CRITICAL ELECTROLYTE CONCENTRATION OF DNA-PROTEIN COMPLEXES IN SPERMATOZOAL AND SOMATIC-CELL NUCLEI OF THE HONEY-BEE, APIS-MELLIFERA

The binding of toluidine blue molecules to DNA phosphates under condit ions of competitive staining,vith Mg2+ was studied in nuclei of sperma tozoa, and in the spermatheca and spermathecal glands of honey bee (Ap is mellifera) queens. The objective,vas to detect differences in the c ritical electrolyte concentration (CEC) for the chromatin of these cel ls, even though an ill histone has also been assumed to occur in the s permatozoa of A, mellifera. The CEC values were found to be the same f or the different somatic cells analysed but to be higher in the sperma tozoa, with even increased values after the lodging of these cells in the queen's spermatheca, A greater availability of DNA phosphates for the dye-Mg2+ competitive binding action was thus demonstrated for the spermatozoa compared to the somatic cells in A. mellifera. This is att ributed to differences in their DNA-protein complexes, contributing to differences in chromatin packing states, The increased CEC found in t he spermatozoa inside the spermatheca is certainly related to addition al changes affecting the DNA-protein complex in the chromatin of the m ale cells after they penetrate the female tract. Copyright (C) 1996 El sevier Science Ltd