This study was supported by the Ministry of Science and Technology, Taiwan (MOST 108-2320-B-110-007-MY3).

The present protocol is described using lovastatin as an example.&#160;Lovastatin was extracted from one-week-old Aspergillus terreus.
1. Compound extraction
NOTE: For details on compound extraction, please see Figure 1.
<ol>
	<li>Culture Aspergillus terreus on the potato dextrose agar (PDA, see Table of Materials) medium at 30 &#176;C.</li>
	<li>Dry the culture at 40 &#176;C for 24 h. Transfer the dried culture into a 50 mL tube using sterilized tweezers and add 15 mL ethyl acetate.</li>
	<li>Shake the mixture vigorously by vortexing for 1 min and incubate for 1 h at 40 &#176;C with shaking at 200 rpm.</li>
	<li>Sonicate the mixture using a 40 kHz ultrasonic bath (see Table of Materials) at 40 &#176;C for 1 h.</li>
	<li>Centrifuge the mixture at 5,000 x g for 1 min at room temperature and filter through an 11 &#181;m filter paper.</li>
	<li>Extract the filtrate with an equal volume of sterile water in a separatory funnel.</li>
	<li>After phase separation, collect the organic layer, and then evaporate in a rotary evaporator (see Table of Materials). Dissolve the residue in 2 mL of ethyl acetate.</li>
</ol>
2. Separation of the crude extract by normal phase (NP) adsorption column
<ol>
	<li>Pack the column with NP silica gel as the stationary phase, and use n-hexane:ethyl acetate:trifluoroacetic acid (H:E:T; 80:20:0.1, v/v/v) as the mobile phase.</li>
	<li>Load 2 mL of the extract (step 1) onto the column and add the mobile phase solvent at a flow rate of 1 mL/min to elute the extract. 
	NOTE: The flow rate was manually controlled using a stopcock.</li>
	<li>Verify the effluent by TLC to confirm the presence of lovastatin, and then evaporate in a rotary evaporator at 45 &#176;C until the solvent gets removed. This step takes approximately 20-25 min.</li>
	<li>Dissolve the residue in 1 mL of ethyl acetate, and then mix with an equal volume of 1% trifluoroacetic acid.</li>
	<li>Centrifuge the mixture at 5,000 x g for 1 min at room temperature and collect the organic layer in a new glass tube.</li>
</ol>
3. Preparation and loading of thin-layer chromatogram (TLC) plates
<ol>
	<li>Spot 5 &#181;L of samples and lovastatin standards (see Table of Materials) onto the baseline of the TLC plate using a capillary pipette, leaving a border of 1 cm on the sides of the TLC plate.</li>
	<li>Dry the TLC plate in a fume hood for 5 min at room temperature.</li>
	<li>Place the plate gently by forceps in a saturated glass chamber containing the mobile phase solvent. Cover the chamber with a glass lid and allow the plate to develop fully.</li>
	<li>Remove the plate from the chamber when the solvent line reaches 1 cm from the top of the plate.</li>
</ol>
4. Analysis by the blue-LED illuminator
<ol>
	<li>Mark the solvent line with a pencil. Dry the plate in the fume hood for 10 min at room temperature.</li>
	<li>After drying, immediately soak the plate in 10% H2SO4 solvent, and then dry in the fume hood for 10 min at room temperature.</li>
	<li>Place the plate on the heating panel until the brown spots appear. Ensure that the plate is not overheated, as this might make visualization of lovastatin difficult.</li>
	<li>Transfer the plate to the blue-LED illuminator and scan using a compatible freeware (MiBio Fluo) (see Table of Materials).</li>
</ol>
5. Yield estimation by the regression model
<ol>
	<li>Measure the dimension of bands using the ImageJ software (see Table of Materials).</li>
	<li>Establish a regression model using data analysis and graphing software (see Table of Materials) based on the descending concentrations of lovastatin standards, including 1 mg/mL, 0.75 mg/mL, 0.5 mg/mL, and 0.25 mg/mL.</li>
	<li>Apply the regression model to estimate the yield of the samples.</li>
</ol>

