Name: coincubation assay for quantifying competitive interactions between vibrio fischeri isolates
Uploaded: 2019-07-22T13:00:00
Description: Watch this Scientific Journal Video about Coincubation Assay for Quantifying Competitive Interactions between Vibrio fischeri Isolates at JoVE.com

We would like to thank reviewers for their helpful feedback. A.N.S. was supported by the Gordon and Betty Moore Foundation through Grant GBMF 255.03 to the Life Sciences Research Foundation.

1. Prepare Strains for Coincubation
<ol>
	<li>Choose an appropriate reference strain that will serve as the target for bacterial competition during the coincubation assay. See Discussion for best practices when selecting a reference strain and how the reference strain will impact results. In this protocol, V. fischeri strain ES114 will serve as the reference strain.</li>
	<li>Determining which selection and screening methods will be used to distinguish between the isolates in coincubat...

<ol>
	<li>Hibbing, M. E., Fuqua, C., Parsek, M. R., Peterson, S. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bacterial+competition:+surviving+and+thriving+in+the+microbial+jungle.">Bacterial competition: surviving and thriving in the microbial jungle.</a> Nature Reviews Microbiology. 8 (1), 15-25 (2010).</li><li>Nyholm, S. V., McFall-Ngai, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+winnowing:+establishing+the+squid-Vibrio+symbiosis.">The winnowing: establishing the squid-Vibrio symbiosis.</a> Nature Reviews Microbiology. 2 (8), 632-642 (2004).</li><li>D&#246;rr, N. C. D., Blockesh, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bacterial+type+VI+secretion+system+facilitates+niche+domination.">Bacterial type VI secretion system facilitates niche domination.</a> Proceedings of the National Academy of Sciences of the United States of America. 115 (36), 8855-8857 (2018).</li><li>Maclntyre, D. L., Miyata, S. T., Kitaoka, M., Pukatzki, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Vibrio+cholerae+type+VI+secretion+system+displays+antimicrobial+properties.">The Vibrio cholerae type VI secretion system displays antimicrobial properties.</a> Proceedings of the National Academy of Sciences of the United States of America. 107 (45), 19520-19524 (2010).</li><li>Salomon, D., Gonzalez, H., Updegraff, B. L., Orth, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Vibrio+parahaemolyticus+type+VI+secretion+system+1+is+activated+in+marine+conditions+to+target+bacteria,+and+is+differentially+regulated+from+system+2.">Vibrio parahaemolyticus type VI secretion system 1 is activated in marine conditions to target bacteria, and is differentially regulated from system 2.</a> PloS One. 8 (4), e61086 (2013).</li><li>Sana, T. G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Salmonella+Typhimurium+utilizes+a+T6SS-mediated+antibacterial+weapon+to+establish+in+the+host+gut.">Salmonella Typhimurium utilizes a T6SS-mediated antibacterial weapon to establish in the host gut.</a> Proceedings of the National Academy of Sciences of the United States of America. 113 (34), E5044-E5051 (2016).</li><li>Schwarz, 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=Burkholderia+type+VI+secretion+systems+have+distinct+roles+in+eukaryotic+and+bacterial+cell+interactions.">Burkholderia type VI secretion systems have distinct roles in eukaryotic and bacterial cell interactions.</a> PLoS Pathogens. 6 (8), e1001068 (2010).</li><li>Wenren, L. M., Sullivan, N. L., Cardarelli, L., Septer, A. N., Gibbs, K. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Two+independent+pathways+for+self-recognition+in+Proteus+mirabilis+are+linked+by+type+VI-dependent+export.">Two independent pathways for self-recognition in Proteus mirabilis are linked by type VI-dependent export.</a> MBio. 4 (4), (2013).</li><li>Garc&#237;a-Bayona, L., Guo, M. S., Laub, M. T. J. