On the biochemical classification of yeast trehalases: Candida albicans contains two enzymes with mixed features of neutral and acid trehalase activities
Abstract Two enzymes endowed with trehalase activity are present in Candida albicans . The cytosolic trehalase (Ntc1p), displayed high activity in exponential phase regardless of the carbon source (glucose, trehalose or glycerol). Ntc1p activity was similar in neutral (pH 7.1) or acid (pH 4.5) conditions, strongly inhibited by ATP, weakly stimulated by divalent cations (Ca 2+ or Mn 2+ ) and unaffected in the presence of cyclic AMP. The Ntc1p activity decreased in stationary phase, except in glycerol-grown cultures, but the catalytic properties did not change. In turn, the cell wall-linked trehalase (Atc1p) showed elevated activity in resting cells or in cultures growing on trehalose or glyc…
Dosage-dependent roles of the Cwt1 transcription factor for cell wall architecture, morphogenesis, drug sensitivity and virulence in Candida albicans.
The Cwt1 transcription factor is involved in cell wall architecture of the human fungal pathogen Candida albicans. We demonstrate here that deficiency of Cwt1 leads to decreased β1,6-glucan in the cell wall, while mannoproteins are increased in the cell wall of exponentially growing cells and are released into the medium of stationary phase cells. Hyphal morphogenesis of cwt1 mutants is reduced on the surfaces of some inducing media. Unexpectedly, the CWT1/cwt1 heterozygous strains shows some stronger in vitro phenotypes compared to the homozygous mutant. The heterozygous but not the homozygous strain is also strongly impaired for its virulence in a mouse model of systemic infection. We sug…
Pga26 mediates filamentation and biofilm formation and is required for virulence in Candida albicans
The Candida albicans gene PGA26 encodes a small cell wall protein and is upregulated during de novo wall synthesis in protoplasts. Disruption of PGA26 caused hypersensitivity to cell wall-perturbing compounds (Calcofluor white and Congo red) and to zymolyase, which degrades the cell wall β-1,3-glucan network. However, susceptibility to caspofungin, an inhibitor of β-1,3-glucan synthesis, was decreased. In addition, pga26Δ mutants show increased susceptibility to antifungals (fluconazol, posaconazol or amphotericin B) that target the plasma membrane and have altered sensitivities to environmental (heat, osmotic and oxidative) stresses. Except for a threefold increase in β-1,6-glucan and a sl…