Name: colorimetric analysis of alkaline phosphatase activity in s. aureus biofilm
Uploaded: 2019-04-12T15:00:00
Description: Watch this Scientific Journal Video about Colorimetric Analysis of Alkaline Phosphatase Activity in S. aureus Biofilm at JoVE.com

We thank William Rainey Harper College and the University of Illinois at Chicago for the facility to conduct these experiments. We also thank McGraw Hill Foundation for their generous support.

1. Medium Preparation
<ol>
	<li>Prepare 1 L of Tryptic Soy Broth (TSB): Into 1 L of distilled water, add 15 g of pancreatic digest of casein, 5 g of papaic digest of soybean meal, 3 g of sodium chloride, 2.5 g of dextrose, and 2.5 g of dipotassium phosphate. Sterilize before use.</li>
	<li>For Tryptic Soy Agar (TSA), add 15 g of agar to 1 L of TSB, autoclave. Then let it cool down to room temperature. Next, pour at a ratio of 20 mL per Petri dish (100 mm x 15 mm).</li>
	<li>Biofilm culture medium: Add 10 g of glucose t...

<ol>
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S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High+frequencies+of+elevated+alkaline+phosphatase+activity+and+rickets+exist+in+extremely+low+birth+weight+infants+despite+current+nutritional+support.">High frequencies of elevated alkaline phosphatase activity and rickets exist in extremely low birth weight infants despite current nutritional support.</a> Boston Medical Center Pediatrics. 9, 47 (2009).</li><li>Fawley, J., Gourlay, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intestinal+alkaline+phosphatase:+A+summary+of+its+role+in+clinical+disease.">Intestinal alkaline phosphatase: A summary of its role in clinical disease.</a> Journal of Surgical Research. 202 (1), 225-234 (2016).</li><li>Derman, A. I., Beckwith, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Escherichia+coli+Alkaline+Phosphatase+Localized+to+the+Cytoplasm+Slowly+Acquires+Enzymatic+Activity+in+Cells+Whose+Growth+Has+Been+Suspended:+a+Caution+for+Gene+Fusion+Studies.">Escherichia coli Alkaline Phosphatase Localized to the Cytoplasm Slowly Acquires Enzymatic Activity in Cells Whose Growth Has Been Suspended: a Caution for Gene Fusion Studies.</a> Journal of Bacteriology. 177 (13), 3764-3770 (1995).</li><li>Danikowski, K. 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H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+use+of+bacterial+alkaline+phosphatase+assay+for+rapid+monitoring+of+bacterial+counts+on+spinach.">The use of bacterial alkaline phosphatase assay for rapid monitoring of bacterial counts on spinach.</a> Journal of Food Science. 73 (5), M236-M238 (2008).</li><li>Barber, M., Kuper, S. W. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Identification+of+Staphylococcus+pyogenes+by+the+phosphatase+reaction.">Identification of Staphylococcus pyogenes by the phosphatase reaction.</a> The Journal of Pathology and Bacteriology. 63, 65-68 (1951).</li><li>Wolf, P. L., Von der Muehll, E., Ludwick, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+new+test+to+differentiate+Serratia+from+Enterobacter.">A new test to differentiate Serratia from Enterobacter.</a> American Journal of Clinical Pathology. 56, 241-243 (1972).</li><li>Rangam, C. M., Katdare, S. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phosphatase+activity+of+Staphylococci+as+an+indication+of+their+pathogenicity.">Phosphatase activity of Staphylococci as an indication of their pathogenicity.</a> Indian Journal of Medical Science. 8, 610-613 (1954).</li><li>Flemming, H. -. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Biofilms:+an+emergent+form+of+bacterial+life.">Biofilms: an emergent form of bacterial life.</a> Nature Reviews Microbiology. 14, 563-575 (2016).</li><li>Hoiby, N., Bjarnsholt, T., Givskov, M., Molin, S., Ciofu, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Antibiotic+resistance+of+bacterial+biofilms.">Antibiotic resistance of bacterial biofilms.</a> International Journal of Antimicrobial Agents. 35, 322-332 (2010).</li><li>Ito, A., Taniuchi, A., May, T., Kawata, K., Okabe, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Increased+antibiotic+resistance+of+Escherichia+coli+in+mature+biofilms.">Increased antibiotic resistance of Escherichia coli in mature biofilms.</a> Applied and Environmental Microbiology. 75, 4093-4100 (2009).</li><li>Witherow, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Ten-Week+Biochemistry+Lab+Project+Studying+Wild-Type+and+Mutant+Bacterial+Alkaline+Phosphatase.">A Ten-Week Biochemistry Lab Project Studying Wild-Type and Mutant Bacterial Alkaline Phosphatase.</a> Biochemistry and Molecular Biology Education. 44 (6), (2016).</li><li>Henthorn, P., Zervos, P., Raducha, M., Harris, H., Kadesch, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Expression+of+a+human+placental+alkaline+phosphatase+gene+in+transfected+cells:+Use+as+a+reporter+for+studies+of+gene+expression.">Expression of a human placental alkaline phosphatase gene in transfected cells: Use as a reporter for studies of gene expression.</a> Proceedings of the National Academy of Science USA. 85, 6324-6346 (1988).</li><li>Horney, B. S., Farmer, A. J., Honor, D. J., MacKenzie, A., Burton, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Agarose+gel+electrophoresis+of+alkaline+phosphatase+isoenzymes+in+the+serum+of+hyperthyroid+cats.">Agarose gel electrophoresis of alkaline phosphatase isoenzymes in the serum of hyperthyroid cats.</a> Veterinary Clinical Pathology. 23 (3), 98-102 (1994).</li><li>Farley, J. R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantification+of+Skeletal+Alkaline+Phosphatase+in+Osteoporotic+Serum+by+Wheat+Germ+Agglutinin+Precipitation,+Heat+Inactivation,+and+a+Two-Site+Immunoradiometric+Assay.">Quantification of Skeletal Alkaline Phosphatase in Osteoporotic Serum by Wheat Germ Agglutinin Precipitation, Heat Inactivation, and a Two-Site Immunoradiometric Assay.</a> Clinical Chemistry. 40 (9), 1749-1756 (1994).</li><li>O&#8217;Toole, G. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microtiter+Dish+Biofilm+Formation+Assay.">Microtiter Dish Biofilm Formation Assay.</a> Journal of Visualized Experience. , (2011).</li><li>Nomoto, M., Ohsawa, M., Wang, H. L., Chen, C. C., Yeh, K. 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In our assay, we used pNPP as the ALP substrate. This is a working solution designed for ELISA and no dilution is needed. After hydrolysis by ALP, a yellow product develops and can be measured at 405 nm. At the end of the enzymatic reaction, we briefly centrifuged the 96 well plate and transferred the supernatant to a fresh 96 well plate to measure absorbance using the plate reader. We found that this extra centrifugation step is critical, since it increases the consistency of absorbance at 405 nm, probably by eliminatin...

