Name: visualizing bacteria in nematodes using fluorescent microscopy
Uploaded: 2012-10-19T12:00:00
Description: Watch this Scientific Journal Video about Visualizing Bacteria in Nematodes using Fluorescent Microscopy at JoVE.com

The authors wish to thank Eugenio Vivas, Kurt Heungens, Eric Martens, Charles Cowles, Darby Sugar, Eric Stabb, and Todd Ciche for their contributions to the development of this protocol and tools used. KEM and JMC were supported by National Institutes of Health (NIH) National Research Service Award T32 (AI55397 "Microbes in Health and Disease"). JMC was supported by a National Science Foundation (NSF) Graduate Research Fellowship. This work was supported by grants from the National Science Foundation (IOS-0920631 and IOS- 0950873).

1. Construction of a Fluorescent Bacterial Strain via Conjugation
<ol>
	<li>Grow the recipient strain (symbiont to be examined) and donor strain overnight. The donor strain, usually Escherichia coli, should be capable of donating DNA through conjugation and should be transformed with a plasmid (Table 2) that carries a gene encoding a fluorescent protein. Depending on the plasmid, a conjugation helper strain may also be required. If so, this strain should also be grown overnight. The donor stra...

<ol>
	<li>Holterman, M., van der Wurff, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phylum-wide+analysis+of+SSU+rDNA+reveals+deep+phylogenetic+relationships+among+nematodes+and+accelerated+evolution+toward+crown+clades.">Phylum-wide analysis of SSU rDNA reveals deep phylogenetic relationships among nematodes and accelerated evolution toward crown clades.</a> Mol. Biol. Evol. 23, 1792-1800 (2006).</li><li>Lambshead, P. J. D., Boucher, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Marine+nematode+deep-sea+biodiversity+-+hyperdiverse+or+hype.">Marine nematode deep-sea biodiversity - hyperdiverse or hype.</a> J. Biogeogr. 30, 475-485 (2003).</li><li>Poinar, G. O. J., Thomas, G. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Significance+of+Achromobacter+nematophilus+Poinar+and+Thomas+(Achromobacteraceae:+Eubacteriales)+in+the+development+of+the+nematode,+DD-136+(Neoaplectana+sp.+Steinernematidae).">Significance of Achromobacter nematophilus Poinar and Thomas (Achromobacteraceae: Eubacteriales) in the development of the nematode, DD-136 (Neoaplectana sp. Steinernematidae).</a> Parasitol. 56, 385-390 (1966).</li><li>Herbert, E. E., Goodrich-Blair, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Friend+and+foe:+the+two+faces+of+Xenorhabdus+nematophila.">Friend and foe: the two faces of Xenorhabdus nematophila.</a> Nat. Rev. Microbiol. 5, 634-646 (2007).</li><li>Kaya, H. K., Gaugler, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Entomopathogenic+nematodes.">Entomopathogenic nematodes.</a> Annu. Rev. Entomol. 38, 181-206 (1993).</li><li>Bird, A. F., Akhurst, R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+nature+of+the+intestinal+vesicle+in+nematodes+of+the+family+Steinernematidae.">The nature of the intestinal vesicle in nematodes of the family Steinernematidae.</a> Int. J. Parasitol. 13, 599-606 (1983).</li><li>Martens, E. C., Goodrich-Blair, 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+Steinernema+carpocapsae+intestinal+vesicle+contains+a+subcellular+structure+with+which+Xenorhabdus+nematophila+associates+during+colonization+initiation.">The Steinernema carpocapsae intestinal vesicle contains a subcellular structure with which Xenorhabdus nematophila associates during colonization initiation.</a> Cell. Microbiol. 7, 1723-1735 (2005).</li><li>Snyder, H. A., Stock, S. P., Kim, S. K., Flores-Lara, Y., Forst, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=New+insights+into+the+colonization+and+release+process+of+Xenorhabdus+nematophila+and+the+morphology+and+ultrastructure+of+the+bacterial+receptacle+of+its+nematode+host,+Steinernema+carpocapsae.">New insights into the colonization and release process of Xenorhabdus nematophila and the morphology and ultrastructure of the bacterial receptacle of its nematode host, Steinernema carpocapsae.</a> Appl. Environ. Microbiol. 73, 5338-5346 (2007).</li><li>Abebe, E., Abebe-Akele, F., Morrison, J., Cooper, V., Thomas, W. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+insect+pathogenic+symbiosis+between+a+Caenorhabditis+and+Serratia.">An insect pathogenic symbiosis between a Caenorhabditis and Serratia.</a> Virulence. 2, 158-161 (2011).</li><li>Abebe, E., Jumba, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+entomopathogenic+Caenorhabditis+briggsae.">An entomopathogenic Caenorhabditis briggsae.