title: Chemical-Free Technique to Study the Ultrastructure of Primary Cilium.
abstract: A primary cilium is a hair-like structure with a width of approximately 200 nm. Over the past few decades, the main challenge in the study of the ultrastructure of cilia has been the high sensitivity of cilia to chemical fixation, which is required for many imaging techniques. In this report, we demonstrate a combined high-pressure freezing (HPF) and freeze-fracture transmission electron microscopy (FFTEM) technique to examine the ultrastructure of a cilium. Our objective is to develop an optimal high-resolution imaging approach that preserves cilia structures in their best natural form without alteration of cilia morphology by chemical fixation interference. Our results showed that a cilium has a swelling-like structure (termed bulb), which was previously considered a fixation artifact. The intramembrane particles observed via HPF/FFTEM indicated the presence of integral membrane proteins and soluble matrix proteins along the ciliary bulb, which is part of an integral structure within the ciliary membrane. We propose that HPF/FFTEM is an important and more suitable chemical-free method to study the ultrastructure of primary cilia.
authors.affiliation: Department of Biomedical &Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, CA 92618.|Department of Urology, University of California at Irvine Medical Campus, Orange, CA 92868.|Department of Medicinal &Biological Chemistry, University of Toledo School of Pharmacy, Toledo, OH 43614.
authors.forename: Ashraf M
authors.initials: AM
authors.lastname: Mohieldin
authors.affiliation: Department of Medicinal &Biological Chemistry, University of Toledo School of Pharmacy, Toledo, OH 43614.
authors.forename: Wissam A
authors.initials: WA
authors.lastname: AbouAlaiwi
authors.affiliation: Liquid Crystal Institute, Kent State University, Kent, OH 44242.
authors.forename: Min
authors.initials: M
authors.lastname: Gao
authors.affiliation: Department of Biomedical &Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, CA 92618.|Department of Urology, University of California at Irvine Medical Campus, Orange, CA 92868.|Department of Medicinal &Biological Chemistry, University of Toledo School of Pharmacy, Toledo, OH 43614.
authors.forename: Surya M
authors.initials: SM
authors.lastname: Nauli
mesh_terms: D000818:Animals; D002462:Cell Membrane / Q000648:ultrastructure; D002478:Cells, Cultured; D002923:Cilia / Q000648:ultrastructure*; D046529:Microscopy, Electron, Transmission / Q000379:methods; D013552:Swine