The authors would like to thank the members of the Henne lab for help and conceptual advice in the completion of this study. W.M.H. is supported by funds from the Welch Foundation (I-1873), the NIH NIGMS (GM119768), the Ara Paresghian Medical Research Fund, and the UT Southwestern Endowed Scholars Program. S.R has been supported by a T32 program grant (5T32GM008297).

1. Growth and labeling of yeast cells with 14C-acetic acid
<ol>
	<li>Inoculate a yeast culture by picking a colony from a plate and dispensing it into 20 mL of synthetic complete (SC) media containing 2% dextrose (see Supplementary File for the recipe of SC media). Incubate at 30 &#730;C for overnight with shaking at 200 rpm. 
	NOTE: Growth condition, sample volume, and treatment will differ based on the lipid(s) of interest. Prior to running full experiments, optimal growth conditions and culture volumes should be empirically determined. This protocol discusses radiolabeling of yeast cultures grown to stationary phase, a growth phase when bio-membrane and cell growth slows, and NL synthesis is very active.</li>
	<li>Measure the OD600 of the overnight culture using a spectrophotometer and dilute the yeast cell culture to a final OD600 of 0.2 in 50 mL of fresh SC media containing 2% dextrose. Grow the cells for 24 h, or until they have reached the stationary phase (which is commonly defined by a flat lining of the cell doubling OD600 measurement).</li>
	<li>Before collecting the cells, make the quenching buffer (see Supplementary File for details). Make two 20 mL aliquots of quenching buffer for each sample (i.e., 40 mL quenching buffer for each sample) and split evenly into two 50 mL conical tubes). Store the quenching buffer aliquots at -80 &#176;C for future use.</li>
	<li>Once the cultures have reached the desired OD or growth phase, collect the cells by centrifuging at 4,100 x g for 10 min. While samples are in the centrifuge, prepare radiolabeling media by adding [1-14C] acetic acid sodium salt to dextrose-free SC media at a final concentration of 10 &#956;Ci/mL. 
	CAUTION: Proper personal protective equipment (PPE) should be worn all times when working with radioactive materials. Always follow local guidelines for the proper storage, usage, and disposal of radioactive materials. 
	NOTE: Both the concentration of 14C-acetic acid in the labeling media and the radiolabeling incubation time should be adjusted according to the metabolite(s) of interest. Here, a 20 min radiolabeling pulse incubation is used, which is sufficient to label NL species with a range of abundance.</li>
	<li>Remove the supernatant from the pelleted cells, and wash the cell pellet once with 20 mL of dextrose-free SC media by resuspending the pellet with a pipette. Collect the cells again by centrifuging at 4,100 x g for 5 min.</li>
	<li>Resuspend the cells in 1 mL of dextrose-free SC media, and transfer the cells to a labeled 2 mL microcentrifuge tube. Collect the cells again by centrifuging at 4,100 x g for 2 min.</li>
	<li>Resuspend the cells once more in 500 &#956;L of dextrose-free SC media. Pre-cool a centrifuge equipped for 50 mL conical tubes to -10 &#176;C or on the lowest temperature setting.</li>
	<li>Begin the radiolabeling period by quickly adding 500 &#956;L of radiolabeling media to each 500 &#956;L of cell suspension (final 14C-acetic acid concentration = 5 &#956;Ci/mL). Incubate the tubes in a rotating incubator at 30 &#176;C for 20 min. 2 min before the end of the labeling period, transfer one 20 mL aliquot of quenching buffer for each sample from the -80 &#176;C freezer to a bucket of ice</li>
	<li>Once the radiolabeling period has ended, use a pipette to plunge the entire 1 mL sample into 20 mL of cold quenching buffer. Vortex the conical tubes for 5-10 s to ensure that the sample has been thoroughly mixed with the quenching buffer. Incubate the samples in quenching buffer for 2 min on ice.</li>
	<li>Collect the cell pellet by spinning in a centrifuge at 5,000 x g for 3 min set to -10 &#176;C or on the lowest temperature setting. While sample tubes are spinning, transfer another set of quenching buffer aliquot from the -80 &#176;C freezer to a bucket filled with ice (i.e., one 20 mL tube of quenching buffer per sample).</li>
	<li>Remove the quenching buffer supernatant from cell pellets and replace it with 20 mL fresh, cold, quenching buffer. Vortex and shake the samples until the pellet has been dislodged from the bottom of the conical tube and resuspended fully in quenching buffer. Centrifuge the samples again at 5,000 x g for 3 min at -10 &#176;C to collect the cells.</li>
	<li>Once the cells are pelleted, thoroughly remove all quenching buffer from the samples by pouring off the supernatant and removing the excess with a pipette. Store tubes at -80 &#176;C for further processing.</li>
</ol>
2. Isolation of total lipids from yeast
NOTE: The following protocol for lipid isolation is based on a well-established and frequently used method that efficiently extracts most neutral lipid species17,18. 
CAUTION: When using organic solvent, always wear appropriate PPE and work inside of a fume hood when possible. During lipid extraction, avoid using plastics that are incompatible with organic solvents. Polypropylene tubes are suitable for the following protocol.
<ol>
	<li>Weigh 0.3 g of acid-washed glass beads for each sample and store them in 2 mL microcentrifuge tubes on ice. Remove the cell pellets from the -80 &#176;C freezer and keep them on ice. Add 350 &#956;L methanol and 700 &#956;L chloroform to each sample, resuspend, and transfer to microcentrifuge tubes containing pre-weighed glass beads.</li>
	<li>Lyse cells by agitating tubes on a vortex 3x for 1 min, with 30 s incubations on ice between agitations. Alternatively, cells can be lysed using a mini bead-beater for three 1-min cycles. Save 25-30 &#956;L of whole cell lysate in a separate tube for scintillation counting. 
	NOTE: The saved lysate will be used to determine the relative amount of radioisotope taken up by each sample during the pulse period, which will influence the amount of each sample loaded onto the TLC plate. This is discussed further in step 3.2.</li>
	<li>Pour the entire contents of the 2 mL microcentrifuge tube into a 15 mL glass centrifuge tube [Tube A]. Wash the 2 mL microcentrifuge tubes by adding 1 mL of methanol and vortexing for 10-15 s. Transfer the 1 mL methanol wash to tube A and add 2 mL of chloroform to tube A followed by 400 &#956;L of water for a final sample volume of 4.45 mL.</li>
	<li>Vortex samples for 1 min followed by a 5 min centrifugation at 1,000 x g. After centrifugation, the aqueous (upper) and organic (lower) phases should be clearly visually separated with cell debris lying at the interface.</li>
	<li>Using a glass Pasteur pipette, collect the organic phase from tube A and move to a new 15 mL glass centrifuge tube (Tube B). Add 1 mL of 1M KCl to tube B. To tube A, add 1 mL of methanol and 2 mL of chloroform, and 200 &#956;L MiliQ water. Repeat the vortexing and centrifugation steps on tube A.</li>
	<li>Once again collect the organic phase from tube A and add it to tube B. Dispose of tube A in an appropriate container. Vortex tube B for 1 min followed by a 5 min centrifugation at 1,000 x g.</li>
	<li>Remove the upper aqueous layer from tube B and dispose. Add 1 mL of fresh 1 M KCl back to tube B and repeat the vortexing/centrifugation step. Once layers are separated, carefully collect the entire bottom organic layer into a labeled 4 mL glass vial. 
	NOTE: At this step, lipid extracts can be stored at -80 &#176;C, or the protocol can be continued for TLC separation of lipids.</li>
</ol>
3. Separation and quantification of radioisotope-labeled NLs by thin layer chromatography
<ol>
	<li>If lipid extracts were placed at -80 &#176;C, slowly bring to room temperature by incubating on ice and subsequently on a benchtop. Completely evaporate solvent from lipid extracts by vacuum drying or using a gentle stream of inert gas (e.g., argon or nitrogen). Meanwhile, pre-heat an oven to 145 &#176;C for heating the TLC plate.</li>
	<li>Before samples can be loaded onto the TLC plate, determine relative amounts of radiolabel taken up by the cells. Pipette 10 &#956;L of the whole cell lysate from step 2.2 into a 6 mL glass scintillation vial, add 6 mL of scintillation fluid and place vials in a rack. Use a scintillation counter to measure the cpm or dpm of each sample using the count single rack option set to a 1 min counting time. Measure each whole cell lysate in duplicate to obtain an average for each sample. Adjust the loading amount according to a wild type or reference sample 
	NOTE: The amount of each sample to load onto the TLC plate can be determined using the following equation: (average sample counts)/(average reference counts) x desired loading volume. For example, if 20 &#956;L of the reference sample is to be loaded onto the TLC plate, and has an average count of 1,000, then an experimental sample with an average count of 2,000 will have 10 &#956;L loaded onto the TLC plate.</li>
	<li>Reconstitute the sample lipids in 40-50 &#956;L of 1:1 (v/v%) chloroform:methanol by vortexing for 5 min. Prepare 101 mL of the mobile phase solvent in a glass graduated cylinder (see the Representative Results section for an example of major NL species separation by a 50:40:10:1 (v/v/v/v%) Hexane:Petroleum ether:Diethyl ether:Acetic acid solvent).</li>
	<li>Pour the solvent into a glass TLC chamber containing a 20 x 20 TLC saturation pad and a tight-fitting lid. Prepare a channeled 20 x 20 silica gel 60 G plate by gently marking a line 1.5 cm above the bottom of the plate using a pencil. The line designates the origin and where the lipids will be loaded. Below the line, gently label the sample that will be loaded in each lane. Once the TLC plate has been prepped, incubate the plate in a 145 &#176;C oven for at least 30 min to pre-heat the plate and remove any excess moisture.</li>
	<li>Once the plate has been sufficiently heated, and the TLC saturation pad is saturated with solvent, remove the TLC plate from the oven and immediately proceed to loading the TLC plate. Loading the plate while it is warm ensures rapid solvent evaporation. For each lipid species of interest, load 5-20 &#956;g of a purified lipid standard onto a lane of the TLC plate to track separation and expected migration distance. Using a pipette, spot 5&#956;L of sample onto the origin of each lane located 1.5 cm above the bottom the of TLC plate. Repeat loading of 5 &#956;L spots until 20-40 &#956;L of sample has been loaded into each lane. 
	NOTE: 5-20 &#956;g of unlabeled purified lipids can be added to each sample lane as tracers that can be stained and visualized following TLC separation of lipids. The presence of a stained standard allows for easy tracking and excision of radiolabeled lipid bands for subsequent scintillation counting. Which purified standards are loaded onto the plate will be determined by the NL species of interest. See the Representative Result&#160;section for examples of separating oleic acid (FFA), 1,2 dioleoyl-glycerol (DG), triolein (TG), cholesterol (Chol), cholesteryl-linoleate (SE), and squalene in lanes adjacent to the sample lanes.</li>
	<li>Once the standard and the experimental samples have been loaded, place the plate in the developing chamber and wait until the solvent has reached the top of the plate (40-60 min). Once the plate is fully developed, remove it from the chamber and allow it to dry in the fume hood for 20 minutes.</li>
	<li>After the plate is dried, cover it with plastic film and place it in a developing cassette with an autoradiography screen. Allow the plate to develop with the screen for 24-48 h.</li>
</ol>
4. Visualization and quantification of TLC separated lipids
<ol>
	<li>Remove the screen from the developing cassette and place inside of a phosphor imager. Select the Phosphor Imaging option and develop at 800-1000 V. 
	NOTE: Phosphor imaging gives a qualitative view of radiolabeled lipids on the TLC plate. However, quantification of radiolabeled lipids is best accomplished by scintillation counting, which is described subsequently.</li>
	<li>Mix 100 mL of p-anisaldehyde reagent (see Supplementary File) and deposit in a glass spray bottle. Spray the TLC plate with p-anisaldehyde reagent until the silica is saturated. Bake the plate in a 145 &#176;C oven for 5 min, or until bands have appeared.</li>
	<li>To quantify individual lipid species using radiolabel scintillation counting, use a razor blade to scrape the silica gel from the glass TLC plate. Transfer each silica gel band corresponding to a single radiolabeled lipid species to a glass scintillation vial and add 6 mL scintillation fluid. Vortex vigorously until the silica band has been reduced to small pieces.
	<ol>
		<li>Alternatively, lipids can be extracted from the silica gel band using the lipid extraction protocol in section 3. If lipids are extracted from the silica gel, evaporate the solvent entirely as in step 3.1, and add 6 mL scintillation fluid to the dried lipids. Place the rack containing scintillation vials into a scintillation counter. Select the Count single rack option and adjust the counting time to 2 min per vial. Results from the scintillation counter will be printed and can be visualized as a bar graph.</li>
	</ol>
	</li>
</ol>

