The banding pattern of the segment 46A–48C in Drosophila hydeï polytene chromosomes as studied by confocal scanning light microscopy (CSLM)

The banding pattern of the tip of the second chromosome in Drosophila hydeï has been investigated using confocal scanning light microscopy (CSLM). In Berendes' map [4] 46 bands were counted in this region, whereas our revised map shows 73 bands, an increase of 60%. Based on these data the entire genome of D. hydeï might be expected to contain at least 3200 bands.     

The banding pattern of the salivary gland chromosomes of Drosophila hydei

The banding pattern of the salivary gland chromosomes of D. hydei was investigated in the electron microscope. We compared the banding pattern of squashed chromosomes with non-squashed preparations and observed that the fixation and squash procedure we used does not introduce artificial changes in the banding pattern of the chromosome. An electron microscopic map was made of the banding pattern of the distal half of the second salivary gland chromosome. On the basis of the number of bands in this part of the second chromosome we calculated a total of about 3700 bands for the whole set of polytene chromosomes of D. hydei. Our data indicate a similar number of bands in the salivary gland chromosomes of evolutionary remote Drosophila species like D. hydei and D. melanogaster.     

Evidence for a migratory capability of rat Kupffer cells to portal tracts and hepatic lymph nodes

The present study concerns the migratory ability of Kupffer cells in the rat. Phagocytic cells were labeled with colloidal carbon or gold, these markers being administered intravenously either into a tail vein, which resulted in generalized reticuloendothelial uptake, or in low dose into the portal vein, which produced uptake by Kupffer cells alone. Cells containing marker were observed in the portal tracts and in hepatic lymph nodes from 1 to 3 days after injection into the portal vein. The direct movement of single marker particles to the portal tracts could be excluded. Since injection of marker into the portal vein labeled Kupffer cells exclusively, whereas blood cells, splenic and bone marrow macrophages remained unlabeled, the labeled cells in the portal tracts and hepatic lymph nodes appeared to be former Kupffer cells migrating which had migrated to these sites.     

Identification of the heat shock band 2-48B of Drosophila hydei and determination of its haploid DNA content

The heat shock locus 2-48B situated at the tip of the second chromosome of Drosophila hydei has been studied by various cytologic methods. Both from puffing behaviour and in situ hybridization on both wildtype animals and heterozygotes for the mutant chromosome Df(2)e20 the actual site is localized in band 2-48B8. Electron microscopically this band appears to be a medium size, dotted band. From cytophotometric measurements on Feulgen stained chromosomes and electron microscopic observations the DNA content of band 2-48B8 is calculated to be approximately 40 kb on the haploid level, with a compaction of the DNA of about 160 times. The interbands 2-48B7-8 and 2-48B8-9, flanking the heat shock band, were calculated to contain on the haploid level 1.5 kb and 3.0 kb, respectively. The results are discussed also in relation to the present data on the molecular organization of this locus.