<ol>
	<li>Pyka, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Detection+progress+of+selected+drugs+in+TLC.">Detection progress of selected drugs in TLC.</a> BioMed Research International. 2014, 732078 (2014).</li><li>Hess, A. V. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Digitally+enhanced+thin-layer+chromatography:+An+inexpensive,+new+technique+for+qualitative+and+quantitative+analysis.">Digitally enhanced thin-layer chromatography: An inexpensive, new technique for qualitative and quantitative analysis.</a> Journal of Chemical Education. 84 (5), 842-847 (2007).</li><li>Ullah, Q., Mohammad, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Vitamins+determination+by+TLC/HPTLC-a+mini-review.">Vitamins determination by TLC/HPTLC-a mini-review.</a> Journal of Planar Chromatography - Modern TLC. 33 (5), 429-437 (2020).</li><li>Chen, Z., Tao, H., Liao, L., Zhang, Z., Wang, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quick+identification+of+xanthine+oxidase+inhibitor+and+antioxidant+from+Erycibe+obtusifolia+by+a+drug+discovery+platform+composed+of+multiple+mass+spectrometric+platforms+and+thin-layer+chromatography+bioautography.">Quick identification of xanthine oxidase inhibitor and antioxidant from Erycibe obtusifolia by a drug discovery platform composed of multiple mass spectrometric platforms and thin-layer chromatography bioautography.</a> Journal of Separation Science. 37 (16), 2253-2259 (2014).</li><li>Duncan, J. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chiral+separations:+A+comparison+of+HPLC+and+TLC.">Chiral separations: A comparison of HPLC and TLC.</a> Journal of Liquid Chromatography. 13 (14), 2737-2755 (1990).</li><li>Sherma, J. <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+chromatography+in+food+and+agricultural+analysis.">Thin-layer chromatography in food and agricultural analysis.</a> Journal of Chromatography A. 880 (1-2), 129-147 (2000).</li><li>Boche&#324;ska, P., Pyka, A., Boche&#324;ska, P., Boche&#324;ska, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Determination+of+acetylsalicylic+acid+in+pharmaceutical+drugs+by+TLC+with+densitometric+detection+in+UV.">Determination of acetylsalicylic acid in pharmaceutical drugs by TLC with densitometric detection in UV.</a> Journal of Liquid Chromatography. 35 (10), 1346-1363 (2012).</li><li>Poole, C. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Planar+chromatography+at+the+turn+of+the+century.">Planar chromatography at the turn of the century.</a> Journal of Chromatography A. 856 (1-2), 399-427 (1999).</li><li>Rapid Johnson, M. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=simple+quantitation+in+thin-layer+chromatography+using+a+flatbed+scanner.">simple quantitation in thin-layer chromatography using a flatbed scanner.</a> Journal of Chemical Education. 77 (3), 368-372 (2000).</li><li>El-Gindy, A., Ashour, A., Abdel-Fattah, L., Shabana, M. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=First+derivative+spectrophotometric,+TLC-densitometric,+and+HPLC+determination+of+acebutolol+HCL+in+presence+of+its+acid-induced+degradation+product.">First derivative spectrophotometric, TLC-densitometric, and HPLC determination of acebutolol HCL in presence of its acid-induced degradation product.</a> Journal of Pharmaceutical and Biomedical Analysis. 24 (4), 527-534 (2001).</li><li>Elkady, E. F., Mahrouse, M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reversed-phase+ion-pair+HPLC+and+TLC-densitometric+methods+for+the+simultaneous+determination+of+ciprofloxacin+hydrochloride+and+metronidazole+in+tablets.">Reversed-phase ion-pair HPLC and TLC-densitometric methods for the simultaneous determination of ciprofloxacin hydrochloride and metronidazole in tablets.</a> Chromatographia. 73 (3-4), 297-305 (2011).</li><li>Musharraf, S. G., Ul Arfeen, ., Shoaib, Q., M, <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+and+validation+of+TLC-densitometric+method+for+the+quantification+of+a+steroidal+drug,+danazol+in+its+pharmaceutical+formulations.">Development and validation of TLC-densitometric method for the quantification of a steroidal drug, danazol in its pharmaceutical formulations.</a> Journal of Planar Chromatography - Modern TLC. 25 (4), 331-337 (2012).</li></ol>

All the authors declare that they have no conflicts of interest.

The present study described a new approach, the blue-LED illuminator, to quantify compounds without using expensive and specialized equipment, such as HPTLC, HPLC, and GC method, and the method was compared with the bioassay and UV-detected methods to evaluate quantification performance. As a result, it was concluded that the blue-LED illumination method is a relatively safe and effective protocol used to quantify the yield of targeted compounds on the TLC plate.
Previous studies have reported...