<ol>
	<li>Konige, M., Wang, H., Sztalryd, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Role+of+adipose+specific+lipid+droplet+proteins+in+maintaining+whole+body+energy+homeostasis.">Role of adipose specific lipid droplet proteins in maintaining whole body energy homeostasis.</a> Biochimica Et Biophysica Acta. 1842 (3), 393-401 (2014).</li><li>Arrese, E. L., Saudale, F. Z., Soulages, J. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lipid+droplets+as+signaling+platforms+linking+metabolic+and+cellular+functions.">Lipid droplets as signaling platforms linking metabolic and cellular functions.</a> Lipid Insights. 7, 7-16 (2014).</li><li>Walther, T. C., Chung, J., Farese, R. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lipid+droplet+biogenesis.">Lipid droplet biogenesis.</a> Annual Review of Cell and Developmental Biology. 33, 491-510 (2017).</li><li>Olzmann, J. A., Carvalho, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dynamics+and+functions+of+lipid+droplets.">Dynamics and functions of lipid droplets.</a> Nature Reviews. Molecular Cell Biology. 20 (3), 137-155 (2019).</li><li>Krahmer, N., Farese, R. V., Walther, T. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Balancing+the+fat:+lipid+droplets+and+human+disease.">Balancing the fat: lipid droplets and human disease.</a> EMBO Molecular Medicine. 5 (7), 973-983 (2013).</li><li>Ross, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+pathogenesis+of+atherosclerosis:+A+perspective+for+the+1990s.">The pathogenesis of atherosclerosis: A perspective for the 1990s.</a> Nature. 362 (6423), 801-809 (1993).</li><li>Zhang, C., Liu, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+lipid+droplet:+A+conserved+cellular+organelle.">The lipid droplet: A conserved cellular organelle.</a> Protein &amp; Cell. 8 (11), 796-800 (2017).</li><li>W&#228;ltermann, 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=Mechanism+of+lipid-body+formation+in+prokaryotes:+How+bacteria+fatten+up:+Lipid-body+formation+in+prokaryotes.">Mechanism of lipid-body formation in prokaryotes: How bacteria fatten up: Lipid-body formation in prokaryotes.</a> Molecular Microbiology. 55 (3), 750-763 (2004).</li><li>Borrull, A., L&#243;pez-Mart&#237;nez, G., Poblet, M., Cordero-Otero, R., Roz&#232;s, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+simple+method+for+the+separation+and+quantification+of+neutral+lipid+species+using+GC-MS.">A simple method for the separation and quantification of neutral lipid species using GC-MS.</a> European Journal of Lipid Science and Technology. 117 (3), 274-280 (2015).</li><li>Kotapati, H. K., Bates, P. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Normal+phase+HPLC+method+for+combined+separation+of+both+polar+and+neutral+lipid+classes+with+application+to+lipid+metabolic+flux.">Normal phase HPLC method for combined separation of both polar and neutral lipid classes with application to lipid metabolic flux.</a> Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences. 1145, 122099 (2020).</li><li>Knittelfelder, O. L., Weberhofer, B. P., Eichmann, T. O., Kohlwein, S. D., Rechberger, G. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+versatile+ultra-high+performance+LC-MS+method+for+lipid+profiling.">A versatile ultra-high performance LC-MS method for lipid profiling.</a> Journal of Chromatography B. 951-952, 119-128 (2014).</li><li>Ruiz, J. I., Ochoa, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantification+in+the+subnanomolar+range+of+phospholipids+and+neutral+lipids+by+monodimensional+thin-layer+chromatography+and+image+analysis.">Quantification in the subnanomolar range of phospholipids and neutral lipids by monodimensional thin-layer chromatography and image analysis.</a> Journal of Lipid Research. 38 (7), 1482-1489 (1997).</li><li>Bui, Q., Sherma, J., Hines, 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=Using+high+performance+thin+layer+chromatography-densitometry+to+study+the+influence+of+the+prion+[RNQ+]+and+its+determinant+prion+protein+Rnq1+on+yeast+lipid+profiles.">Using high performance thin layer chromatography-densitometry to study the influence of the prion [RNQ+] and its determinant prion protein Rnq1 on yeast lipid profiles.</a> Separations. 5 (1), 5010006 (2018).</li><li>Pronk, J. T., de Steensma, H., Van Dijken, J. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pyruvate+metabolism+in+Saccharomyces+cerevisiae.">Pyruvate metabolism in Saccharomyces cerevisiae.</a> Yeast. 12 (16), 1607-1633 (1996).</li><li>Buttke, T. M., Pyle, A. L. <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+unsaturated+fatty+acid+deprivation+on+neutral+lipid+synthesis+in+Saccharomyces+cerevisiae.">Effects of unsaturated fatty acid deprivation on neutral lipid synthesis in Saccharomyces cerevisiae.</a> Journal of Bacteriology. 152 (2), 747-756 (1982).</li><li>Touchstone, 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=Thin-layer+chromatographic+procedures+for+lipid+separation.">Thin-layer chromatographic procedures for lipid separation.</a> Journal of Chromatography B: Biomedical Sciences and Applications. 671 (1-2), 169-195 (1995).</li><li>Folch, J., Lees, M., Sloane Stanley, G. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+simple+method+for+the+isolation+and+purification+of+total+lipides+from+animal+tissues.">A simple method for the isolation and purification of total lipides from animal tissues.</a> The Journal of Biological Chemistry. 226 (1), 497-509 (1957).</li><li>Breil, C., Abert Vian, M., Zemb, T., Kunz, W., Chemat, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term="Bligh+and+Dyer"+and+Folch+methods+for+solid-liquid-liquid+extraction+of+lipids+from+microorganisms.+Comprehension+of+solvatation+mechanisms+and+towards+substitution+with+alternative+solvents.">"Bligh and Dyer" and Folch methods for solid-liquid-liquid extraction of lipids from microorganisms. Comprehension of solvatation mechanisms and towards substitution with alternative solvents.</a> International Journal of Molecular Sciences. 18 (4), 708 (2017).</li><li>Fuchs, B., S&#252;&#223;, R., Teuber, K., Eibisch, M., Schiller, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lipid+analysis+by+thin-layer+chromatography-A+review+of+the+current+state.">Lipid analysis by thin-layer chromatography-A review of the current state.</a> Journal of Chromatography A. 1218 (19), 2754-2774 (2011).</li></ol>