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Contact-dependent+killing+by+Caulobacter+crescentus+via+cell+surface-associated,+glycine+zipper+proteins.">Contact-dependent killing by Caulobacter crescentus via cell surface-associated, glycine zipper proteins.</a> Elife. 6, 24869 (2017).</li><li>Stubbendieck, R. M., Straight, 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=Multifaceted+interfaces+of+bacterial+competition.">Multifaceted interfaces of bacterial competition.</a> Journal of bacteriology. 198 (16), 2145-2155 (2016).</li><li>Cornforth, D. M., Foster, K. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Antibiotics+and+the+art+of+bacterial+war.">Antibiotics and the art of bacterial war.</a> Proceedings of the National Academy of Sciences of the United States of America. 112 (35), 10827-10828 (2015).</li><li>Shank, E. A., Kolter, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=New+developments+in+microbial+interspecies+signaling.">New developments in microbial interspecies signaling.</a> Current Opinion in Microbiology. 12 (2), 205-214 (2009).</li><li>Roelofs, K. G., Coyne, M. J., Gentyala, R. R., Chatzidaki-Livanis, M., Comstock, L. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bacteroidales+secreted+antimicrobial+proteins+target+surface+molecules+necessary+for+gut+colonization+and+mediate+competition+in+vivo.">Bacteroidales secreted antimicrobial proteins target surface molecules necessary for gut colonization and mediate competition in vivo.</a> MBio. 7 (4), e01055-e01016 (2016).</li><li>Dey, A., Vassallo, C. N., Conklin, A. C., Pathak, D. T., Troselj, V., Wall, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sibling+rivalry+in+Myxococcus+xanthus+is+mediated+by+kin+recognition+and+a+polyploid+prophage.">Sibling rivalry in Myxococcus xanthus is mediated by kin recognition and a polyploid prophage.</a> Journal of bacteriology. 198 (6), (2016).</li><li>Danka, E. S., Garcia, E. C., Cotter, P. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Are+CDI+systems+multicolored,+facultative,+helping+greenbeards?.">Are CDI systems multicolored, facultative, helping greenbeards?.</a> Trends in Microbiology. 25 (5), 391-401 (2017).</li><li>Willett, J. L., Ruhe, Z. C., Coulding, C. W., Low, D. A., Hayes, C. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Contact-dependent+growth+inhibition+(CDI)+and+CdiB/CdiA+two-partner+secretion+proteins.">Contact-dependent growth inhibition (CDI) and CdiB/CdiA two-partner secretion proteins.</a> Journal of molecular biology. 427 (23), 3754-3765 (2015).</li><li>Cianfanelli, F. R., Monlezun, L., Coulthurst, S. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Aim,+load,+fire:+the+type+VI+secretion+system,+a+bacterial+nanoweapon.">Aim, load, fire: the type VI secretion system, a bacterial nanoweapon.</a> Trends in Microbiology. 24 (1), 51-62 (2016).</li><li>Joshi, A., Kostiuk, B., Rogers, A., Teschler, J., Pukatzki, S., Yildiz, F. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rules+of+engagement:+the+type+VI+secretion+system+in+Vibrio+cholerae.">Rules of engagement: the type VI secretion system in Vibrio cholerae.</a> Trends in microbiology. 25 (4), 267-279 (2017).</li><li>Speare, L., 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=Bacterial+symbionts+use+a+type+VI+secretion+system+to+eliminate+competitors+in+their+natural+host.">Bacterial symbionts use a type VI secretion system to eliminate competitors in their natural host.</a> Proceedings of the National Academy of Sciences of the United States of America. 115 (36), E8528-E8537 (2018).</li><li>Shank, E. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Using+coculture+to+detect+chemically+mediated+interspecies+interactions.">Using coculture to detect chemically mediated interspecies interactions.</a> Journal of Visualized Experiments. (80), (2013).