Thin-layer chromatography (TLC) is widely used as a qualitative and quantitative technique in the field of organic chemistry1,2,3. The main advantages of TLC are that it provides fast detection, flexible sample requirements, and does not require specialized equipment4. To date, even though many advanced approaches have been established, TLC is still the main method for identifying unknown samples in a mixture. However, the challenge of this approach is the lack of safe and inexpensive equipment for quantifying the sample yield, especially for developing laboratories with limited budgets. The present study, therefore, aimed to develop an efficient, safe, and inexpensive method combining with TLC to estimate the yield of the samples.
Unlike high-performance TLC (HPTLC), high-performance liquid chromatography (HPLC), and gas chromatography (GC) with strict sample requirements, time-consuming, and involvement of multistep for sample preparation1,5, TLC showed several advantages. First, for sample preparation, the HPLC and GC cannot detect the crude extract because the crude extract may plug the column of HPLC and GC. Second, when the samples are not UV-suitable (important for HPLC analysis) or with low volatility (important for GC analysis), TLC can be applied to these samples, and the use of visualization reagent makes the isolated samples visible on thin layers6,7,8. Third, for general users, HPLC and GC generally require a relatively long time pre-training before working independently, compared to TLC. In addition, quantitative TLC analysis, known as high-performance TLC (HPTLC), can digitize the information on a TLC plate with a highly sensitive scanner. However, the cost of the HPTLC system is relatively expensive. As such, developing a cost-effective and fast approach to quantify samples on the TLC plate is an important topic.
Similar methods have been developed for TLC yield quantification; for example, Johnson9 reported a technique that allows the quantification of the samples on a TLC plate by using a flatbed scanner attached to a computer. In 2001, El-Gindy et al.10 developed the TLC- densitometric method, which was used to detect the compound with optical density, and the technique was also applied by Elkady et al.11. In 2007, Hess2 presented the digitally enhanced-TLC (DE-TLC) method applied to detect the yield of a compound on a TLC plate using a digital camera combined with UV light. Hess also compared the cost differences between HPTLC and DE-TLC method and concluded that the DE-TLC method could be used in high school and college labs because of its affordable cost2. However, the cost of the TLC-densitometric method was still expensive, and the operation of ultraviolet light requires adequate pre-training in case the users might get exposed to ultraviolet radiation. Therefore, compatible with TLC, developing an efficient, safe, and inexpensive method to quantify the sample yield is desirable.
The present study described a protocol for detecting the sample on a TLC plate using the blue-LED illuminator, and developed a regression model with high reliability (high R-square value) to measure the dimensions of the bands, and then determine the compound yield. Finally, it was found that the blue-LED illumination method is a relatively safe (vs. UV-detection method), cheap (vs. GC, HPLC, and HPTLC), and effective (vs. bioassay method) approach for yield quantification.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>American bacteriological Agar</td>
			<td>Condalab</td>
			<td>1802.00</td>
			<td></td>
		</tr>
		<tr>
			<td>Aspergillus terreus&#160;</td>
			<td></td>
			<td>ATCC 20542</td>
			<td></td>
		</tr>
		<tr>
			<td>Blue-LED illuminator</td>
			<td>MICROTEK</td>
			<td>Bio-1000F</td>
			<td></td>
		</tr>
		<tr>
			<td>Centrifuge</td>
			<td>Thermo Scientific&#160;</td>
			<td>HERAEUS Megafuge 8</td>
			<td></td>
		</tr>
		<tr>
			<td>Compact UV lamp</td>
			<td>UVP</td>
			<td>UVGL-25</td>
			<td></td>
		</tr>
		<tr>
			<td>Ethyl Acetate</td>
			<td>MACRON</td>
			<td>MA-H078-10</td>
			<td></td>
		</tr>
		<tr>
			<td>Filter Paper 125mm</td>
			<td>ADVANTEC</td>
			<td>60311102</td>
			<td></td>
		</tr>
		<tr>
			<td>ImageJ</td>
			<td>NIH</td>
			<td>Freeware</td>
			<td>https://imagej.nih.gov/ij/download.html</td>
		</tr>
		<tr>
			<td>Lovastatin standard</td>
			<td>ACROS</td>
			<td>A0404262</td>
			<td></td>
		</tr>
		<tr>
			<td>MiBio Fluo&#160;</td>
			<td>MICROTEK</td>
			<td>V1.04</td>
			<td></td>
		</tr>
		<tr>
			<td>n-Hexane</td>
			<td>C-ECHO</td>
			<td>HH3102-000000-72EC</td>
			<td></td>
		</tr>
		<tr>
			<td>OriginPro</td>
			<td>OriginLab</td>
			<td>9.1</td>
			<td>https://www.originlab.com/origin</td>
		</tr>
		<tr>
			<td>Potato dextrose broth H</td>
			<td>STBIO MEDIA</td>
			<td>110533</td>
			<td></td>
		</tr>
		<tr>
			<td>Rotary evaporator</td>
			<td>EYELA</td>
			<td>SB-1000</td>
			<td></td>
		</tr>
		<tr>
			<td>Sulfuric acid</td>
			<td>Fluka</td>
			<td>30743-2.5L-GL</td>
			<td></td>
		</tr>
		<tr>
			<td>TLC silica gel 60 F254</td>
			<td>MERCK</td>
			<td>1.05554.0001</td>
			<td></td>
		</tr>
		<tr>
			<td>Trifluoroacetic acid</td>
			<td>Alfa Aesar</td>
			<td>10229873</td>
			<td></td>
		</tr>
		<tr>
			<td>Ultrasonic vibration machine</td>
			<td>DELTA</td>
			<td>DC600</td>
			<td></td>
		</tr>
	</tbody>
</table>

