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J Jonasson

Publications and source records attributed to J Jonasson.

At least 55 records · Page 3Linked to original sources
PubMed1972

Unrelatedness of temperate Bacillus subtilis bacteriophages SP02 and phi105.

SPO2 and phi105 are temperate Bacillus subtilis bacteriophages which have been suggested to belong to a cluster of related bacteriophages. In the present work, we show that SPO2 does not complement any of the 11 essential genes known in phi105 and that the phages do not recombine. Deoxyribonucleic acid (DNA)-DNA hybridization shows less than 10% homology between SPO2 and phi105 DNA. DNA synthesis in phi105 shows a greater dependence on host functions than does SPO2 DNA synthesis. Growth of phi105 but not of SPO2 is inhibited by the uracil analogue 6-(p-hydroxyphenylazo)-uracil. Infection of a DNA polymerase-deficient strain of B. subtilis with SPO2 leads to an increase in DNA polymerase activity in crude extracts, whereas no such increase is found after infection of this strain with phi105. It is concluded that SPO2 and phi105 are unrelated bacteriophages.

Azo Compounds↗
PubMedDate not supplied

Prevalence of urogenital Chlamydia trachomatis infection in El Salvador. I. Infection during pregnancy and perinatal transmission.

One-hundred and twenty-nine pregnant women in labour (age range 15-46 years; median age 23) and 42 infants born to chlamydia-positive mothers (age range 5-15 days; median age 10) were investigated to estimate the prevalence and incidence, respectively, of Chlamydia trachomatis infection in San Salvador, El Salvador. Urethral and cervical samples were obtained from all women and conjunctival specimens were taken from both eyes of each child. The chlamydial antigen was detected with the commercial Pharmacia Chlamydia EIA kit. Direct immunofluorescence (DFA) (Syva MicroTrak) was used for confirmation. In the newborns both EIA and DFA tests on direct preparations from ocular smears were performed on all the samples. The prevalence of chlamydial infection in pregnant women was 44% (57/129). The incidence of chlamydial infection in neonates was 64% (27/42), and the majority of the infected children (56%) had conjunctivitis. Referring to individuals rather than specimens the sensitivity of EIA tests on conjunctival samples from the infants was low (37%) as compared with 91% on urethral and cervical specimens from the pregnant women.

Adolescent↗