, Volume 77, Issue 2, pp 69–73 | Cite as

Cysteine-independent and cysteine-requiring yeast-strains of Histoplasma capsulatum

  • E. S. Jacobson
  • A. C. Harrell


Recently we described a strain of Histoplasma capsulatum, designated H-35, which is able to grow as yeast on a minimal medium consisting of inorganic salts, glucose and a trace of biotin. Using this strain as a prototrophic wild type we sought auxotrophic mutants. Mutagenized yeast-cells were starved for inorganic sulfate in sulfur-free minimal medium. Sulfate was then added, and growing prototrophic cells were killed by addition of amphotericin B. After 24 hours non-growing auxotrophs were ‘rescued’ by removal of amphotericin and addition of yeast extract. This ‘mutant enrichment’ cycle was repeated two additional times, after which the cells were plated on blood agar and 800 yeast-colonies were picked. Seventeen of these yeast-strains required cysteine for growth, as compared with strain H-35, which grew as yeast on minimal medium.


Glucose Sulfate Agar Cysteine Yeast Extract 
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Copyright information

© Dr W. Junk Publishers 1982

Authors and Affiliations

  • E. S. Jacobson
    • 1
    • 2
  • A. C. Harrell
    • 1
    • 2
  1. 1.Research ServiceMcGuire V. A. Medical CenterRichmondUSA
  2. 2.Division of Infectious Diseases, Department of Medicine, Medical College of VirginiaVirginia Commonwealth UniversityRichmondUSA

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