estimating the yield of compounds on the tlc plate via the blue-led illumination technique

Thin-layer chromatography (TLC) is an accessible analytical technique that has been extensively used in organic chemistry research to quantify the yield of unknown samples. The present study developed an effective, cheap, and safe method to estimate the yield of samples on a TLC plate using the blue-LED illuminator. Lovastatin extracted from Aspergillus terreus was the example compound used in the present study. Regression models based on the lovastatin standard were used to evaluate the yield of lovastatin. Three methods were compared: bioassay, UV detection, and blue-LED illumination. The result showed that the blue-LED illumination method is significantly more time-effective than UV detection and bioassay methods. Additionally, the blue-LED illumination was a relatively safe option because of the concern of biological hazards in the bioassay method (e.g., microbial infection) and ultraviolet exposure in the UV detection method. Compared to the expensive methods requiring specialized instruments and long-term training before working independently, such as GC, HPLC, and HPTLC, using the blue-LED illuminator was an economical option to estimate the yield of samples from a TLC plate.

This study presented the blue-LED illumination method to estimate the yield of compounds, and this method was validated and compared to bioassay and UV-detected methods (Table 1). The regression models were developed based on the dimensions of bands and concentration of standards for three methods, respectively, to predict the yield of samples. First, in the results of the bioassay method, the R-square between the dimensions of the inhibition zone and lovastatin standards was 0.99, and the sample yield w...

Watch this Scientific Journal Video about Estimating the Yield of Compounds on the TLC Plate via the Blue-LED Illumination Technique at JoVE.com

Estimating the Yield of Compounds on the TLC Plate via the Blue-LED Illumination Technique

The present protocol developed a method to estimate the yield of compounds on the TLC plate using the blue-LED illumination technique. The advantages of this approach are that it is safe, effective, inexpensive, and allows the researcher to measure multiple samples simultaneously.

Estimating the Yield of Compounds on the TLC Plate via the Blue-LED Illumination Technique

Thin-layer chromatography (TLC) is an accessible analytical technique that has been extensively used in organic chemistry research to quantify the yield ...

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1.6K Views.  National Sun Yat-sen University. The present protocol developed a method to estimate the yield of compounds on the TLC plate using the blue-LED illumination technique. The advantages of this approach are that it is safe, effective, inexpensive, and allows the researcher to measure multiple samples simultaneously.

Video: Estimating the Yield of Compounds on the TLC Plate via the Blue-LED Illumination Technique

