Characterization of testudine melanomacrophage linear, membrane extension processes--cablepodia--by phase and atomic force microscopy.
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.
Johnson
James C
JC
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
Nettikadan
Saju R
SR
Vengasandra
Srikanth G
SG
Lovan
Sai
S
Muys
James
J
Henderson
Eric
E
Christiansen
James
J
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
D008543:Melanins