Localization of ions in the mesophyll cells of the succulent halophyteSuaeda monoica forssk. by X-ray microanalysis

Zusammenfassung Die Verteilung von Natrium, Chlorid, Kalium und Phosphor im Zytoplasma und in den Vakuolen der Blattzellen vonSuaeda-monoica-Pflanzen wurde mittels Röntgen-Mikrosonde untersucht. Natrium neigte zur Anreicherung im Zytoplasma, während Chlorid gleichmässig im Zytoplasma und in Vakuolen verteilt war.     

Neurosecretory cells inArtemia salina L.

Zusammenfassung Mit der Gömöri-Technik wurden beiArtemia drei Typen neurosektretorischer Zellen nachgewiesen. Im Gehirn sind grosse, ovale Zellen mit vakuolisiertem Cytoplasma vorhanden, von denen einige grosse Axone besitzen. Der 2. Typus ist kleiner und weist keine zum Augenstiel führenden Fortsätze auf. Der 3. Typus liegt als traubenförmige Gruppen von Zellen im X-Organ des Augenstiels. Wahrscheinlich ist ventral am Gehirn ein Depotorgan für das Sekret des 1. Typus vorhanden. Die Beziehung dieser Zellen zur parthenogenetischen Vermehrung der Art wird untersucht.     

Localization of sodium ions in dog submandibular gland tissue by the use of potassium pyroantimonate

Résumé Des glandes sousmaxillaires de chiens ont été coupées en morceaux et mises dans un fixatif composé de 2% KSB(OH)₆ et soit de 6.25% d'aldéhyde glutarique, soit de 2% d'osmium et préparées pour l'examen au microscope électronique. Quand les tissus sont fixés à l'aldéhyde glutarique, le précipité est principalement extracellulaire. Par contre, avec le fixatif à l'osmium, le précipité est plus diffus et se trouve partout dans la cellule. Cependant, on ne peut pas se fier à cette méthode pour localiser des ions de sodium in vivo.     

Localization of pyruvate carboxylase in the cells ofNeurospora crassa

Summary The cell wall ofNeurospora crassa was digested enzymatically and the cytosolic and the mitochondrial fractions were separated. The activity of pyruvate carboxylase (EC 6.4.1.1) was detected entirely in the cytosolic fraction. This indicates that the location of pyruvate carboxylase ofN. crassa is in the cytosol, but is not in the mitochondria; this is different from the situation in animal tissues.     

Tonofilament aggregations in ultimobranchial gland cells of Rana temporaria L.

Résumé Observations ultrastructurales sur les corps ultimobranchiaux des grenouilles adultes (Rana temporaria) au printemps ont montré des accumulations de microfibrilles cytoplasmiques.     

Localization of pyruvate carboxylase in the cells of Neurospora crassa

The cell wall of Neurospora crassa was digested enzymatically and the cytosolic and the mitochondrial fractions were separated. The activity of pyruvate carboxylase (EC 6.4.1.1) was detected entirely in the cytosolic fraction. This indicates that the location of pyruvate carboxylase of N. crassa is in the cytosol, but is not in the mitochondria; this is different from the situation in animal tissues.     

Orientation of Giemsa C-bands in interphase cells of Allium cepa L.

Orientation of Giemsa C-bands in Allium cepa was studied in both mitotic and interphase cells. It has been shown that telophase orientation of the chromosome is maintained throughout the interphase and early phophase. It has been assumed that this non-random orientation is due to anchorage of the telomeres with the nuclear membrane. Contrary to earlier observations, 2 by 2 pairing of the telomers could not be traced to this species.     

Orientation of Giemsa C-bands in interphase cells of Allium cepa L.

Summary Orientation of Giemsa C-bands in Allium cepa was studied in both mitotic and interphase cells. It has been shown that telophase orientation of the chromosome is maintained throughout the interphase and early prophase. It has been assumed that this non-random orientation is due to anchorage of the telomeres with the nuclear membrane. Contrary to earlier observations, 2 by 2 pairing of the telomeres could not be traced in this species.     

Localization of cholesterol in the Golgi apparatus of cardiac muscle cells

Summary Filipin (a polyene) interacts with cholesterol in membranes, producing distinctive deformations that can be detected by freeze-fracture. The distribution of filipin-induced deformations in the Golgi apparatus of cardiac myocytes suggests a role for this organelle in the transformation of cholesterol-poor membrane to cholesterol-rich membrane.Acknowledgments. This work was supported by a grant (No. 779) from the British Heart Foundation. I thank Dr E. Massey and Mr A. Slade for their help. Filipin was generously donated by Upjohn Ltd, Crawley, Sussex, U.K.     

Localization of the exogenous fluorescent histones in Ehrlich Ascites tumour cells

Résumé Les auteurs ont étudié la localisation des histones fluorescents dans des cellules tumereuses d'ascites Ehrlich soumises à l'incubation in vitro avec les dérivés fluorescents de l'histone de thymus bovin ou avec quelques fractions du même histone. Ils ont démontré qu'après une incubation de courte durée les histones ont été adsorbés sur la surface des cellules, tandis que lors d'une incubation de longue durée les histones ont réussi à pénétrer dans les cellules.     

Localization of substance P-like immunoreactivity in Hydra.

Substance P-like immunoreactivity was found in Hydra attenuata mainly but not exclusively in the nerve and interstitial cells, localized in the cytoplasm and on the cell surface membranes.