Cytophotometric determinations of nuclear DNA content in tissues of the wax moth larva, Galleria mellonella Linnaeus

Graduation date: 1965The present study was undertaken to determine, by measurement\ud of nuclear DNA, the degrees and frequencies of ploidy in the\ud last larval instar of the moth Galleria mellonella Linnaeus. While\ud such data have been amassed for a wide variety of vertebrate tissues,\ud few studies have been concerned with invertebrates and especially\ud insects where somatic polyploidy is developed to an unusually high\ud degree.\ud Relative amounts of DNA were determined cytophotometrically\ud on individual Feulgen-stained nuclei of hypodermis, ventriculus, fat\ud cells, blood cells, anterior silk gland, and proventriculus. Graphs\ud of the determined DNA values indicated the presence of nuclear\ud classes falling into polyploid ratios,\ud The majority of blood cell and fat cell nuclei had class I\ud values (= diploid), while class II and III (= tetraploid and octoploid) DNA values represented about 17 to 20 percent of the total nuclear\ud population. The majority of DNA values of the ventriculus nuclei fell\ud into the second class while 6.8 percent were considered as class I.\ud The hypodermal nuclei were mostly of class I, while class II values\ud represented 5.5 percent of the total number of determinations.\ud Nuclei of the proventriculus and the anterior silk gland showed\ud a broad spectrum of DNA values ranging from classes IV to VIII\ud including many intermediate values.\ud The method of measurement was analyzed for sources of\ud error. Various interpretations were offered for the variations in DNA\ud values including the role of endomitosis, definitive polyploidy, aneuploidy,\ud differential gene replication, etc. In the case of the anterior\ud silk gland and the proventriculus a possible relationship between DNA\ud amounts and ceIl activity is indicated