A method is described for the isolation, according to size, of mini segregants produced by the abnormal cleavage of reversibly arrested mitotic HeLa cells. Many of these mini segregants contain small amounts of DNA, as judged by Feulgen staining and chromosome analysis. After fusion with mitotic HeLa cells, the interphase chromosomes of the mini segregants are seen as either monovalent or bival...

One of the most important questions in clinical routine is to find out patients with good or worse prognosis to apply an optimal therapy scheme for each patient. In this study 58 patients with different neuroendocrine tumours of the lung were investigated. Histological sections were prepared with different stainings (MIB-1, AgNOR, Feulgen). By means of high resolution image cytometry stereologi...

A direct staining procedure is described for fluorescence microscopy of fungal nuclei, chromosomes and mitochondria. The fluorochrome is a benzimidazol derivative (33258 Hoechst) known to bind selectively to deoxyribonucleic acid at neutral pH. The advantages of 33258 Hoechst relative to Feulgen compounds used previously to stain these structures include a greater intensity of fluorescence, th...

Breakthroughs in microscopy technology provide new insights into cell biology. Early microscopes allowed Robert Hooke to see cells. Improved staining techniques enabled Camillo Golgi to see the apparatus that bears his name, and Robert Feulgen to visualize DNA in chromosomes. Similarly, EM allowed Keith Porter to visualize the endomembrane system. More recently, transgenic technology using fluo...

Acid hydrolysis of tissue has long been recognized as a necessary part of the Feulgen method for demonstrating the presence of DNA (deoxyribonucleic acid) in histological preparations (Feulgen and Rossenbeck, 1924). When attempts were made to use the method for the quantitative determination of DNA (Pollister and Ris, 1947; Di Stefano, 1948; Ris and Mirsky, 1949; Swift, 1950 a), the role of hyd...

Despite of a huge amount of literature on the Feulgen reaction for DNA relatively few in­ vestigations deal with the special needs of plant scientists. As a consequence various mod­ ifications of the method are practised in different laboratories, which may in part be re­ sponsible for contradictory results. In the present work tests are conducted to find out, which steps of the procedure must ...

Chromosome morphology was studied in lily genotypes L. candidum, L. × formolongi, L. henryi and L. pumilum, and cultivars ‘Alma Ata,’ ‘Expression,’ ‘Marco Polo,’ ‘Muscadet’ and ‘Star Gazer’ belonging to the horticultural group Oriental hybrids. All genotypes tested represented 2n = 2x = 24 chromosomes. Chromosomal markers were established after Feulgen and silver staining, from analysis of the ...

Diploid isolates of Hansenula holstii Wick. and H. wingei Wick. usually produce two or three ascospores per ascus. An unusual nuclear event during meiosis might account for less than the expected number of four. When acridine orange or Feulgen staining was used, meiosis in both species followed the pattern established in higher plants and animals. Deoxyribonuclease treatment destroyed nuclear s...