摘要:

AbstractMNNG‐induzierte Mutanten mit einer blockierten Nikotinsäurebiosynthese wurden bei einem imperfekten und einem zur sexuellen Vermehrung befähigten Stamm vonC. lipolyticaisoliert und phänotypisch charakterisiert. Es konnten Mutanten mit einer inaktiven Tryptophanpyrrolase (nic1), Kynureninhydroxylase (nic2), 3‐Hydroxykynureninase (nic3) und einer blockierten Synthese von Nikotinsäure aus 3‐Hydroxyanthranilsäure (nic4) erhalten werden.Mit Hilfe der Mutanten wurde festgestellt, daß in beidenC. lipolytica‐Stämmen die Nikotinsäure nur ein Folgeprodukt des Tryptophanabbaus über Formylkynurenin, Kynurenin, 3‐Hydroxykynurenin und 3‐Hydroxyanthranilsäure ist. Der Kurzschluß‐ sowie der Bakterienweg der Nikotinsäurebiosynthese können auch nicht bei Anthranilsäure‐ oder Glycerinfütterung bzw. unter Bedingungen, die Katabolitrepression ausschließen, realisiert werden. In dieser Hinsicht unterscheidet sichC. lipolyticavon den anderen bisher untersuchten Hefen.Eine Regulation des Tryptophan‐Nikotinsäure‐Weges durch Endprod

ISSN:0044-2208    

DOI:10.1002/jobm.19750150402

出版商:Akademie‐Verlag    

年代:1975

数据来源: WILEY

摘要:

AbstractUntil now it has not been possible to obtain nuclear bodies fromEscherichia coliafter treatment with rifampicin. It was generally assumed that the cross‐connections between the DNA double strands which are sensitive towards ribonuclease are destroyed under the influence of inhibitors of RNA synthesis like rifampicin. In this paper a new lysis procedure is described for preparing nuclear bodies fromE. coli. These particles differ in some respects, especially in salt sensitivity from those prepared by earlier methods. Using the new lysis method it is also possible to obtain folded chromosomes from cells after treatment with rifampicin. These nuclear bodies can be destroyed by ribonuclease. Therefore, it has to be postulated that a fraction of RNA being sufficient to hold the chromosome in the folded shape is not susceptible to the action of rifampici

ISSN:0044-2208    

DOI:10.1002/jobm.19750150403

出版商:Akademie‐Verlag    

年代:1975

数据来源: WILEY

摘要:

AbstractUntil recently it has been assumed that the factors being responsible for the condensation of the DNA in the nucleoid ofEscherichia coliare destroyed by rifampicin because it has been impossible to obtain folded chromosomes from cells treated with this inhibitor. In this paper it is shown by viscosity and sedimentation measurements that unfolding of the DNA does not take place during the process of the cell lysis as it should be predicted from this assumption, but is occurring distinctly afterwards. Since the observed unfolding process is too slow to be caused simply by molecular movements it is concluded that it is brought about by the action of salts or detergents of the lysis medium. The structure of the nucleoid is still intactin vivodespite inhibition of RNA synthesis by rifampicin.

ISSN:0044-2208    

DOI:10.1002/jobm.19750150404

出版商:Akademie‐Verlag    

年代:1975

数据来源: WILEY

摘要:

AbstractThe possible role of some metabolic systems producing acetyl‐CoA, malonyl‐CoA, and methylmalonyl‐CoA as initial precursors in the biosynthesis of the macrolide antibiotic A 6599 byStreptomyces hygroscopicusJA 6599 was studied.The activities of pyruvate decarboxylase exceeded in two higher producing strains about twofold those found in the mycelium of a lower producing one suggesting that in this organism an enhanced production of acetyl‐CoA should be one of the prerequisites necessary for an improved antibiotic biosynthesis. No clear interrelationship was established, however, between the biosynthesis of the secondary metabolite A 6599 on the one hand and the acetate and propionate kinase content on the other hand.InS. hygroscopicusJA 6599 the carboxylation of acetyl‐CoA or propionyl‐CoA seems to be the major pathway giving malonyl‐CoA or methylmalonyl‐CoA, respectively. Thus, the activities of acetyl‐CoA and propionyl‐CoA carboxylases corresponded with both the levels of antibiotic production in several strains and with variations observed in the specific antibiotic production rate during the cultivation. Some other pathways synthesizing these precursors,e.g.via oxaloacetate, are assumed to be negligible since even in the mycelium of the lower producing strain increased activities of phosphoenolpyruvate carbo

ISSN:0044-2208    

DOI:10.1002/jobm.19750150405

出版商:Akademie‐Verlag    

年代:1975

数据来源: WILEY

摘要:

