The authors wish to thank the Biosecurity Tick Colony (Queensland Department of Agriculture &amp; Fisheries, Australia) for the provision of Rhipicephalus microplus ticks utilized for this study, and Lucas Karbanowicz for assistance with video filming.

1. Dissection of the Gut Epithelium from R. microplus

<ol>
	<li>Collect semi-engorged ticks from cattle on the day of experiment. Dissect ticks within 24 h after removal from the host.</li>
	<li>Adhere a strip of duct tape to the bottom of the 92 mm x 16 mm Petri dish. Add a drop of super glue to the tape. Place the tick, ventral side down on the super glue, allow to dry for 2 min.</li>
	<li>Pour 100 mL of phosphate buffered saline (PBS) into the petri dish, or until the tick is completely submerged.</li>
	<li>Utilizing a size 11 scalpel, cut from the top of the eyes to the bottom festoons, on both sides of the tick.</li>
	<li>Using sterile forceps, completely remove the scutum and alloscutum, to expose the internal organs.</li>
	<li>Remove the fine white thread-like organs (trachea) and other membranes to prevent contamination.</li>
	<li>Remove the gut using forceps, by pinching the upper region and pulling from the carcass. Remove any remaining gut tissues, ensuring that no other tissues have been dissected.</li>
	<li>Store gut in ice-cold Hank&#39;s Balanced Salt Solution (HBSS) without calcium chloride and magnesium sulfate with proteinase-inhibitor cocktail (PIC). Snap freeze the guts in dry ice and store at -20 &#176;C. 
	Note: To assist with gut dissection and details of the tick internal organs refer to Chapter 3.1 of D. Sonenshine, &#34;Biology of Ticks&#34;19.</li>
</ol>
2. Epithelial Cell Dissociation
<ol>
	<li>Pour the dissected gut onto a 70 &#181;m cell strainer inside a 50 mL tube.</li>
	<li>Flush the gut tissue with 50 mL ice cold HBSS with PIC until the solution runs clear, and the guts take on a white/clear appearance.</li>
	<li>Re-suspend guts in 30 mL ice cold HBSS with PIC, mix gently and centrifuge at 500 x g at 4 &#176;C for 10 min to pellet the gut. Remove the supernatant and repeat the wash process three times.</li>
	<li>To dislodge epithelial gut cells, re-suspend the gut in 10 mL of cell culture medium Dulbecco&#39;s modified eagle medium (DMEM), 2% fetal calf serum (FCS), 0.5 mM ethylenediaminetetraacetic acid (EDTA), 1 mM Tris(2-carboxyethyl)phosphine (TCEP), PIC and incubate for 60 min at 37 &#176;C under slow rotation using a roller at 6 rpm.</li>
	<li>Filter the suspension through a 250 &#181;m cell strainer, vortex the flow-through and filter through a 70 &#181;m cell strainer collecting the remaining flow-through.</li>
	<li>Centrifuge the suspension at 500 x g at 4 &#176;C for 20 min to pellet the single cells.</li>
</ol>
3. Isolation of Single Epithelial Cells using a density centrifugation gradient
<ol>
	<li>Prepare density centrifugation gradient (e.g., Percoll) by filtering through an AP15 pre-filter paper. Prepare 40% and a 20% Percoll in mqH20 (v/v) and cool at 4 &#176;C for 1 h prior to layering the gradient.</li>
	<li>Using a peristaltic pump set at the lowest speed, layer 3 mL of 40% density centrifugation gradient into a 16 mL ultracentrifuge tube, allowing it to settle on ice for 15 min. Speed of the pump should lead to a &#60;1 mL per min flow rate.</li>
	<li>Tilting the tube to a 45&#176; angle, use the peristaltic pump to layer the 20% density centrifugation gradient on top of the 40% layer. Speed of the pump should lead to &#60;1 mL per min flow rate. Allow the layers to settle on ice for 15 min.</li>
	<li>Use the peristaltic pump at &#60;1 mL per min flow rate to layer 3 mL of DMEM medium containing tick gut cells over the 20-40% density centrifugation gradient.</li>
	<li>Program the centrifuge for maximum acceleration and minimum deceleration. Centrifuge at 600 x g for 10 min. Collect interphases between the DMEM:20% density centrifugation gradient, and the 20%: 40% density centrifugation gradients to isolate epithelial single cells. Store collected interphases at 4 &#176;C for subsequent analyses.</li>
</ol>
4. Assessment of Cell Isolation
<ol>
	<li>Hemacytometer
	<ol>
		<li>Clean the hemacytometer slide with alcohol.</li>
		<li>.Re-suspend the cells by gently pipetting the cells up and down. Pipette 100 &#181;L of the cell suspension and place in a 1.5 mL microcentrifuge tube.</li>
		<li>Add 400 &#181;L of 0.4% Trypan Blue. Gently mix by flicking the tube.</li>
		<li>Pipette 100 &#181;L of the Trypan Blue-treated cell suspension to slowly fill both chambers of the hemocytometer.</li>
		<li>Place the hemocytometer under a light microscope, focusing upon the grid lines of the hemocytometer with a 10X objective.</li>
		<li>Using a hand-held tally counter, count the live unstained cells within a set of 16 squares. Within the same square, count the blue dead cells. Continue counting until four sets of 16 squares are counted.</li>
		<li>Calculate the total cells per mL by using the formula: 
		<img alt="Equation 1" src="/files/ftp_upload/55747/55747eq1.jpg" /></li>
		<li>Calculate the percentage cell viability by using the formula: 
		<img alt="Equation 2" src="/files/ftp_upload/55747/55747eq2.jpg" /></li>
	</ol>
	</li>
	<li>Cell Isolate Visualization
	<ol>