</li><li>Long, R. A., Rowley, D. C., Zamora, E., Liu, J., Bartlett, D. H., Azam, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Antagonistic+interactions+among+marine+bacteria+impede+the+proliferation+of+Vibrio+cholerae.">Antagonistic interactions among marine bacteria impede the proliferation of Vibrio cholerae.</a> Applied and Environmental Microbiology. 71 (12), 8531-8536 (2005).</li><li>Dunn, A. K., Millikan, D. S., Adin, D. M., Bose, J. L., Stabb, E. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=New+rfp-and+pES213-derived+tools+for+analyzing+symbiotic+Vibrio+fischeri+reveal+patterns+of+infection+and+lux+expression+in+situ.">New rfp-and pES213-derived tools for analyzing symbiotic Vibrio fischeri reveal patterns of infection and lux expression in situ.</a> Applied and Environmental Microbiology. 72 (1), 802-810 (2006).</li><li>Sana, T. G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+second+type+VI+secretion+system+of+Pseudomonas+aeruginosa+strain+PAO1+is+regulated+by+quorum+sensing+and+Fur+and+modulates+internalization+in+epithelial+cells.">The second type VI secretion system of Pseudomonas aeruginosa strain PAO1 is regulated by quorum sensing and Fur and modulates internalization in epithelial cells.</a> Journal of Biological Chemistry. 287 (32), 27095-27105 (2012).</li><li>Bachmann, V., Kostiuk, B., Unterweger, D., Diaz-Satizabal, L., Ogg, S., Pukatzki, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bile+salts+modulate+the+mucin-activated+type+VI+secretion+system+of+pandemic+Vibrio+cholerae.">Bile salts modulate the mucin-activated type VI secretion system of pandemic Vibrio cholerae.</a> PLoS. 9 (8), e0004031 (2015).</li><li>Ishikawa, T., Rompikuntal, P. K., Lindmark, B., Milton, D. L., Wai, 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=Quorum+sensing+regulation+of+the+two+hcp+alleles+in+Vibrio+cholerae+O1+strains.">Quorum sensing regulation of the two hcp alleles in Vibrio cholerae O1 strains.</a> PloS One. 4 (8), e6734 (2009).</li><li>Ishikawa, T., 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=Pathoadaptive+conditional+regulation+of+the+type+VI+secretion+system+in+Vibrio+cholerae+O1+strains.">Pathoadaptive conditional regulation of the type VI secretion system in Vibrio cholerae O1 strains.</a> Infection and immunity. 80 (2), 575-584 (2012).</li><li>Pollack-Berti, A., Wollenberg, M. S., Ruby, E. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Natural+transformation+of+Vibrio+fischeri+requires+tfoX+and+tfoY.">Natural transformation of Vibrio fischeri requires tfoX and tfoY.</a> Environmental Microbiology. 12 (8), 2302-2311 (2010).</li><li>Meibom, K. L., Blockesh, M., Dolganov, N. A., Wu, C. Y., Schoolnik, G. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chitin+induces+natural+competence+in+Vibrio+cholerae.">Chitin induces natural competence in Vibrio cholerae.</a> Science. 310 (5755), 1824-1827 (2005).</li><li>Borgeaud, S., Metzger, L. C., Scrignari, T., Blockesh, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+type+VI+secretion+system+of+Vibrio+cholerae+fosters+horizontal+gene+transfer.">The type VI secretion system of Vibrio cholerae fosters horizontal gene transfer.</a> Science. 347 (6217), 63-67 (2015).</li><li>Townsley, L., Mangus, M. P. S., Mehic, S., Yildiz, F. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Response+of+Vibrio+cholerae+to+low-temperature+shift:+CpsV+regulates+type+VI+secretion,+biofilm+formation,+and+association+with+zooplankton.">Response of Vibrio cholerae to low-temperature shift: CpsV regulates type VI secretion, biofilm formation, and association with zooplankton.</a> Applied and Environmental Microbiology. 82 (14), 00807-00816 (2016).</li><li>Huang, Y., 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=Functional+characterization+and+conditional+regulation+of+the+type+VI+secretion+system+in+Vibrio+fluvialis.">Functional characterization and conditional regulation of the type VI secretion system in Vibrio fluvialis.</a> Frontiers in microbiology. 8, 528 (2017).</li></ol>