</a> J. Exp. Biol. 213, 3223-3229 (2010).</li><li>Torres-Barragan, A., Suazo, A., Buhler, W. G., Cardoza, Y. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Studies+on+the+entomopathogenicity+and+bacterial+associates+of+the+nematode+Oscheius+carolinensis.">Studies on the entomopathogenicity and bacterial associates of the nematode Oscheius carolinensis.</a> Biol. Control. 59, 123-129 (2011).</li><li>Ye, W. M., Torres-Barragan, A., Cardoza, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Oscheius+carolinensis+n.+sp+(Nematoda:+Rhabditidae),+a+potential+entomopathogenic+nematode+from+vermicompost.">Oscheius carolinensis n. sp (Nematoda: Rhabditidae), a potential entomopathogenic nematode from vermicompost.</a> Nematology. 12, 121-135 (2010).</li><li>Zhang, C., Liu, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Heterorhabditidoides+chongmingensis+gen.+nov.,+sp.+nov.+(Rhabditida:+Rhabditidae),+a+novel+member+of+the+entomopathogenic+nematodes.">Heterorhabditidoides chongmingensis gen. nov., sp. nov. (Rhabditida: Rhabditidae), a novel member of the entomopathogenic nematodes.</a> J. Invertebr. Pathol. 98, 153-168 (2008).</li><li>Martens, E. C., Heungens, K., Goodrich-Blair, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Early+colonization+events+in+the+mutualistic+association+between+Steinernema+carpocapsae+nematodes+and+Xenorhabdus+nematophila+bacteria.">Early colonization events in the mutualistic association between Steinernema carpocapsae nematodes and Xenorhabdus nematophila bacteria.</a> J. Bacteriol. 185, 3147-3154 (2003).</li><li>Ciche, T. A., Ensign, 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=For+the+insect+pathogen,+Photorhabdus+luminescens,+which+end+of+a+nematode+is+out.">For the insect pathogen, Photorhabdus luminescens, which end of a nematode is out.</a> Appl. Environ. Microbiol. 69, 1890-1897 (2003).</li><li>Ciche, T. A., Kim, K. S., Kaufmann-Daszczuk, B., Nguyen, K. C., Hall, D. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cell+invasion+and+matricide+during+Photorhabdus+luminescens+transmission+by+Heterorhabditis+bacteriophora+nematodes.">Cell invasion and matricide during Photorhabdus luminescens transmission by Heterorhabditis bacteriophora nematodes.</a> Appl. Environ. Microbiol. 74, 2275-2287 (2008).</li><li>Easom, C. A., Joyce, S. A., Clarke, D. J. <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+genes+involved+in+the+mutualistic+colonization+of+the+nematode+Heterorhabditis+bacteriophora+by+the+bacterium+Photorhabdus+luminescens.">Identification of genes involved in the mutualistic colonization of the nematode Heterorhabditis bacteriophora by the bacterium Photorhabdus luminescens.</a> BMC Microbiol. 10, 45 (2010).</li><li>Somvanshi, V. S., Kaufmann-Daszczuk, B., Kim, K. S., Mallon, S., Ciche, T. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Photorhabdus+phase+variants+express+a+novel+fimbrial+locus,+mad,+essential+for+symbiosis.">Photorhabdus phase variants express a novel fimbrial locus, mad, essential for symbiosis.</a> Mol. Microbiol. 77, 1021-1038 (2010).</li><li>Martens, E. C., Russell, F. M., Goodrich-Blair, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Analysis+of+Xenorhabdus+nematophila+metabolic+mutants+yields+insight+into+stages+of+Steinernema+carpocapsae+nematode+intestinal+colonization.">Analysis of Xenorhabdus nematophila metabolic mutants yields insight into stages of Steinernema carpocapsae nematode intestinal colonization.</a> Mol. Microbiol. 51, 28-45 (2005).</li><li>Sugar, D. R., Murfin, K. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phenotypic+variation+and+host+interactions+of+Xenorhabdus+bovienii+SS-2004,+the+entomopathogenic+symbiont+of+Steinernema+jollieti+nematodes.">Phenotypic variation and host interactions of Xenorhabdus bovienii SS-2004, the entomopathogenic symbiont of Steinernema jollieti nematodes.</a> Env. Microbiol. 14, 924-939 (2012).</li><li>Cowles, C. E., Goodrich-Blair, 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+Xenorhabdus+nematophila+nilABC+genes+confer+the+ability+of+Xenorhabdus+spp.+to+colonize+Steinernema+carpocapsae+nematodes.">The Xenorhabdus nematophila nilABC genes confer the ability of Xenorhabdus spp. to colonize Steinernema carpocapsae nematodes.</a> J. Bacteriol. 190, 4121-4128 (2008).</li><li>Heungens, K., Cowles, C. E., Goodrich-Blair, H. <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+Xenorhabdus+nematophila+genes+required+for+mutualistic+colonization+of+Steinernema+carpocapsae+nematodes.">Identification of Xenorhabdus nematophila genes required for mutualistic colonization of Steinernema carpocapsae nematodes.