From owner-celegans@net.bio.net Thu Jan 18 22:00:00 1996 Path: biosci!lamg.com!Tritech_Research From: Tritech_Research@lamg.com (Tritech Research) Newsgroups: bionet.celegans Subject: Re: identification of different strains in large cultures Date: 19 Jan 1996 04:33:20 -0800 Organization: Los Angeles Macintosh Group BBS Lines: 51 Sender: daemon@net.bio.net Distribution: world Message-ID: <3410489310.1230947@lamg.com> Reply-To: Tritech_Research@lamg.com NNTP-Posting-Host: net.bio.net 1. Is there a way to determine population size of large cultures without having to count thousands of worms by eye? It might be easy enough to do this when the culture consists of only one strain, but in the future we are likely going need a way of determining relative numbers of two or more strains within the same culture (competition experiments). My notion is this: to find genetic markers specific to various strains, extract the DNA from an entire culture, and screen for relative amounts of each marker. Since we just got a new phosphoimager here at UMass, it would be nice use it. Does this seem plausible? Are there enough known strain-specific markers or mutations to be able to do this kind of thing? I can think of a few problems with this idea, but I think they should be able to be ironed out. -------------- Yes, there are a variety of strain-specific RFLP's (already cloned), including those due to cloned transposons, such as TC1. 2. Along the same lines: is it possible to screen for different strains by somehow simply labelling the exterior cuticle? Better yet, can this be done without killing that animals? Seems unlikely, but thought I'd ask. ---------------- I am sure there is something. There are cuticle-specific antibodies. 3. Any other idea on how to determine relative numbers of different strains in the same culture? ---------------- Not that I'd want to do it, but you could certainly grow one strain on Tritium-labeled E. coli and the other with C14, then count the samples in a scint-counter and monitor the H3:C14 ratio. 4. It's possible that we may someday need to do parasity-host or predator-prey types of experiments. What are some of the worms' natural enemies, and does anyone have any on hand? I imagine it's the type of thing most people don't want hanging aroung in their labs... ------------ There is a parasitic fungus. I forget its name. 5. What are some other foods the worms eat (different bacterial strains, etc.), and what other substrates do they like to live on? ------------ They eat a wide variety of bacteria. Besides agar, they certainly like rich soil! Good Luck, Andy Papp TRITECH_RESEARCH@LAMG.COM .