		<li>Dilute 1 &#181;L of the isolated cells in 9 &#181;L of HBSS in a 1.5 mL microcentrifuge tube. Flick the microcentrifuge tube gently to mix.</li>
		<li>Pipette 5 &#181;L of isolated cells in HBSS into the middle of a glass slide. Apply three drops of mounting medium with 4&#39;, 6-diamidino-2-phenylindole (DAPI).</li>
		<li>Incubate the slide at room temperature for 5 min. Carefully place a cover slip over the preparation, avoiding air bubbles.</li>
		<li>Visualize cells stained with DAPI at excitation 360 nm and emission at 460 nm under a fluorescent microscope.</li>
	</ol>
	</li>
</ol>
5. Cell Surface Protein Biotinylation
<ol>
	<li>Biotinylate 100 &#181;L of single cell epithelial cells using Biotin (Type A) Conjugation kit, at a molar ratio of 1:1 surface protein to conjugate, as per manufacturer&#39;s instructions</li>
	<li>For cell lysis, add 100 &#181;L of PBS, 1% Triton X-100, 10% glycerol, 100 &#181;M oxidized glutathione and PIC to the biotinylated cells. Incubate on ice for 1 h with gentle mixing every 10 min.</li>
	<li>Centrifuge the biotinylated cells at 20,000 x g at 4 &#176;C for 20 min to pellet insoluble material. Collect the supernatant containing cytoplasmic, and biotinylated membrane proteins.</li>
	<li>Determine the protein concentration using the Bradford assay.</li>
</ol>
6. Isolation of Biotinylated Surface Proteins
<ol>
	<li>Add 50 &#181;L of Streptavidin Magnetic Beads into a 1.5 mL microcentrifuge tube.</li>
	<li>Place the tube into a magnetic stand, collecting the beads against the side of the tube. Remove and discard the supernatant.</li>
	<li>Add 1000 &#181;L of TBS, 0.1% Tween-20 to the tube. Mix gently and collect the beads with the magnetic stand. Remove and discard the supernatant.</li>
	<li>Combine 40 &#181;g of biotinylated cell surface proteins, diluted to 300 &#181;L in 1x PBS with washed magnetic beads. Incubate for 2 h at room temperature with agitation.</li>
	<li>Collect the beads with a magnetic stand, remove and discard the supernatant.</li>
	<li>Add 300 &#181;L of TBS, 0.1% Tween-20 to the tube, gently mixing to re-suspend the beads. Collect beads, remove and discard the supernatant. Repeat this wash step twice.</li>
	<li>Add 100 &#181;L of the 0.1 M glycine pH 2.0 to the magnetic beads, and incubate at room temperature for 5 min. Collect beads and remove supernatant containing eluted biotinylated surface proteins.</li>
	<li>Visualize isolated surface proteins on a 4-20% Tris-MOPS SDS-PAGE gel.</li>
</ol>
7. Assessment of Biotinylated Surface Protein
<ol>
	<li>Dot Blot
	<ol>
		<li>Cut a 7 cm x 3 cm strip of nitrocellulose membrane.</li>
		<li>Apply 10 &#181;g total tick gut contents (from 1.8 above), and 10 &#181;g of biotinylated surface protein to the membrane. Allow drying for 15 min at room temperature.</li>
		<li>Transfer to a container and submerge in 100 mL of blocking buffer. Incubate at room temperature with agitation for an hour. Discard blocking buffer.</li>
		<li>Wash nitrocellulose membrane in 100 &#181;L PBS, 0.05% Tween-20 for 5 min with agitation. Discard wash buffer and repeat the washes for three times.</li>
		<li>Incubate in 1/5000 Streptavidin- horseradish peroxidase (HRP)in 100 &#181;L PBS, 0.05% Tween-20 for 2 h with agitation at room temperature, and discard any remaining solution.</li>
		<li>Wash nitrocellulose membrane in 100 &#181;L of PBS, 0.05% Tween-20 for 5 min with agitation. Discard wash buffer and repeat the wash three times.</li>
		<li>For detection, dissolve 1 tablet of 4-chloro-1-napthol in 10 mL of ice cold methanol. Add 4 mL of methanol stock to 20 mL of TBS. Add 10 &#181;L of fresh 30% hydrogen peroxide and immediately apply to nitrocellulose membrane.</li>
		<li>Incubate with agitation at room temperature until substrate produces an insoluble blue end product. This may take between 2-15 min.</li>
		<li>Discard detection solution and wash the membrane three times in 100 &#181;L mqH2O.</li>
	</ol>
	</li>
	<li>ELISA Assay
	<ol>
		<li>Dilute 200 ng of each sample with 400 &#181;L of 100 mM Carbonate coating buffer and coat 2 lanes of the first row (A#) of the ELISA plate (flat bottom wells)</li>
		<li>Add 100 &#181;L of 100 mM carbonate coating buffer to all other corresponding wells in rows (B-H).</li>
		<li>Prepare serial dilutions of each sample by pipetting 100 &#181;L from each well in row A, and transferring into row B. Mix gently by pipetting and avoid producing bubbles. Repeat the dilutions down each row, discarding the final 100 &#181;L from each well in row H.</li>
		<li>Cover the plate with parafilm and incubate at 4 &#176;C overnight.</li>
		<li>Wash the plate with 200 &#181;L PBS, 0.05% Tween-20 per well three times.</li>
		<li>Add 200 &#181;L of blocking buffer to the coated wells, cover with Parafilm and incubate at 4 &#176;C overnight.</li>
		<li>Dilute 1/15,000 Streptavidin-HRP in blocking buffer and add 100 &#181;L to each well of the plate. Cover with parafilm and incubate at 4 &#176;C overnight.</li>
		<li>Wash the plate in 200 &#181;L PBS, 0.05% Tween-20 per well five times.</li>
		<li>To detect, add 100 &#181;L of TMB reagent per well. After sufficient color development, usually between 10-15 min, add 100 &#181;L of 1 M phosphoric acid to stop the reaction.</li>
		<li>Read the absorbance of each well at &#955; = 450nm.</li>
	</ol>
	</li>
</ol>

