Die Selbstdifferenzierungsfähigkeit und Induktionsfähigkeit medianer und Lateraler Teile der Rumpfmedullarplatte bei Urodelen

Ohne Zusammenfassung     

Die lichtabhängige Vakuolisation der Chloroplasten in Nikotinlösungen

Ohne ZusammenfassungDie vorliegende Arbeit wurde als Teil einer Dissertation am Botanischen Institut der Universität Münster (Westfalen) ausgeführt.Meinem hochverehrten Lehrer, Herrn Prof. Dr. S. Strugger, bin ich für die Überlassung des Arbeitsplatzes und für die ständige Förderung meiner Arbeit zu größtem Dank verpflichtet.     

THE METABOLISM OF TISSUE CULTURES : I. PRELIMINARY STUDIES ON CHICK EMBRYO

1. The metabolism of chick embryo tissues has been followed by analysis of the culture media after various periods of incubation in roller bottles. 2. The initial rate of glucose utilization is increased by increasing glucose in the medium from 100 to 500 mg. per cent. Total glucose used can be increased in the same way or by daily addition of small amounts. Glucose is used in greatest amount when the medium containing 100 mg. per cent is replaced daily. 3. Although glucose consumption appears necessary for survival of cultures it may be used at a rate far in excess of that required for life and maximal growth. Complete blocking of mitosis by colchicine does not alter the rate of glucose utilization. 4. Proteolytic activity of the cultures is shown by an increase in the amino nitrogen of the peptone medium after incubation with tissue. 5. Utilization of nitrogen from an amino acid medium is shown by a decrease in the amino nitrogen of this medium. Cells obtaining their nitrogen from amino acids proliferate as rapidly as those grown in a medium identical except for the substitution of peptone, but the cell type is markedly different, in that embryo muscle forms cells resembling regenerating adult muscle. 6. Lactic acid was formed in both the presence and absence of glucose. Its formation increased with increased glucose utilization. There is some evidence that lactate may be utilized, and that it favors growth in the absence of glucose. 7. Added pyruvate was rapidly metabolized by the tissues. It, too, favors growth slightly in the absence of glucose.     

Structure of the N- and O-glycans of the A-chain of human plasma alpha 2HS-glycoprotein as deduced from the chemical compositions of the derivatives prepared by stepwise degradation with exoglycosidases.

The structure of the glycans of the A-chain of human plasma alpha 2HS-glycoprotein was established from the chemical compositions of its derivatives prepared by sequential enzymatic degradation of the carbohydrate moiety, from the determination of the kind and amount of the monosaccharides liberated after each step of the enzymatic digestion, and from the distinct specificity of the highly purified exoglycosidases. The exoglycosidases were three sialidases (Vibrio cholerae, fowl plague virus, and Arthrobacter ureafaciens), two beta-galactosidases (Streptococcus pneumoniae and bovine testis), one alpha-N-acetylgalactosaminidase, one beta-N-acetylglucosaminidase, and one alpha-mannosidase. Utilizing sialidases with different cleavage specificities, the number of alpha 2-3- and alpha 2-6-linked sialic acid residues could be separately determined. As to the beta-galactosidases, the enzyme isolated from S. pneumoniae cleaves only beta 1-4-linked galactose residues, whereas the bovine testes enzyme acts on both the beta 1-4- and beta 1-3-linked galactose residues. Jack bean beta-N-acetylglucosaminidase cleaves beta 1-2, beta 1-4, and beta 1-6 GlcNAc with higher activity for the beta 1-2. Jack bean alpha-mannosidase cleaves alpha 1-2, alpha 1-6, and alpha 1-3 Man with greater activity for alpha 1-2 and alpha 1-6. Bovine liver alpha-N-acetylgalactosaminidase cleaves O-linked GalNAc. On the basis of these results, the A-chain of alpha 2 HS-glycoprotein was found to possess two biantennary N-glycans and two O-linked trisaccharides.     

Neural differentiation of amphibian gastrula ectoderm exposed to phorbol ester

Summary Ectoderm from early gastrula stages of amphibians was isolated and treated with phorbol 12-myristate 13-acetate. The ectoderm formed neural tissue and in a few cases also mesenchyme and melanophores. The control explants formed atypical epidermis. In explants treated with phorbol 12-myristate 13-acetate the mitotic rate was increased.     

Beiträge zur Kenntnis der Lebensgeschichte des Xanthoriapilzes

Ohne Zusammenfassung     

Physiologische Untersuchungen am Ei der Mehlmotte Ephestia Kuehniella

Ohne ZusammenfassungErklÄrung der Abkürzungen Au Auge - A _1–9 Abdominalsegment 1–9 - Am Amnion - Amh Amnionhöhle - At Antenne - Bl Blastoderm - Br Brenndefekt - Ch Chorion - Do Dotter - dR dorsaler Rand der Keimanlage - EBl Embryonales Blastoderm - ExBl ExtraembryonalesBlastoderm - Gl Ganglion - Gk Gewebeklumpen - Gr Geweberest - K Kopf - K _1–4 KopfextremitÄten - Ka Keimanlage - Ka.h.R. hinterer Rand der Keimanlage - Ka.v.R. vorderer Rand der Keimanlage - Kb Kopflappenbucht - Kbl Keimhautblastem - Ke Keimepithel - Kk Kopfkapsel - Ksph KernsphÄre - l... linker - lAb durch Spaltung entstandene Abdominalteilbildung der linken Seite - M Mandibel - Ma Mitteldarmanlage - Mx _1,2 Maxillensegmente bzw. -extremitÄten - N Narbe - 0 Oberlippe - Pr Proktodaeum - r... rechter ... - rAb durch Spaltung entstandene Abdominalteilbildung der rechten Seite - R ... Rest ... - Rz Randzellen der Keimanlage - S Serosa - Sp Spalt - Spi Spinndrüse - St Stomodaeum - Sti Stigmen - t ... totes - Th _1–3 Thoraxsegmente bzw. -extremitÄten - Tr Trachee - Üz Übergangszone