Biochemical comparison of the Cu,Zn superoxide dismutases of Cryptococcus neoformans var. neoformans and Cryptococcus neoformans var. gattii

Hamilton, Andrew J.; Holdom, Mary D.

doi:10.1128/iai.65.2.488-494.1997

Cited by 36 publications

(11 citation statements)

References 27 publications

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“…Using this information, we were able to identify in the cDNA library clones containing 12 different entire ORFs. Six of these genes turned out to be identical to previously described ones (Hamilton & Holdom, 1997;Mandel et al, 2000;Levitz et al, 2001;Biondo et al, 2002;Huang et al, 2002;Lian et al, 2005; Table 2).…”

Section: Fractionation and N-terminal Sequencingsupporting

confidence: 63%

Identification of major proteins secreted byCryptococcus neoformans

Biondo

Mancuso

Midiri

et al. 2006

FEMS Yeast Research

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The characterization of proteins secreted by Cryptococcus neoformans is of relevance to the identification of vaccine candidates, because concentrated supernatants from the fungus have been shown to be immunoprotective in previous studies. After fractionation of supernatants by anion exchange chromatography and preparative electrophoresis, we obtained the N-terminal amino acid sequences of 13 major proteins. Using a C. neoformans nucleotide database, we were able to clone and sequence the ORFs coding for 12 of these proteins. Some of the genes are identical to previously described ones, while six encode novel proteins, including four putative mannoproteins. The molecular characterization of these and other secreted products may provide useful information in the development of immune-based strategies to control cryptococcosis.

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Section: Fractionation and N-terminal Sequencingsupporting

confidence: 63%

Identification of major proteins secreted byCryptococcus neoformans

Biondo

Mancuso

Midiri

et al. 2006

FEMS Yeast Research

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“…This is consistent with other studies that have found superoxide dismutases in concentrated supernatants from Cry. neoformans, suggesting that it is a secreted protein (Hamilton & Holdom, 1997;Biondo et al, 2006).…”

Section: Discussionmentioning

confidence: 99%

Extracellular glycosylphosphatidylinositol-anchored mannoproteins and proteases ofCryptococcus neoformans

Eigenheer¹,

Lee

Blumwald

et al. 2007

FEMS Yeast Research

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Extracellular proteins of Cryptococcus neoformans are involved in the pathogenesis of cryptococcosis, and some are immunoreactive antigens that may potentially serve as candidates for vaccine development. To further study the extracellular proteome of the human fungal pathogen Cry. neoformans, we conducted a proteomic analysis of secreted and cell wall-bound proteins with an acapsular strain of Cry. neoformans. Proteins were identified from both intact cells and cell walls. In both cases, extracellular proteins were removed with trypsin or beta-glucanase, and then all proteins/peptides were purified by solid-phase extraction, spin dialysis, and HPLC, and identified by liquid chromatography-mass spectrometry. This study identified 29 extracellular proteins with a predicted N-terminal signal sequence and also a predicted glycosylphosphatidylinositol anchor motif in more than half. Among the novel proteins identified were five glycosylphosphatidylinositol-anchored proteins with extensive Ser/Thr-rich regions but no apparent functional domains, a glycosylphosphatidylinositol-anchored aspartic protease, and a metalloprotease with structural similarity to an elastinolytic metalloprotease of Aspergillus fumigatus. This study suggests that Cry. neoformans has the machinery required to target glycosylphosphatidylinositol-anchored proteins to the cell wall, and it confirms the extracellular proteolytic ability of Cry. neoformans.

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“…It was hypothesized that this differential phagocyte response could result from innate differences among the antioxidants of these varieties. Support for this observation comes from our earlier work on comparative analysis of Cu,Zn superoxide dismutase (SOD; encoded by SOD1 ) from three Cn varieties, which revealed significant differences in the physical, biochemical, molecular and structural properties of this enzyme (Hamilton and Holdom, 1997;Chaturvedi et al ., 2001). These results are important, as SOD is one of the essential elements of the primary antioxidant defence system.…”

Section: Introductionmentioning

confidence: 95%

Characterization of Cu,Zn superoxide dismutase (SOD1) gene knock‐out mutant of Cryptococcus neoformans var. gattii: role in biology and virulence

Narasipura¹,

Ault

Behr

et al. 2003

Molecular Microbiology

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SummaryThe pathogenic yeast Cryptococcus neoformans ( Cn ) var. gattii causes meningoencephalitis in healthy individuals, unlike the better known Cn varieties grubii and neoformans , which are common in immunocompromised individuals. The virulence determinants and mechanisms of host predilection are poorly defined for var. gattii . The present study focused on the characterization of a Cu,Zn superoxide dismutase ( SOD1 ) gene knock-out mutant constructed by developing a DNA transformation system. The sod1 mutant was highly sensitive to the redox cycling agent menadione, and showed fragmentation of the large vacuole in the cytoplasm, but no other defects were seen in growth, capsule synthesis, mating, sporulation, stationary phase survival or auxotrophies for sulphurcontaining amino acids. The sod1 mutant was markedly attenuated in virulence in a mouse model, and it was significantly susceptible to in vitro killing by human neutrophils (PMNs). The deletion of SOD1 also resulted in defects in the expression of a number of virulence factors, i.e. laccase, urease and phospholipase. Complementation of the sod1 mutant with SOD1 resulted in recovery of virulence factor expression and menadione resistance, and in restoration of virulence. Overall, these results suggest that the antioxidant function of Cu,Zn SOD is critical for the pathogenesis of the fungus, but is dispensable in its saprobic life. This report constitutes the first instance in which superoxide dismutase has been directly implicated in the virulence of a fungal pathogen.

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Biochemical comparison of the Cu,Zn superoxide dismutases of Cryptococcus neoformans var. neoformans and Cryptococcus neoformans var. gattii

Cited by 36 publications

References 27 publications

Identification of major proteins secreted byCryptococcus neoformans

Identification of major proteins secreted byCryptococcus neoformans

Extracellular glycosylphosphatidylinositol-anchored mannoproteins and proteases ofCryptococcus neoformans

Characterization of Cu,Zn superoxide dismutase (SOD1) gene knock‐out mutant of Cryptococcus neoformans var. gattii: role in biology and virulence

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