<ol>
	<li>Rodriguez-Valle, 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=Efficacy+of+Rhipicephalus+(Boophilus)+microplus+Bm86+against+Hyalomma+dromedarii+and+Amblyomma+cajennense+tick+infestations+in+camels+and+cattle.">Efficacy of Rhipicephalus (Boophilus) microplus Bm86 against Hyalomma dromedarii and Amblyomma cajennense tick infestations in camels and cattle.</a> Vaccine. 30, 3453-3458 (2012).</li><li>De Rose, R., 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=Bm86+antigen+induces+a+protective+immune-response+against+Boophilus+microplus+following+DNA+and+protein+vaccination+in+sheep.">Bm86 antigen induces a protective immune-response against Boophilus microplus following DNA and protein vaccination in sheep.</a> Vet. Immunol. Immunopathol. 71, 151-160 (1999).</li><li>Garc&#237;a-Garc&#237;a, J. 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=Sequence+variations+in+the+Boophilus+microplus+Bm86+locus+and+implications+for+immunoprotection+in+cattle+vaccinated+with+this+antigen.">Sequence variations in the Boophilus microplus Bm86 locus and implications for immunoprotection in cattle vaccinated with this antigen.</a> Exp. Appl. Acarol. 23, 883-895 (1999).</li><li>Abbas, R. Z., Zaman, M. A., Colwell, D. D., Gilleard, J., Iqbal, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Acaricide+resistance+in+cattle+ticks+and+approaches+to+its+management:+The+state+of+play.">Acaricide resistance in cattle ticks and approaches to its management: The state of play.</a> Vet. Parasitol. 203, 6-20 (2014).</li><li>Kearney, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Acaricide (chemical) resistance in cattle ticks. , (2013).</li><li>Foil, L. D., 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=Factors+that+influence+the+prevalence+of+acaricide+resistance+and+tick-borne+diseases.">Factors that influence the prevalence of acaricide resistance and tick-borne diseases.</a> Vet. Parasitol. 125, 163-181 (2004).</li><li>Rodriguez, 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=High+level+expression+of+the+B.+microplus+Bm86+antigen+in+the+yeast+Pichia+pastoris+forming+highly+immunogenic+particles+for+cattle.">High level expression of the B. microplus Bm86 antigen in the yeast Pichia pastoris forming highly immunogenic particles for cattle.</a> J Biotechnol. 33, 135-146 (1994).</li><li>Rodriguez, 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=Effect+of+vaccination+with+a+recombinant+Bm86+antigen+preparation+on+natural+infestations+of+Boophilus+microplus+in+grazing+dairy+and+beef+pure+and+cross-bred+cattle+in+Brazil.">Effect of vaccination with a recombinant Bm86 antigen preparation on natural infestations of Boophilus microplus in grazing dairy and beef pure and cross-bred cattle in Brazil.</a> Vaccine. 13 (18), 1804-1808 (1995).</li><li>Lew-Tabor, A. E., Rodriguez Valle, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+review+of+reverse+vaccinology+approaches+for+the+development+of+vaccines+against+ticks+and+tick+borne+diseases.">A review of reverse vaccinology approaches for the development of vaccines against ticks and tick borne diseases.</a> Ticks Tick Borne Dis. 7, 573-585 (2016).</li><li>Capella, A. N., Terra, W. R., Ribeiro, A. F., Ferreira, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cytoskeleton+removal+and+characterization+of+the+microvillar+membranes+isolated+from+two+midgut+regions+of+Spodoptera+frugiperda+(Lepidoptera).">Cytoskeleton removal and characterization of the microvillar membranes isolated from two midgut regions of Spodoptera frugiperda (Lepidoptera).</a> Insect Biochem. Mol. Biol. 27, 793-801 (1997).</li><li>Cioffi, M., Wolfersberger, M. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isolation+of+separate+apical,+lateral+and+basal+plasma+membrane+from+cells+of+an+insect+epithelium.+A+procedure+based+on+tissue+organization+and+ultrastructure.">Isolation of separate apical, lateral and basal plasma membrane from cells of an insect epithelium. A procedure based on tissue organization and ultrastructure.</a> Tissue Cell. 15, 781-803 (1983).</li><li>Koefoed, B. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+simple+mechanical+method+to+isolate+the+basal+lamina+of+insect+midgut+epithelial+cells.">A simple mechanical method to isolate the basal lamina of insect midgut epithelial cells.</a> Tissue Cell. 17, 763-768 (1985).</li><li>Roche, J. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isolation+of+a+purified+epithelial+cell+population+from+human+colon.">Isolation of a purified epithelial cell population from human colon.</a> Methods Mol. Med. 50, 15-20 (2001).</li><li>Terra, W. R., Costa, R. H., Ferreira, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Plasma+membranes+from+insect+midgut+cells.">Plasma membranes from insect midgut cells.</a> An. Acad. Bras. Ci&#234;nc. 78, 255-269 (2006).</li><li>Vargas, A. E., Markoski, M. M., Ca&#241;edo, A. D., Helena, F., Nardi, N. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Identification,+isolation+and+culture+of+intestinal+epithelial+stem+cells+from+murine+intestine.">Identification, isolation and culture of intestinal epithelial stem cells from murine intestine.</a> Stem Cells. 879, 479-490 (2012).</li><li>Autengruber, A., Gereke, M., Hansen, G., Hennig, C., Bruder, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Impact+of+enzymatic+tissue+disintegration+on+the+level+of+surface+molecule+expression+and+immune+cell+function.">Impact of enzymatic tissue disintegration on the level of surface molecule expression and immune cell function.</a> Eur. J. Microbiol. Immunol. 2, 112-120 (2012).</li><li>Karhemo, P. R., 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=An+optimized+isolation+of+biotinylated+cell+surface+proteins+reveals+novel+players+in+cancer+metastasis.">An optimized isolation of biotinylated cell surface proteins reveals novel players in cancer metastasis.</a> J. Proteomics. 77, 87-100 (2012).</li><li>Obenchain, F. R., Galun, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Physiology+of+Ticks.">Physiology of Ticks.</a> Current Themes in Tropical Science Volume 1. , 201-205 (1982).</li><li>Sonenshine, D., Roe, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chapter+3.1.">Chapter 3.1.</a> &amp;#34;Biology of Ticks&amp;#34. 1, (2014).</li><li>Raikhel, A. S., Balashov, Y. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> &amp;#34;An Atlas of Ixodid Tick Ultrastructure&amp;#34 (English Translation). , (1983).</li></ol>

