title: Genesis of amorphous calcium carbonate containing alveolar plates in the ciliate Coleps hirtus (Ciliophora, Prostomatea).
abstract: In the protist world, the ciliate Coleps hirtus (phylum Ciliophora, class Prostomatea) synthesizes a peculiar biomineralized test made of alveolar plates, structures located within alveolar vesicles at the cell cortex. Alveolar plates are arranged by overlapping like an armor and they are thought to protect and/or stiffen the cell. Although their morphology is species-specific and of complex architecture, so far almost nothing is known about their genesis, their structure and their elemental and mineral composition. We investigated the genesis of new alveolar plates after cell division and examined cells and isolated alveolar plates by electron microscopy, energy-dispersive X-ray spectroscopy, FTIR and X-ray diffraction. Our investigations revealed an organic mesh-like structure that guides the formation of new alveolar plates like a template and the role of vesicles transporting inorganic material. We further demonstrated that the inorganic part of the alveolar plates is composed out of amorphous calcium carbonate. For stabilization of the amorphous phase, the alveolar vesicles, the organic fraction and the element phosphorus may play a role.
authors.affiliation: Biological Institute, Zoology, University of Stuttgart, Pfaffenwaldring 57,70569 Stuttgart, Germany. Marie-Louise.Lemloh@bio.uni-stuttgart.de
authors.forename: Marie-Louise
authors.initials: ML
authors.lastname: Lemloh
authors.forename: Frédéric
authors.initials: F
authors.lastname: Marin
authors.forename: Frédéric
authors.initials: F
authors.lastname: Herbst
authors.forename: Laurent
authors.initials: L
authors.lastname: Plasseraud
authors.forename: Michael
authors.initials: M
authors.lastname: Schweikert
authors.forename: Johannes
authors.initials: J
authors.lastname: Baier
authors.forename: Joachim
authors.initials: J
authors.lastname: Bill
authors.forename: Franz
authors.initials: F
authors.lastname: Brümmer
mesh_terms: D002119:Calcium Carbonate / Q000032:analysis*; D016798:Ciliophora / Q000737:chemistry* / Q000648:ultrastructure*; D008854:Microscopy, Electron; D013052:Spectrometry, X-Ray Emission; D017550:Spectroscopy, Fourier Transform Infrared; D014961:X-Ray Diffraction
chemical_list: D002119:Calcium Carbonate