The authors declare there are no competing interests in the preparation of this manuscript.

Here, a versatile radiolabeling protocol to quantitatively monitor the synthesis of NL species in yeast is presented. This protocol is very modular, which allows for the procedure to be finished within 3-6 days. Additionally, a wealth of literature exists on the use of TLC to separate lipid species and metabolites, which should permit the user to detect several lipid species of interest with a simple change of TLC solvent systems16,19.This protocol is conducive t...

Acetyl-CoA is the fundamental building block of diverse biomolecules including neutral lipids (NLs), which serve as a versatile biomolecular currency for building membranes, generating ATP, and regulating cell signaling1,2. The availability of NLs to be shunted into any of these respective pathways is, in part, regulated by their storage. Lipid droplets (LDs), cytoplasmic organelles composed of hydrophobic cores of triglycerides (TGs) and sterol-esters (SEs), are the main storage compartments of most cellular NLs. As such, LDs sequester and regulate NLs, which can be degraded and subsequently utilized for biochemical and metabolic processes3,4. It is known that the mis-regulation of NL and LD-associated proteins is correlated with the onset of pathologies including lipodystrophy and metabolic syndromes5,6. Because of this, current LD research is intensely focused on how NL synthesis is regulated spatially, temporally, and across distinct tissues of multi-cellular organisms. Due to the ubiquitous cellular roles for NLs, many enzymes responsible for the synthesis and regulation of NLs are conserved throughout eukaryotes7. Indeed, even some prokaryotes store NLs in LDs8. Therefore, genetically tractable model organisms such as Saccharomyces cerevisiae (budding yeast) have been useful for the study of NL synthesis and regulation.
The separation and quantification of NLs from cell extracts can be accomplished in a myriad of ways, including gas chromatography-mass spectrometry (GC-MS), high-performance liquid chromatography (HPLC), and ultra-performance liquid chromatography-mass spectrometry (UPLC-MS)9,10,11. Perhaps the simplest method for separating NLs is via thin layer chromatography (TLC), which allows for subsequent densitometric quantification from a standard curve12,13. Although TLC provides only a course-grained separation of NLs, it remains a powerful technique because it is inexpensive, and it allows for the rapid separation of NLs from several samples simultaneously. Two of the most considerable challenges facing the study of NLs via TLC are: 1) the broad range of cellular abundances of NL species and their intermediates, and 2) the range of hydrophilicity/hydrophobicity of lipid intermediates within NL synthesis pathways. Consequently, the quantification of NL species via TLC is typically restricted to the most abundant species; however, introduction of a 14C-acetic acid radiolabel can significantly enhance the detection of low abundance intermediates within NL pathways. Acetic acid is rapidly converted into acetyl-CoA by the acetyl-CoA synthetase ACS214, which makes 14C-acetic acid a suitable radiolabeling substrate in yeast15. Additionally, separation of both hydrophobic NLs and hydrophilic intermediates of NLs can be achieved by TLC through the use of multiple solvent systems16. Here, a method is presented for the separation of NLs using 14C-acetic acid metabolic labeling in yeast. Lipids labeled during the pulse period are subsequently isolated by a well-established total lipid isolation protocol17, followed by the separation of NL species by TLC. Developing of TLC plates by both autoradiography to visualize labeled lipids, and a chemical spray to visualize total lipids, permits for multiple methods of quantification. Individual lipid bands can also be easily extracted from the TLC plate using a razor blade, and scintillation counting can be used to quantify amount of radiolabeled material within the band.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>[1-C14] Acetic acid sodium salt specific activity: 45-60mCi</td>
			<td>PerkinElmer</td>
			<td>NEC084H001MC</td>
			<td></td>
		</tr>
		<tr>
			<td>18:1 1,2 dioleoyl-sn-glycerol</td>
			<td>Avanti</td>
			<td>800811O</td>
			<td></td>
		</tr>
		<tr>
			<td>200 proof absolute ethanol</td>
			<td>Sigma</td>
			<td>459836</td>
			<td></td>
		</tr>
		<tr>
			<td>Acid washed glass beads 425-600um</td>
			<td>Sigma</td>
			<td>G8772</td>
			<td></td>
		</tr>
		<tr>
			<td>Amber bulbs for Pastuer pipettes</td>
			<td>Fisher</td>
			<td>03-448-24</td>
			<td></td>
		</tr>
		<tr>
			<td>Ammonium Sulfate &#62;99%</td>
			<td>Sigma</td>
			<td>A4418</td>
			<td></td>
		</tr>
		<tr>
			<td>Beckman LS6500 scintillation counter</td>
			<td>PerkinElmer</td>
			<td>A481000</td>
			<td></td>
		</tr>
		<tr>
			<td>Chloroform (HPLC grade)</td>
			<td>Fisher</td>
			<td>C607SK</td>
			<td></td>
		</tr>
		<tr>
			<td>Cholesterol &#62;99%</td>
			<td>Sigma</td>
			<td>C8667</td>
			<td></td>
		</tr>
		<tr>
			<td>Cholesteryl-linoleate &#62;98%</td>
			<td>Sigma</td>
			<td>C0289</td>
			<td></td>
		</tr>
		<tr>
			<td>Concentrated sulfuric acid</td>
			<td>Sigma</td>
			<td>339741</td>
			<td></td>
		</tr>
		<tr>
			<td>Corning 50mL conical tubes, polypropylene with centristar cap</td>
			<td>Sigma</td>
			<td>CLS430829</td>
			<td></td>
		</tr>
