Light-induced absorbance changes in extracts of Phycomyces sporangiophores: Modifications in night-blind mutants

Chafia H. Trad, Benjamin A. Horwitz, Edward D. Lipson

Research output: Contribution to journalArticle

9 Scopus citations


The absorbance of extracts of Phycomyces blakesleeanus sporangiophores was changed by irradiation with either blue or near-UV light. In three strains with normal phototropism, the first blue irradiation caused a small absorbance change. UV light induced a larger change of opposite sign when given either as the first irradiation or after the blue. When applied several minutes after the UV, blue light caused an absorbance change in the control strains larger by a factor of 2 - 3. "Night-blind" (madC) phototropism mutants also showed absorbance changes. In eight madC strains including five different alleles, the decay of the UV-induced absorbance changes in the dark was slower than in the controls. The modification in the mutants provides genetic evidence that the absorbance changes are related to photoreception and may serve as an assay for isolation of the photoreceptors for phototropism.

Original languageEnglish (US)
Pages (from-to)305-313
Number of pages9
JournalJournal of Photochemistry and Photobiology, B: Biology
Issue number3
StatePublished - Mar 1988



  • Blue light
  • Phycomyces
  • absorbance changes
  • night-blind mutant
  • photoreceptor pigments.
  • phototropism

ASJC Scopus subject areas

  • Radiation
  • Radiological and Ultrasound Technology
  • Biophysics
  • Radiology Nuclear Medicine and imaging

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