</a> Mol. Microbiol. 45, 1337-1353 (2002).</li><li>Goetsch, M., Owen, H., Goldman, B., Forst, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Analysis+of+the+PixA+inclusion+body+protein+of+Xenorhabdus+nematophila.">Analysis of the PixA inclusion body protein of Xenorhabdus nematophila.</a> J. Bacteriol. 188, 2706-2710 (2006).</li><li>Bhasin, A., Chaston, J. M., Goodrich-Blair, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mutational+Analyses+Reveal+Overall+Topology+and+Functional+Regions+of+NilB,+a+Bacterial+Outer+Membrane+Protein+Required+for+Host+Association+in+a+Model+of+Animal-Microbe+Mutualism.">Mutational Analyses Reveal Overall Topology and Functional Regions of NilB, a Bacterial Outer Membrane Protein Required for Host Association in a Model of Animal-Microbe Mutualism.</a> J. Bacteriol. 194, 1763-1776 (2012).</li><li>Ciche, T. A., Goffredi, S. K., Reddy, C. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Methods in General and Molecular Microbiology. , 394-419 (2007).</li><li>Goodrich-Blair, H., Clarke, D., Grewal, P. S., Ciche, T. A., Stock, S. P., Boemare, N., Vandenberg, J., Glazar, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Insect Pathogens, Molecular Approaches and Techniques. , 239-269 (2009).</li><li>Stock, S. P., Goodrich-Blair, H., Lacey, L. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Manual of Techniques in Invertebrate Pathology. , 375-425 (2012).</li><li>Martens, E. C., Gawronski-Salerno, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Xenorhabdus+nematophila+requires+an+intact+iscRSUA-hscBA-fdx+locus+to+colonize+Steinernema+carpocapsae+nematodes.">Xenorhabdus nematophila requires an intact iscRSUA-hscBA-fdx locus to colonize Steinernema carpocapsae nematodes.</a> J. Bacteriol. 185, 3678-3682 (2003).</li><li>Vivas, E. I., Goodrich-Blair, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Xenorhabdus+nematophilus+as+a+model+for+host-bacterium+interactions:+rpoS+is+necessary+for+mutualism+with+nematodes.">Xenorhabdus nematophilus as a model for host-bacterium interactions: rpoS is necessary for mutualism with nematodes.</a> J. Bacteriol. 183, 4687-4693 (2001).</li><li>White, G. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+method+for+obtaining+infective+nematode+larvae+from+cultures.">A method for obtaining infective nematode larvae from cultures.</a> Science. 66, 302-303 (1927).</li><li>Ciche, T. A., Ensign, 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=For+the+insect+pathogen+Photorhabdus+luminescens,+which+end+of+a+nematode+is+out.">For the insect pathogen Photorhabdus luminescens, which end of a nematode is out.</a> Appl. Environ. Microbiol. 69, 1890-1897 (2003).</li><li>Sicard, M., Brun, N. 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=Effect+of+native+Xenorhabdus+on+the+fitness+of+their+Steinernema+hosts:+contrasting+types+of+interaction.">Effect of native Xenorhabdus on the fitness of their Steinernema hosts: contrasting types of interaction.</a> Parasitol. Res. 91, 520-524 (2003).</li><li>Lambertsen, L., Sternberg, C., Molin, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mini-Tn7+transposons+for+site-specific+tagging+of+bacteria+with+fluorescent+proteins.">Mini-Tn7 transposons for site-specific tagging of bacteria with fluorescent proteins.</a> Environ. Microbiol. 6, 726-732 (2004).</li><li>Miller, W. G., Leveau, J. H., Lindow, S. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Improved+gfp+and+inaZ+broad-host-range+promoter-probe+vectors.">Improved gfp and inaZ broad-host-range promoter-probe vectors.</a> Mol. Plant Microbe Int. 13, 1243-1250 (2000).</li><li>Teal, T. K., Lies, D. P., Wold, B. J., Newman, D. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spatiometabolic+stratification+of+Shewanella+oneidensis+biofilms.">Spatiometabolic stratification of Shewanella oneidensis biofilms.</a> Appl. Environ. Microbiol. 72, 7324-7330 (2006).</li><li>Bao, Y., Lies, D. P., Fu, H., Roberts, G. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+improved+Tn7-based+system+for+the+single-copy+insertion+of+cloned+genes+into+chromosomes+of+Gram-negative+bacteria.">An improved Tn7-based system for the single-copy insertion of cloned genes into chromosomes of Gram-negative bacteria.</a> Gene. 109, 167-168 (1991).</li><li>Woodring, J. L., Kaya, H. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Steinernematid+and+Heterorhabditid+Nematodes:+A+Handbook+of+Biology+and+Techniques.">Steinernematid and Heterorhabditid Nematodes: A Handbook of Biology and Techniques.</a> Southern Cooperative Series Bulletin 331. , (1988).</li></ol>

