title: Impact of glucose levels on expression of hypha-associated secreted aspartyl proteinases in Candida albicans.
abstract: BACKGROUND
  Ten secreted aspartyl proteinase (Sap) genes were identified in Candida albicans. The products of SAP genes are considered to be virulent factors of C. albicans that participated in causing mucocutaneous and systemic candidiasis in humans. Depending on environmental conditions, C. albicans may stay in yeast-form or convert into invasive hypha-form, and these issues may affect the expression of SAP genes. In this study we explored the component(s) of culture media that may affect the expression of hypha-associated SAP genes.
  
  
  RESULTS
  We demonstrate that glucose levels modulate both the hyphae development and the expression strength of hypha-associated SAP genes (SAP4-6). In contrast to high glucose concentration (2%), lower glucose level (0.1%) is more potent to promote hyphae development and to promptly elicit the expression of hypha-associated Sap proteins during yeast-to-hypha transition of C. albicans. Both Cph1-mediated MAP kinase cascade and Efg1-mediated cAMP/PKA pathway, although the latter seemed dominant, participate in convey the glucose signaling to regulate the expression of hypha-associated SAP genes and this glucose level effect may perform at very early stage of yeast-to-hypha transition. In addition, when C. albicans was co-cultured with THP-1 human monocytes, the engulfed C. albicans was developing hypha efficiently within 1 hr and the expression of hypha-associated Sap proteins could be detected on the distal surface of hyphae.
  
  
  CONCLUSIONS
  We propose that the glucose level of bloodstream (approximately 0.1%) may be facilitated for stimulation of C. albicans to develop invasive hypha-form and to elicit promptly production of high-level hypha-associated Sap proteins.
authors.forename: Leh-Miauh
authors.initials: LM
authors.lastname: Buu
authors.affiliation: Division of Infectious Diseases, Department of Internal Medicine, National Taiwan University Hospital, No, 7, Chung-Shan South Road, Taipei 10002, Taiwan. yeechunchen@gmail.com.
authors.forename: Yee-Chun
authors.initials: YC
authors.lastname: Chen
mesh_terms: D057055:Aspartic Acid Proteases / Q000096:biosynthesis* / Q000235:genetics; D002176:Candida albicans / Q000201:enzymology / Q000235:genetics; D002177:Candidiasis / Q000235:genetics* / Q000382:microbiology / Q000473:pathology; D015966:Gene Expression Regulation, Fungal; D005947:Glucose / Q000378:metabolism* / Q000494:pharmacology; D006801:Humans; D025301:Hyphae / Q000235:genetics* / Q000254:growth & development; D009000:Monocytes / Q000378:metabolism
chemical_list: D057055:Aspartic Acid Proteases; D005947:Glucose