PRESENCE OF SIALIC-ACID IN PROTHORACIC GLANDS OF GALLERIA-MELLONELLA (LEPIDOPTERA)

The presence of sialic acid (SA) in prothoracic glands (PGs) of Galler ia mellonella was determined by the methods of electron microscopy (EM ), histochemistry, spectrophotometry (SP) and electronic ionization (E I)-mass spectroscopy. Histochemical observations were carried out by t he cationic dye ruthenium red (RR), staining with and without neuramin idase digestion in the larval stage. Neuraminidase-sensitive SA was de monstrated by the decrease in the amount of RR-binding following neura minidase digestion. The total amount of SA was found to be 0.09016 mg g(-1) in dry tissue by spectrophotometric determination. EI-mass spect roscopy results confirmed the EM and SP observations. The fragmentatio n scheme derived from EI-mass analysis exhibited the presence of the l actonized form of Neu5Gc7, 9Ac(2). On the basis of the various pieces of evidence described above, it was firmly concluded that Neu5Gc7, 9Ac (2) molecules were present in PGs of G. mellonella.