Stress tolerance and pathogenic potential of a mannitol mutant of Cryptococcus neoformans

Vishnu Chaturvedi, Timothy Flynn, Walter G. Niehaus, Brian Wong

Research output: Contribution to journalArticle

72 Citations (Scopus)

Abstract

Cryptococcus neoformans produces large amounts of the acydic hexitol mannitol in culture and infected animals, but the functional and pathogenic significance of mannitol production by this fungus is not known. We exposed neoformans H99 (Cn H99) to UV irradiation (1 x LD50) and screened survivors for mannitol production. A mutant, Cn MLP (Mannitol Low Producer), synthesized less mannitol from glucose (2.7 vs 8.2 nmol per 108 cells min-1 at 37°C) and contained less intracellular mannitol (1 vs 11 μmol per 106 cells at 37°C) than did Cn H99. Cn MLP and Cn H99 were similar with respect to carbon assimilation patterns, rates of glucose consumption, growth rates at 30°C, urease and phenoloxidase activities, morphology, capsule formation, mating type, electrophoretic karyotype, rapid amplification of polymorphic DNA (RAPD) patterns and antifungal susceptibility. However, Cn MLP was more susceptible than was Cn H99 to growth inhibition and killing by heat and high NaCl concentrations. Also, the LD50 values in mice injected intravenously were 3.7 x 106 c.f.u, for Cn MLP compared to 6.9 x 102 c.f.u. for Cn H99. Moreover, 500 c.f.u. Cn H99 intravenously killed 12 of 12 mice by 60 d, whereas all mice given the same inoculum of Cn MLP survived. Classical genetic studies were undertaken to determine if these differences were due to a single mutation, but the basidiospores were nonviable. These results suggest that the abilities of C. neoformans to produce and accumulate mannitol may influence its tolerance to heat and osmotic stresses and its pathogenicity in mice.

Original languageEnglish (US)
Pages (from-to)937-943
Number of pages7
JournalMicrobiology
Volume142
Issue number4
StatePublished - Apr 1996
Externally publishedYes

Fingerprint

Cryptococcus neoformans
Mannitol
Lethal Dose 50
Glucose
Monophenol Monooxygenase
Urease
Osmotic Pressure
Growth
Karyotype
Capsules
Virulence
Fungi
Carbon
Hot Temperature

Keywords

  • Cryptococcus neoformans
  • Heat stress
  • Mannitol
  • Osmotic stress
  • Pathogenicity

ASJC Scopus subject areas

  • Microbiology

Cite this

Chaturvedi, V., Flynn, T., Niehaus, W. G., & Wong, B. (1996). Stress tolerance and pathogenic potential of a mannitol mutant of Cryptococcus neoformans. Microbiology, 142(4), 937-943.

Stress tolerance and pathogenic potential of a mannitol mutant of Cryptococcus neoformans. / Chaturvedi, Vishnu; Flynn, Timothy; Niehaus, Walter G.; Wong, Brian.

In: Microbiology, Vol. 142, No. 4, 04.1996, p. 937-943.

Research output: Contribution to journalArticle

Chaturvedi, V, Flynn, T, Niehaus, WG & Wong, B 1996, 'Stress tolerance and pathogenic potential of a mannitol mutant of Cryptococcus neoformans', Microbiology, vol. 142, no. 4, pp. 937-943.
Chaturvedi V, Flynn T, Niehaus WG, Wong B. Stress tolerance and pathogenic potential of a mannitol mutant of Cryptococcus neoformans. Microbiology. 1996 Apr;142(4):937-943.
Chaturvedi, Vishnu ; Flynn, Timothy ; Niehaus, Walter G. ; Wong, Brian. / Stress tolerance and pathogenic potential of a mannitol mutant of Cryptococcus neoformans. In: Microbiology. 1996 ; Vol. 142, No. 4. pp. 937-943.
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