On the reported occurrence of an ecdysone-like steroid in the freshwater snail, Biomphalaria glabrata (Pulmonata; Basommatophora), intermediate host of Schistosoma mansoni

Abstract

Attempts to repeat the isolation of an ecdysone-like steroid from Biomphalaria glabrata revealed that some of the manipulations described by Muftic (1969) were physically impossible to repeat. With modified procedures no ecdysone-like steroid was found. The original publication gives scant attention to certain experimental details. Some sections of the text bear very close resemblance to earlier publications by different authors. The amount of substance claimed to have been isolated, and the long survival period claimed for Schistosoma mansoni larvae in vitro, are claims which, amongst others, seem highly unlikely a priori. All attempts to contact Muftic have proved to be futile. It is suggested that the paper is, at least in part, erroneous and that any future reference to it should clearly indicate its suspected invalidity.Despite these results, it is considered likely that future investigations will demonstrate physiological roles for steroids in snails.I wish to acknowledge the stimulating communications of Drs E. L. Hansen, M. Voge, R. E. Thorson, C. S. Richards, J. N. Kaplanis, G. Nace, R. Monroe, and of E. Chernin, who first brought this matter to my attention. Theanalytical steroid work could not have been done nor interpreted without the considerable time and effort willingly given by Drs F. Kohen and R. Counsell of the University of Michigan College of Pharmacy. My snail populations were supplemented with snails from the tanks of Mrs B. Caveny. Technical help was given by E. Perisho, G. Lindsay and P. LoVerde. Financial support was kindly provided by Dr J. B. Burch. This investigation was supported in part by the United States-Japan Cooperative Medical Science Program administered by the National Institute of Allergy and Infectious Diseases of the National Institutes of Health, Department of Health, Education and Welfare, grant N.I.A.I.D. AI-7364, and in part by NSF grant GB-29315. Improvements were made to the first draft of the manuscript after it was critically read by Drs E. L. Hansen, F. Kohen, M. Voge, E. Chernin, R. E. Thorson and J. N. Kaplanis.