The protocol described here provides a method for the optical detection of bacteria within a nematode host (Figure 1). This method takes advantage of the optical transparency of nematodes and the ability to fluorescently label bacteria, enabling in vivo analysis of bacteria within the nematode host (Figure 3). Specifically, this approach identifies bacterial localization within its host. By counting a nematode population and scoring for bacterial presence, the frequency of bacte...

<table border="1">
 <tbody>
 <tr>
 <td>Name of the reagent</td>
 <td>Company</td>
 <td>Catalogue number</td>
 <td>Comments (optional)</td>
 </tr>
 <tr>
 <td>Lipid Agar 
 (sterile)</td>
 <td></td>
 <td></td>
 <td>8 grams nutrient broth, 15 grams agar, 5 grams yeast extract, 890 ml water, 10 ml 0.2 g/ml MgCl2. 6H20, 96 ml corn syrup solution*, 4 ml corn oil* 
 Stir media while pouring plates 
 *add sterile ingredient after autoclaving </td>
 </tr>
 <tr>
 <td>Corn Syrup Solution 
 (sterile)</td>
 <td></td>
 <td></td>
 <td>7 ml corn syrup, 89 ml water 
 mix and autoclave</td>
 </tr>
 <tr>
 <td>Egg Solution</td>
 <td></td>
 <td></td>
 <td>16.6 ml 12% sodium hypochlorite, 5 ml 5M KOH, 80 ml water</td>
 </tr>
 <tr>
 <td>Lysogeny Broth 
 (sterile)</td>
 <td></td>
 <td></td>
 <td>5 grams yeast extract, 10 grams tryptone, 5 grams salt, 1 L water 
 mix and autoclave</td>
 </tr>
 <tr>
 <td>Microfuge</td>
 <td>Fisher</td>
 <td>13-100-675</td>
 <td>Any microfuge that holds microfuge tubes will work</td>
 </tr>
 <tr>
 <td>Centrifuge</td>
 <td>Beckman</td>
 <td>366802 </td>
 <td>Large table top centrifuge that holds 15 ml and 50 ml conical tubes</td>
 </tr>
 <tr>
 <td>Sterile 60 mm X 15 mm Petri Dish</td>
 <td>Fisher</td>
 <td>0875713</td>
 <td></td>
 </tr>
 <tr>
 <td>50 ml centrifuge tubes</td>
 <td>Fisher</td>
 <td>05-539-6</td>
 <td></td>
 </tr>
 <tr>
 <td>15 ml centrifuge tubes</td>
 <td>Fisher</td>
 <td>05-531-6</td>
 <td></td>
 </tr>
 <tr>
 <td>Sterile 100 mm X 20 mm Petri Dish</td>
 <td>Fisher</td>
 <td>0875711Z</td>
 <td>Deeper than standard Petri dishes</td>
 </tr>
 <tr>
 <td>24-well plate</td>
 <td>Greiner Bio-One</td>
 <td>662000-06</td>
 <td></td>
 </tr>
 <tr>
 <td>Microscope</td>
 <td></td>
 <td></td>
 <td>The microscope needs florescent capabilities compatible with your fluorophore </td>
 </tr>
 <tr>
 <td>Paraformaldehyde</td>
 <td>Electron Microscopy Sciences</td>
 <td>15710</td>
 <td></td>
 </tr>
 <tr>
 <td>PBS 
 (sterile)</td>
 <td></td>
 <td></td>
 <td>8 g NaCL 
 0.2 g KCL 
 1.44 g Na2HPO4 
 0.24 g KH2PO4 
 1 L water Adjust to a pH of 7.4 and water to 1 L and autoclave</td>
 </tr>
 <tr>
 <td>Microfuge tubes</td>
 <td>Fisher</td>
 <td>05-408-138</td>
 <td>2 ml or 1.5 ml tubes</td>
 </tr>
 <tr>
 <td>Shaker</td>
 <td></td>
 <td></td>
 <td>Any shaker that causes the liquid to gently move will work</td>
 </tr>
 <tr>
 <td>Diaminopimelic acid</td>
 <td>Sigma</td>
 <td>D-1377</td>
 <td>If needed, supplement media to a concentration or 1 mM</td>
 </tr>
 </tbody>
</table>

