MICROSPECTROFLUORIMETRY OF THE NATURALLY FLUORESCENT SUBSTANCES OF THE MALPIGHIAN TUBULES OF TRIATOMA INFESTANS AND PANSTRONGYLUS MEGISTUS

Abstract

The autofluorescence of the Malpighian tubules of blood-sucking insects was studied microspectrofluorimetrically. Spectral emission profiles were determined for the naturally fluorescent substances present at the lumen of the proximal region and in the cytoplasm of the distal region of the organ. These were compared with the emission profiles exhibited by standards of fluorescent substances generally found in insect Malpighian tubules. The fluorescence detected at the proximal region was then concluded to be provided by uric acid whereas that of the distal region was attributed to kynurenine. The results did not vary as a function of the developmental stage of the insects. If pteridins are present in the tubules, they appear not to affect the fluorescence patterns determined in this work.