SUM~XARY. The enterocinogeny and lysogeny of enterococci was studied with a double layer agar method and 21 indicator strains of enterococci. Of 77 strains examined, 76 produced enterocine, and of 19 strains examined, 5 were sensitive to their own enterocine. All 77 strains were lysogenic when cultures killed with chloroform were examined for lysogeny by the method of Liegeois-Miiller & Fredericq (1952). By the same method, 4 of 7 strains were found to produce phages active against themselves.
This study confirmed that Feinberg and Whittington medium was suitable for the cultivation and detailed study of the growth cycle of two clinical strains of Trichomonas vaginalis under anaerobic conditions. Both strains showed a similar growth pattern characterised by early but slow growth, extended duration of the logarithmic phase and limited survival never exceeding 144 h. Duration of survival and growth rate were inversely proportional to the inoculum density. Growth rate was pH dependent; pH values in the range 6.9-6.5 delayed the initiation of growth of 1': vaginalis for at least 48 h. On the other hand, pH values of 6.4-4.5 were indifferent or slightly favourable for growth during the logarithmic and survival in the early decline phase. Normal saline and Ringer's solution exerted an early and progressively lethal effect on trichomonads and led to the disappearance of protozoa suspended in them in 150 min. In general, these in-vitro results shed light on some aspects of the biology of 1': vaginalis and contribute to a better understanding of the epidemiology and clinical manifestations of the infection.
The bacteriocinogeny of 45 bovine and human group B streptococci strains was studied. All 45 strains were examined as producers and indicators. Of the 45 strains tested, 30 (66.6 %) were bacteriocinogenic and 30 (66.6%) were sensitive to bacteriocines. Generally, group B streptococci were weak bacteriocine producers. Bacteriocinogeny and sensitivity to bacteriocines may coexist in the same organism, but sensitivity to a homologous bacteriocine was never observed. Inhibitory activity of bovine strains against other bovine and human strains was stronger than that exerted by strains of human origin. The spectra of activity of the strains tested were narrow. In one strong bacteriocinogenic strain, loss of bacteriocinogeny was observed. Hemolysin production by this particular strain remained unaffected.
Summary. Specimens of plant foliage and flowers collected in the region of Attica from various situations and geographical regions were examined over a period of 13 months for the presence of coli‐aerogenes bacteria able to grow at 37°. Twenty‐five (12.2%) of 204 specimens carried coli‐aerogenes bacteria of which Escherichia coli type I was isolated from 12 (5.8%). Coli‐aerogenes bacteria were seldom isolated from plants grown in uninhabited areas, and they occured more frequently during summer and autumn.
Vegetables and fruits sold in the central market of Athens are frequently contaminated with coli‐aerogenes bacteria. Of 76 specimens of vegetables examined 66 (86.8%) were positive for coli‐aerogenes bacteria, and 17 (22.3%) for E. coli type I. The figures from 41 specimens of fruits were 26 (65.8%) and 4 (9.7%), respectively.
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