visualizing bacteria in nematodes using fluorescent microscopy

Symbioses, the living together of two or more organisms, are widespread throughout all kingdoms of life. As two of the most ubiquitous organisms on earth, nematodes and bacteria form a wide array of symbiotic associations that range from beneficial to pathogenic 1-3. One such association is the mutually beneficial relationship between Xenorhabdus bacteria and Steinernema nematodes, which has emerged as a model system of symbiosis 4. Steinernema nematodes are entomopathogenic, using their bacterial symbiont to kill insects 5. For transmission between insect hosts, the bacteria colonize the intestine of the nematode's infective juvenile stage 6-8. Recently, several other nematode species have been shown to utilize bacteria to kill insects 9-13, and investigations have begun examining the interactions between the nematodes and bacteria in these systems 9.
We describe a method for visualization of a bacterial symbiont within or on a nematode host, taking advantage of the optical transparency of nematodes when viewed by microscopy. The bacteria are engineered to express a fluorescent protein, allowing their visualization by fluorescence microscopy. Many plasmids are available that carry genes encoding proteins that fluoresce at different wavelengths (i.e. green or red), and conjugation of plasmids from a donor Escherichia coli strain into a recipient bacterial symbiont is successful for a broad range of bacteria. The methods described were developed to investigate the association between Steinernema carpocapsae and Xenorhabdus nematophila 14. Similar methods have been used to investigate other nematode-bacterium associations 9,15-18and the approach therefore is generally applicable.
The method allows characterization of bacterial presence and localization within nematodes at different stages of development, providing insights into the nature of the association and the process of colonization 14,16,19. Microscopic analysis reveals both colonization frequency within a population and localization of bacteria to host tissues 14,16,19-21. This is an advantage over other methods of monitoring bacteria within nematode populations, such as sonication 22or grinding 23, which can provide average levels of colonization, but may not, for example, discriminate populations with a high frequency of low symbiont loads from populations with a low frequency of high symbiont loads. Discriminating the frequency and load of colonizing bacteria can be especially important when screening or characterizing bacterial mutants for colonization phenotypes 21,24. Indeed, fluorescence microscopy has been used in high throughput screening of bacterial mutants for defects in colonization 17,18, and is less laborious than other methods, including sonication 22,25-27and individual nematode dissection 28,29.