The authors have nothing to disclose.

Cattle tick infestations constitute a major problem for the cattle industry in tropical and subtropical regions of the world, with the most common method of control reliant upon the use of acaricides1,4. Bm86 was previously identified within the tick gut epithelial surface as a protective antigen against R. microplus infestation10, with limited success as a vaccine strategy due to Bm86 geographic sequence variation and the require...

Rhipicephalus microplus, the cattle tick, is the most significant ectoparasite in terms of economic impact on the cattle industry of tropical and sub-tropical regions as it vectors bovine tick fever (babesiosis), anaplasmosis and equine piroplasmosis1,2,3,4. Efforts have been dedicated to cattle tick control, to diminish the deleterious effect, however conventional methods such as the use of chemical acaricides have implicit drawbacks, such as the presence of chemical residues in milk and meat, and the increase in prevalence of chemically resistant ticks5,6,7. Consequently, the development of alternative methods of tick control have been studied, such as the use of natural resistance cattle, biological control (biopesticides) and vaccines4,5,6,7,8,9.
In the pursuit of proteins capable of being utilized as vaccine candidates, current research is focused upon the tick gut. The midgut wall is built from a single layer of epithelial cells resting on a thin basal lamina, with the outside of the basal lamina forming a network of muscle. Light and electron microscope observations indicate that the midgut consists of three types of cells: reserve (undifferentiated), secretory, and digestive. The number of cell types varies considerably depending upon the physiological phase. Secretory and digestive cells both originate from reserve cells18,19,20.
The construction of cDNA libraries to examine the composition of the tick gut has led to the identification of antigenic proteins, such as Bm86, as potential vaccine candidates2,3,4. The glycoprotein Bm86 is localized at the surface of tick gut cells and induces a protective immune response against the cattle tick (R. microplus) in vaccinated cattle. Anti-Bm86 IgGs produced by the immunized host are ingested by the tick, recognize this antigen on the surface of tick gut cells, and subsequently disturb tick gut tissue function and integrity. Vaccines based upon Bm86 antigens have shown effective control of R. microplus and Rhipicephalus annulatus, by reducing the number, weight and reproductive capacity of engorging females, resulting in a reduced larval infestation in subsequent tick generations4. However, Bm86 based vaccines are not effective against all tick stages and have demonstrated unsatisfactory efficacy against some geographical strains of R. microplus, consequently the beef and dairy industries have poorly adopted these vaccines2,4.
The ability to isolate epithelial cells from the tick gut is a significant innovation which would enable the progression of research to determine protein membrane composition including morphology and physiology under different environmental conditions. The method described here utilizes the chelating agent ethylenediaminetetraacetic acid (EDTA) and the reducing agent tris(2-carboxyethyl)phosphine (TCEP) to release the epithelium from its sub-epithelial support tissues10. The epithelium is recovered following mechanical disruption of the tissues by shaking, followed by discontinuous gradient centrifugation in Percoll. This paper describes a feasible and novel technique for the isolation of tick gut epithelial cells. Biotinylated cell surface proteins, isolated from the surface of these epithelial cells can subsequently analyzed in downstream applications such as FACS and/or LC-MS/MS-analysis.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>0.4% Trypan Blue</td>
			<td>ThermoFisher Scientific</td>
			<td>15250061</td>
			<td></td>
		</tr>
		<tr>
			<td>1.5 mL microcentrifuge tube</td>
			<td>Eppendorf</td>
			<td>3322</td>
			<td></td>
		</tr>
		<tr>
			<td>100mM Carbonate Buffer</td>
			<td></td>
			<td></td>
			<td>3.03 g Na2CO3, 6.0 g NaHCO3 1000 ml distilled water pH 9.6</td>
		</tr>
		<tr>
			<td>16 mL centrifuge tubes with sealing cap</td>
			<td>Thermo Scientific</td>
			<td>3138-0016</td>
			<td>Cool in ice prior to gradient</td>
		</tr>
		<tr>
			<td>250 &#181;M cell strainer</td>
			<td>Thermo Fisher</td>
			<td>87791</td>
			<td></td>
		</tr>
		<tr>
			<td>3,3&#8242;,5,5&#8242;-Tetramethylbenzidine (TMB) Liquid Substrate System for ELISA</td>
			<td>Sigma</td>
			<td>T0440</td>
			<td>Stored at 4C</td>
		</tr>
		<tr>
			<td>30% Hydrogen Peroxide</td>
			<td>Labscene</td>
			<td>BSPA5.500</td>
			<td></td>
		</tr>
		<tr>
			<td>4-20% Tris-MOPS Gel</td>
			<td>Gen Script</td>
			<td>M42015</td>
			<td></td>
		</tr>
		<tr>
			<td>4-Chloro-1-naphthol tablet</td>
			<td>Sigma-Aldrich</td>
			<td>C6788</td>
			<td></td>
		</tr>
		<tr>
			<td>50 mL Falcon Tube</td>
			<td>Corning Blue</td>
			<td></td>
			<td>30 x 115mm style. Polyproplyene conical tube.</td>
		</tr>
		<tr>