Intraperitoneal Injection into Adult Zebrafish

A convenient method for chemically treating zebrafish is to introduce the reagent into the tank water, where it will be taken up by the fish. However, this method makes it difficult to know how much reagent is absorbed or taken up per fish. Some experimental questions, particularly those related to metabolic studies, may be better addressed by delivering a defined quantity to each fish, based on weight. Here we present a method for intraperitoneal (IP) injection into adult zebrafish. Injection is into the abdominal cavity, posterior to the pelvic girdle. This procedure is adapted from veterinary methods used for larger fish. It is safe, as we have observed zero mortality. Additionally, we have seen bleeding at the injection site in only 5 out of 127 injections, and in each of those cases the bleeding was brief, lasting several seconds, and the quantity of blood lost was small. Success with this procedure requires gentle handling of the fish through several steps including fasting, weighing, anesthetizing, injection, and recovery. Precautions are required to minimize stress throughout the procedure. Our precautions include using a small injection volume and a 35G needle. We use Cortland salt solution as the vehicle, which is osmotically balanced for freshwater fish. Aeration of the gills is maintained during the injection procedure by first bringing the fish into a surgical plane of anesthesia, which allows slow operculum movements, and second, by holding the fish in a trough within a water-saturated sponge during the injection itself. We demonstrate the utility of IP injection by injecting glucose and monitoring the rise in blood glucose level and its subsequent return to normal. As stress is known to increase blood glucose in teleost fish, we compare blood glucose levels in vehicle-injected and non-injected adults and show that the procedure does not cause a significant rise in blood glucose.

We demonstrate intraperitoneal injection into adult zebrafish. We use a 10 &mu;l NanoFil microsyringe controlled by a Micro4 controller and UltraMicroPump III. This demonstration includes the use of cold water as an anesthetic.

A convenient method for chemically treating zebrafish is to introduce the reagent into the tank water, where it will be taken up by the fish. However, ...

Analyzing the Function of Small GTPases by Microinjection of Plasmids into Polarized Epithelial Cells

Epithelial cells polarize their plasma membrane into biochemically and functionally distinct apical and basolateral domains where the apical domain faces the 'free' surfaces and the basolateral membrane is in contact with the substrate and neighboring cells. Both membrane domains are separated by tight junctions, which form a diffusion barrier. Apical-basolateral polarization can be recapitulated successfully in culture when epithelial cells such as Madin-Darby Canine Kidney (MDCK) cells are seeded at high density on polycarbonate filters and cultured for several days 1 2. Establishment and maintenance of cell polarity is regulated by an array of small GTPases of the Ras superfamily such as RalA, Cdc42, Rab8, Rab10 and Rab13 3 4 5 6 7. Like all GTPases these proteins cycle between an inactive GDP-bound state and an active GTP-bound state. Specific mutations in the nucleotide binding regions interfere with this cycling 8. For example, Rab13T22N is permanently locked in the GDP-form and thus dubbed 'dominant negative', whereas Rab13Q67L can no longer hydrolyze GTP and is thus locked in a 'dominant active' state 7. To analyze their function in cells both dominant negative and dominant active alleles of GTPases are typically expressed at high levels to interfere with the function of the endogenous proteins 9. An elegant way to achieve high levels of overexpression in a short amount of time is to introduce the plasmids encoding the relevant proteins directly into the nuclei of polarized cells grown on filter supports using microinjection technique. This is often combined with the co-injection of reporter plasmids that encode plasma membrane receptors that are specifically sorted to the apical or basolateral domain. A cargo frequently used to analyze cargo sorting to the basolateral domain is a temperature sensitive allele of the vesicular stomatitis virus glycoprotein (VSVGts045) 10. This protein cannot fold properly at 39&deg;C and will thus be retained in the endoplasmic reticulum (ER) while the regulatory protein of interest is assembled in the cytosol. A shift to 31&deg;C will then allow VSVGts045 to fold properly, leave the ER and travel to the plasma membrane 11. This chase is typically performed in the presence of cycloheximide to prevent further protein synthesis leading to cleaner results. Here we describe in detail the procedure of microinjecting plasmids into polarized cells and subsequent incubations including temperature shifts that allow a comprehensive analysis of regulatory proteins involved in basolateral sorting.

This article details the procedures involved in overexpression and analysis of small GTPases in polarized epithelial cells using microinjection technique.

Epithelial cells polarize their plasma membrane into biochemically and functionally distinct apical and basolateral domains where the apical domain faces ...