Alkaline phosphatase (ALP) is ubiquitously expressed in both prokaryotic and eukaryotic cells1. It can catalyze the hydrolysis of monophosphate from different molecules such as nucleotides, proteins, alkaloids, phosphate esters and anhydrides of phosphoric acid. In humans, eukaryotic ALP is present in many tissues including liver, bone, intestine and placenta2. It plays important roles in protein phosphorylation, cell growth, apoptosis, stem cell processes as well as normal skeletal mineralization. Eukaryotic ALP is also a key serum indicator for the presence of diseases in bone, liver, and other tissues/organs when elevated3,4.
Prokaryotic ALP has been detected in a variety of bacterial cells, including E. coli5, S. aureus6,7 and some common rumen bacteria in the soils8. Bacterial ALP activity has been used as a biosensor in the detection of pesticides, heavy metals9 and bacterial contamination10. The constitutive expression of ALP has been used to identify Staphylococci11 and to differentiate Serratia from Enterobacter12. It is further suggested that constitutive ALP production is correlated with pathogenicity in staphylococci13. Although ALP has been studied in different settings3,4, yet little is reported for its activity and function in biofilms cultures.
A biofilm has been documented to have a differently functioning bacterial life as compared with its free-living bacterial cell counterpart14. In S. aureus, the formation of biofilm has been identified in a variety of clinical conditions and accounts for the antibiotic resistance and chronic inflammation15,16. Many molecules had been reported to be found in a biofilm matrix such as polysaccharides, proteins, nucleic acids, and lipids, but the mechanism of biofilm formation is not fully understood14. To understand the role of ALP in biofilm formation, we cultured S. aureus biofilms in 96 well tissue culture plates and measured the ALP activity using para-nitrophenylphosphate (pNPP).
The molecule pNPP is a ready-to-use substrate for ALP and has been widely used to measure ALP activity6,17,18. This colorimetric assay is based on the conversion of para-nitrophenyl phosphate (pNPP) to para-nitrophenol resulting in a colored product at 405 nm. Compared to other conventional ALP assay, such as agarose gel electrophoresis19, wheat germ agglutinin (WGA) precipitation, and WGA-HPLC20, this assay is highly specific, sensitive, easy to reproduce, and most importantly, allows for high throughput.