		<tr>
			<td>Dextrose, anhydrous grade</td>
			<td>Sigma</td>
			<td>D9434</td>
			<td></td>
		</tr>
		<tr>
			<td>Diethyl ether anhydrous grade</td>
			<td>Sigma</td>
			<td>296082</td>
			<td></td>
		</tr>
		<tr>
			<td>Drying oven</td>
			<td>Fisher</td>
			<td>11-475-155</td>
			<td></td>
		</tr>
		<tr>
			<td>EcoLume scintillation liquid</td>
			<td>VWR</td>
			<td>IC88247001</td>
			<td></td>
		</tr>
		<tr>
			<td>Eppendorf 5424R centrifuge</td>
			<td>Fisher</td>
			<td>05-401-205</td>
			<td></td>
		</tr>
		<tr>
			<td>GE Storage phosphor screen</td>
			<td>Sigma</td>
			<td>GE28-9564-75</td>
			<td></td>
		</tr>
		<tr>
			<td>GE Typhoon FLA9500 imager</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Glacial acetic acid, ACS grade</td>
			<td>Sigma</td>
			<td>695092</td>
			<td></td>
		</tr>
		<tr>
			<td>Glass 6mL scintillation vials</td>
			<td>Sigma</td>
			<td>M1901</td>
			<td></td>
		</tr>
		<tr>
			<td>Glass centrifuge tube caps</td>
			<td>Fisher</td>
			<td>14-595-36A</td>
			<td></td>
		</tr>
		<tr>
			<td>Glass centrifuge tubes</td>
			<td>Fisher</td>
			<td>14-595-35A</td>
			<td></td>
		</tr>
		<tr>
			<td>Glass Pasteur pipette</td>
			<td>Fisher</td>
			<td>13-678-20C</td>
			<td></td>
		</tr>
		<tr>
			<td>Hexane, anhydrous grade</td>
			<td>Sigma</td>
			<td>296090</td>
			<td></td>
		</tr>
		<tr>
			<td>L-Adenine &#62;99%</td>
			<td>Sigma</td>
			<td>A8626</td>
			<td></td>
		</tr>
		<tr>
			<td>L-Alanine &#62;98%</td>
			<td>Sigma</td>
			<td>A7627</td>
			<td></td>
		</tr>
		<tr>
			<td>L-Arginine &#62;99%</td>
			<td>Sigma</td>
			<td>A1270000</td>
			<td></td>
		</tr>
		<tr>
			<td>L-Asparagine &#62;98%</td>
			<td>Sigma</td>
			<td>A0884</td>
			<td></td>
		</tr>
		<tr>
			<td>L-Aspartate &#62;98%</td>
			<td>Sigma</td>
			<td>A9256</td>
			<td></td>
		</tr>
		<tr>
			<td>L-Cysteine &#62;97%</td>
			<td>Sigma</td>
			<td>W326305</td>
			<td></td>
		</tr>
		<tr>
			<td>L-Glutamic acid monosodium salt monohydrate &#62;98%</td>
			<td>Sigma</td>
			<td>49621</td>
			<td></td>
		</tr>
		<tr>
			<td>L-Glutamine &#62;99%</td>
			<td>Sigma</td>
			<td>G3126</td>
			<td></td>
		</tr>
		<tr>
			<td>L-Glycine &#62;99%</td>
			<td>Sigma</td>
			<td>G8898</td>
			<td></td>
		</tr>
		<tr>
			<td>L-Histidine &#62;99%</td>
			<td>Sigma</td>
			<td>H8000</td>
			<td></td>
		</tr>
		<tr>
			<td>L-Isoleucine &#62;98%</td>
			<td>Sigma</td>
			<td>I2752</td>
			<td></td>
		</tr>
		<tr>
			<td>L-Leucine &#62;98%</td>
			<td>Sigma</td>
			<td>L8000</td>
			<td></td>
		</tr>
		<tr>
			<td>L-Lysine &#62;98%</td>
			<td>Sigma</td>
			<td>L5501</td>
			<td></td>
		</tr>
		<tr>
			<td>L-Methionine, HPLC grade</td>
			<td>Sigma</td>
			<td>M9625</td>
			<td></td>
		</tr>
		<tr>
			<td>L-Phenylalanine, reagent grade</td>
			<td>Sigma</td>
			<td>P2126</td>
			<td></td>
		</tr>
		<tr>
			<td>L-Proline &#62;99%</td>
			<td>Sigma</td>
			<td>P0380</td>
			<td></td>
		</tr>
		<tr>
			<td>L-Serine &#62;99%</td>
			<td>Sigma</td>
			<td>S4500</td>
			<td></td>
		</tr>
		<tr>
			<td>L-Theronine, reagent grade</td>
			<td>Sigma</td>
			<td>T8625</td>
			<td></td>
		</tr>
		<tr>
			<td>L-Tryptophan &#62;98%</td>
			<td>Sigma</td>
			<td>T0254</td>
			<td></td>
		</tr>
		<tr>
			<td>L-Tyrosine &#62;98%</td>
			<td>Sigma</td>
			<td>T3754</td>
			<td></td>
		</tr>
		<tr>
			<td>L-Uracil &#62;99%</td>
			<td>Sigma</td>
			<td>U0750</td>
			<td></td>
		</tr>
		<tr>
			<td>L-Valine &#62;98%</td>
			<td>Sigma</td>
			<td>V0500</td>
			<td></td>
		</tr>
		<tr>
			<td>Methanol, ACS grade</td>
			<td>Fisher</td>
			<td>A412</td>
			<td></td>
		</tr>
		<tr>
			<td>Oleic acid &#62;99%</td>
			<td>Sigma</td>
			<td>O1008</td>
			<td></td>
		</tr>
		<tr>
			<td>p-anisaldehyde</td>
			<td>Sigma</td>
			<td>A88107</td>
			<td></td>
		</tr>
		<tr>
			<td>Petroleum ether, ACS grade</td>
			<td>Sigma</td>
			<td>184519</td>
			<td></td>
		</tr>
		<tr>
			<td>Phosphatidylcholine, dipalmitoyl &#62;99%</td>
			<td>Sigma</td>
			<td>P1652</td>
			<td></td>
		</tr>
		<tr>
			<td>Pipettes</td>
			<td>Eppendorf</td>
			<td>2231000713</td>
			<td></td>
		</tr>
		<tr>
			<td>Potassium chloride, ACS grade</td>
			<td>Sigma</td>
			<td>P3911</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium Hydroxide pellets, certified ACS</td>
			<td>Fisher</td>
			<td>S318-100</td>
			<td></td>
		</tr>
		<tr>
			<td>Squalene &#62;98%</td>
			<td>Sigma</td>
			<td>S3626</td>
			<td></td>
		</tr>
		<tr>
			<td>Succinic Acid crystalline/certified</td>
			<td>Fisher</td>
			<td>110-15-6</td>
			<td></td>
		</tr>
		<tr>
			<td>TLC saturation pad</td>
			<td>Sigma</td>
			<td>Z265225</td>
			<td></td>
		</tr>
		<tr>
			<td>TLC silica gel 60G glass channeled plate</td>
			<td>Fisher</td>
			<td>NC9825743</td>
			<td>No fluorescent indicators</td>
		</tr>
		<tr>
			<td>Transparency plastic film</td>
			<td>Apollo</td>
			<td>829903</td>
			<td></td>
		</tr>
		<tr>
			<td>Tricine</td>
			<td>Sigma</td>
			<td>T0377</td>
			<td></td>
		</tr>
		<tr>
			<td>Triolein &#62;99%</td>
			<td>Sigma</td>
			<td>T7140</td>
			<td></td>
		</tr>
		<tr>
			<td>Vortex mixer</td>
			<td>Fisher</td>
			<td>02-215-414</td>
			<td></td>
		</tr>
		<tr>
			<td>Whatman exposure cassette</td>
			<td>Sigma</td>
			<td>WHA29175523</td>
			<td></td>
		</tr>
		<tr>
			<td>Yeast nitrogen base without ammonium sulfate and amino acids</td>
			<td>Sigma</td>
			<td>Y1251</td>
			<td></td>
		</tr>
	</tbody>
</table>

