title: Comparative effects of hypoxia and hypoxia mimetic cobalt chloride on in vitro adhesion, biofilm formation and susceptibility to amphotericin B of Candida glabrata.
abstract: OBJECTIVE
  Candida glabrata has emerged as potent pathogen in nosocomial infections. The objective of this study is to investigate the effects of hypoxia (an important host factor) and hypoxia mimetic cobalt chloride upon growth, in vitro adhesion, biofilm formation and susceptibility to amphotericin B of Candida glabrata.
  
  
  METHODS
  Growth was checked by spotting assays. Expression of TDH3, a gene of glycolytic pathway was analyzed as intracellular hypoxia marker by reverse transcription PCR. In vitro adhesion, biofilm development and susceptibility of biofilm to amphotericin B were performed on polystyrene plates and quantified by XTT assay in RPMI 1640 and YNB media. Experiments were performed in triplicates and Student's t-test was used for statistical analysis.
  
  
  RESULTS
  Hypoxia did not compromise the growth of C. glabrata unlike CoCl2. Hypoxia and CoCl2 upregulated TDH3 expression. Adhesion was reduced upon exposure to hypoxia and CoCl2. Biofilm activity remained unchanged in the presence of CoCl2 in both media. In comparison to normoxia control, hypoxia increased biofilm activity to 259.33 ± 22.05% in RPMI 1640, while hypoxia reduced it to 70.99 ± 2.99% in YNB. Biofilm susceptibility to amphotericin B was significantly decreased in RPMI 1640 and remained unaffected in YNB in hypoxia.
  
  
  CONCLUSIONS
  C. glabrata grows well even under hypoxia but not upon CoCl2 exposures. CoCl2 mimics hypoxia like expression of TDH3 but affects the virulence properties unlike hypoxia. Both, hypoxia and CoCl2 affects adhesion adversely. Hypoxia increases biofilm development and reduces the susceptibility of biofilm to amp B in RPMI 1640 but not in YNB.
authors.affiliation: Department of Biotechnology, Graphic Era University, 566/6, Bell Road, Clement Town, Dehradun, 248001 Uttarakhand, India.
authors.forename: P
authors.initials: P
authors.lastname: Gupta
authors.affiliation: Department of Molecular Biology, Defence Institute of Physiology and Allied Sciences, Lucknow Road, Timarpur, 110054 Delhi, India.
authors.forename: S
authors.initials: S
authors.lastname: Nath
authors.affiliation: Department of Molecular Biology, Defence Institute of Physiology and Allied Sciences, Lucknow Road, Timarpur, 110054 Delhi, India.
authors.forename: R C
authors.initials: RC
authors.lastname: Meena
authors.affiliation: Department of Biotechnology, Graphic Era University, 566/6, Bell Road, Clement Town, Dehradun, 248001 Uttarakhand, India. Electronic address: navinbajpai@gmail.com.
authors.forename: N
authors.initials: N
authors.lastname: Kumar
mesh_terms: D000666:Amphotericin B / Q000494:pharmacology / Q000627:therapeutic use*; D018441:Biofilms / Q000187:drug effects*; D041221:Candida glabrata / Q000187:drug effects* / Q000254:growth & development / Q000502:physiology; D002448:Cell Adhesion / Q000187:drug effects; D003035:Cobalt / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D010100:Oxygen / Q000494:pharmacology*
chemical_list: D003035:Cobalt; D000666:Amphotericin B; C018021:cobaltous chloride; D010100:Oxygen
keywords: 1% O(2); Adhesion; Adhérence; Amphotericin B; Amphotéricine B; Biofilm; Candida glabrata; Chlorure de Cobalt; Cobalt chloride; Hypoxia; Hypoxie; Virulence