			<td>70 &#181;M cell strainer</td>
			<td>BD Falcon</td>
			<td>352350</td>
			<td></td>
		</tr>
		<tr>
			<td>AP15 filter paper</td>
			<td>Millipore</td>
			<td>AO1504200</td>
			<td></td>
		</tr>
		<tr>
			<td>Biotin (Type A) Conjugation Kit</td>
			<td>Abcam</td>
			<td>Ab102865</td>
			<td></td>
		</tr>
		<tr>
			<td>Dissection microscope</td>
			<td>Olympus</td>
			<td>SZX7</td>
			<td></td>
		</tr>
		<tr>
			<td>DP Manager&#160;</td>
			<td>Olympus</td>
			<td>2.2.1.195</td>
			<td>Cell imagery software</td>
		</tr>
		<tr>
			<td>Duct Tape</td>
			<td>Home Handyman</td>
			<td></td>
			<td>48mm x 25mm Duct Tape</td>
		</tr>
		<tr>
			<td>Dulbecco&#8217;s Modified Eagle Medium</td>
			<td>Gibco</td>
			<td>11995-065</td>
			<td>DMEM - ice cold for protocol</td>
		</tr>
		<tr>
			<td>EDTA</td>
			<td>Amresco</td>
			<td>0105-500G</td>
			<td></td>
		</tr>
		<tr>
			<td>F96 Maxisorp Immuno Plate</td>
			<td>Nunc</td>
			<td>439454</td>
			<td></td>
		</tr>
		<tr>
			<td>Fetal Bovine Serum</td>
			<td>Sigma-Aldrich</td>
			<td>12003C</td>
			<td>FCS</td>
		</tr>
		<tr>
			<td>Fluorescence microscope&#160;</td>
			<td>&#160;Olympus&#160;</td>
			<td>BX51</td>
			<td></td>
		</tr>
		<tr>
			<td>Fluoroshield with DAPI</td>
			<td>Sigma-Aldrich</td>
			<td>F6057-20ML</td>
			<td>DAPI</td>
		</tr>
		<tr>
			<td>Forceps</td>
			<td>Dumont</td>
			<td></td>
			<td>#9 Dumont - Switerzland</td>
		</tr>
		<tr>
			<td>Glycerol</td>
			<td>Sigma-Aldrich</td>
			<td>G5516</td>
			<td>Glycerol for molecular biology &#62;99%</td>
		</tr>
		<tr>
			<td>Glycine</td>
			<td>Sigma-Aldrich</td>
			<td>410225</td>
			<td></td>
		</tr>
		<tr>
			<td>Hand-Held Counter</td>
			<td>Officeworks</td>
			<td>JA0376230</td>
			<td></td>
		</tr>
		<tr>
			<td>Hank&#8217;s Balanced Salt Solution</td>
			<td>Sigma Life Sciences</td>
			<td>H9394</td>
			<td>HBSS &#8211; ice cold for protocol</td>
		</tr>
		<tr>
			<td>Hemacytometer</td>
			<td>Optik Lakor</td>
			<td>-</td>
			<td>-</td>
		</tr>
		<tr>
			<td>L-Glutathione oxidized</td>
			<td>Sigma-Aldrich</td>
			<td>G4376</td>
			<td></td>
		</tr>
		<tr>
			<td>Magnetic Separation Stand</td>
			<td>Novagen</td>
			<td>-</td>
			<td>4-Tube Magnetic Separation Rack</td>
		</tr>
		<tr>
			<td>Methanol</td>
			<td>Sigma-Aldrich</td>
			<td>179337</td>
			<td></td>
		</tr>
		<tr>
			<td>Milli-Q Water</td>
			<td>Millipore</td>
			<td>ZRXQ003WW</td>
			<td>Integral Water Purification System for Ultrapure Water</td>
		</tr>
		<tr>
			<td>Nitrocellulose Membrane</td>
			<td>Life Sciences</td>
			<td>66485</td>
			<td>30cm x 3M pure nitrocellulose membrane</td>
		</tr>
		<tr>
			<td>PageRuler Prestained protein Ladder</td>
			<td>Thermo-Fisher</td>
			<td>SM0671</td>
			<td></td>
		</tr>
		<tr>
			<td>PBS</td>
			<td></td>
			<td></td>
			<td>1.16 g Na2HPO4, 0.1 g KCl, 0.1 g K3PO4, 4.0 g NaCl (500 ml distilled water) pH 7.4</td>
		</tr>
		<tr>
			<td>Percoll</td>
			<td>Sigma-Aldrich</td>
			<td>P1644-500ML</td>
			<td></td>
		</tr>
		<tr>
			<td>Peristaltic Pump</td>
			<td>Masterflex</td>
			<td>7518-10</td>
			<td></td>
		</tr>
		<tr>
			<td>Phosphoric Acid</td>
			<td>Sigma-Aldrich</td>
			<td>P6560</td>
			<td></td>
		</tr>
		<tr>
			<td>Pierce Protein-Free T20 PBS Blocking Buffer</td>
			<td>Thermo-Scientific</td>
			<td>37573</td>
			<td>Stored at 4C. Blocking Buffer</td>
		</tr>
		<tr>
			<td>Protease Inhibitor Cocktail</td>
			<td>Sigma-Aldrich</td>
			<td>P8215-5ML</td>
			<td>PIC &#8211; stored at -20 &#176;C</td>
		</tr>
		<tr>
			<td>Quick Start Bradford Dye Reagent 1x</td>
			<td>Biorad</td>
			<td>500-0205</td>
			<td>For Bradford Assay</td>
		</tr>
		<tr>
			<td>Quick Start BSA Standards</td>
			<td>Biorad</td>
			<td>500-0207</td>
			<td>BSA standards for Bradford Assay</td>
		</tr>
		<tr>
			<td>Scalpel</td>
			<td>Lab. Co</td>
			<td></td>
			<td>Size 11 Scalpel</td>
		</tr>
		<tr>
			<td>SilverQuest TM Staining Kit</td>
			<td>Invitrogen</td>
			<td>LC6070</td>
			<td></td>
		</tr>
		<tr>
			<td>Simply Blue TM Safe Stain&#160;</td>
			<td>Invitrogen</td>
			<td>LC6060</td>
			<td></td>
		</tr>
		<tr>
			<td>Sorvall C6+ Ultracentrifuge</td>
			<td>Thermo Scientific</td>
			<td>46910</td>
			<td></td>
		</tr>
		<tr>
			<td>Streptavidin (HRP)</td>
			<td>Abcam</td>
			<td>AB7403</td>
			<td></td>
		</tr>
		<tr>
			<td>Streptavidin Magnetic Beads</td>
			<td>New England Biolabs</td>
			<td>S1420S</td>
			<td></td>
		</tr>
		<tr>
			<td>Super Glue - Ultra Fast Mini</td>
			<td>UHU</td>
			<td></td>
			<td>UHU Super Glue 1mg. Ultra Fast mini</td>
		</tr>
		<tr>
			<td>Table-top Centrifuge</td>
			<td>Eppendorf</td>
			<td>22331</td>
			<td></td>
		</tr>
		<tr>
			<td>TCEP</td>
			<td>Thermo Fisher</td>
			<td>20490</td>
			<td></td>
		</tr>
		<tr>
			<td>Triton X-100</td>
			<td>Biorad</td>
			<td>161-0407</td>
			<td></td>
		</tr>
		<tr>
			<td>Tween-20</td>
			<td>Sigma</td>
			<td>P2287-500ML</td>
			<td></td>
		</tr>
		<tr>
			<td>Vortex Mixer</td>
			<td>Ratek</td>
			<td>VM1</td>
			<td></td>
		</tr>
		<tr>
			<td>Water Bath</td>
			<td>Grant</td>
			<td>GD100</td>
			<td></td>
		</tr>
	</tbody>
</table>