analysis of neutral lipid synthesis in saccharomyces cerevisiae by metabolic labeling and thin layer chromatography

Neutral lipids (NLs) are a class of hydrophobic, chargeless biomolecules that play key roles in energy and lipid homeostasis. NLs are synthesized de novo&#160;from acetyl-CoA and are primarily present in eukaryotes in the form of triglycerides (TGs) and sterol-esters (SEs). The enzymes responsible for the synthesis of NLs are highly conserved from Saccharomyces cerevisiae (yeast) to humans, making yeast a useful model organism to dissect the function and regulation of NL metabolism enzymes. While much is known about how acetyl-CoA is converted into a diverse set of NL species, mechanisms for regulating NL metabolism enzymes, and how mis-regulation can contribute to cellular pathologies, are still being discovered. Numerous methods for the isolation and characterization of NL species have been developed and used over decades of research; however, a quantitative and simple protocol for the comprehensive characterization of major NL species has not been discussed. Here, a simple and adaptable method to quantify the de novo&#160;synthesis of major NL species in yeast is presented. We apply 14C-acetic acid metabolic labeling coupled with thin layer chromatography to separate and quantify a diverse range of physiologically important NLs. Additionally, this method can be easily applied to study in vivo reaction rates of NL enzymes or degradation of NL species over time.

