Effects of precocene analogs on the nematode Caenorhabditis remanei (var. Bangaloreiensis). II. Competitions with a juvenile hormone analog (Methoprene).

A Fodor, T Tímár

Index: Gen. Comp. Endocrinol. 74(1) , 32-44, (1989)

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Abstract

Fourteen 7-alkoxy-2,2-dimethychromenes were synthetized and studied in JH competition experiments: precocenes (Ps) PI and PII, and synthetic analogs (PAs) including (i) three with both antiallatal and P-like activities: 7-ethoxy-PII (7-EPII); 7-(prop-2-ynyloxy)-2,-2-dimethylchromene (PPI); and 6-methoxy-7-(prop-2-ynyloxy)-2,2-dimethylchromene (PPIII); (ii) six without antiallatal activity, exerting P-like activity in nematodes; and (iii) three without either antiallatal or P-like activity, but with a strong nematocidal effect. Within the dose range 8-1000 micrograms/ml, different concentrations of each PA were applied to nematode growth medium which did or did not contain 1000 micrograms methoprene (a juvenile hormone analog JHA)/ml. Plates inoculated with Caenorhabditis embryos were incubated and scored for developmentally affected survivors. The JHA did not compete with any PA mentioned as (iii). It competed moderately with some nonantiallatal PAs (8-Me-PPI, 8-MeO-PPI, and 3,4-diCl-PPI) with strong P-like and nematocidal activities. The JHA competed most efficiently with all Ps, antiallatal PAs, and two nonantiallatal PAs (PPII and thio-PI) which exerted severe P-like activities in nematodes. Parameters assumed to be indicators of the P-like (rather than nematocidal) activity of the PAs proved more sensitive to the JHA than those of nematocidal activity. Whether the JH-compensable P-like activity of some PAs can be regarded as a real anti-JH action needs further clarification.