Abstract26 plant growth regulators including herbicides were investigated in their effect on the multiplication ofEscherichia coli, Bacillus subtilis, and the blue‐green algaPlectonema boryanumas well as the RNA phages M 12 and Qβ and the DNA phages λ, Ø 105, and LPP‐1 employing the agar diffusion method. Nearly all of the compounds inhibited and/or stimulated one or some of the prokaryotes tested. The most frequent and strongest effects occurred inPl. boryanum, the least effects inE. coli. The multiplication of phages was also influenced by plant growth regulators leading to increase, decrease or non‐appearance of plaques. The investigations with the temperate phages λ and Ø 105 suggested part of the compounds to be able to interfere with the process of lysogenization. The results are discussed comparatively involving correspondent findings referred to in

ISSN:0044-2208    

DOI:10.1002/jobm.19750150406

出版商:Akademie‐Verlag    

年代:1975

数据来源: WILEY

摘要:

AbstractThin sections of exponentially growing and stationary‐phase cells ofL. fermentumfrom thiamine sufficient and thiamine deficient media were studied by electron microscopy. Compared to the exponential‐phase cells the stationary‐phase cells from both types of media had thicker cell walls and cross walls and fewer and smaller granules of storage material. Exponential‐phase, thiamine deficient cells had rather thin cell walls and small me

ISSN:0044-2208    

DOI:10.1002/jobm.19750150407

出版商:Akademie‐Verlag    

年代:1975

数据来源: WILEY

摘要:

AbstractPhage χ ofSerratia marcescenswas treated with different mutagens to induce thermoconditional clear plaque‐mutants. 176 mutants obtained were analysed by crosses and found to be located in clear plaque‐region III. Two types resembling the mutants t2 and t1 of phage λ were identified. Lysogens for the mutant l 26 can be induced by heat and even by cold whereas they are scarcely inducible by uv. Nevertheless, a l 26 prophage like a uv induciblect163 prophage can be sensitized to thermoinduction by short preirradiation if the cells are incubated for 30 to 45 min between uv exposure and heating. Withct163 this time corresponds to the minimum extension of latent period after uv induction compared with infection at low moi.A mutant of clear plaque‐region II, cl54, shows an inverted thermoconditional behaviour forming clear plaques at 30 °C and turbid plaques due to lysogenization

ISSN:0044-2208    

DOI:10.1002/jobm.19750150408

出版商:Akademie‐Verlag    

年代:1975

数据来源: WILEY

摘要:

AbstractAmong methionineless mutants ofPseudomonas aeruginosastrain PAO lacking the ability of methylating homocysteine we found two different types: One of them responding to methionine only, the other one to methionine or vitamin B12alternatively. That means thatP. aeruginosaPAO as well as other B12‐producing bacteria (with one exception:Aerobacter aerogenes) use only the B12pathway (metH) for methionine synthesis.The effect of somecys‐auxotrophs equally growing on vitamin B12as described by CALHOUN and FEARY (1969) was confirmed forP. aeruginosaPAO by our mutants. In aP. aeruginosastrain of other origin, PAE, neithermet‐ norcys‐mutants responding to B12have been found, although strain PAE as well as strain PAO excessively synthes

ISSN:0044-2208    

DOI:10.1002/jobm.19750150409

出版商:Akademie‐Verlag    

年代:1975

数据来源: WILEY

摘要:

AbstractEin neues, acidotolerantes, gram‐negatives Stäbchen, charakterisiert durch eine polare, bis zu 12 μm lange Geißel, wurde aus lateritischen Relikten unweit von Gießen isoliert. Die physiologischen Eigenschaften, die Unempfindlichkeit gegenüber Antibiotica sowie das GC% (DNS) bestätigen den Organismus als eine neue Art der GattungPseudomonas. Die Isolate bilden eine homogene Gruppe von prototrophen, Oxidase und Katalase bildenden Stäbchen mit obligataerobem Stoffwechsel und ENTNER‐DOUDOROFF‐Abbauweg. Stickstoffbindung wird durch starkes Wachstum auf “N‐freiem” Glucose‐Agar simuliert; Acetylen wird jedoch nicht signifikant reduziert. Die meisten organischen Säuren (darunter Oxalat), sämtliche geprüfte Aldosen, Hexosen, Desoxyzucker, Zuckeralkohole sowie Gluconat, 2‐ und 5‐Ketogluconat werden als einzige C‐Quelle verwertet. Alkohole, ausgenommen 2,3‐Butandiol, werden nicht angegriffen. Di‐, Tri‐ und Polysaccharide, mit Ausnahme von Lactose, Melezitose und Melibiose, werden nicht verwertet. Der neue Organismus unterscheidet sich in mehreren Merkmalen von den Denitrifikanten derP. stutzeri‐mendocinaGruppe. Der NamePseudomon

ISSN:0044-2208    

DOI:10.1002/jobm.19750150410

出版商:Akademie‐Verlag    

年代:1975

数据来源: WILEY

ISSN:0044-2208    

DOI:10.1002/jobm.19750150413

出版商:Akademie‐Verlag    

年代:1975

数据来源: WILEY