In this protocol, we have demonstrated that the labeling, detection, and quantification of NL species can be accomplished by 14C-acetic acid metabolic labeling. Major NL species can be separated in a solvent system of 50:40:10:1 (v/v/v/v%) Hexane:Petroleum ether:Diethyl ether:Acetic acid (Figure 1A,B). Phosphor imaging allows for visualization of labeled free fatty acid (FFA), triacylglycerol (TG), diacylglycerol (DG), cholesterol (Chol), and squalene (SQ) (<stron...

Watch this Scientific Journal Video about Analysis of Neutral Lipid Synthesis in Saccharomyces cerevisiae by Metabolic Labeling and Thin Layer Chromatography at JoVE.com

Analysis of Neutral Lipid Synthesis in Saccharomyces cerevisiae by Metabolic Labeling and Thin Layer Chromatography

Here, a protocol is presented for the metabolic labeling of yeast with 14C-acetic acid, which is coupled with thin layer chromatography for the separation of neutral lipids.

Analysis of Neutral Lipid Synthesis in Saccharomyces cerevisiae by Metabolic Labeling and Thin Layer Chromatography

Neutral lipids (NLs) are a class of hydrophobic, chargeless biomolecules that play key roles in energy and lipid homeostasis. NLs are synthesized de ...

analysis-neutral-lipid-synthesis-saccharomyces-cerevisiae-metabolic

Research

JoVE Journal

Biochemistry

3.0K Views.  University of Texas Southwestern Medical Center. Here, a protocol is presented for the metabolic labeling of yeast with 14C-acetic acid, which is coupled with thin layer chromatography for the separation of neutral lipids.

Video: Analysis of Neutral Lipid Synthesis in Saccharomyces cerevisiae by Metabolic Labeling and Thin Layer Chromatography

Deep Proteome Profiling by Isobaric Labeling, Extensive Liquid Chromatography, Mass Spectrometry, and Software-assisted Quantification

Many exceptional advances have been made in mass spectrometry (MS)-based proteomics, with particular technical progress in liquid chromatography (LC) coupled to tandem mass spectrometry (LC-MS/MS) and isobaric labeling multiplexing capacity. Here, we introduce a deep-proteomics profiling protocol that combines 10-plex tandem mass tag (TMT) labeling with an extensive LC/LC-MS/MS platform, and post-MS computational interference correction to accurately quantitate whole proteomes. This protocol includes the following main steps: protein extraction and digestion, TMT labeling, 2-dimensional (2D) LC, high-resolution mass spectrometry, and computational data processing. Quality control steps are included for troubleshooting and evaluating experimental variation. More than 10,000 proteins in mammalian samples can be confidently quantitated with this protocol. This protocol can also be applied to the quantitation of post translational modifications with minor changes. This multiplexed, robust method provides a powerful tool for proteomic analysis in a variety of complex samples, including cell culture, animal tissues, and human clinical specimens.

We present a protocol to accurately quantitate proteins with isobaric labelling, extensive fractionation, bioinformatics tools, and quality control steps in combination with liquid chromatography interfaced to a high-resolution mass spectrometer.

Many exceptional advances have been made in mass spectrometry (MS)-based proteomics, with particular technical progress in liquid chromatography (LC) ...

Analysis of Protein Folding, Transport, and Degradation in Living Cells by Radioactive Pulse Chase

Radioactive pulse-chase labeling is a powerful tool for studying the conformational maturation, the transport to their functional cellular location, and the degradation of target proteins in live cells. By using short (pulse) radiolabeling times (&lt;30 min) and tightly controlled chase times, it is possible to label only a small fraction of the total protein pool and follow its folding. When combined with nonreducing/reducing SDS-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoprecipitation with (conformation-specific) antibodies, folding processes can be examined in great detail. This system has been used to analyze the folding of proteins with a huge variation in properties such as soluble proteins, single and multi-pass transmembrane proteins, heavily N- and O-glycosylated proteins, and proteins with and without extensive disulfide bonding. Pulse-chase methods are the basis of kinetic studies into a range of additional features, including co- and posttranslational modifications, oligomerization, and polymerization, essentially allowing the analysis of a protein from birth to death. Pulse-chase studies on protein folding are complementary with other biochemical and biophysical methods for studying proteins in vitro by providing increased temporal resolution and physiological information. The methods as described within this paper are adapted easily to study the folding of almost any protein that can be expressed in mammalian or insect-cell systems.

Here we describe a protocol for a general pulse-chase method that allows the kinetic analysis of folding, transport, and degradation of proteins to be followed in live cells.

Radioactive pulse-chase labeling is a powerful tool for studying the conformational maturation, the transport to their functional cellular location, and ...

Absolute Quantification of Cell-Free Protein Synthesis Metabolism by Reversed-Phase Liquid Chromatography-Mass Spectrometry

Cell-free protein synthesis (CFPS) is an emerging technology in systems and synthetic biology for the in vitro production of proteins. However, if CFPS is going to move beyond the laboratory and become a widespread and standard just in time manufacturing technology, we must understand the performance limits of these systems. Toward this question, we developed a robust protocol to quantify 40 compounds involved in glycolysis, the pentose phosphate pathway, the tricarboxylic acid cycle, energy metabolism and cofactor regeneration in CFPS reactions. The method uses internal standards tagged with 13C-aniline, while compounds in the sample are derivatized with 12C-aniline. The internal standards and sample were mixed and analyzed by reversed-phase liquid chromatography-mass spectrometry (LC/MS). The co-elution of compounds eliminated ion suppression, allowing the accurate quantification of metabolite concentrations over 2-3 orders of magnitude where the average correlation coefficient was 0.988. Five of the forty compounds were untagged with aniline, however, they were still detected in the CFPS sample and quantified with a standard curve method. The chromatographic run takes approximately 10 min to complete. Taken together, we developed a fast, robust method to separate and accurately quantify 40 compounds involved in CFPS in a single LC/MS run. The method is a comprehensive and accurate approach to characterize cell-free metabolism, so that ultimately, we can understand and improve the yield, productivity and energy efficiency of cell-free systems.

Here, we present a robust protocol to quantify 40 compounds involved in central carbon and energy metabolism in cell-free protein synthesis reactions. The cell-free synthesis mixture is derivatized with aniline for effective separation using reversed-phase liquid chromatography and then quantified by mass spectrometry using isotopically labelled internal standards.

Cell-free protein synthesis (CFPS) is an emerging technology in systems and synthetic biology for the in vitro production of proteins. However, if CFPS is ...

