Immunological studies of Escherichia coli mutants lacking one or two ribosomal proteins

Summary A battery of immunological tests were used to investigate mutants which had been determined as lacking one or two ribosomal proteins on the basis of two-dimensional polyacrylamide gels. Proteins which were confirmed as missing from the ribosome in one or more mutants were large subunit proteins L1, L15, L19, L24, L27, L28, L30 and L33 and small subunit proteins S1, S9, S17 and S20. Cross-reacting material (CRM) was also absent from the post-ribosomal supernatant except in the case of protein S1. Since mutants lacking protein L11 have been previously described, any one of 13 of the 52 ribosomal proteins can be missing. None of these 13 proteins, except S1, can therefore have an indispensable role in ribosome function or assembly. In several mutants in which a protein was not missing but altered, it was present as several moieties of differing charge and size.     

Calcification by Escherichia coli

Escherichia coli K-12, grown in a synthetic medium containing metastable calcium phosphate, formed intracellular biological apatite crystals.     

Genetic polymorphism of lactate dehydrogenase isoenzymes in the carp (Cyprinus carpio) apparently due to a “null allele”

As a consequence of polyploidization, the carp is endowed with three genetic loci coding for LDH in most tissues (and additional ones in liver). However, each such duplicated gene may not be functionally essential for the organism and could be eliminated. In a population survey, an electrophoretic polymorphism was detected which may best be interpreted by the assumption of a null allele, which is apparently not subject to selective pressure. Thus this originally duplicated gene would have diverged in the course of evolution without the origin of differences in function, so that one or the other of the genes is dispensable.     

Dielectric properties of hemoglobin and myoglobin. I. Influence of solvent and particle size on the dielectric dispersion

Dielectric dispersion measurements with aqueous solutions of hemoglobin and myoglobin have been performed in the frequency range from 100 kcps to 15 Mcps. The influence of preparation, particle size, and solvent conditions was studied. The results are analyzed in terms of an orientational polarization mechanism.     

On the composition of the nucleolus with special reference to its filamentous structure

Summary Different staining procedures, various digestion methods and autoradiographic techniques were employed to study the structure and composition of the nucleolus and of the nucleolonema, after unmasking the latter by adenosine treatment. The presence of DNA, RNA, protein and lipid in these structures has been shown. It has been demonstrated that the filamentous structure within the nucleolus — the nucleolonema— has a core of DNA, around which RNA and protein have accumulated. The structure of the nucleolonema suggests that it is in a highly active state, in synthesizing ribosomal RNA and protein.We take the opportunity to express our gratefulness to the Director, Prof. Dr. Hans Lettré, for providing facilities to work in this Institute. We like to thank our other colleagues, particularly Dr. N. Paweletz, for their valuable help during the course of the investigations.     

Die Rolle der Fimbrien bei der eigenartigen Sternbildung von Agrobacterium luteum

Zusammenfassung Die bemerkenswerte Sternbildung von Agrobacterium luteum Stamm A61 (Moll et al., 1967; Ahrens, 1968) ist auf polare Fimbrien zurückzuführen, die um die Sternaggregate ausgebreitet sind. Es wird angenommen, daß sich Schwärmzellen an den Fimbrien verfangen und durch Kontraktion rasch zum Stern gezogen werden. Nach elektronenoptischen Präparaten sind die Fimbrien bis zu 10,5 lang und können die beobachtete Sternbildung gut erklären. Agrobacterium luteum Stamm B14 besitzt ebenfalls lange polare Fimbrien. Beide Stämme tragen peritriche Geißeln, deren Struktur sich deutlich von den dünnen und unregelmäßigen Fimbrien unterscheidet.

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The function of fimbriae in the peculiar star formation of Agrobacterium luteum

Summary The remarkable way of star formation in Agrobacterium luteum strain A61 (Moll et al., 1967; Ahrens, 1968) was found to be due to polar fimbriae which are spread around the star-shaped aggregates. It is assumed that swarmers adhere to the fimbriae and, by contraction, are swiftly pulled towards the star. As seen in electron microscopic preparations, the fimbriae are up to 10,5 long and may well explain the star formation observed. Agrobacterium luteum strain B 14 also possesses long polar fimbriae. Both strains have peritrichous flagella, the structure of which being clearly distinct from the delicate and irregular fimbriae.