Watch this Scientific Journal Video about Visualizing Bacteria in Nematodes using Fluorescent Microscopy at JoVE.com

Visualizing Bacteria in Nematodes using Fluorescent Microscopy

To study the mutualism between Xenorhabdus bacteria and Steinernema nematodes, methods were developed to monitor bacterial presence and location within nematodes. The experimental approach, which can be applied to other systems, entails engineering bacteria to express the green fluorescent protein and visualizing, using fluorescence microscopy bacteria within the transparent nematode.

 
Symbioses, the living together of two or more organisms, are widespread throughout all kingdoms of life. As two of the most ubiquitous organisms on ...

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JoVE Journal

Biology

Visualizing the Live Drosophila Glial-neuromuscular Junction with Fluorescent Dyes

Visualizing the Live Drosophila Glial-neuromuscular Junction with Fluorescent Dyes

Our project identified GFP labeled glial structures at the developing larval fly neuromuscular synapse. To look at development of live glial-nerve-muscle ...

Visualizing Single Molecular Complexes In Vivo Using Advanced Fluorescence Microscopy

Visualizing Single Molecular Complexes In Vivo Using Advanced Fluorescence Microscopy

Full insight into the mechanisms of living cells can be achieved only by investigating the key processes that elicit and direct events at a cellular ...

Visualizing Single-molecule DNA Replication with Fluorescence Microscopy

We describe a simple fluorescence microscopy-based real-time method for observing DNA replication at the single-molecule level. A circular, forked DNA ...

Intravital Microscopy for Imaging Subcellular Structures in Live Mice Expressing Fluorescent Proteins

Here we describe a procedure to image subcellular structures in live rodents that is based on the use of confocal intravital microscopy. As a model organ, ...

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

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 ...

In vivo Clonal Tracking of Hematopoietic Stem and Progenitor Cells Marked by Five Fluorescent Proteins using Confocal and Multiphoton Microscopy

In vivo Clonal Tracking of Hematopoietic Stem and Progenitor Cells Marked by Five Fluorescent Proteins using Confocal and Multiphoton Microscopy

We developed and validated a fluorescent marking methodology for clonal tracking of hematopoietic stem and progenitor cells (HSPCs) with high spatial and ...

Visualizing Stromule Frequency with Fluorescence Microscopy

Stromules, or "stroma-filled tubules", are narrow, tubular extensions from the surface of the chloroplast that are universally observed in plant cells but ...

Split Green Fluorescent Protein System to Visualize Effectors Delivered from Bacteria During Infection

Bacteria, one of the most important causative agents of various plant diseases, secrete a set of effector proteins into the host plant cell to subvert the ...

Visualizing and Tracking Endogenous mRNAs in Live Drosophila melanogaster Egg Chambers

Visualizing and Tracking Endogenous mRNAs in Live Drosophila melanogaster Egg Chambers

Fluorescence-based imaging techniques, in combination with developments in light microscopy, have revolutionized how cell biologists conduct live cell ...