purification of biotinylated cell surface proteins from rhipicephalus microplus epithelial gut cells

Rhipicephalus microplus &#8211; the cattle tick &#8211; is the most significant ectoparasite in terms of economic impact on livestock as a vector of several pathogens. Efforts have been dedicated to the cattle tick control to diminish its deleterious effects, with focus on the discovery of vaccine candidates, such as BM86, located on the surface of the tick gut epithelial cells. Current research focuses upon the utilization of cDNA and genomic libraries, to screen for other vaccine candidates. The isolation of tick gut cells constitutes an important advantage in investigating the composition of surface proteins upon the tick gut cells membrane. This paper constitutes a novel and feasible method for the isolation of epithelial cells, from the tick gut contents of semi-engorged R. microplus. This protocol utilizes TCEP and EDTA to release the epithelial cells from the subepithelial support tissues and a discontinuous density centrifugation gradient to separate epithelial cells from other cell types. Cell surface proteins were biotinylated and isolated from the tick gut epithelial cells, using streptavidin-linked magnetic beads allowing for downstream applications in FACS or LC-MS/MS-analysis.

Epithelial cells were isolated from the gut tissues of R. microplus as per the schematic presented in Figure 1. Representative fluorescence microscopy imagery of tick gut epithelial cells prepared using this protocol are shown in Figure 2A and 2B. As the cell isolation is conducted upon semi-engorged R. microplus, cells appear as singular, spher...

Watch this Scientific Journal Video about Purification of Biotinylated Cell Surface Proteins from Rhipicephalus microplus Epithelial Gut Cells at JoVE.com

Purification of Biotinylated Cell Surface Proteins from Rhipicephalus microplus Epithelial Gut Cells

A modified density centrifugation gradient-based methodology was utilized to isolate epithelial cells from Rhipicephalus microplus gut tissue. Surface-bound proteins were biotinylated and purified through streptavidin magnetic beads for utilization in downstream applications.

Purification of Biotinylated Cell Surface Proteins from Rhipicephalus microplus Epithelial Gut Cells

Rhipicephalus microplus &#8211; the cattle tick &#8211; is the most significant ectoparasite in terms of economic impact on livestock as a vector of ...

purification-biotinylated-cell-surface-proteins-from-rhipicephalus

Universidad San Sebastian

Research

JoVE Journal

Biochemistry

9.4K Views.  The University of Queensland. A modified density centrifugation gradient-based methodology was utilized to isolate epithelial cells from Rhipicephalus microplus gut tissue. Surface-bound proteins were biotinylated and purified through streptavidin magnetic beads for utilization in downstream applications.

Video: Purification of Biotinylated Cell Surface Proteins from Rhipicephalus microplus Epithelial Gut Cells

Tandem Affinity Purification of Protein Complexes from Eukaryotic Cells

The purification of active protein-protein and protein-nucleic acid complexes is crucial for the characterization of enzymatic activities and de novo identification of novel subunits and post-translational modifications. Bacterial systems allow for the expression and purification of a wide variety of single polypeptides and protein complexes. However, this system does not enable the purification of protein subunits that contain post-translational modifications (e.g., phosphorylation and acetylation), and the identification of novel regulatory subunits that are only present/expressed in the eukaryotic system. Here, we provide a detailed description of a novel, robust, and efficient tandem affinity purification (TAP) method using STREP- and FLAG-tagged proteins that facilitates the purification of protein complexes with transiently or stably expressed epitope-tagged proteins from eukaryotic cells. This protocol can be applied to characterize protein complex functionality, to discover post-translational modifications on complex subunits, and to identify novel regulatory complex components by mass spectrometry. Notably, this TAP method can be applied to study protein complexes formed by eukaryotic or pathogenic (viral and bacterial) components, thus yielding a wide array of downstream experimental opportunities. We propose that researchers working with protein complexes could utilize this approach in many different ways.

We describe here a novel, robust, and efficient tandem affinity purification (TAP) method for the expression, isolation, and characterization of protein complexes from eukaryotic cells. This protocol could be utilized for the biochemical characterization of discrete complexes as well as the identification of novel interactors and post-translational modifications that regulate their function.

The purification of active protein-protein and protein-nucleic acid complexes is crucial for the characterization of enzymatic activities and de novo ...

Biotinylated Cell-penetrating Peptides to Study Intracellular Protein-protein Interactions

Here we present a protocol to study intracellular protein-protein interactions that is based on the widely used biotin-avidin pull-down system. The modification presented includes the combination of this technique with cell-penetrating sequences. We propose to design cell-penetrating baits that can be incubated with living cells instead of cell lysates and therefore the interactions found will reflect those that occur within the intracellular context. Connexin43 (Cx43), a protein that forms gap junction channels and hemichannels is down-regulated in high-grade gliomas. The Cx43 region comprising amino acids 266-283 is responsible for the inhibition of the oncogenic activity of c-Src in glioma cells. Here we use TAT as the cell-penetrating sequence, biotin as the pull-down tag and the region of Cx43 comprised between amino acids 266-283 as the target to find intracellular interactions in the hard-to-transfect human glioma stem cells. One of the limitations of the proposed method is that the molecule used as bait could fail to fold properly and, consequently, the interactions found could not be associated with the effect. However, this method can be especially interesting for the interactions involved in signal transduction pathways because they are usually carried out by intrinsically disordered regions and, therefore, they do not require an ordered folding. In addition, one of the advantages of the proposed method is that the relevance of each residue on the interaction can be easily studied. This is a modular system; therefore, other cell-penetrating sequences, other tags, and other intracellular targets can be employed. Finally, the scope of this protocol is far beyond protein-protein interaction because this system can be applied to other bioactive cargoes such as RNA sequences, nanoparticles, viruses or any molecule that can be transduced with cell-penetrating sequences and fused to pull-down tags to study their intracellular mechanism of action.

This is a protocol to study intracellular protein-protein interactions based on the biotin-avidin pull-down system with the novelty of combining cell-penetrating sequences. The main advantage is that the target sequence is incubated with living cells instead of cell lysates and therefore the interactions will occur within the cellular context.

Here we present a protocol to study intracellular protein-protein interactions that is based on the widely used biotin-avidin pull-down system. The ...

