title: Foveolar Müller Cells of the Pied Flycatcher: Morphology and Distribution of Intermediate Filaments Regarding Cell Transparency.
abstract: Specialized intermediate filaments (IFs) have critical importance for the clearness and uncommon transparency of vertebrate lens fiber cells, although the physical mechanisms involved are poorly understood. Recently, an unusual low-scattering light transport was also described in retinal Müller cells. Exploring the function of IFs in Müller cells, we have studied the morphology and distribution pattern of IFs and other cytoskeletal filaments inside the Müller cell main processes in the foveolar part of the avian (pied flycatcher) retina. We found that some IFs surrounded by globular nanoparticles (that we suggest are crystallines) are present in almost every part of the Müller cells that span the retina, including the microvilli. Unlike IFs implicated in the mechanical architecture of the cell, these IFs are not connected to any specific cellular membranes. Instead, they are organized into bundles, passing inside the cell from the endfeet to the photoreceptor, following the geometry of the processes, and repeatedly circumventing numerous obstacles. We believe that the presently reported data effectively confirm that the model of nanooptical channels built of the IFs may provide a viable explanation of Müller cell transparency.
authors.affiliation: 1Sechenov Institute of Evolutionary Physiology and Biochemistry,Russian Academy of Sciences,194223 St-Petersburg,Russia.
authors.forename: Lidia
authors.initials: L
authors.lastname: Zueva
authors.affiliation: 2Department of Vertebrate Zoology,Lomonosov Moscow State University,119992 Moscow,Russia.
authors.forename: Tatiana
authors.initials: T
authors.lastname: Golubeva
authors.affiliation: 3Institute of Higher Nervous Activity and Neurophysiology,Russian Academy of Sciences,117485 Mosсow,Russia.
authors.forename: Elena
authors.initials: E
authors.lastname: Korneeva
authors.affiliation: 4Department of Physics,University of Puerto Rico,San Juan, PR 00931,USA.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Makarov
authors.affiliation: 5Faculty of Sciences and Technology,University of the Algarve,Faro 8005-139,Algarve,Portugal.
authors.forename: Igor
authors.identifier: http://orcid.org/0000-0002-6116-184X
authors.initials: I
authors.lastname: Khmelinskii
authors.affiliation: 6Department of Physiology,Central University of the Caribbean,Bayamon, PR 00956,USA.
authors.forename: Mikhail
authors.initials: M
authors.lastname: Inyushin
mesh_terms: D000818:Animals; D055592:Biophysical Phenomena; D063928:Ependymoglial Cells / Q000737:chemistry / Q000502:physiology / Q000648:ultrastructure*; D007382:Intermediate Filaments / Q000648:ultrastructure*; D012160:Retina / Q000166:cytology* / Q000502:physiology; D020308:Songbirds / Q000033:anatomy & histology* / Q000502:physiology
keywords: IFs; Müller cells; avian retina; transparency