Studien an einer farbig beringten Population des Braunkehlchens (Saxicola rubetra)

Ohne ZusammenfassungMrs. Margaret M. Nice gewidmet zum 70. Geburtstag am 6. Dezember 1953In verkürzter Form vorgetragen vonK. Schmidt auf der 67. Tagung der D. O.-G. am 16. August 1953 in Köln. — 291. Ringfundmitteilung der Vogelwarte Radolfzell.     

Indo-Pacific and Atlantic spurs and grooves revisited: the possible effects of different Holocene sea-level history,exposure, and reef accretion rate in the shallow fore reef

Shallow fore-reef areas worldwide are usually characterized by spurs and grooves. A comparison of examples from the three world oceans suggests that Indo-Pacific spurs and grooves are shaped predominantly by erosion, whereas western Atlantic spur and groove systems are largely a product of constructive processes. I propose that this difference is caused by regional differences in Holocene sea-level change, which controlled exposure to waves and currents, and reef-accretion rates. The transgressive–regressive sea-level curve in the Indo-Pacific realm, i.e., the Mid-to-Late Holocene sea-level fall in these areas has maintained high-energy conditions in the shallow fore reef. Higher exposure to waves and currents favors erosion and leads to a dominance of crustose coralline algae that have relatively slow growth rates. In the western Atlantic, the transgressive Holocene sea level has caused Mid-to-Late Holocene deepening and has maintained accommodation space for reef accretion. Fast-growing acroporid corals thrive under lower exposure and are more common than coralline algae. The fossil record of the spur and groove system is rather poor, which is probably a consequence of the need of excellent, three-dimensional outcrops for identification.     

Degradation of phosphorylated chromosomal nonhistone proteins

In experiments with in vivo 32P-labelled nonhistone proteins of rat liver nuclei it was shown that these components are more sensitive against degradation than the mass of the nonhistone proteins. In the presence of 0.1 mM phenylmethylsulfonylfluoride and 1 mM sodium molybdate, however, they are protected against degradation.     

Schiffs bases and derived secondary amines as plant growth inhibitors

Seventy-two Schiffs bases, 44 corresponding secondary amines, and 12 N-acetylated compounds were tested on their growth activity. Eighty-one compounds were active as growth inhibitors in at least one of three bioassays.     

High hydrostatic pressure and the dissection of fertilization responses : I. The relationship between cortical granule exocytosis and proton efflux during fertilization of the sea urchin egg

High hydrostatic pressure applied between sperm attachment and the onset of cortical granule exocytosis will inhibit this exocytotic event in sea urchin eggs. Such pressure-treated zygotes, nevertheless, are activated and capable of development. Thus, this technique can be used as a tool to study the relationship between cortical granule breakdown and other fertilization-related responses. We have studied whether the exocytosis of cortical granules is necessary for proton efflux (acid release) to occur. Our results indicate that although Ca²⁺ is released while the eggs are under pressure (a prerequisite for the following events to take place), cortical granule exocytosis and acid release are pressure-sensitive and completely inhibited at pressures above 400 atm (6000 psi) and 275 atm (4000 psi), respectively. However, upon decompression, acid release is initiated which amounts to 65–70% of that seen in the unpressurized controls, suggesting that the efflux mechanism does not require cortical granule exocytosis and must result from some modification of the original plasma membrane of the egg. The remaining 30–35% of the acid release is related to cortical granule exocytosis, since it can be obtained upon induction of the cortical granule fusion 30 min later under atmospheric pressure. The initiation of acid release after decompression indicates that the efflux mechanism is not transiently turned on at fertilization, but undergoing long-term modification; the recovery of the ability to induce cortical granule fusion after fertilization under pressure suggests a refilling of cytoplasmic Ca²⁺ stores within this time course.