Search PubMed⌕ Search

Biomedical subjects

H Delius

Publications and source records attributed to H Delius.

At least 145 records · Page 8Linked to original sources
PubMed1974

Structure and molecular weight of the 60-70S RNA and the 30-40S RNA of the Rous sarcoma virus.

The structure and molecular weight of the 60-70S RNA complex and the 30-40S RNA species of Rous sarcoma virus were analyzed in an electron microscope after treatment of the RNAs with the bacteriophage T4 gene-32 protein to stretch out the RNA strands. Although all RNA preparations treated with gene-32 protein showed considerable heterogeneity in length, a significant fraction of the RNA retained its original sedimentation coefficient after treatment to allow the following conclusions to be made: The 30-40S RNA was confirmed to be a linear polynucleotide with a molecular weight of about 3 x 10(6). The 60-70S RNA exhibited a network structure with a molecular weight predominantly of about 6 x 10(6). Therefore, the subunit hypothesis for the 60-70S RNA is confirmed. A model for the structure and molecular weight of the 60-70S RNA postulates that the complex consists of two 30-40S RNA subunits held together at many points. This model elucidates the biological observation that the infectivity of RNA tumor viruses is proportional to the amount of 30-40S RNA in a virus preparation and not to the amount of 60-70S RNA.

Avian Sarcoma Viruses↗
PubMed1974

Molecular weight determination of Sendai and Newcastle disease virus RNA.

The molecular weights of Sendai and Newcastle disease virus RNA were estimated by sedimentation in sucrose gradients and by length measurements in the electron microscope under both denaturing and nondenaturing conditions. Sedimentation analyses under denaturing conditions yielded molecular weight estimates of 2.3 x 10(6) to 2.6 x 10(6), whereas length measurements yielded estimates of 5.2 x 10(6) to 5.6 x 10(6) for both denatured and nondenatured viral RNA. It would appear that the conditions of denaturation used (99% dimethyl sulfoxide at 26 C, and reaction with 1.1 M formaldehyde for 10 min at 60 C) do not equally denature parainfluenza virus RNA and other RNAs, such as cellular rRNA, 45S rRNA precursor, and R17 RNA.

Animals↗
PubMed1974

Specific fragmentation of DNA of adenovirus serotypes 3, 5, 7, and 12, and adeno-simian virus 40 hybrid virus Ad2+ND1 by restriction endonuclease R.EcoRI.

The products of complete digestion of duplex DNA of each of seven human adenoviruses with restriction endonuclease R. EcoRI ranged from two fragments for adenovirus 7 DNA (Ad7) to six fragments for Ad12 and Ad2 DNA. Viral serotypes from the same subgroups appeared to have related cleavage sites; Ad3 DNA and Ad7 (cl E46-LL) DNA were each cleaved into three fragments, and Ad7 (cl 19) DNA lacked one of the cleavage sites present in Ad3 and Ad7 (cl E46-LL) DNA. One of the cleavage sites in Ad2 DNA was deleted in the DNA' of adeno-SV40 hybrid virus Ad2(+)ND1, and three of the cleavage sites in Ad2 DNA were missing in Ad5 DNA. Thus, Ad2(+)ND1 DNA was cleaved into five and Ad5 DNA into three fragments. Each fragment represented a unique segment of viral DNA since each fragment was obtained in equimolar amounts and since the sum of the molecular weights of the fragments equaled the molecular weight of the homologous intact adenovirus DNA.

Adenoviridae↗
PubMed1972

Specificity of the break produced by restricting endonuclease R 1 in Simian virus 40 DNA, as revealed by partial denaturation mapping.

Superhelical circular (form I) SV40 DNA was converted to linear molecules by the action of a partially purified restriction enzyme of Resistance Transfer Factor-R(1) of Escherichia coli. The resulting linear DNA molecules are full length, as judged by their sedimentation through alkaline sucrose gradient and by direct observation in an electron microscope. Nicked circular (form II) DNA was found as an intermediate in the conversion of form I DNA to linear DNA. Analysis of partial denaturation maps obtained by alkaline denaturation of the unitlength linear molecules showed that the break in SV40 DNA occurred at a specific site on the DNA.

Centrifugation, Density Gradient↗
PubMed1972

A DNA-unwinding protein isolated from Escherichia coli: its interaction with DNA and with DNA polymerases.

A DNA-unwinding protein has been purified to homogeneity from E. coli. This protein has a molecular weight of about 22,000, as judged by its electrophoretic mobility on polyacrylamide gels containing sodium dodecylsulfate, and it appears to be present in about 800 copies per log-phase cell. It binds tightly and cooperatively to single-stranded DNA, and much less tightly, if at all, to RNA or double-stranded DNA. Like the T4 gene-32 protein characterized previously, the E. coli DNA-unwinding protein depresses the melting temperature of double-stranded DNAs, with regions rich in A-T base-pairs being preferentially melted. The E. coli protein strongly stimulates in vitro DNA synthesis by E. coli DNA polymerase II on appropriate templates; however, no stimulation is found with purified polymerases I or III of E. coli, or with T4 DNA polymerase. In contrast, gene-32 protein stimulates only the T4 DNA polymerase in a parallel assay.

Adenosine Triphosphate↗
PubMed1971

Structure of the replicating DNA from bacteriophage T4.

At an early stage of replication, parental T4 DNA shows a loop structure often displaying two 3'-ended, single-stranded "whiskers", located in trans configuration at the branching-points. Several such loops have been observed within a single T4 molecule. Occasionally, reinitiation occurred in the middle of a loop, which suggests that the loop was growing in both directions.

Centrifugation, Density Gradient↗