title: Dissociation and Re-Aggregation of Multicell-Ensheathed Fragments Responsible for Rapid Production of Massive Clumps of Leptothrix Sheaths.
abstract: Species of the Fe/Mn-oxidizing bacteria Leptothrix produce tremendous amounts of microtubular, Fe/Mn-encrusted sheaths within a few days in outwells of groundwater that can rapidly clog water systems. To understand this mode of rapid sheath production and define the timescales involved, behaviors of sheath-forming Leptothrix sp. strain OUMS1 were examined using time-lapse video at the initial stage of sheath formation. OUMS1 formed clumps of tangled sheaths. Electron microscopy confirmed the presence of a thin layer of bacterial exopolymer fibrils around catenulate cells (corresponding to the immature sheath). In time-lapse videos, numerous sheath filaments that extended from the periphery of sheath clumps repeatedly fragmented at the apex of the same fragment, the fragments then aggregated and again elongated, eventually forming a large sheath clump comprising tangled sheaths within two days. In this study, we found that fast microscopic fragmentation, dissociation, re-aggregation and re-elongation events are the basis of the rapid, massive production of Leptothrix sheaths typically observed at macroscopic scales.
authors.affiliation: Core Research for Evolutionary Science and Technology (CREST), Japan Science and Technology Agency (JST), Okayama 700-0082, Japan. tkunoh06@cc.okayama-u.ac.jp.|Graduate School of Natural Science and Technology, Okayama University, Okayama 700-0082, Japan. tkunoh06@cc.okayama-u.ac.jp.
authors.forename: Tatsuki
authors.initials: T
authors.lastname: Kunoh
authors.affiliation: Advanced Research Center for Oral and Craniofacial Sciences, Okayama University Dental School, Okayama 700-8558, Japan. nagaoka@okayama-u.ac.jp.
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Nagaoka
authors.affiliation: Department of Physics and Astronomy, University of Southern California, Los Angeles, CA 90089, USA. ian.r.mcfarlane@gmail.com.
authors.forename: Ian R
authors.initials: IR
authors.lastname: McFarlane
authors.affiliation: Core Research for Evolutionary Science and Technology (CREST), Japan Science and Technology Agency (JST), Okayama 700-0082, Japan. ktamura@okayama-u.ac.jp.|Graduate School of Natural Science and Technology, Okayama University, Okayama 700-0082, Japan. ktamura@okayama-u.ac.jp.
authors.forename: Katsunori
authors.initials: K
authors.lastname: Tamura
authors.affiliation: Department of Physics and Astronomy, University of Southern California, Los Angeles, CA 90089, USA. mnaggar@usc.edu.|Molecular and Computational Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA. mnaggar@usc.edu.|Department of Chemistry, University of Southern California, Los Angeles, CA 90089, USA. mnaggar@usc.edu.
authors.forename: Mohamed Y
authors.initials: MY
authors.lastname: El-Naggar
authors.affiliation: Core Research for Evolutionary Science and Technology (CREST), Japan Science and Technology Agency (JST), Okayama 700-0082, Japan. hkunoh@cc.okayama-u.ac.jp.|Graduate School of Natural Science and Technology, Okayama University, Okayama 700-0082, Japan. hkunoh@cc.okayama-u.ac.jp.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Kunoh
authors.affiliation: Core Research for Evolutionary Science and Technology (CREST), Japan Science and Technology Agency (JST), Okayama 700-0082, Japan. jtakada@cc.okayama-u.ac.jp.|Graduate School of Natural Science and Technology, Okayama University, Okayama 700-0082, Japan. jtakada@cc.okayama-u.ac.jp.
authors.forename: Jun
authors.initials: J
authors.lastname: Takada
keywords: Leptothrix; bacterial sheath apex; massive sheath production; sheath clump; sheath fragmentation; time-lapse microscopy