The coincubation assay described above provides a powerful method to discover interbacterial competition. This approach allowed for the identification of intraspecific competition among V. fischeri isolates and characterization of the competitive mechanism19. Although the method described was optimized for the marine bacterium V. fischeri, it can be easily modified to accommodate other bacterial species including clinical and environmental isolates. It is important to note that c...

This manuscript outlines a culture-based method to determine whether two bacterial isolates are capable of competitive interactions. When studying mixed populations, it is important to assess the extent to which the bacterial isolates interact, particularly whether isolates are directly competing through interference mechanisms. Interference competition refers to interactions where one population directly inhibits the growth or kills a competitor population1. These interactions are important to identify because they can have profound effects on a microbial community&#8217;s structure and function2,3.
Mechanisms for microbial competition have been discovered broadly in genomes of bacteria from diverse environments including both host-associated and free-living bacteria4,5,6,7,8,9. A variety of competition strategies have been described10,11 including diffusible mechanisms, such as bactericidal chemicals1,12 and secreted antimicrobial peptides13, as well as contact-dependent mechanisms that require cell-cell contact to transfer an inhibitory effector into target cells9,14,15,16,17,18.
Although culture-based coincubations are commonly used in microbiology5,8,19, this manuscript outlines how to use the assay to characterize the mechanism of competition, as well as suggestions for adapting the protocol for use with other bacterial species. Furthermore, this method describes multiple approaches for analyzing and presenting the data to answer different questions about the nature of the competitive interactions. Although the techniques described here were used previously to identify the interbacterial killing mechanism underlying intraspecific competition between symbiotic strains of coisolated Vibrio fischeri bacteria19, they are suitable for many bacterial species including environmental isolates and human pathogens, and can be utilized to evaluate both contact-dependent and diffusible competitive mechanisms. Steps in the protocol may require optimization for other bacterial species. Given that more model systems are expanding their studies beyond the use of isogenic organisms to include different genotypes10,16,20,21, this method will be a valuable resource for researchers seeking to understand how competition impacts multi-strain or multi-species systems.

