The Bacteriophages of Pseudomonas pyocyanea: 2. Bacteriophage Reproduction in an Iridescent Strain

Abstract

SUMMARY: Two new compounds inhibited the increase of phage when two phages of Pseudomonas pyocyanea were grown on an indicator strain. These compounds also inhibited the appearance of iridescence in a lysogenic strain of this organism.One iridescent lysogenic strain showed a rise in phage titre a t 1&2 hr., which corresponded to the latent period of the phage when it acted on an indicator strain.Both these increases were inhibited by the compounds. This lysogenic strain also showed a rise in phage titre a t 4 hr. but this was unaffected by the compounds. The final phage titre of the lysogenic culture was not affected significantly, unlike the complete and permanent suppression of phage increase when free phage acted on an indicator strain. Cultures and filtrates of three lysogenic strains of Ps. pyocyanea showed a great increase in phage titre when assay plates (against an indicator strain) were incubated for a further period after the initial reading a t 18 hr.Many workers have described iridescent strains of Pseudomonas pyocyaneu. Warner (1950) gave a. detailed description and concluded that the iridescent clearing was not caused by bacteriophage action but was a distinct lytic phenomenon, probably the result of bacterial variation. Don & van den Ende (1950) studied thirty strains of Ps. pyocyama with particular reference to the metallic lytic effect and bacteriophage action but the relationship, if any, between these two effects remained obscure. Following an investigation of drug action on the phages of Ps. pyocyanea (Dickinson, 1948), an explanation was sought for the lack of action of drugs on phages associated with iridescent cultures of this organism. It was decided to investigate the reproduction of phage in one of these cultures. The present paper reports this work and includes observations which correlate iridescence with bacteriophage action in this particular strain.The following abbreviations and definitions are used in this paper.

Interference with Multiplication of Pc Phage by a Factor Produced by Exposure of Pseudomonas aeruginosa to Inactivated Pc Phage

“…All tests were made by using single cycles of phage multiplication according to the method of Dickinson & Codd (1952). Phage yield (measured 2Q hr.…”

“…Other experiments The phage-inhibitory factor was tested in a single experiment against Pa phage (Dickinson & Codd, 1952), a phage serologically unrelated to Pc phage but growing on the same host; the factor was active against phage Pa. The phage-inhibitory factor was also tested against Newcastle Disease virus in tissue culture by Dr Lois Dickinson (personal communication) and was inactive.…”

Observations on Bacteriophage Typing of Pseudomonas Aeruginosa

“…aeruginosa: motile, gram-negative rods; typical colonial morphology on 10 per cent sheep's blood agar and on eosin methylene blue agar; for most, but not all, 1 This is host C10 of Dickinson and Codd (30,31). 2064 strains a diffusible green, or, in a few, a reddish-brown pigment on trypticase soybean agar; pellicle formation in liquid media; growth at 30 to 420 C; glucose the only one of the commonly-used sugars fermented; and characteristic odor.…”

Iridescence of a Marine Bacterium and Classification of Prokaryotic Structural Colors

“…Until now, the phenomenon has been observed only on colonies or concentrated cell suspensions (53,54,57), and detailed illustrations are limited. Various general terms such as "shine," "sheen," "glistening," "metallic effect," "bright colors," "luster," "glow," "glisten," or "rainbow-like" were employed to describe the visual effects observed (15,19,28). Confusion with fluorescence has also been made (8,13,29).…”

“…The two most described iridescent bacteria are Pseudomonas aeruginosa (9,14,15,16,28,31,77,80) and Haemophilus influenzae (8,19,42,44,55). Two distinct observation methods were used, direct epi-illumination and transillumination, respectively, for P. aeruginosa and H. influenzae.…”