Purification of Hepatocytes and Sinusoidal Endothelial Cells from Mouse Liver Perfusion

This protocol demonstrates a method for obtaining high yield and viability for mouse hepatocytes and sinusoidal endothelial cells (SECs) suitable for culturing or for obtaining cell lysates. In this protocol, the portal vein is used as the site for catheterization, rather than the vena cava, as this limits contamination of other possible cell types in the final liver preparation. No special instrumentation is required throughout the procedure. A water bath is used as a source of heat to maintain the temperature of all the buffers and solutions. A standard peristaltic pump is used to drive the fluid, and a refrigerated table-top centrifuge is required for the centrifugation procedures. The only limitation of this technique is the placement of the catheter within the portal vein, which is challenging on some of the mice in the 18 - 25 g size range. An advantage of this technique is that only one vein is utilized for the perfusion and the access to the vein is quick, which minimizes ischemia and reperfusion of the liver that reduces hepatic cell viability. Another advantage to this protocol is that it is easy to distinguish live from dead hepatocytes by eyesight due to the difference in cellular density during the centrifugation steps. Cells from this protocol may be used in cell culture for any downstream application as well as processed for any biochemical assessment.

The goal of this protocol is to obtain high viability and high yield of hepatocytes and sinusoidal endothelial cells from liver. This is accomplished by perfusing the liver with a type IV collagenase solution via the portal vein, followed by differential centrifugation to obtain hepatocytes and sinusoidal endothelial cells.

This protocol demonstrates a method for obtaining high yield and viability for mouse hepatocytes and sinusoidal endothelial cells (SECs) suitable for ...

Isolation of Glomeruli and In Vivo Labeling of Glomerular Cell Surface Proteins

Proteinuria results from the disruption of the glomerular filter that is composed of the fenestrated endothelium, glomerular basement membrane, and podocytes with their slit diaphragms. The delicate structure of the glomerular filter, especially the slit diaphragm, relies on the interplay of diverse cell surface proteins. Studying these cell surface proteins has so far been limited to in vitro studies or histologic analysis. Here, we present a murine in vivo biotinylation labeling method, which enables the study of glomerular cell surface proteins under physiologic and pathophysiologic conditions. This protocol contains information on how to perfuse mouse kidneys, isolate glomeruli, and perform endogenous immunoprecipitation of a protein of interest. Semi-quantitation of glomerular cell surface abundance is readily available with this novel method, and all proteins accessible to biotin perfusion and immunoprecipitation can be studied. In addition, isolation of glomeruli with or without biotinylation enables further analysis of glomerular RNA and protein as well as primary glomerular cell culture (i.e., primary podocyte cell culture).

Isolation of Glomeruli and In Vivo Labeling of Glomerular Cell Surface Proteins

Here we present a protocol for murine in vivo labeling of glomerular cell surface proteins with biotin. This protocol contains information on how to perfuse mouse kidneys, isolate glomeruli, and perform endogenous immunoprecipitation of the protein of interest.

Proteinuria results from the disruption of the glomerular filter that is composed of the fenestrated endothelium, glomerular basement membrane, and ...

Translating Ribosome Affinity Purification (TRAP) for RNA Isolation from Endothelial Cells In Vivo

Many studies have been limited to using in vitro cellular assays and whole tissues or isolating of specific cell types from animals for in vitro analysis of transcriptome and gene expression by qPCR and RNA sequencing. Comprehensive transcriptome and gene expression analysis of specific cell types in complex tissues and organs will be critical to understand cellular and molecular mechanisms by which genes are regulated and their association with tissue homeostasis and organ functions. In this article, we demonstrate the methodology for isolation of ribosome-bound RNA directly in vivo in the vascular endothelia of animal lungs as an example. The specific materials and procedures for tissue processing and RNA purification will be described, including the assessment of RNA quality and yield as well as real time qPCR for arteriogenic gene assays. This approach, known as translating ribosome affinity purification (TRAP) technique, can be utilized for characterization of gene expression and transcriptome analysis of certain cell types directly in vivo in any specific type in complex tissues.

Translating Ribosome Affinity Purification TRAP for RNA Isolation from Endothelial Cells In Vivo

We present an approach to purify ribosome-bound mRNA from vascular endothelial cells (ECs) directly in mouse brain, lung and heart tissues via EC-specific genetic tag of enhanced green fluorescence protein (EGFP)in ribosomes in combination with RNA purification.

Many studies have been limited to using in vitro cellular assays and whole tissues or isolating of specific cell types from animals for in vitro analysis ...

Expression, Purification, Crystallization, and Enzyme Assays of Fumarylacetoacetate Hydrolase Domain-Containing Proteins

Fumarylacetoacetate hydrolase (FAH) domain-containing proteins (FAHD) are identified members of the FAH superfamily in eukaryotes. Enzymes of this superfamily generally display multi-functionality, involving mainly hydrolase and decarboxylase mechanisms. This article presents a series of consecutive methods for the expression and purification of FAHD proteins, mainly FAHD protein 1 (FAHD1) orthologues among species (human, mouse, nematodes, plants, etc.). Covered methods are protein expression in E. coli, affinity chromatography, ion exchange chromatography, preparative and analytical gel filtration, crystallization, X-ray diffraction, and photometric assays. Concentrated protein of high levels of purity (&#62;98%) may be employed for crystallization or antibody production. Proteins of similar or lower quality may be employed in enzyme assays or used as antigens in detection systems (Western-Blot, ELISA). In the discussion of this work, the identified enzymatic mechanisms of FAHD1 are outlined to describe its hydrolase and decarboxylase bi-functionality in more detail.

Expression and purification of fumarylacetoacetate hydrolase domain-containing proteins is described with examples (expression in E. coli, FPLC). Purified proteins are used for crystallization and antibody production and employed for enzyme assays. Selected photometric assays are presented to display the multi-functionality of FAHD1 as oxaloacetate decarboxylase and acylpyruvate hydrolase.

Fumarylacetoacetate hydrolase (FAH) domain-containing proteins (FAHD) are identified members of the FAH superfamily in eukaryotes. Enzymes of this ...

