Cellular location of (2R, 3R, 7Z)-2-aminotetradec-7-ene-1, 3-diol, a potent antimicrobial metabolite produced by the Caribbean sponge Haliclona vansoesti

The Caribbean sponge Haliclona vansoesti has been found to contain large am ounts of a new sphingosine derivative, (2R, 3R, 7Z)-2-aminotetradec-7-ene-1 , 3-diol (compound 1). To determine the localization of this compound withi n the organism, cell distribution and quantitative determination of the ami nodiol content of cell fractions obtained by differential centrifugation ha ve been performed. Results show that choanocytes and archaeocytes are the m ajor sponge cell types and that H. vansoesti harbour small photosynthetic s ymbionts (cyanobacteria) and few heterotrophic bacteria. Reverse-phase HPLC analyses of the cell fractions reveal that the aminodiol 1 is not associat ed with the prokaryotic endobionts but with the sponge cells, in particular the archaeocytes. This is clearly established by the positive significant correlation existing between the numbers of archaeocytes and the amounts of aminodiol 1. The mean aminodiol concentration is estimated to be 2 mug/10( 5) archaeocytes. The aminodiol 1 is also found in substantial amounts in pr imary cell cultures, so that cell culture can be envisaged as an option for its production. Sponge cell suspensions display potent antibacterial and a ntiyeast activities, in correlation with their aminodiol content, indicatin g that this compound is at least in part responsible for these activities i n the sponge. The release of the aminodiol 1 into C, the external medium su ggests that this substance may be involved in the defence mechanisms of the sponge.