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1985 (1)
1984 (1)
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1978 (1)
1Author    D. W. Erner, R. StripfRequires cookie*
 Title    Differentiation of Rhizobium japonicum, I. Enzymatic Comparison of Nitrogenase Repressed and Derepressed Free Living Cells and of Bacteroids  
 Abstract    Derepressed free living cells of Rhizobium japonicum strain 61-A-101 with leucine as single nitrogen source develop a maximum nitrogenase activity of 180 nmol C2H4-mg protein-1 -h _1 in liquid culture under 2% 0 2 in the gas phase. Only \0% of this activity is found with no oxygen in the gas phase during a 90 min incubation period. The maximum activity under 2% oxygen in the gas phase is unaffected by addition of 1 —100 m M NH4+ and by addition of low concentrations of glutamine (0.36 —1.44 m M) . Specific activities of alanine dehydrogenase (E.C. 1.4.1.1.) aspartate aminotransferase (E.C. 2.6.1.1.) and, with much lower activities, of GOGAT (E.C. 1.4.1.13) in nitrogenase active free living cells are more similar to bacteroids than to nitrogenase repressed free living cells from liquid culture. The activities in nitrogenase repressed cells were about 50% lower. Glutamine synthetase (E.C. 6.3.1.2.) activity in bacteroids and in nitrogenase active cells were also similar, but only about 25 — 30% of that found in nitrogenase repressed Rhizobium japonicum cells. 
  Reference    Z. Naturforsch. 33c, 245 (1978); received February 9 1978 
  Published    1978 
  Keywords    Rhizobium japonicum, Bacteroids, Derepressed Nitrogenase, Differentiation, N-Metabolism 
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 TEI-XML for    default:Reihe_C/33/ZNC-1978-33c-0245.pdf 
 Identifier    ZNC-1978-33c-0245 
 Volume    33 
2Author    Rainer Gilles, Lothar JaenickeRequires cookie*
 Title    Differentiation in Volvox carteri: Study of Pattern Variation of Reproductive Cells  
 Abstract    Asexual spheroids of the multicellular green alga Volvox are composed o f two types o f cells: non-flagellated reproductive gonidia and Chlamydomonas-\ike flagellated somatic cells. They are committed by a differentiating cleavage during embryogenesis. The gonidia o f the adult spheroids form a symmetrical pattern consisting o f four layers o f four gonidia each; their position is established already in the embryos by the gonidial initials. Whereas, generally, the 16-gonidia pattern is assumed to be the basic one, most o f the spheroids have fewer gonidia (down to 8). The nine possible gonidial patterns (8 to 16 gonidia) are described and correlated to the gonidial stem cells which have been differentiated. Defects in gonidial pattern are o f particular interest, since any model of differentiation has to explain not only the basic pattern formed, but also its systematic variations. Our study shows that the pattern reduction is by no means random, but governed by an intrinsic mechanism which shifts the first unequal cleavage from the 32-celled stage to the 16-celled stage. All the patterns formed can be deduced from cleavage pathways involving non-synchronous differentiation of the stem cells. Thus, pattern formation can be correlated to timing and spacing signals regulating events during embryogenesis. 
  Reference    Z. Naturforsch. 37c, 1023—1030 (1982); received June 1 1982 
  Published    1982 
  Keywords    Volvox carteri, Differentiation, Embryogenesis, Cell Lineages, Pattern Formation 
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 TEI-XML for    default:Reihe_C/37/ZNC-1982-37c-1023.pdf 
 Identifier    ZNC-1982-37c-1023 
 Volume    37 
3Author    Hanna Modrzejewska, Grażyna Gałązka, Janusz Szemraj, Henryk PanuszRequires cookie*
 Title    Distribution of the H I Histone Subfractions in Syrian Hamster Chromatin Fractions  
 Abstract    Chromatin from two Syrian hamster tissues: the Kirkman-Robbins hepatoma and the liver, has been separated into soluble (S) and insoluble (P) fractions. Both fractions contain the complete set of five main histones but differ in respect of H I subfractions. The hepatoma chromatin is known to contain an unusual HI subfraction, H I slow [12, 13], probably identical with a similar subfration present in hamster testes. The content of H 1 slow in total H 1 histone has been estimated for total, S and P chromatin from hamster hepatoma. The values 20.9 ± 7.2, 13.8 ± 1.8 and 26.8 + 4.2%, respectively, were obtained. 
  Reference    Z. Naturforsch. 39c, 958—961 (1984); received May 18 1984 
  Published    1984 
  Keywords    HI Subfractions, Chromatin, Hepatoma, Hamster, Differentiation 
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 TEI-XML for    default:Reihe_C/39/ZNC-1984-39c-0958.pdf 
 Identifier    ZNC-1984-39c-0958 
 Volume    39 
4Author    D. Ie Te, M. Ü Ller-E, EvaB. Noch, A. Üttgen, N. En, M. Ach ErRequires cookie*
 Title    Regioselective O-Demethylation of Scoparone: Differentiation between Rat Liver Cytochrome P-450 Isozymes  
 Abstract    The ratios of the scoparone O-demethylation products scopoletin to isoscopoletin were deter­ mined for reconstituted complexes of NADPH-P-450 reductase and each of four P-450 isozymes in a 2:1 molar ratio with a 1:1 mixture of [7-0-methyl-14C]-and [6-0-methyl-l4 C]-scoparone as substrate. The two phenobarbital inducible forms P-450pb.b and P-450PB.D have a 1:0.8 ± 0.05 scopoletin to isoscopoletin ratio, and the two ß-naphthoflavone inducible forms P-450pNF_B and P-450pNF/ISF.G have ratios of 1:4.4 ± 0.1 and 1:3.8 ± 0.1, respectively. The scoparone-O-demethy-lation activities of the reconstituted preformed complexes of the four P-450 isozymes are given. 
  Reference    Z. Naturforsch. 40c, 682—684 (1985); received May 2/June 28 1985 
  Published    1985 
  Keywords    Regioselective Scoparone O-Demethylation, Cytochrome P-450 Isozymes, Differentiation 
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 TEI-XML for    default:Reihe_C/40/ZNC-1985-40c-0682.pdf 
 Identifier    ZNC-1985-40c-0682 
 Volume    40