Real-Time, Semi-Automated Fluorescent Measurement of the Airway Surface Liquid pH of Primary Human Airway Epithelial Cells

In recent years, the importance of mucosal surface pH in the airways has been highlighted by its ability to regulate airway surface liquid (ASL) hydration, mucus viscosity and activity of antimicrobial peptides, key parameters involved in innate defense of the lungs. This is of primary relevance in the field of chronic respiratory diseases such as cystic fibrosis (CF) where these parameters are dysregulated. While different groups have studied ASL pH both in vivo and in vitro, their methods report a relatively wide range of ASL pH values and even contradictory findings regarding any pH differences between non-CF and CF cells. Furthermore, their protocols do not always provide enough details in order to ensure reproducibility, most are low throughput and require expensive equipment or specialized knowledge to implement, making them difficult to establish in most labs. Here we describe a semi-automated fluorescent plate reader assay that enables the real-time measurement of ASL pH under thin film conditions that more closely resemble the in vivo situation. This technique allows for stable measurements for many hours from multiple airway cultures simultaneously and, importantly, dynamic changes in ASL pH in response to agonists and inhibitors can be monitored. To achieve this, the ASL of fully differentiated primary human airway epithelial cells (hAECs) are stained overnight with a pH-sensitive dye in order to allow for the reabsorption of the excess fluid to ensure thin film conditions. After fluorescence is monitored in the presence or absence of agonists, pH calibration is performed in situ to correct for volume and dye concentration. The method described provides the required controls to make stable and reproducible ASL pH measurements, which ultimately could be used as a drug discovery platform for personalized medicine, as well as adapted to other epithelial tissues and experimental conditions, such as inflammatory and/or host-pathogen models.

We present a protocol to make dynamic measurements of the airway surface liquid pH under thin film conditions using a plate-reader.

In recent years, the importance of mucosal surface pH in the airways has been highlighted by its ability to regulate airway surface liquid (ASL) ...

PeptiQuick, a One-Step Incorporation of Membrane Proteins into Biotinylated Peptidiscs for Streamlined Protein Binding Assays

Membrane proteins, including transporters, channels, and receptors, constitute nearly one-fourth of the cellular proteome and over half of current drug targets. Yet, a major barrier to their characterization and exploitation in academic or industrial settings is that most biochemical, biophysical, and drug screening strategies require these proteins to be in a water-soluble state. Our laboratory recently developed the peptidisc, a membrane mimetic offering a &#8220;one-size-fits-all&#8221; approach to the problem of membrane protein solubility. We present here a streamlined protocol that combines protein purification and peptidisc reconstitution in a single chromatographic step. This workflow, termed PeptiQuick, allows for bypassing dialysis and incubation with polystyrene beads, thereby greatly reducing exposure to detergent, protein denaturation, and sample loss. When PeptiQuick is performed with biotinylated scaffolds, the preparation can be directly attached to streptavidin-coated surfaces. There is no need to biotinylate or modify the membrane protein target. PeptiQuick is showcased here with the membrane receptor FhuA and antimicrobial ligand colicin M, using biolayer interferometry to determine the precise kinetics of their interaction. It is concluded that PeptiQuick is a convenient way to prepare and analyze membrane protein-ligand interactions within one&#160;day in a detergent-free environment.

We present a method that combines membrane protein purification and reconstitution into peptidiscs in a single chromatographic step. Biotinylated scaffolds are used for direct surface attachment and measurement of protein-ligand interactions via biolayer interferometry.

Membrane proteins, including transporters, channels, and receptors, constitute nearly one-fourth of the cellular proteome and over half of current drug ...

Transverse Sectioning of Mature Rice (Oryza sativa L.) Kernels for Scanning Electron Microscopy Imaging Using Pipette Tips as Immobilization Support

Starch granules (SGs) exhibit different morphologies depending on the plant species, especially in the endosperm of the Poaceae family. Endosperm phenotyping can be used to classify genotypes based on SG morphotype using scanning electron microscopic (SEM) analysis. SGs can be visualized using SEM by slicing through the kernel (pericarp, aleurone layers, and endosperm) and exposing the organellar contents. Current methods require the rice kernel to be embedded in plastic resin and sectioned using a microtome or embedded in a truncated pipette tip and sectioned by hand using a razor blade. The former method requires specialized equipment and is time-consuming, while the latter introduces a new host of problems depending on rice genotype. Chalky rice varieties, particularly, pose a problem for this type of sectioning due to the friable nature of their endosperm tissue. Presented here is a technique for preparing translucent and chalky rice kernel sections for microscopy, requiring only pipette tips and a scalpel blade. Preparing the sections within the confines of a pipette tip prevents rice kernel endosperm from shattering (for translucent or &#8216;vitreous&#8217; phenotypes) and crumbling (for chalky phenotypes). Using this technique, endosperm cell patterning and the structure of intact SGs can be observed.

Transverse Sectioning of Mature Rice Oryza sativa L. Kernels for Scanning Electron Microscopy Imaging Using Pipette Tips as Immobilization Support

This protocol allows for the preparation of transverse sections of cereal seeds (e.g., rice) for the analysis of endosperm and starch granule morphology using scanning electron microscopy.

Starch granules (SGs) exhibit different morphologies depending on the plant species, especially in the endosperm of the Poaceae family. Endosperm ...

Cell Fractionation of U937 Cells by Isopycnic Density Gradient Purification

This protocol describes a method to obtain subcellular protein fractions from mammalian cells using a combination of detergents, mechanical lysis, and isopycnic density gradient centrifugation. The major advantage of this procedure is that it does not rely on the sole use of solubilizing detergents to obtain subcellular fractions. This makes it possible to separate the plasma membrane from other membrane-bound organelles of the cell. This procedure will facilitate the determination of protein localization in cells with a reproducible, scalable, and selective method. This method has been successfully used to isolate cytosolic, nuclear, mitochondrial, and plasma membrane proteins from the human monocyte cell line, U937. Although optimized for this cell line, this procedure may serve as a suitable starting point for the subcellular fractionation of other cell lines. Potential pitfalls of the procedure and how to avoid them are discussed as are alterations that may need to be considered for other cell lines.

This fractionation protocol will allow researchers to isolate cytoplasmic, nuclear, mitochondrial, and membrane proteins from mammalian cells. The latter two subcellular fractions are further purified via isopycnic density gradient.

This protocol describes a method to obtain subcellular protein fractions from mammalian cells using a combination of detergents, mechanical lysis, and ...