Stimulation of yeast respiration by ultraviolet radiations

✍ Scribed by Giese, Arthur C.

• Publisher: Wiley (John Wiley & Sons)
• Year: 1942
• Tongue: English
• Weight: 570 KB
• Volume: 20
• Category: Article
• ISSN: 0095-9898
• DOI: 10.1002/jcp.1030200104

✦ Synopsis

That ultraviolet radiations affect living things is wcll known and it is to be expected that respiration, as one of the fundamental activities of life, would be influenced by these radiations. A number of studies by various investigators have claimed that respiration is retarded by ultraviolet rays (see Giese, '41 f o r literature) while others have claimed stimulation, but the latter experiments have always been subject to criticism and careful studies have never repeatedly and consistently demonstrated such an effect on the irradiated cells themselves (Tanner and Byerley, '34; Fardon, Carroll, Ruddy, '37 ; Fardon and Ruddy, '37 ; Norris and Ruddy, '37). Experiments reported here show that iindcr certain conditions an increased respiration is always obtainable but under certain other conditions a depression is just as regularly observed. The experiments are described below.

Cultures of Saccharomyces cereviseae (strain No. 8.1.1.) grown at 25'C. on 0.25% yeast extract (Difco), 1% glucose and 2% agar were brushed off and washed twice by centrifuging and were finally suspended in tap water 31/32 Sorensen buffer of pH 7.0-7.2. This pH was