<table>
	<tbody>
		<tr>
			<td>1.5 mL Microcentrifuge Tubes</td>
			<td>Fisher</td>
			<td>05-408-129</td>
			<td></td>
		</tr>
		<tr>
			<td>10 &#956;L multichannel pipette</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>100 &#956;L multichannel pipette</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>300 &#956;L multichannel pipette</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>10 &#956;L single channel pipette</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>20 &#956;L single channel pipette</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>200 &#956;L single channel pipette</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>1000 &#956;L single channel pipette</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>24-well plates</td>
			<td>Fisher</td>
			<td>07-200-84</td>
			<td>sterile with lid</td>
		</tr>
		<tr>
			<td>96-well plates</td>
			<td>VWR</td>
			<td>10062-900</td>
			<td>sterile with lid</td>
		</tr>
		<tr>
			<td>Calculator</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Chloramphenicol</td>
			<td>Sigma</td>
			<td>C0378</td>
			<td>stock (20 mg/mL in Ethanol); final concentration in media (2 &#956;g /mL LBS)</td>
		</tr>
		<tr>
			<td>Fluorescence dissecting microscope with camera and imaging software</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>forceps</td>
			<td>Fisher</td>
			<td>08-880</td>
			<td></td>
		</tr>
		<tr>
			<td>Kanamycin Sulfate</td>
			<td>Fisher</td>
			<td>BP906-5</td>
			<td>stock (100 mg/mL in water, filter sterilize); final concentration in media (1 &#956;g/mL LBS)</td>
		</tr>
		<tr>
			<td>Nitrocellulose membrane (FS MCE, 25MM, NS)</td>
			<td>Fisher</td>
			<td>SA1J788H5</td>
			<td>0.22 &#956;m nitrocellulose membrane (pk of 100)</td>
		</tr>
		<tr>
			<td>petri plates</td>
			<td>Fisher</td>
			<td>FB0875713</td>
			<td>sterile with lid</td>
		</tr>
		<tr>
			<td>Spectrophotometer</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Semi-micro cuvettes</td>
			<td>VWR</td>
			<td>97000-586</td>
			<td></td>
		</tr>
		<tr>
			<td>TipOne 0.1-10 &#956;L starter system</td>
			<td>USA Scientific</td>
			<td>1111-3500</td>
			<td>10 racks</td>
		</tr>
		<tr>
			<td>TipOne 200 &#956;L starter system</td>
			<td>USA Scientific</td>
			<td>1111-500</td>
			<td>10 racks</td>
		</tr>
		<tr>
			<td>TipOne 1000 &#956;L starter system</td>
			<td>USA Scientific</td>
			<td>1111-2520</td>
			<td>10 racks</td>
		</tr>
		<tr>
			<td>Vortex</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Name</td>
			<td>Company</td>
			<td>Catalog Number</td>
			<td>Comments</td>
		</tr>
		<tr>
			<td>LBS media</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>1M Tris Buffer (pH ~7.5)</td>
			<td></td>
			<td></td>
			<td>50 mL 1 M stock buffer (62 mL HCl, 938 mL DI water, 121 g Trizma Base)</td>
		</tr>
		<tr>
			<td>Agar Technical</td>
			<td>Fisher</td>
			<td>DF0812-17-9</td>
			<td>15 g (Add only for plates)</td>
		</tr>
		<tr>
			<td>DI water</td>
			<td></td>
			<td></td>
			<td>950 mL</td>
		</tr>
		<tr>
			<td>Sodium Chloride</td>
			<td>Fisher</td>
			<td>S640-3</td>
			<td>20 g</td>
		</tr>
		<tr>
			<td>Tryptone</td>
			<td>Fisher</td>
			<td>BP97265</td>
			<td>10 g</td>
		</tr>
		<tr>
			<td>Yeast Extract</td>
			<td>Fisher</td>
			<td>BP9727-2</td>
			<td>5 g</td>
		</tr>
	</tbody>
</table>

coincubation assay for quantifying competitive interactions between vibrio fischeri isolates

This manuscript describes a culture-based, coincubation assay for detecting and characterizing competitive interactions between two bacterial populations. This method employs stable plasmids that allow each population to be differentially tagged with distinct antibiotic resistance capabilities and fluorescent proteins for selection and visual discrimination of each population, respectively. Here, we describe the preparation and coincubation of competing Vibrio fischeri strains, fluorescence microscopy imaging, and quantitative data analysis. This approach is simple, yields quick results, and can be used to determine whether one population kills or inhibits the growth of another population, and whether competition is mediated through a diffusible molecule or requires direct cell-cell contact. Because each bacterial population expresses a different fluorescent protein, the assay permits the spatial discrimination of competing populations within a mixed colony. Although the described methods are performed with the symbiotic bacterium V. fischeri using conditions optimized for this species, the protocol can be adapted for most culturable bacterial isolates.

In order to assess competitive interactions between bacterial populations, a coincubation assay protocol was developed and optimized for V. fischeri. This method utilizes stable plasmids that encode antibiotic resistance genes and fluorescent proteins, allowing for differential selection and visual discrimination of each strain. By analyzing the data collected from the coincubation assay, the competitive outcome of an interaction and the mechanism of the interaction can be identi...

