PubMed Health⌕ Search

Biomedical subjects

L Johnson

Publications and source records attributed to L Johnson.

At least 505 records · Page 28Linked to original sources
PubMed1970

In vitro biosynthesis of pseudouridine at the polynucleotide level by an enzyme extract from Escherichia coli.

DNA from Mycoplasma sp. Kid which was enriched for tRNA genes (containing about 10% tDNA) was transcribed by E. coli RNA polymerase. The RNA transcription product labeled with [(14)C]uridine was formed in good yield (70-fold net synthesis). After incubation of this [(14)C]uridine-labeled RNA with E. coli extracts, nucleotide analyses revealed that [(14)C]pseudouridine was formed. The experiments support the idea that the conversion of uridine to pseudouridine takes place at the macromolecular level. Furthermore, the conversion was shown to be specific for a uridine residue in tRNA-like material since neither [(14)C]polyuridylic acid nor the [(14)C]uridine-labeled RNA transcribed from lambda DNA served as substrate for the pseudouridine-forming enzyme(s).

Autoradiography↗
PubMed1969

Changing incidence of trachoma in the West Midlands.

An increasing incidence of trachoma in an urban Midland population has been shown to be mainly due to immigration of infected carriers from the Punjab. In areas where trachoma is common special clinics should be established for the treatment and follow-up of patients and contacts. Public health measures should be introduced to prevent the spread of the infection. Laboratory methods should be more widely used in the diagnosis and control of trachoma.

Adolescent↗