Quantitative Analysis of the Cellular Lipidome of Saccharomyces Cerevisiae Using Liquid Chromatography Coupled with Tandem Mass Spectrometry

Lipids are structurally diverse amphipathic molecules that are insoluble in water. Lipids are essential contributors to the organization and function of biological membranes, energy storage and production, cellular signaling, vesicular transport of proteins, organelle biogenesis, and regulated cell death. Because the budding yeast Saccharomyces cerevisiae is a unicellular eukaryote amenable to thorough molecular analyses, its use as a model organism helped uncover mechanisms linking lipid metabolism and intracellular transport to complex biological processes within eukaryotic cells. The availability of a versatile analytical method for the robust, sensitive, and accurate quantitative assessment of major classes of lipids within a yeast cell is crucial for getting deep insights into these mechanisms. Here we present a protocol to use liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) for the quantitative analysis of major cellular lipids of S. cerevisiae. The LC-MS/MS method described is versatile and robust. It enables the identification and quantification of numerous species (including different isobaric or isomeric forms) within each of the 10 lipid classes. This method is sensitive and allows identification and quantitation of some lipid species at concentrations as low as 0.2 pmol/&#181;L. The method has been successfully applied to assessing lipidomes of whole yeast cells and their purified organelles. The use of alternative mobile phase additives for electrospray ionization mass spectrometry in this method can increase the efficiency of ionization for some lipid species and can be therefore used to improve their identification and quantitation.

Quantitative Analysis of the Cellular Lipidome of Saccharomyces Cerevisiae Using Liquid Chromatography Coupled with Tandem Mass Spectrometry

We present a protocol using liquid chromatography coupled with tandem mass spectrometry to identify and quantify major cellular lipids in Saccharomyces cerevisiae. The described method for a quantitative assessment of major lipid classes within a yeast cell is versatile, robust, and sensitive.

Lipids are structurally diverse amphipathic molecules that are insoluble in water. Lipids are essential contributors to the organization and function of ...

Untargeted Liquid Chromatography-Mass Spectrometry-Based Metabolomics Analysis of Wheat Grain

Understanding the interactions between genes, the environment and management in agricultural practice could allow more accurate prediction and management of product yield and quality. Metabolomics data provides a read-out of these interactions at a given moment in time and is informative of an organism&#39;s biochemical status. Further, individual metabolites or panels of metabolites can be used as precise biomarkers for yield and quality prediction and management. The plant metabolome is predicted to contain thousands of small molecules with varied physicochemical properties that provide an opportunity for a biochemical insight into physiological traits and biomarker discovery. To exploit this, a key aim for metabolomics researchers is to capture as much of the physicochemical diversity as possible within a single analysis. Here we present a liquid chromatography-mass spectrometry-based untargeted metabolomics method for the analysis of field-grown wheat grain. The method uses the liquid chromatograph quaternary solvent manager to introduce a third mobile phase and combines a traditional reversed-phase gradient with a lipid-amenable gradient. Grain preparation, metabolite extraction, instrumental analysis and data processing workflows are described in detail. Good mass accuracy and signal reproducibility were observed, and the method yielded approximately 500 biologically relevant features per ionization mode. Further, significantly different metabolite and lipid feature signals between wheat varieties were determined.

A method for the untargeted analysis of wheat grain metabolites and lipids is presented. The protocol includes an acetonitrile metabolite extraction method and reversed phase liquid chromatography-mass spectrometry methodology, with acquisition in positive and negative electrospray ionization modes.

Understanding the interactions between genes, the environment and management in agricultural practice could allow more accurate prediction and management ...

Semi-Quantitative Analysis of Peptidoglycan by Liquid Chromatography Mass Spectrometry and Bioinformatics

Peptidoglycan is an important component of bacterial cell walls and a common cellular target for antimicrobials. Although aspects of peptidoglycan structure are fairly conserved across all bacteria, there is also considerable variation between Gram-positives/negatives and between species. In addition, there are numerous known variations, modifications, or adaptations to the peptidoglycan that can occur within a bacterial species in response to growth phase and/or environmental stimuli. These variations produce a highly dynamic structure that is known to participate in many cellular functions, including growth/division, antibiotic resistance, and host defense avoidance. To understand the variation within peptidoglycan, the overall structure must be broken down into its constitutive parts (known as muropeptides) and assessed for overall cellular composition. Peptidoglycomics uses advanced mass spectrometry combined with high-powered bioinformatic data analysis to examine peptidoglycan composition in fine detail. The following protocol describes the purification of peptidoglycan from bacterial cultures, the acquisition of muropeptide intensity data through a liquid chromatograph&#8212;mass spectrometer, and the differential analysis of peptidoglycan composition using bioinformatics.

This protocol covers a detailed analysis of peptidoglycan composition using liquid chromatography mass spectrometry coupled with advanced feature extraction and bioinformatic analysis software.

Peptidoglycan is an important component of bacterial cell walls and a common cellular target for antimicrobials. Although aspects of peptidoglycan ...

Utilization of Grafix for the Detection of Transient Interactors of Saccharomyces cerevisiae Spliceosome Subcomplexes

Pre-mRNA splicing is a very dynamic process that involves many molecular rearrangements of the spliceosome subcomplexes during assembly, RNA processing, and release of the complex components. Glycerol gradient centrifugation has been used for the separation of protein or RNP (RiboNucleoProtein) complexes for functional and structural studies. Here, we describe the utilization of Grafix (Gradient Fixation), which was first developed to purify and stabilize macromolecular complexes for single particle cryo-electron microscopy, to identify interactions between splicing factors that bind transiently to the spliceosome complex. This method is based on the centrifugation of samples into an increasing concentration of a fixation reagent to stabilize complexes. After centrifugation of yeast total extracts loaded on glycerol gradients, recovered fractions are analyzed by dot blot for the identification of the spliceosome sub-complexes and determination of the presence of individual splicing factors.

Utilization of Grafix for the Detection of Transient Interactors of Saccharomyces cerevisiae Spliceosome Subcomplexes

Here, we describe the utilization of Grafix (Gradient Fixation), a glycerol gradient centrifugation in the presence of a crosslinker, to identify interactions between splicing factors that bind transiently to the spliceosome complex.

Pre-mRNA splicing is a very dynamic process that involves many molecular rearrangements of the spliceosome subcomplexes during assembly, RNA processing, ...

