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H Schnabel

Publications and source records attributed to H Schnabel.

25 records · Page 2Linked to original sources
PubMed1984

An immune strain of Halobacterium halobium carries the invertible L segment of phage PhiH as a plasmid.

The structure of the circular prophage genome of PhiH varies with high frequency in single colony progeny of the defective lysogen Halobacterium halobium R(1)-3. As in linear PhiH DNA, a segment flanked by two copies of the insertion element ISH1.8 is inverted frequently. This L segment can also circularize to a plasmid of 12 kilobase pairs with simultaneous loss of the remaining phage DNA. Strain R(1)-L, which contains this plasmid, is immune to phage infection. A phage variant, PhiHL1, is able to grow on R(1)-L and carries an insertion of 1 kilobase pair in its L segment. PhiHL1 does not grow on normal lysogens. This shows that the plasmid confers to R(1)-L only part of the immunity of normal lysogens.

Journal Article↗
PubMed1984

Genome organization and transcription in archaebacteria.

The genome organization of the archaebacteria is investigated in three model systems: a) rRNA genes of various archaebacteria, b) a plasmid of 15.6 kb from Sulfolobus acidocaldarius which exists in free or integrated form, c) the 59 kb genome of phage phi H of Halobacterium halobium as a model for the unusual structural variability of DNA in this organism. Several variants of this phage have been isolated, their genomes differ by several insertions, a deletion, and an inversion. The frequent inversion and circularization of a 12 kb segment of DNA appears to be linked to the presence of two copies of an IS element at its flanks. DNA-dependent RNA polymerases have been isolated from a large number of archaebacteria including representatives of 4 families of the novel order Thermoproteales . As shown by immunological methods, they are closely related to those of eukaryotes. Two different types of RNA polymerase exist in the two main branches of the archaebacteria. The role of one component of the enzyme of Thermoplasma acidophilum was elucidated using an in vitro transcription system.

Archaea↗
PubMed1982

Component E of the DNA-dependent RNA polymerase of the archaebacterium Thermoplasma acidophilum is required for the transcription of native DNA.

The role of component E of the DNA-dependent RNA polymerase of the archaebacterium Thermoplasma acidophilum in the transcription of Thermoplasma DNA has been analyzed. Component E (Mr 22000) is released upon formation of the binary complex of the polymerase with the DNA. Enzyme not containing component E is inactive on DNA but active on poly[d(A-T) X d(A-T)]. The activity on DNA can be restored by addition of component E. Two states of the binding complex between RNA polymerase and DNA, differing in their ionic strength stabilities, have been distinguished both in the presence and absence of component E. The transition temperature between the two states is 43 degrees C. Component E appears to open productive binding sites in native DNA in addition to the non-productive strong binding sites available for component-E-deficient enzyme.

Bacterial Proteins↗
PubMed1982

Halobacterium halobium phage øH.

Phage øH, a novel virus of the archaebacterium Halobacterium halobium, resembles in size and morphology two other Halobacterium phages. One-step growth curves show a 5.5 h eclipse, a latent period of 7 h, and an apparent burst size of 170. Phage øH contains linear, double-stranded DNA which has a molecular weight of 39 x 10 and a GC content of 65%. A packaging model accounting for the partial circular permutation and terminal redundancy of øH DNA is suggested. Partial homology of øH DNA with the DNA of H. halobium, predominantly with the AT-rich satellite DNA, was observed. The presence of minor restriction fragments of øH DNA which could be removed by purification of phage from single plaques suggests the existence of phage variants with rearranged DNA. A strain of H. halobium containing øH DNA was isolated which is resistant to infection by phage øH.

Journal Article↗