Super-resolution Imaging of the Cytokinetic Z Ring in Live Bacteria Using Fast 3D-Structured Illumination Microscopy (f3D-SIM)

Imaging of biological samples using fluorescence microscopy has advanced substantially with new technologies to overcome the resolution barrier of the diffraction of light allowing super-resolution of live samples. There are currently three main types of super-resolution techniques &#8211; stimulated emission depletion (STED), single-molecule localization microscopy (including techniques such as PALM, STORM, and GDSIM), and structured illumination microscopy (SIM). While STED and single-molecule localization techniques show the largest increases in resolution, they have been slower to offer increased speeds of image acquisition. Three-dimensional SIM (3D-SIM) is a wide-field fluorescence microscopy technique that offers a number of advantages over both single-molecule localization and STED. Resolution is improved, with typical lateral and axial resolutions of 110 and 280 nm, respectively and depth of sampling of up to 30 &#181;m from the coverslip, allowing for imaging of whole cells. Recent advancements (fast 3D-SIM) in the technology increasing the capture rate of raw images allows for fast capture of biological processes occurring in seconds, while significantly reducing photo-toxicity and photobleaching. Here we describe the use of one such method to image bacterial cells harboring the fluorescently-labelled cytokinetic FtsZ protein to show how cells are analyzed and the type of unique information that this technique can provide.

Super-resolution Imaging of the Cytokinetic Z Ring in Live Bacteria Using Fast 3D-Structured Illumination Microscopy f3D-SIM

Spatiotemporal information about dynamic proteins inside live cells is crucial for understanding biology. A type of super-resolution microscopy called fast 3D-structured illumination microscopy (f3D-SIM) reveals unique information about the cytokinetic Z ring in bacteria: both its bead-like appearance and the rapid dynamics of FtsZ within the ring.

Imaging of biological samples using fluorescence microscopy has advanced substantially with new technologies to overcome the resolution barrier of the ...

Method for the Assessment of Effects of a Range of Wavelengths and Intensities of Red/near-infrared Light Therapy on Oxidative Stress In Vitro

Red/near-infrared light therapy (R/NIR-LT), delivered by laser or light emitting diode (LED), improves functional and morphological outcomes in a range of central nervous system injuries in vivo, possibly by reducing oxidative stress. However, effects of R/NIR-LT on oxidative stress have been shown to vary depending on wavelength or intensity of irradiation. Studies comparing treatment parameters are lacking, due to absence of commercially available devices that deliver multiple wavelengths or intensities, suitable for high through-put in vitro optimization studies. This protocol describes a technique for delivery of light at a range of wavelengths and intensities to optimize therapeutic doses required for a given injury model. We hypothesized that a method of delivering light, in which wavelength and intensity parameters could easily be altered, could facilitate determination of an optimal dose of R/NIR-LT for reducing reactive oxygen species (ROS) in vitro.
Non-coherent Xenon light was filtered through narrow-band interference filters to deliver varying wavelengths (center wavelengths of 440, 550, 670 and 810nm) and fluences (8.5 x 10-3 to 3.8 x 10-1 J/cm2) of light to cultured cells. Light output from the apparatus was calibrated to emit therapeutically relevant, equal quantal doses of light at each wavelength. Reactive species were detected in glutamate stressed cells treated with the light, using DCFH-DA and H2O2 sensitive fluorescent dyes.&#160;
We successfully delivered light at a range of physiologically and therapeutically relevant wavelengths and intensities, to cultured cells exposed to glutamate as a model of CNS injury. While the fluences of R/NIR-LT used in the current study did not exert an effect on ROS generated by the cultured cells, the method of light delivery is applicable to other systems including isolated mitochondria or more physiologically relevant organotypic slice culture models, and could be used to assess effects on a range of outcome measures of oxidative metabolism.

Method for the Assessment of Effects of a Range of Wavelengths and Intensities of Red/near-infrared Light Therapy on Oxidative Stress In Vitro

Non-coherent Xenon light was passed through narrow-band interference and neutral density filters to deliver light of varying wavelength and intensity to cultured cells. This protocol was used to assess the effects of red/near-infrared light therapy on production of reactive species in vitro: no effects were observed using the tested parameters.

Red/near-infrared light therapy (R/NIR-LT), delivered by laser or light emitting diode (LED), improves functional and morphological outcomes in a range of ...

High Yield Expression of Recombinant Human Proteins with the Transient Transfection of HEK293 Cells in Suspension

The art of producing recombinant proteins with complex post-translational modifications represents a major challenge for studies of structure and function. The rapid establishment and high recovery from transiently-transfected mammalian cell lines addresses this barrier and is an effective means of expressing proteins that are naturally channeled through the ER and Golgi-mediated secretory pathway. Here is one protocol for protein expression using the human HEK293F and HEK293S cell lines transfected with a mammalian expression vector designed for high protein yields. The applicability of this system is demonstrated using three representative glycoproteins that expressed with yields between 95-120 mg of purified protein recovered per liter of culture. These proteins are the human Fc&#947;RIIIa and the rat &#945;2-6 sialyltransferase, ST6GalI, both expressed with an N-terminal GFP fusion, as well as the unmodified human immunoglobulin G1 Fc. This robust system utilizes a serum-free medium that is adaptable for expression of isotopically enriched proteins and carbohydrates for structural studies using mass spectrometry and nuclear magnetic resonance spectroscopy. Furthermore, the composition of the N-glycan can be tuned by adding a small molecule to prevent certain glycan modifications in a manner that does not reduce yield.

