Die Aktivität von Hypophyse,Thyreoidea, Epiphyse und ihre Beeinflussung durch Parahydroxypropiophenon, Östradiol und Testosteron während der Larvalentwicklung vonBufo bufo L.

Ohne ZusammenfassungDiss. T. H. Stuttgart 1957.     

Bovine somatic cell nuclear transfer using recipient oocytes recovered by ovum pick-up: effect of maternal lineage of oocyte donors.

The efficiency of bovine nuclear transfer using recipient oocytes recovered by ultrasound-guided follicle aspiration (ovum pick-up [OPU]) was investigated. Oocyte donors were selected from 2 distinct maternal lineages (A and B) differing in 11 nucleotide positions of the mitochondrial DNA control region. A total of 1342 cumulus-oocyte complexes (COCs) were recovered. The numbers of total COCs and class I/II COCs recovered from donors of lineage A were higher (P < 0.001) than those obtained from lineage B. Follicle aspiration once per week yielded a higher (P < 0.001) total number of COCs per session than aspiration twice per week, whereas the reproduction status of donors (heifer vs. cow) had no effect on OPU results. Of the 1342 oocytes recovered, 733 (55%) were successfully matured in vitro and used for nuclear transfer. Fusion was achieved in 550 (75%) karyoplast-cytoplast complexes (KCCs), resulting in 277 (50%) cleaved embryos on Day 3. On Day 7 of culture, 84 transferable embryos (15% based on fused KCCs) were obtained. After 38 transfers (10 single, 22 double, and 6 triple transfers), 9 recipients (8 double and 1 triple transfer) were diagnosed as pregnant on Day 28, corresponding to a pregnancy rate of 24%. The proportion of transferable embryos on Day 7 was significantly (P < 0.05) influenced by maternal lineage of oocyte donors and by the frequency of follicle aspiration. Our study demonstrates the feasibility of generating nuclear transfer embryos with defined cytoplasmic background. These will be valuable tools to experimentally dissect the effects of nuclear and cytoplasmic components on embryonic, fetal, and postnatal development.     

A Nematode Growth Factor from Baker's Yeast

An extract prepared from commercially available yeast supported maturation of the free-living nematode Caenorhabditis briggsae. The extract can be used to supplement a chemically defined medium or, after a limited dialysis, as a complete medium. Several biologically active fractions were prepared; those containing larger amounts of ribonucleic acid (RNA) had greater biological activity, the most active being a pellet resuspended after centrifugation at 30,000 × g for 30 min. This fraction could be substituted for serum in a medium which supports the maturation of the animal parasites Trichinella spiralis and Hymenolepis nana. Addition of protamine sulfate decreased the RNA content, leaving inactive protein fractions which could be reactivated by specific treatments that caused protein precipitation. It is postulated that biological activity is associated with protein sedimented with ribosomes.     

Zur Lokalisation der Cholinesteraseaktivität in der motorischen Endplatte mit der Kupferferrocyanidmethode

Zusammenfassung Die Cholinesteraseaktivität in der motorischen Endplatte der quergestreiften Muskulatur von Frosch und Ratte wurde durch die Kupferferrocyanidmethode von Karnovsky (1964) untersucht. Nach etwa 4 min Inkubationszeit bei 20° C tritt der erste Niederschlag in der Synapse auf. In ihr ist nur die Basalmembran markiert, während die prae- und die subsynaptische Membran frei bleiben. Im Bindegewebe über der motorischen Endplatte hat sich ebenfalls Kupferferrocyanid abgelagert. Nach Zugabe von Eserinsalicylat (10^–4 M) zum Waschpuffer vor der Inkubation wird die erforderliche Inkubationsdauer wesentlich verlängert. Zusätzlich zur Basalmembran zeigen jetzt auch prä- und subsynaptische Membran auf ihre Außenseite einen Kupferferrocyanidniederschlag. Dagegen fehlt er im Bindegewebe über der Synapse.

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On the localization of the cholinesterase activity in the motor endplate with the copper-ferrocyanide method

Summary The cholinesterase activity in the motor endplate of the striated muscle from frog and rat was investigated by the copper-ferrocyanide method of Karnovsky (1964). After an incubation time of ca. 4 minutes at 20° C the precipitate appears in the synapse. In it only the basement membrane is marked, while the prae- and subsynaptic membranes remain free. In the connective tissue above the motor endplate copper-ferrocyanide also precipitates. After addition of eserine-salicylate (10^–4 M) to the washing buffer before the incubation the required incubation time is prolonged. Not only the basement membrane but also prae- and subsynaptic membranes then show on their external layer the copper-ferrocyanide precipitate. On the contrary it is absent in the connective tissue above the motor endplate.

     

Flavonoids and phenolic acids in adenostoma, a dominant genus of the californian chaparral

The flavonoid and phenolic acid pattern of Adenostoma fasciculatum and A. sparsifolium, two dominant, endemic species of the Californian chaparral, was analysed qualitatively and quantitatively. Adenostoma sparsifolium was found to secrete large amounts of lipophilic, unusually substituted flavonoids onto the leaf surface; A. fasciculatum produces five hydrophilic flavonol 3-O-glycosides of kaempferol, quercetin and isorhamnetin. The phenolic acid pattern differed quantitatively but not qualitatively between the species. The amounts of phenolic acids that could be detected within the leaves, leaf litter and soil beneath the shrubs seem too small to explain allelopathic effects as the main reason for the dominance of the two species.