The biomechanical role of overall-shape transformation in a primitive multicellular organism: a case study of dimorphism in the filamentous cyanobacterium Arthrospira platensis

Chaiyasitdhi, A., Miphonpanyatawichok, W., Riehle, M. O. , Phatthanakun, R., Surareungchai, W., Kundhikanjana, W. and Kuntanawat, P. (2018) The biomechanical role of overall-shape transformation in a primitive multicellular organism: a case study of dimorphism in the filamentous cyanobacterium Arthrospira platensis. PLoS ONE, 13(5), e0196383. (doi:10.1371/journal.pone.0196383) (PMID:29746494)

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Abstract

Morphological transformations in primitive organisms have long been observed; however, its biomechanical roles are largely unexplored. In this study, we investigate the structural advantages of dimorphism in Arthrospira platensis, a filamentous multicellular cyanobacterium. We report that helical trichomes, the default shape, have a higher persistence length (Lp), indicating a higher resistance to bending or a large value of flexural rigidity (kf), the product of the local cell stiffness (E) and the moment of inertia of the trichomes’ cross-section (I). Through Atomic Force Microscopy (AFM), we determined that the E of straight and helical trichomes were the same. In contrast, our computational model shows that I is greatly dependent on helical radii, implying that trichome morphology is the major contributor to kf variation. According to our estimation, increasing the helical radii alone can increase kf by 2 orders of magnitude. We also observe that straight trichomes have improved gliding ability, due to its structure and lower kf. Our study shows that dimorphism provides mechanical adjustability to the organism and may allow it to thrive in different environmental conditions. The higher kf provides helical trichomes a better nutrient uptake through advection in aquatic environments. On the other hand, the lower kf improves the gliding ability of straight trichomes in aquatic environments, enabling it to chemotactically relocate to more favorable territories when it encounters certain environmental stresses. When more optimal conditions are encountered, straight trichomes can revert to their original helical form. Our study is one of the first to highlight the biomechanical role of an overall-shape transformation in cyanobacteria.

Item Type:Articles
Additional Information:PK received funding from Thailand Research Fund (TRF) http://www.trf.or.th/ (contract number TRG5880260). WK received funding from Suranaree University of Technology (SUT) www.sut.ac.th, and the Office of the Higher Education Commission under the National Research University (NRU) project.
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Riehle, Dr Mathis
Creator Roles:
Riehle, M. O.Methodology, Supervision, Writing – review and editing
Authors: Chaiyasitdhi, A., Miphonpanyatawichok, W., Riehle, M. O., Phatthanakun, R., Surareungchai, W., Kundhikanjana, W., and Kuntanawat, P.
College/School:College of Medical Veterinary and Life Sciences > Institute of Molecular Cell and Systems Biology
Journal Name:PLoS ONE
Publisher:Public Library of Science
ISSN:1932-6203
ISSN (Online):1932-6203
Copyright Holders:Copyright © 2018 Chaiyasitdhi et al.
First Published:First published in PLoS ONE 13(5): e0196383
Publisher Policy:Reproduced under a Creative Commons License

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