title: Statistical analysis of the quantal basis of secretory granule formation.
abstract: The size distribution of vesicles exocytosed from secretory cells displays quantal nature, vesicle volume is periodic multi-modal, suggesting that these heterogeneous vesicles are aggregate sums of a variable number of homogeneous basic granules. Whether heterogeneity is a lumping-together artifact of the measurement or an inherent intra-cell feature of the vesicles is an unresolved question. Recent empirical evidence will be provided for the quantal nature of intra-cell vesicle volume, supporting the controversial paradigm of homotypic fusion: basic cytoplasmic granules fuse with each other to create heterogeneously sized vesicles. An EM-algorithm-based method is presented for the conversion of multi-modal to quantal data that provides as by-product estimates of means and variances of basic granule packaging.
authors.affiliation: Department of Econometrics, Faculty of Informatics and Statistics, University of Economics, Nám. W. Churchilla 4, 13067 Praha 3, Czech Republic.
authors.forename: Marika
authors.initials: M
authors.lastname: Křepelová-Dror
authors.forename: Ilan
authors.initials: I
authors.lastname: Hammel
authors.forename: Isaac
authors.initials: I
authors.lastname: Meilijson
mesh_terms: D000818:Animals; D003585:Cell Biology / Q000706:statistics & numerical data; D003594:Cytoplasmic Granules / Q000737:chemistry* / Q000378:metabolism; D003627:Data Interpretation, Statistical; D006801:Humans; D010316:Particle Size; D011506:Proteins / Q000378:metabolism; D022142:Secretory Vesicles / Q000737:chemistry* / Q000378:metabolism; D013572:Synaptic Vesicles / Q000737:chemistry* / Q000378:metabolism
chemical_list: D011506:Proteins
keywords: EM algorithm; Wicksell corpuscle problem; multimodality; stereology; unit granule