Effects of sinus gland extract on mandibular organ size and methyl farnesoate synthesis in the crawfish.
Eyestalk inhibition of farnesoic acid O-methyl transferase, which mediates the final step of methyl farnesoate synthesis in the mandibular organ of the crawfish Procambarus clarkii, was evaluated. Eyestalk removal caused a 20-100-fold increase in methyl transferase activity 8-12 days following surgery. The surge in activity following eyestalk removal in males was approximately 4 days ahead of that of the females. This was accompanied by a three-fold increase in mandibular organ protein content. Methyl transferase inhibition was accomplished in vitro after only a 15-min exposure to sinus gland extract. The inhibition obtained by injecting animals in vivo was noticeably attenuated 6 h following injection. The contrast of the short-lived inhibition with the growth and prolonged increase following eyestalk removal suggests that the eyestalk exerts both chronic and acute effects on the mandibular organ.
Department of Biology, Texas A & M University, 77843, College Station, TX, USA. archaves54@hotmail.com
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D000818:Animals; D003400:Astacoidea / Q000033:anatomy & histology* / Q000378:metabolism; D005231:Fatty Acids, Unsaturated / Q000096:biosynthesis*; D005260:Female; D008297:Male; D008780:Methyltransferases / Q000037:antagonists & inhibitors / Q000378:metabolism; D012679:Sense Organs / Q000378:metabolism*
D005231:Fatty Acids, Unsaturated; C032429:methyl farnesoate; D008780:Methyltransferases; C032433:farnesoic acid O-methyltransferase