title: Characterization of testudine melanomacrophage linear, membrane extension processes--cablepodia--by phase and atomic force microscopy.
abstract: Melanomacrophages (MMs) are a component of an internal, pigmented cell system in liver and splenic tissues of some fishes, anurans, and reptiles. The cells have been found in centers or aggregates in sinusoids and are associated with cells capable of producing a peptide cytokine and immunoglobulins. A unique cell extension process has been observed in turtle MMs placed into cell culture, and this process has been studied by light and atomic force microscopy. These structures, referred to as cablepodia, are uniquely straight, narrow, and unbranching and appear to originate from growth cones opposite lamellipodia. Cablepodia were found to connect with other turtle MMs and fibroblasts forming cell networks. Dividing fibroblasts to which a cablepodium attached ceased cell division. The observations collectively suggest that a principal reason for aggregations of MMs in internal organs of lower vertebrates is their ability to form interconnected networks of cell processes for trapping and processing of particulate matter, cells, and infectious organisms and, possibly, for the communication of cell signals and transfer of intracellular materials.
authors.affiliation: Department of Microbiology, Des Moines University, Des Moines, Iowa 50312, BioForce Nanosciences Inc., 1615 Golden Aspen Drive, Suite 101, Ames, Iowa 50010, USA. james.johnson@dmu.edu
authors.forename: James C
authors.initials: JC
authors.lastname: Johnson
authors.forename: Saju R
authors.initials: SR
authors.lastname: Nettikadan
authors.forename: Srikanth G
authors.initials: SG
authors.lastname: Vengasandra
authors.forename: Sai
authors.initials: S
authors.lastname: Lovan
authors.forename: James
authors.initials: J
authors.lastname: Muys
authors.forename: Eric
authors.initials: E
authors.lastname: Henderson
authors.forename: James
authors.initials: J
authors.lastname: Christiansen
mesh_terms: D000818:Animals; D048430:Cell Shape; D022081:Cell Surface Extensions / Q000378:metabolism / Q000648:ultrastructure*; D002478:Cells, Cultured; D005347:Fibroblasts / Q000166:cytology / Q000502:physiology; D008099:Liver / Q000166:cytology; D008264:Macrophages / Q000378:metabolism / Q000648:ultrastructure*; D008543:Melanins; D018625:Microscopy, Atomic Force; D008858:Microscopy, Phase-Contrast; D013154:Spleen / Q000166:cytology; D014426:Turtles
chemical_list: D008543:Melanins