Glycerophospholipid Analysis of Eastern Red Bat (Lasiurus Borealis) Hair by Electrospray Ionization Tandem Mass Spectrometry

Abstract

Pilosebaceous units found in the mammalian integument are composed of a hair follicle, the proximal portion of the hair shaft, a sebaceous gland, and the erector pili muscle. Pilosebaceous units release protective oils, or sebum, by holocrine secretion onto skin and hair through rupturing of sebocytes. Sebum is largely composed of polar and neutral lipids including glycerolipids, free fatty acids, sterols, wax esters, sterol esters, and squalene. In addition to these lipid classes, there is a small proportion of ionic/anionic glycerophospholipids (GPs). Composition of GPs on hair is rarely addressed despite their broad biological activities as signaling molecules and membrane stability. Furthermore, knowledge on GP composition in bats is lacking. Bat GP composition is important to document due to GP roles ranging from decreasing drag during migration to interaction with the integumentary microbiome. In this study, we analyzed GP molecular composition with liquid chromatography electrospray ionization tandem mass spectrometry and compared GP content to previous literature. A total of 152 GPs were detected. Broad GP classes identified include lysophosphatidylcholine, phosphatidylcholine (PC), lysophosphatidylethanolamine, phosphatidylethanolamine, phosphatidylinositol, phosphatidylserine, phosphatidic acid, and phosphatidylglycerol, with PC being the most abundant class. The acyl components were consistent with fatty acid methyl esters and triacylglyceride moieties found in Eastern red bat sebum. GP proportions of the hair surface were different from a previous study on bat lung surfactants. This study determined the broad class and molecular species of bat sebum GPs that may be used in future ecological studies in vespertilionid bats.

Glycerophospholipid Profiles of Bats with White-Nose Syndrome

“…SM FAs from R. aegyptiacus brain and spinal cord (primarily 18:0, 24:0/24:1, and >24 C lengths; van der Westhuyzen and Cantrill 1983) are characterized by longer chain lengths compared to M. lucifugus wing tissue SM FAs we describe (predominantly 16:0 with lower amounts of 18:0, 22:1, 22:0, 24:1, and 24:0). The GP fraction in our study was similar to that observed for L. borealis hair sebaceous lipid (Pannkuk et al 2014b), but there were minor differences. While PC (~70%) and PI (~15%) were dominant GP classes in L. borealis hair (Pannkuk et al 2014b), here we found that PC (~30%) and PS (~21%) were dominant in wing tissue.…”

“…The GP fraction in our study was similar to that observed for L. borealis hair sebaceous lipid (Pannkuk et al 2014b), but there were minor differences. While PC (~70%) and PI (~15%) were dominant GP classes in L. borealis hair (Pannkuk et al 2014b), here we found that PC (~30%) and PS (~21%) were dominant in wing tissue. LPCs were similar between L. borealis hair and M. lucifugus wing tissue with 16:0, 18:0, and 18:1 dominant FAs.…”

“…Lipid extract samples were overnight shipped to Kansas Lipidomics Research Center (KLRC) (Pannkuk et al 2014b). GP and SM profiling was performed with ESI tandem MS by determining the mass-to-charge ratio ( m/z ) of intact ions and the m/z of head group fragments (see Wanjie et al 2005).…”

“…Previous studies have documented SM composition in Rousettus aegyptiacus (van der Westhuyzen and Cantrill 1983), and GP composition in Nyctophilus geoffroyi (Slocombe et al 2000), Chalinolobus gouldii (Lang et al 2005), five Pteropus spp. (Melville et al 2012), Lasiurus cinereus (McGuire et al 2013), and Lasiurus borealis (Pannkuk et al 2014b) in tissues ranging from pulmonary surfactants to flight muscle and fur. In addition to variation in tissues and species, only two studies have used electrospray ionization (ESI) tandem mass spectrometry (MS), quickly identifying GPs to a molecular species level (Lang et al 2005; Pannkuk et al 2014b).…”

“…(Melville et al 2012), Lasiurus cinereus (McGuire et al 2013), and Lasiurus borealis (Pannkuk et al 2014b) in tissues ranging from pulmonary surfactants to flight muscle and fur. In addition to variation in tissues and species, only two studies have used electrospray ionization (ESI) tandem mass spectrometry (MS), quickly identifying GPs to a molecular species level (Lang et al 2005; Pannkuk et al 2014b). ESI tandem MS is the most common method for polar lipid analysis, while atmospheric-pressure chemical ionization is more suitable for non-polar lipids, such as waxes (Cajka and Fiehn 2014).…”