Watch this Scientific Journal Video about Coincubation Assay for Quantifying Competitive Interactions between Vibrio fischeri Isolates at JoVE.com

Coincubation Assay for Quantifying Competitive Interactions between Vibrio fischeri Isolates

Bacteria encode diverse mechanisms for engaging in interbacterial competition. Here, we present a culture-based protocol for characterizing competitive interactions between bacterial isolates and how they impact the spatial structure of a mixed population.

Coincubation Assay for Quantifying Competitive Interactions between Vibrio fischeri Isolates

This manuscript describes a culture-based, coincubation assay for detecting and characterizing competitive interactions between two bacterial populations. ...

Research

JoVE Journal

Immunology and Infection

Colonization of Euprymna scolopes Squid by Vibrio fischeri

Colonization of Euprymna scolopes Squid by Vibrio fischeri

Specific bacteria are found in association with animal tissue1-5. Such host-bacterial associations (symbioses) can be detrimental (pathogenic), have no ...

Monitoring Dendritic Cell Migration using 19F / 1H Magnetic Resonance Imaging

Monitoring Dendritic Cell Migration using 19F / 1H Magnetic Resonance Imaging

Continuous  advancements in noninvasive imaging modalities such as magnetic resonance  imaging (MRI) have greatly improved our ability to study ...

A Novel In vitro Model for Studying the Interactions Between Human Whole Blood and Endothelium

A Novel In vitro Model for Studying the Interactions Between Human Whole Blood and Endothelium

The majority of all known diseases are accompanied by disorders of the cardiovascular system. Studies into the complexity of the interacting pathways ...

Assay of Adhesion Under Shear Stress for the Study of T Lymphocyte-Adhesion Molecule Interactions

Overall, T cell adhesion is a critical component of function, contributing to the distinct processes of cellular recruitment to sites of inflammation and ...

Evaluation of the Efficacy And Toxicity of RNAs Targeting HIV-1 Production for Use in Gene or Drug Therapy

Small RNA therapies targeting post-integration steps in the HIV-1 replication cycle are among the top candidates for gene therapy and have the potential ...

Development of a More Sensitive and Specific Chromogenic Agar Medium for the Detection of Vibrio parahaemolyticus and Other Vibrio Species

Development of a More Sensitive and Specific Chromogenic Agar Medium for the Detection of Vibrio parahaemolyticus and Other Vibrio Species

Foodborne infections in the US caused by Vibrio species have shown an upward trend. In the genus Vibrio, V. parahaemolyticus is responsible for the ...

Laboratory Techniques Used to Maintain and Differentiate Biotypes of Vibrio cholerae Clinical and Environmental Isolates

Laboratory Techniques Used to Maintain and Differentiate Biotypes of Vibrio cholerae Clinical and Environmental Isolates

The aquatic Gram-negative bacterium Vibrio cholerae is the etiological agent of the infectious gastrointestinal disease cholera. Due to the global ...

Induction of Cellular Differentiation and Single Cell Imaging of Vibrio parahaemolyticus Swimmer and Swarmer Cells

Induction of Cellular Differentiation and Single Cell Imaging of Vibrio parahaemolyticus Swimmer and Swarmer Cells

The ability to study the intracellular localization of proteins is essential for the understanding of many cellular processes. In turn, this requires the ...

Ex Vivo Infection of Human Lymphoid Tissue and Female Genital Mucosa with Human Immunodeficiency Virus 1 and Histoculture

Ex Vivo Infection of Human Lymphoid Tissue and Female Genital Mucosa with Human Immunodeficiency Virus 1 and Histoculture

Histocultures allow studying intercellular interactions within human tissues, and they can be employed to model host-pathogen interactions under ...

Quantifying Vibrio cholerae Colonization and Diarrhea in the Adult Zebrafish Model

Quantifying Vibrio cholerae Colonization and Diarrhea in the Adult Zebrafish Model

Vibrio cholerae is best known as the infectious agent that causes the human disease cholera. Outside the human host, V. cholerae primarily exists in the ...