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Morphology of Penicillium marneffei under oxidative stress in vitro
Donghua Liu1, Ling Liang, Qiuhong Luo
1Department of Dermatology and Venereology, First Affiliated Hospital, Guangxi Medical University, Nanning, China.
Abstract:
Penicillium marneffei is an intracellular pathogen; the mechanism allowing it to survive under oxidative stress remains unclear. For a better understanding of the response of P. marneffei to oxidative stress, the change in ultrastructure of this fungus before and after treatment with hydrogen peroxide was examined. A bamboo rat isolate and human isolate of P. marneffei were cultured on PDA at 25 °C and on BHI agar at 37 °C for 7 days respectively, with and without hydrogen peroxide; the morphology of strains was examined by optical microscopy and transmission electron microscopy. While comparing the human isolate with the bamboo rat isolate cultured without hydrogen peroxide, it showed no significant difference in ultrastructure. Microbodies were seen under transmission electron microscope in the yeast form, but could not be seen in mould form. After the strains were cultured with hydrogen peroxide, the mould form produced more rose red pigment; organelles of the fungal cells had been involved at different levels. Furthermore, the mould form of the human isolate with decreased conidia production and the yeast form with apoptosis could be observed. These results indicated that different strains of P. marneffei may have different levels of power to survive under oxidative stress.
Insights
Penicillium marneffei survives oxidative stress through cellular changes. Different strains exhibit varying survival powers, with human isolates showing reduced conidia and yeast forms undergoing apoptosis.
Area of Science:
- Mycology
- Pathogen Biology
- Cellular Ultrastructure
Background:
- Penicillium marneffei is an intracellular pathogen.
- Mechanisms of oxidative stress survival in P. marneffei are not well understood.
Purpose of the Study:
- To investigate the ultrastructural changes in Penicillium marneffei in response to hydrogen peroxide-induced oxidative stress.
- To compare the oxidative stress response between a bamboo rat isolate and a human isolate of P. marneffei.
Main Methods:
- Culturing of P. marneffei isolates (bamboo rat and human) on PDA and BHI agar with and without hydrogen peroxide.
- Examination of fungal morphology using optical microscopy and transmission electron microscopy.
- Analysis of cellular ultrastructure, pigment production, conidia formation, and apoptosis.
Main Results:
- No significant ultrastructural differences were observed between isolates without hydrogen peroxide.
- Microbodies were present in the yeast form but not the mould form.
- Hydrogen peroxide treatment induced increased rose red pigment in the mould form, affected cellular organelles, decreased conidia production in the human mould isolate, and induced apoptosis in the yeast form.
Conclusions:
- Penicillium marneffei undergoes significant ultrastructural and morphological changes when exposed to oxidative stress.
- Different isolates of P. marneffei demonstrate varying capacities for surviving oxidative stress.
- The study highlights potential strain-specific differences in P. marneffei's response to environmental challenges.