<table>
	<tbody>
		<tr>
			<td>Agar</td>
			<td>VWR</td>
			<td>9002-18-0</td>
			<td></td>
		</tr>
		<tr>
			<td>Eppendorf Centrifuge</td>
			<td>Thomas Scientific</td>
			<td>5810</td>
			<td></td>
		</tr>
		<tr>
			<td>Gluose</td>
			<td>VWR</td>
			<td>50-99-7</td>
			<td></td>
		</tr>
		<tr>
			<td>NaOH pellets</td>
			<td>VWR</td>
			<td>SS0550-500GR</td>
			<td></td>
		</tr>
		<tr>
			<td>Para-nitrophenylphosphate (pNPP)&#160;</td>
			<td>Sigma</td>
			<td>P7998-100ML</td>
			<td>Typical concentrations of pNPP liquid substrates, often used in enzyme-linked immunesorbent assays (ELISA), range between 10 to 50 mM. Similar to most ready-to-use pNPP liquid substrates like the one used here, the exact pNPP concentration is not disclosed due to its proprietary nature.</td>
		</tr>
		<tr>
			<td>10X PBS, pH7.4. 
			173 mM NaCl, 
			2.7 mM KCl, 
			8 mM Na2HPO4, 
			2 mM KH2PO4</td>
			<td>Sigma</td>
			<td>P3288-1VL</td>
			<td></td>
		</tr>
		<tr>
			<td>Plate Reader</td>
			<td>Biotek</td>
			<td>ELx808</td>
			<td></td>
		</tr>
		<tr>
			<td>S. aureus</td>
			<td>ATCC</td>
			<td>ATCC25923</td>
			<td></td>
		</tr>
		<tr>
			<td>Tryptic Soy Agar&#160;&#160;&#160;&#160;&#160;&#160; 15g / L TSB</td>
			<td>VWR</td>
			<td>9002-18-0</td>
			<td></td>
		</tr>
		<tr>
			<td>Tryptic Soy Broth:&#160;&#160;&#160;&#160;&#160; g/L 
			Pancreatic Digest of Casein............ 15.0 
			Papaic Digest of Soyben Meal.........5.00 
			Sodium chloride.............................. 3.00 
			Dextrose........................................&#160; 2.50 
			Dipotassium phosphate..................2.50</td>
			<td>VWR</td>
			<td>90006-098</td>
			<td></td>
		</tr>
		<tr>
			<td>96 well tissue culture plates</td>
			<td>BD</td>
			<td>6902D09</td>
			<td>U shaped bottom</td>
		</tr>
	</tbody>
</table>

colorimetric analysis of alkaline phosphatase activity in s. aureus biofilm

Alkaline phosphatase (ALP) is a common enzyme expressed in both prokaryotic and eukaryotic cells. It catalyzes the hydrolysis of phosphate monoesters from many molecules at basic pH and plays an indispensable role in phosphate metabolism. In humans, eukaryotic ALP is one of the most frequently used enzymatic signals in diagnosing various diseases, such as cholestasis and rickets. In S. aureus, ALP is detected exclusively on the cell membrane; it is also expressed as a secretory form as well. Yet, little is known about its function in biofilm formation.
The purpose of this manuscript is to develop a quick and reliable assay to measure ALP activity in S. aureus biofilm that does not require protein isolation. Using p-nitrophenyl phosphate (pNPP) as a substrate, we measured ALP activity in S. aureus biofilm formed in 96-well tissue culture plates. Activity was based on the formation of the soluble reaction product measured by 405 nm absorbance. The high throughput nature of the 96 well tissue culture plate method provides a sensitive and reproducible method for ALP activity assays. The same experimental set up can also be extended to measure other extracellular molecular markers related to biofilm formation.

