Melatonin synthesis by rabbit platelets

Platelets of reserpinized rabbits, incubated in buffer containing tritiated 5-hydroxytryptamine (³H-5HT), have the ability to convert ³H-5HT into labelled compound (s) extractable with alkaline-chloroform. The bulk of the chloroform-extractable radioactivity showed a Rf value similar to authentic melatonin on silicagel thin-layer chromatography.The labelled product eluted with ethanol from the silicagel area where melatonin was suspected to reside was indentified as melatonin by mass spectrometry and radioimmunoassay.Our in vitro experiments demonstrate that rabbit platelets are capable of converting 5-HT into melatonin apparently because they possess the enzymatic equipment necessary for this biosynthesis i.e. serotonin N-acetyltransferase and hydroxyindole-O-methyltransferase.     

A double-feed anaerobic filter for the treatment of high strength wastewaters

Summary An Upflow Anaerobic Filter (UAF) treating cheese whey showed a non-homogeneous biomass distribution and COD degradation along the reactor. Higher biomass concentration with a higher methanogenic activity was present in the lower than in the upper part of the filter. In order to increase the methanogenic capacity of the filter, a double-feed system was tested. The UAF with the double feeding presented higher methane production and completely homogeneous characteristics regarding biomass distribution and activity as well as COD removal along the reactor.