Effects of ultraviolet radiation on the germination and morphology of spores of rhizopus suinus

✍ Scribed by Dimond, A. E. ;Duggar, B. M.

• Publisher: Wiley (John Wiley & Sons)
• Year: 1940
• Tongue: English
• Weight: 408 KB
• Volume: 16
• Category: Article
• ISSN: 0095-9898
• DOI: 10.1002/jcp.1030160107

✦ Synopsis

T W O FIGURES

The germination behavior of fungous spores surviving doses of ultraviolet radiation lethal to the major part of the irradiated population has recently received considerable attention. Oster ( '34) has presented curves showing that the rate of budding of yeast is decreased with increased dosage of radiation. Hollaender and Emmons ( '39) observed a delayed appearance of colonies from spores of Trichophyton as compared with untreated spores. Zahl, Koller and Haskins ( '39) and Landen ('39) have published the results of studies on Aspergillus niger and Ustilago Zeae and present curves showing that as the dosage of radiation is increased, the germination of these fungous spores is retarded.

Methods

The source of radiation employed in this study was a water-cooled, capillary, quartz, mercury-vapor lamp of the Daniels-Heidt type, operated on 500 volts and 1 to 2 amperes current. Monochromatic radiation was obtained by means of a Rausch and Lomb quartz monochromator and intensity measurements of the radiation were made by means of a, standardized thermopile. Throughout this work, monochromatic radiation of wavelength 2650 A. was used.

Rhizopus suinus Niels. was used as the test organism. Spore suspensions for irradiation were prepared in a non-absorbing salt solution from 4-day cultures of the fungus by the method described by Duggar and Hollaender ( '34). Exposure was made in liquid suspension in a quartz exposure cell. The concentration of spores in exposed suspensions was determined with a hemocytometer and was a factor in computing the dosage of radiation given suspensions. After exposure, spore suspensions were added to a potato-dextrose solution to which a