Laboratory-scale production of eukaryotic proteins with appropriate post-translational modification represents a significant barrier. Here is a robust protocol with rapid establishment and turnaround for protein expression using a mammalian expression system. This system supports selective amino acid, selective labeling of proteins and small molecule modulators of glycan composition.

The art of producing recombinant proteins with complex post-translational modifications represents a major challenge for studies of structure and ...

Gap Junctional Intercellular Communication: A Functional Biomarker to Assess Adverse Effects of Toxicants and Toxins, and Health Benefits of Natural Products

This protocol describes a scalpel loading-fluorescent dye transfer (SL-DT) technique that measures intercellular communication through gap junction channels, which is a major intercellular process by which tissue homeostasis is maintained. Interruption of gap junctional intercellular communication (GJIC) by toxicants, toxins, drugs, etc. has been linked to numerous adverse health effects. Many genetic-based human diseases have been linked to mutations in gap junction genes. The SL-DT technique is a simple functional assay for the simultaneous assessment of GJIC in a large population of cells. The assay involves pre-loading cells with a fluorescent dye by briefly perturbing the cell membrane with a scalpel blade through a population of cells. The fluorescent dye is then allowed to traverse through gap junction channels to neighboring cells for a designated time. The assay is then terminated by the addition of formalin to the cells. The spread of the fluorescent dye through a population of cells is assessed with an epifluorescence microscope and the images are analyzed with any number of morphometric software packages that are available, including free software packages found on the public domain. This assay has also been adapted for in vivo studies using tissue slices from various organs from treated animals. Overall, the SL-DT assay can serve a broad range of in vitro pharmacological and toxicological needs, and can be potentially adapted for high throughput set-up systems with automated fluorescence microscopy imaging and analysis to elucidate more samples in a shorter time.

This protocol describes a scalpel loading-fluorescent dye transfer technique that measures intercellular communication through gap junction channels. Gap junctional intercellular communication is a major cellular process by which tissue homeostasis is maintained and disruption of this cell signaling has adverse health effects.

This protocol describes a scalpel loading-fluorescent dye transfer (SL-DT) technique that measures intercellular communication through gap junction ...

SA-&#946;-Galactosidase-Based Screening Assay for the Identification of Senotherapeutic Drugs

Cell senescence is one of the hallmarks of aging known to negatively influence a healthy lifespan. Drugs able to kill senescent cells specifically in cell culture, termed senolytics, can reduce the senescent cell burden in vivo and extend healthspan. Multiple classes of senolytics have been identified to date including HSP90 inhibitors, Bcl-2 family inhibitors, piperlongumine, a FOXO4 inhibitory peptide and the combination of Dasatinib/Quercetin. Detection of SA-&#946;-Gal at an increased lysosomal pH is one of the best characterized markers for the detection of senescent cells. Live cell measurements of senescence-associated &#946;-galactosidase (SA-&#946;-Gal) activity using the fluorescent substrate C12FDG in combination with the determination of the total cell number using a DNA intercalating Hoechst dye opens the possibility to screen for senotherapeutic drugs that either reduce overall SA-&#946;-Gal activity by killing of senescent cells (senolytics) or by suppressing SA-&#946;-Gal and other phenotypes of senescent cells (senomorphics). Use of a high content fluorescent image acquisition and analysis platform allows for the rapid, high throughput screening of drug libraries for effects on SA-&#946;-Gal, cell morphology and cell number.

SA-&amp;#946;-Galactosidase-Based Screening Assay for the Identification of Senotherapeutic Drugs

Cellular senescence is the key factor in the development of chronic age-related pathologies. Identification of therapeutics that target senescent cells show promise for extending healthy aging. Here, we present a novel assay to screen for the identification of senotherapeutics based on measurement of senescence associated &#946;-Galactosidase activity in single cells.

Cell senescence is one of the hallmarks of aging known to negatively influence a healthy lifespan. Drugs able to kill senescent cells specifically in cell ...