Figure 1 shows a representative result of ALP activity from biofilm cultures of S. aureus in 96 well tissue culture plates. 75 &#956;L of commercially available pNPP solution was added to each well and incubated at room temperature. After incubation for different times (0 min, 15 min, 30 min, 45 min, 60 min, and 75 min, respectively) 75 &#956;L of 5 M NaOH was added to stop the reaction. The product was then measured in a 96 well plate reader at 405 ...

Watch this Scientific Journal Video about Colorimetric Analysis of Alkaline Phosphatase Activity in S. aureus Biofilm at JoVE.com

Colorimetric Analysis of Alkaline Phosphatase Activity in S. aureus Biofilm

In this manuscript, we established a high throughput method to quantify alkaline phosphatase activity in S. aureus biofilm culture from 96-well tissue culture plate

Colorimetric Analysis of Alkaline Phosphatase Activity in S. aureus Biofilm

Alkaline phosphatase (ALP) is a common enzyme expressed in both prokaryotic and eukaryotic cells. It catalyzes the hydrolysis of phosphate monoesters from ...

This protocol presented an easy and reliable method to measure alkalized phosphatase activity in S.aureus biofilm culture. It will help us to understand the function of ALP in biofilm formation. The major advantage of this technique is high throughput.It is very sensitive and easy to perform. Demonstrating the procedure will be Kevin Danikowski, a former student from Harper College. To prepare TSB, add pancreatic digest of casein, papaic digest of soybean meal, sodium chloride, dextrose, and dipotassium phosphate into distilled water.Cover the flask with aluminum foil and put it in an autoclave to sterilize before use. To prepare a TSA, add agar to TSB and put it in the autoclave for sterilization. Then let it cool to room temperature.Next, pour it into the Petri dish at a ratio of 20 milliliters per dish. To prepare a biofilm culture medium, add glucose to autoclaved TSB to achieve the concentration of 10 grams per liter. Using a vacuum filtration kit, filtrate the solution with a 0.2 micrometer pore sized filter.To inoculate, use a sterilized inoculation loop to pick one individual colony of Staph aureus from the Petri dish and place it in the culture tube filled with 10 milliliters of TSB. Put the tube in the incubator to grow overnight at 37 degrees Celsius. With a micropipette, draw 100 microliters of overnight culture and transfer it to a culture tube filled with 10 milliliters of TSB with glucose for a 1:100 volume ratio dilution.Vortex gently to mix for a consistent concentration. Use a micropipette to transfer 200 microliters of diluted culture into a total of 18 wells from one 96 well plate. Incubate the 96 well plate at 37 degrees Celsius for 24 hours for biofilm formation.For the best biofilm formation of S.aureus, it is better to pick a flat or round bottom 96 well plate. After that, slightly tilt the plate to decant the supernatant by aspiration from the edge of each well. Wash each well with 1X PBS.Put the plate in the centrifuge to spin for five minutes at 8, 000 revolutions per minute and decant the supernatant by aspiration. Add 75 microliters of buffered ALP substrate consisting of commercially available PNPP to each well and use a timer to record each time point in triplicate. After each incubation time point, add 75 microliters of five molar sodium hydroxide to each of three wells to stop the reaction.Centrifuge the plate for five minutes at 800 revolutions per minute. Use a pipette to transfer 100 microliters of supernatant into a new 96 well plate for calorimetric measurement. Use a 96 well plate reader to measure the absorbance of each well at 405 nanometers.Use the 30-minute time point wells to control for background noise. Repeat the entire experiment in three 96 well plates. This protocol develops a quick and reliable assay to measure ALP activity in S.aureus biofilm that does not require protein isolation.The representative result of ALP activity shows an increased trend for up to 75 minutes. After 75 minutes, no increase of the ALP activity was observed. It is very important to establish a good biofilm culture and it may take quite a few trials to master.You can confirm biofilm formation by performing crystal violet assay as previously reported by us and others or you can pre-treat the plate with human plasma to facilitate biofilm formation. After its development, you can screen potential ALP inhibitors that might interfere biofilm formation. The result will provide important information toward biofilm management in medical field.Five molar sodium hydroxide might be hazardous in case of contact. Be sure to wear personal protective equipment when handling.

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