Yngve Melander

Gomori's Hematoxylin as a cHromosome Stain

The chromic hematoxylin of Gomori (1941) can be used as an excellent chromosome stain after hydrolysis of the tissue in warm 1–N hydrochloric acid. The hydrolysis must be accurately timed for different material as in the case of the Feulgen reaction. The staining of sections can be performed at room temperature and requires about 15 minutes. For pieces of tissue and whole preparations, it is recommended to stain at 60°C. for 40 minutes. Sections stained at room temperature can be differentiated in 1% hydrochloric acid alcohol for one minute and can be counterstained with phloxine according to Gomoris formula. Whole preparations or sections stained at 60°C. must be differentiated in 45% acetic acid for half an hour or more. Tissue pieces may, after staining, be squashed and examined in the acetic acid, but the preparations can also be made permanent. The blue-black stain is very selective and has the advantage of giving high contrast, and it is nonfading, and insoluble in water and other common reagents. ...

Meiosis in Cepaea nemoralis studied by microcinematography

SummarySome aspects of meiosis in spermiocytes of Cepaea nemoralis L. are presented. They are based on in vitro studies with the use of time-lapse 16 mm film recording. The main results are:1.The nucleus changes its shape irregularly during diakinesis (and probably earlier stages) until the disappearance of the nuclear membrane. During this period the prophase bivalents inside the nucleus change their position and shape irregularly. Suggestions concerning the importance of such movements are made.2.In many spermiocyte divisions the spindle oscillates regularly in one or several planes. In all cells the periodicity is of more or less the same duration, about 2 mins.3.The volume of the nucleus diminishes during the 1–2 hour period before the disappearance of the nuclear membrane and increases again rapidly a few minutes before the nuclear membrane disappears. The disappearance of the nuclear membrane is followed by a rapid condensation of the space occupied by the chromosomes (contraction stage). This space increases again during prometaphase. The latter events closely resemble those in mitosis of plant endosperm cells.