in parallel in a matter of hours, allowing for the optimization of HMO manufacturing.

We describe here the high-throughput detection and quantification of fucosylated human milk oligosaccharides (HMOs) using a whole-cell biosensor. We also demonstrate here, the adaptation of this platform towards analysis of HMO production strains, focusing on improving the signal to noise ratio.

Human milk oligosaccharides (HMOs) are complex carbohydrate components of human breast milk that exhibit plentiful benefits on infant health. However, ...

Study on the Metabolism of Six Systemic Insecticides in a Newly Established Cell Suspension Culture Derived from Tea (Camellia Sinensis L.) Leaves

A platform for studying insecticide metabolism using in vitro tissues of tea plant was developed. Leaves from sterile tea plantlets were induced to form loose callus on Murashige and Skoog (MS) basal media with the plant hormones 2,4-dichlorophenoxyacetic acid (2,4-D, 1.0 mg L-1) and kinetin (KT, 0.1 mg L-1). Callus formed after 3 or 4 rounds of subculturing, each lasting 28 days. Loose callus (about 3 g) was then inoculated into B5 liquid media containing the same plant hormones and was cultured in a shaking incubator (120 rpm) in the dark at 25 &#177; 1 &#176;C. After 3&#8722;4 subcultures, a cell suspension derived from tea leaf was established at a subculture ratio ranging between 1:1 and 1:2 (suspension mother liquid: fresh medium). Using this platform, six insecticides (5 &#181;g mL-1 each thiamethoxam, imidacloprid, acetamiprid, imidaclothiz, dimethoate, and omethoate) were added into the tea leaf-derived cell suspension culture. The metabolism of the insecticides was tracked using liquid chromatography and gas chromatography. To validate the usefulness of the tea cell suspension culture, the metabolites of thiamethoxan and dimethoate present in treated cell cultures and intact plants were compared using mass spectrometry. In treated tea cell cultures, seven metabolites of thiamethoxan and two metabolites of dimethoate were found, while in treated intact plants, only two metabolites of thiamethoxam and one of dimethoate were found. The use of a cell suspension simplified the metabolic analysis compared to the use of intact tea plants, especially for a difficult matrix such as tea.

Study on the Metabolism of Six Systemic Insecticides in a Newly Established Cell Suspension Culture Derived from Tea Camellia Sinensis L. Leaves

This work presents a protocol for establishing a cell suspension culture derived from tea (Camellia sinensis L.) leaves that can be used to study the metabolism of external compounds that can be taken up by the whole plant, such as insecticides.

A platform for studying insecticide metabolism using in vitro tissues of tea plant was developed. Leaves from sterile tea plantlets were induced to form ...

Analysis and Specification of Starch Granule Size Distributions

Starch from all plant sources are made up of granules in a range of sizes and shapes having different occurrence frequencies, i.e., exhibiting a size and a shape distribution. Starch granule size data determined using several types of particle sizing techniques are often problematic due to poor reproducibility or lack of statistical significance resulting from some insurmountable systematic errors, including sensitivity to granule shapes and limits of granule-sample sizes. We outlined a procedure for reproducible and statistically valid determinations of starch granule size distributions using the electrical sensing zone technique, and for specifying the determined granule lognormal size distributions using an adopted two-parameter multiplicative form with improved accuracy and comparability. It is applicable to all granule sizing analyses of gram-scale starch samples, and, therefore, could facilitate studies on how starch granule sizes are molded by the starch biosynthesis apparatus and mechanisms; and how they impact properties and functionality of starches for food and industrial uses. Representative results are presented from replicate analyses of granule size distributions of sweetpotato starch samples using the outlined procedure. We further discussed several key technical aspects of the procedure, especially, the multiplicative specification of granule lognormal size distributions and some technical means for overcoming frequent aperture blockage by granule aggregates.

Presented here is a procedure for reproducible and statistically valid determinations of starch granule size distributions, and for specifying the determined granule lognormal size distributions using a two-parameter multiplicative form. It is applicable to all granule sizing analyses of gram-scale starch samples for plant and food science research. &#160;

Starch from all plant sources are made up of granules in a range of sizes and shapes having different occurrence frequencies, i.e., exhibiting a size and ...