Labelling and Visualization of Mitochondrial Genome Expression Products in Baker's Yeast Saccharomyces cerevisiae

Mitochondria are essential organelles of eukaryotic cells capable of aerobic respiration. They contain circular genome and gene expression apparatus. A mitochondrial genome of baker&#8217;s yeast encodes eight proteins: three subunits of the cytochrome c oxidase (Cox1p, Cox2p, and Cox3p), three subunits of the ATP synthase (Atp6p, Atp8p, and Atp9p), a subunit of the ubiquinol-cytochrome c oxidoreductase enzyme, cytochrome b (Cytb), and mitochondrial ribosomal protein Var1p. The purpose of the method described here is to specifically label these proteins with 35S methionine, separate them by electrophoresis and visualize the signals as discrete bands on the screen. The procedure involves several steps. First, yeast cells are cultured in a galactose-containing medium until they reach the late logarithmic growth stage. Next, cycloheximide treatment blocks cytoplasmic translation and allows 35S methionine incorporation only in mitochondrial translation products. Then, all proteins are extracted from yeast cells and separated by polyacrylamide gel electrophoresis. Finally, the gel is dried and incubated with the storage phosphor screen. The screen is scanned on a phosphorimager revealing the bands. The method can be applied to compare the biosynthesis rate of a single polypeptide in the mitochondria of a mutant yeast strain versus the wild type, which is useful for studying mitochondrial gene expression defects. This protocol gives valuable information about the translation rate of all yeast mitochondrial mRNAs. However, it requires several controls and additional experiments to make proper conclusions.

Labelling and Visualization of Mitochondrial Genome Expression Products in Baker's Yeast Saccharomyces cerevisiae

Baker&#8217;s yeast mitochondrial genome encodes eight polypeptides. The goal of the current protocol is to label all of them and subsequently visualize them as separate bands.

Mitochondria are essential organelles of eukaryotic cells capable of aerobic respiration. They contain circular genome and gene expression apparatus. A ...

Quantitative Metabolomics of Saccharomyces Cerevisiae Using Liquid Chromatography Coupled with Tandem Mass Spectrometry

Metabolomics is a methodology used for the identification and quantification of many low-molecular-weight intermediates and products of metabolism within a cell, tissue, organ, biological fluid, or organism. Metabolomics traditionally focuses on water-soluble metabolites. The water-soluble metabolome is the final product of a complex cellular network that integrates various genomic, epigenomic, transcriptomic, proteomic, and environmental factors. Hence, the metabolomic analysis directly assesses the outcome of the action for all these factors in a plethora of biological processes within various organisms. One of these organisms is the budding yeast Saccharomyces cerevisiae, a unicellular eukaryote with the fully sequenced genome. Because S. cerevisiae is amenable to comprehensive molecular analyses, it is used as a model for dissecting mechanisms underlying many biological processes within the eukaryotic cell. A versatile analytical method for the robust, sensitive, and accurate quantitative assessment of the water-soluble metabolome would provide the essential methodology for dissecting these mechanisms. Here we present a protocol for the optimized conditions of metabolic activity quenching in and water-soluble metabolite extraction from S. cerevisiae cells. The protocol also describes the use of liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) for the quantitative analysis of the extracted water-soluble metabolites. The LC-MS/MS method of non-targeted metabolomics described here is versatile and robust. It enables the identification and quantification of more than 370 water-soluble metabolites with diverse structural, physical, and chemical properties, including different structural isomers and stereoisomeric forms of these metabolites. These metabolites include various energy carrier molecules, nucleotides, amino acids, monosaccharides, intermediates of glycolysis, and tricarboxylic cycle intermediates. The LC-MS/MS method of non-targeted metabolomics is sensitive and allows the identification and quantitation of some water-soluble metabolites at concentrations as low as 0.05 pmol/&#181;L. The method has been successfully used for assessing water-soluble metabolomes of wild-type and mutant yeast cells cultured under different conditions.

Quantitative Metabolomics of Saccharomyces Cerevisiae Using Liquid Chromatography Coupled with Tandem Mass Spectrometry

We present a protocol for the identification and quantitation of major classes of water-soluble metabolites in the yeast Saccharomyces cerevisiae. The described method is versatile, robust, and sensitive. It allows the separation of structural isomers and stereoisomeric forms of water-soluble metabolites from each other.

Metabolomics is a methodology used for the identification and quantification of many low-molecular-weight intermediates and products of metabolism within ...

Preparation and Cryo-FIB micromachining of Saccharomyces cerevisiae for Cryo-Electron Tomography

Today, cryo-electron tomography (cryo-ET) is the only technique that can provide near-atomic resolution structural data on macromolecular complexes in situ. Owing to the strong interaction of an electron with the matter, high-resolution cryo-ET studies are limited to specimens with a thickness of less than 200 nm, which restricts the applicability of cryo-ET only to the peripheral regions of a cell. A complex workflow that comprises the preparation of thin cellular cross-sections by cryo-focused ion beam micromachining (cryo-FIBM) was introduced during the last decade to enable the acquisition of cryo-ET data from the interior of larger cells. We present a protocol for the preparation of cellular lamellae from a sample vitrified by plunge freezing utilizing Saccharomyces cerevisiae as a prototypical example of a eukaryotic cell with wide utilization in cellular and molecular biology research. We describe protocols for vitrification of S. cerevisiae into isolated patches of a few cells or a continuous monolayer of the cells on a TEM grid and provide a protocol for lamella preparation by cryo-FIB for these two samples.

Preparation and Cryo-FIB micromachining of Saccharomyces cerevisiae for Cryo-Electron Tomography

We present a protocol for lamella preparation of plunge frozen biological specimens by cryo-focused ion beam micromachining for high-resolution structural studies of macromolecules in situ with cryo-electron tomography. The presented protocol provides guidelines for the preparation of high-quality lamellae with high reproducibility for structural characterization of macromolecules inside the&#160;Saccharomyces cerevisiae.

Today, cryo-electron tomography (cryo-ET) is the only technique that can provide near-atomic resolution structural data on macromolecular complexes in ...

Analysis of Neutral Lipid Synthesis in Saccharomyces cerevisiae by Metabolic Labeling and Thin Layer Chromatography

Summary

Explore More Videos

Chapters in this video

Deep Proteome Profiling by Isobaric Labeling, Extensive Liquid Chromatography, Mass Spectrometry, and Software-assisted Quantification

Analysis of Protein Folding, Transport, and Degradation in Living Cells by Radioactive Pulse Chase

Absolute Quantification of Cell-Free Protein Synthesis Metabolism by Reversed-Phase Liquid Chromatography-Mass Spectrometry

Quantitative Analysis of the Cellular Lipidome of Saccharomyces Cerevisiae Using Liquid Chromatography Coupled with Tandem Mass Spectrometry

Untargeted Liquid Chromatography-Mass Spectrometry-Based Metabolomics Analysis of Wheat Grain

Semi-Quantitative Analysis of Peptidoglycan by Liquid Chromatography Mass Spectrometry and Bioinformatics

Utilization of Grafix for the Detection of Transient Interactors of Saccharomyces cerevisiae Spliceosome Subcomplexes

Labelling and Visualization of Mitochondrial Genome Expression Products in Baker's Yeast Saccharomyces cerevisiae

Quantitative Metabolomics of Saccharomyces Cerevisiae Using Liquid Chromatography Coupled with Tandem Mass Spectrometry

Preparation and Cryo-FIB micromachining of Saccharomyces cerevisiae for Cryo-Electron Tomography