Spirostomum ambiguum: a protozoan model for primordial musculoskeletal exchange?

Abstract

Event Abstract Back to Event Spirostomum ambiguum: a protozoan model for primordial musculoskeletal exchange? PE Garner1*, PE Garner2, V Fallon1 and JE Aaron1 1 University of Leeds, IMSB, FBS, United Kingdom 2 University of Leeds, IMBE, United Kingdom The skeleton is responsive to mechanical usage, yet the basis for its remarkable sensitivity remains uncertain. Abundant osteocytes seem central. Their cytoplasmic syncitium is pervasive and well placed to bridge the gap between mechanical signal transduction and cellular. However, its calcified entombment limits accessibility, while isolation or manipulation may alter its specific threshold characteristics. Insight into the rudiments of musculoskeletal exchange may be found in certain protozoa from which the metazoan pathway apparently evolved (Pautard 1960, 1970; Ruffalo 1978). In particular is the organism Spirostomum ambiguum (a cigar-shaped creature visible to the naked eye) which fabricates and accumulates calcium phosphate particles resembling those found in bone. Moreover, their intracellular, golgi-directed synthesis (Fallon, Garner and Aaron, in press) is determined by their active life-cycle. This modulates between a free-swimming state when calcified particles are few and a burrowing stage when calcified particles are many. Thus when the mineral of cultured S. ambiguum was labelled with the fluorochrome tetracycline the green fluorescence intensity (AU), mapped using laser confocal microscopy, recorded a high mineral level in the burrowing animals (138.0 + SD4.0) compared with the free-swimmers (89.7 SD 3.3). Similarly when the live organisms were transfected with a GFP construct (Fallon, 2006) the resulting mannosidase II enzyme, as an expression of Golgi activity, differed significantly (p<0.0001) between tunnelling (104.6 SD 2.7) and free-swimming (74.5 6.7) by the two-sample t-test. Also it was observed that the distribution of the calcified particles was not random. A proportion related in disposition to a regular and well-defined pattern of contractile muscle myonemes, the fibres of which were arranged longitudinally within the high stress burrowers in contrast to their transverse alignment in the low stress swimmers. The capacity exhibited by this animal model not only to package bone-like mineral in response to changing environmental pressures, but also to relate them to their intracellular contractile elements may suggest an early integrated musculoskeletal system that substantially predated the vertebrates which eventually exploited this major advantage. The protozoan model described may therefore serve as a valuable tool for future fundamental investigation of osteocyte ancestry, mechanotransduction, perception and response. Keywords: Bones, Bone Research Conference: 2011 joint meeting of the Bone Research Society & the British Orthopaedic Research Society, Cambridge, United Kingdom, 27 Jun - 29 Jun, 2011. Presentation Type: Oral Topic: Abstracts Citation: Garner P, Garner P, Fallon V and Aaron J (2011). Spirostomum ambiguum: a protozoan model for primordial musculoskeletal exchange?. Front. Endocrinol. Conference Abstract: 2011 joint meeting of the Bone Research Society & the British Orthopaedic Research Society. doi: 10.3389/conf.fendo.2011.02.00021 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 30 Sep 2011; Published Online: 30 Sep 2011. * Correspondence: Prof. PE Garner, University of Leeds, IMSB, FBS, United Kingdom, bms2peg@leeds.ac.uk Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers PE Garner PE Garner V Fallon JE Aaron Google PE Garner PE Garner V Fallon JE Aaron Google Scholar PE Garner PE Garner V Fallon JE Aaron PubMed PE Garner PE Garner V Fallon JE Aaron Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.