A Simple Permanent Aceto-Orcein Stain for Free Cells, Cultures and Homogenates

A simplified technic for preparation of the aceto-orcein stain permits the storage of cells in the stain or squash preparations at room temperature for long periods without in* jury to or distortion of the cells and mitotic plates. Fresh cells from tumor ascites, tissue culture cells growing in free suspension or over cover slips, and homogenates of whole tissues are stained directly in a test tube in either (1) regular aceto-orcein and subsequently mounted in glycerol, or (2) aceto-orcein-glycerol mixture. These preparations are squashed for chromosome counts, and the permanent slides are kept from drying out by ringing the cover slip with Damar or Permount.     

Ornithologishe Mittheilungen aus Oesterreich-Ungarn 1880

Ohne Zusammenfassung     

Ornithologische Mittheilungen aus Oesterreich und Ungarn. (1876.)

Ohne Zusammenfassung     

Ornithologische Mittheilungen aus Oesterreich (1871)

Ohne Zusammenfassung     

Das Anti-inv-l-Rie

Ohne ZusammenfassungDirektor: Prof. Dr. Dr. H. Baitsch Mit 1 TextabbildungMit Unterstützung durch die Deutsche Forschungsgemeinschaft.Die vorliegende Arbeit bildet einen wesentlichen Teil der Dissertation von E. Schmidtmann.     

Orientierende Untersuchungen über die Einwirkung von gasförmigem Formaldehyd auf die grüne Pflanze

Ohne Zusammenfassung     

Transition of rhodopsin into the active metarhodopsin II state opens a new light-induced pathway linked to Schiff base isomerization

Rhodopsin bears 11-cis-retinal covalently bound by a protonated Schiff base linkage. 11-cis/all-trans isomerization, induced by absorption of green light, leads to active metarhodopsin II, in which the Schiff base is intact but deprotonated. The subsequent metabolic retinoid cycle starts with Schiff base hydrolysis and release of photolyzed all-trans-retinal from the active site and ends with the uptake of fresh 11-cis-retinal. To probe chromophore-protein interaction in the active state, we have studied the effects of blue light absorption on metarhodopsin II using infrared and time-resolved UV-visible spectroscopy. A light-induced shortcut of the retinoid cycle, as it occurs in other retinal proteins, is not observed. The predominantly formed illumination product contains all-trans-retinal, although the spectra reflect Schiff base reprotonation and protein deactivation. By its kinetics of formation and decay, its low temperature photointermediates, and its interaction with transducin, this illumination product is identified as metarhodopsin III. This species is known to bind all-trans-retinal via a reprotonated Schiff base and forms normally in parallel to retinal release. We find that its generation by light absorption is only achieved when starting from active metarhodopsin II and is not found with any of its precursors, including metarhodopsin I. Based on the finding of others that metarhodopsin III binds retinal in all-trans-C(15)-syn configuration, we can now conclude that light-induced formation of metarhodopsin III operates by Schiff base isomerization ("second switch"). Our reaction model assumes steric hindrance of the retinal polyene chain in the active conformation, thus preventing central double bond isomerization.     

Embryonic and larval development of jundiá (Rhamdia quelen, Quoy and Gaimard, 1824, Pisces, TeleosteI), a South American catfish.

The jundiá (Rhamdia quelen, Quoy and Gaimard) is an endemic South American fish species. Because this species supports cold winters and grows faster during warm months, it has begun to be viewed as an ideal species for fish production in southern South America. In the present study, jundiá oocytes used were obtained by extrusion from females after hormone injection. Soon after hydration, the eggs were transferred to 50 L conic glass incubators, with constant and controlled water influx. Samples of fertilized eggs were transferred to Petri dishes and, examined under a stereoscopic microscope, were spherical, demersal, and non-adhesive with defined perivitelline space and resistant chorion. Cleavage stages occurred during the first 3.5 h. After hatching, larvae were transferred to 200 L glass fiber incubators. First signs of embryo movement were observed 21 h after fertilization; larval eclosion occurred 30.5 h after fertilization. Present findings may provide a basis for studies aimed at determining the complete ontogeny of jundiá and may be useful in eco-toxicological studies.