Production of age-synchronous mass cultures of Caenorhabditis elegans

Methods are described for culturing large populations of age-synchronous Caenorhabditis elegans throughout the adult life span. Contamination of adult populations by progeny was prevented by constructing double-mutant strains that produce progeny at a frequency of less than .005 per adult at the nonpermissive temperature (25.5 degrees C). Of four double-mutant strains that we have characterized, three have wild-type life spans at 25.5 degrees. The other strain contains a mutant allele, age-1(hx542), that results in an increase in life span of 60% over wild type. All four strains produced sufficient numbers of progeny at the permissive temperature (20 degrees C) to generate populations containing 1-5 x 10(6) nematodes within two weeks. Age-synchronous young adult populations were produced using these strains and have been maintained as adults both in liquid culture and on agar medium. Procedures that reduce E. coli contamination by 30-fold in harvested samples of adults are also described.