Assessment of Vascular Tone Responsiveness using Isolated Mesenteric Arteries with a Focus on Modulation by Perivascular Adipose Tissues

Altered vascular tone responsiveness to pathophysiological stimuli contributes to the development of a wide range of cardiovascular and metabolic diseases. Endothelial dysfunction represents a major culprit for the reduced vasodilatation and enhanced vasoconstriction of arteries. Adipose (fat) tissues surrounding the arteries play important roles in the regulation of endothelium-dependent relaxation and/or contraction of the vascular smooth muscle cells. The cross-talks between the endothelium and perivascular adipose tissues can be assessed ex vivo using mounted blood vessels by a wire myography system. However, optimal settings should be established for arteries derived from animals of different species, ages, genetic backgrounds and/or pathophysiological conditions.

The protocol describes the use of wire myography to evaluate the transmural isometric tension of mesenteric arteries isolated from mice, with special consideration of the modulation by factors released from endothelial cells and perivascular adipose tissues.

Altered vascular tone responsiveness to pathophysiological stimuli contributes to the development of a wide range of cardiovascular and metabolic ...

Y-27632 Enriches the Yield of Human Melanocytes from Adult Skin Tissues

The isolation and culture of primary melanocytes from skin tissues is very important for biological research and has been widely used for clinical applications. Isolating primary melanocytes from skin tissues by the conventional method usually takes about 3 to 4 weeks to passage sufficiently. More importantly, the tissues used are usually newborn foreskins and it is still a challenge to efficiently isolate primary melanocytes from adult tissues. We recently developed a new isolation method for melanocytes that adds Y-27632, a Rho kinase inhibitor, to the initial culture medium for 48 h. Compared with the conventional protocol, this new method dramatically increases the yield of melanocytes and shortens the time required to isolate melanocytes from foreskin tissues. We now describe this new method in more detail using adult epidermis to efficiently culture primary melanocytes. Importantly, we show that melanocytes obtained from adult tissues prepared by this new method can function normally. This new protocol will significantly benefit studies of pigmentation defects and melanomas using primary melanocytes prepared from easily accessed adult skin tissues.

This paper reports that the addition of Y-27632 to TIVA medium can significantly increase the yield of melanocytes from adult skin tissues.

The isolation and culture of primary melanocytes from skin tissues is very important for biological research and has been widely used for clinical ...

The Use of the Patch-Clamp Technique to Study the Thermogenic Capacity of Mitochondria

Mitochondrial thermogenesis (also known as mitochondrial uncoupling) is one of the most promising targets for increasing energy expenditure to combat metabolic syndrome. Thermogenic tissues such as brown and beige fats develop highly specialized mitochondria for heat production. Mitochondria of other tissues, which primarily produce ATP, also convert up to 25% of the total mitochondrial energy production into heat and can, therefore, have a considerable impact on the physiology of the whole body. Mitochondrial thermogenesis is not only essential for maintaining the body temperature, but also prevents diet-induced obesity and reduces the production of reactive oxygen species (ROS) to protect cells from oxidative damage. Since mitochondrial thermogenesis is a key regulator of cellular metabolism, a mechanistic understanding of this fundamental process will help in the development of therapeutic strategies to combat many pathologies associated with mitochondrial dysfunction. Importantly, the precise molecular mechanisms that control acute activation of thermogenesis in mitochondria are poorly defined. This lack of information is largely due to a dearth of methods for the direct measurement of uncoupling proteins. The recent development of patch-clamp methodology applied to mitochondria enabled, for the first time, the direct study of the phenomenon at the origin of mitochondrial thermogenesis, H+ leak through the IMM, and the first biophysical characterization of mitochondrial transporters responsible for it, the uncoupling protein 1 (UCP1), specific of brown and beige fats, and the ADP/ATP transporter (AAC) for all other tissues. This unique approach will provide new insights into the mechanisms that control H+ leak and mitochondrial thermogenesis and how they can be targeted to combat metabolic syndrome. This paper describes the patch-clamp methodology applied to mitochondria to study their thermogenic capacity by directly measuring H+ currents through the IMM.

This method article details the main steps in measuring H+ leak across the inner mitochondrial membrane with the patch-clamp technique, a new approach to study the thermogenic capacity of mitochondria.

Mitochondrial thermogenesis (also known as mitochondrial uncoupling) is one of the most promising targets for increasing energy expenditure to combat ...