title: Triacylglyceride composition and fatty acyl saturation profile of a psychrophilic and psychrotolerant fungal species grown at different temperatures.
abstract: Pseudogymnoascus destructans is a psychrophilic fungus that infects cutaneous tissues in cave dwelling bats, and it is the causal agent for white nose syndrome (WNS) in North American (NA) bat populations. Geomyces pannorum is a related psychrotolerant keratinolytic species that is rarely a pathogen of mammals. In this study, we grew P. destructans and G. pannorum in static liquid cultures at favourable and suboptimal temperatures to: 1) determine if triacylglyceride profiles are species-specific, and 2) determine if there are differences in fatty acyl (FA) saturation levels with respect to temperature. Total lipids isolated from both fungal spp. were separated by thin-layer chromatography and determined to be primarily sterols (∼15 %), free fatty acids (FFAs) (∼45 %), and triacylglycerides (TAGs) (∼50 %), with minor amounts of mono-/diacylglycerides and sterol esters. TAG compositions were profiled by matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI-TOF). Total fatty acid methyl esters (FAMEs) and acyl lipid unsaturation levels were determined by gas chromatography-mass spectrometry (GC-MS). Pseudogymnoascus destructans produced higher proportions of unsaturated 18C fatty acids and TAGs than G. pannorum. Pseudogymnoascus destructans and G. pannorum produced up to a two-fold increase in 18:3 fatty acids at 5 °C than at higher temperatures. TAG proportion for P. destructans at upper and lower temperature growth limits was greater than 50 % of total dried mycelia mass. These results indicate fungal spp. alter acyl lipid unsaturation as a strategy to adapt to cold temperatures. Differences between their glycerolipid profiles also provide evidence for a different metabolic strategy to support psychrophilic growth, which may influence P. destructans' pathogenicity to bats.
authors.affiliation: Graduate Program of Environmental Science, Arkansas State University, Jonesboro, AR 72467, USA. Electronic address: elp44@georgetown.edu.
authors.forename: Evan L
authors.initials: EL
authors.lastname: Pannkuk
authors.affiliation: Department of Biological Sciences, Arkansas State University, Jonesboro, AR 72467, USA.
authors.forename: Hannah B
authors.initials: HB
authors.lastname: Blair
authors.affiliation: Department of Biological Sciences, Arkansas State University, Jonesboro, AR 72467, USA.
authors.forename: Amy E
authors.initials: AE
authors.lastname: Fischer
authors.affiliation: Department of Biological Sciences, Arkansas State University, Jonesboro, AR 72467, USA.
authors.forename: Cheyenne L
authors.initials: CL
authors.lastname: Gerdes
authors.affiliation: Department of Biological Sciences, Arkansas State University, Jonesboro, AR 72467, USA.
authors.forename: David F
authors.initials: DF
authors.lastname: Gilmore
authors.affiliation: Arkansas Biosciences Institute, Arkansas State University, Jonesboro, AR 72467, USA.
authors.forename: Brett J
authors.initials: BJ
authors.lastname: Savary
authors.affiliation: Graduate Program of Environmental Science, Arkansas State University, Jonesboro, AR 72467, USA; Department of Biological Sciences, Arkansas State University, Jonesboro, AR 72467, USA.
authors.forename: Thomas S
authors.initials: TS
authors.lastname: Risch
mesh_terms: D000818:Animals; D001203:Ascomycota / Q000254:growth & development* / Q000302:isolation & purification / Q000378:metabolism / Q000528:radiation effects*; D002685:Chiroptera; D002855:Chromatography, Thin Layer; D003600:Cytosol / Q000737:chemistry*; D005227:Fatty Acids / Q000032:analysis*; D008401:Gas Chromatography-Mass Spectrometry; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013696:Temperature; D014280:Triglycerides / Q000032:analysis*
chemical_list: D005227:Fatty Acids; D014280:Triglycerides
keywords: FAME analysis; Fungal lipids; Gas chromatography; Glycerolipid saturation; Matrix-assisted laser desorption–ionization time-of-flight mass spectrometry; Thin-layer chromatography; White nose syndrome