George S. La Rue

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The localization, structure and function of two types of nuclear bodies have been investigated by cytological and cytochemical electron microscopy methods in oocytes from the Hoplonemertean, Amphiporus lactifloreus. Type I nuclear bodies differentiate in contact with the nucleolus-DNA body complex, whereas type II nuclear bodies develop close to the(More)
The components of the nucleolus-DNA body complex of oocytes from the hoplonemertean, Amphiporus lactifloreus, were studied by electron microscopy and cytochemistry. In the early stages of meiotic prophase I, the nucleus of female germ cells was characterized by a large heterochromatic body. From this body a polymorphic nucleolar apparatus, the nucleolus-DNA(More)
A fully digital feedforward Σ∆ modulator is described. The technique, here applied to a second order low-pass modulator, strongly reduces the operational amplifiers output swing, thus allowing the use of power effective single stage architectures. The method enables reduced slew-rate requirements and allows operation at lower power supply voltages. The(More)
After the deprivation of gonad-inhibiting factor (GIF) from the brain in adult Nemertines of both sexes, the sexual characters appear and/or grow rapidly. Very early, RNA synthesis is promoted in young oocytes, DNA synthesis is increased in spermatogonia and primary spermatocytes and protein synthesis is significantly increased in germ cells and sexual(More)
Deprivation of gonadostatin (gonad-inhibiting hormone: GIH) performed during the quiescent period of the annual reproductive cycle in the hoplonemertean, Amphiporus lactifloreus, resulted in precocious sexual maturation. In female worms, the oometrical analysis showed that the hormone target, the ovary, responds to GIH deprivation by accelerated growth of a(More)
In Physarum polycephalum, the study of RNA metabolism just after metaphasis shows an important 3H-uridine incorporation. Most of the labelling is found in the nucleolus when we can see it again during interphasis. Therefore a ribosomal RNA synthesis does exist before any visible nucleolar structure.
During Lineus ruber oogenesis, there is a very high uridine uptake by the oocyte before the yolk formation. At the end of this stage, the nucleolus shows a special structure that seems to be related to a decrease of the ribosomal RNA synthesis. During the yolk formation, the nucleolus scatters in the nucleus, allowing ribonucleoprotein granules to go(More)