Anatomy of the Planarian Dugesia japonica I. The Muscular System Revealed by Antisera against Myosin Heavy Chains

Orii, Hidefumi; Ito, Hideki; Watanabe, Kenji

doi:10.2108/zsj.19.1123

Cited by 38 publications

(30 citation statements)

References 22 publications

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“…We found an asymmetric double-Gaussian distribution for the waist location based on imaging n=1335 specimen within 3 days after fission (see Fig.2B and Materials and Methods). Of note, the area of low fission probability between the peaks, as determined by manual inspection of a subpopulation of n=40 specimen, coincides with the location of the pharynx, which is a powerful muscle used to ingest food (19). Thus, planarians divide neither at a pole nor at the pharynx, but have a non-zero probability of dividing anywhere else along the head-tail axis, with the majority of events happening post-pharyngeally.…”

Section: Resultsmentioning

confidence: 84%

Mechanics dictate where and how freshwater planarians fission

Malinowski

Cochet‐Escartin

Kaj

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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Asexual freshwater planarians reproduce by tearing themselves into two pieces by a process called binary fission. The resulting head and tail pieces regenerate within about a week forming two new worms. Understanding this process of ripping oneself into two parts poses a challenging biomechanical problem. Since planarians stop "doing it" at the slightest disturbance, this remained a centuries-old puzzle. We focus on Dugesia japonica fission and show that it proceeds in three stages: a local constriction ("waist formation"), pulsationwhich increases waist longitudinal stresses -and transverse rupture. We developed a linear mechanical model with a planarian represented by a thin shell. The model fully captures the pulsation dynamics leading to rupture and reproduces empirical time scales and stresses. It asserts that fission execution is a mechanical process. Furthermore, we show that the location of waist formation, and thus fission, is determined by physical constraints. Together, our results demonstrate that where and how a planarian rips itself apart during asexual reproduction can be fully explained through biomechanics.Keywords: planarians, biomechanics, fission, rupture, traction forces Significance Statement: How planarians reproduce by ripping themselves into a head and a tail piece, which subsequently regenerate into two new worms, is a centuries-old biomechanics problem. Michael Faraday contemplated how this feat can be achieved in the 1800s, but it remained unanswered because it is experimentally difficult to observe planarians "doing it". We recorded Dugesia japonica planarians in the act and developed a physical model which captures pivotal steps of their reproduction dynamics. The model reproduces experimental time scales and rupture stresses without fit parameters. The key to rupture is a local reduction of the animal's cross-sectional area, which greatly amplifies the stresses exerted by the planarian's musculature and enables rupture at substrate stresses in the Pa range. \body Already Michael Faraday and his contemporaries were intrigued by the observation that asexual freshwater planarians, squishy worms a few mm in length, reproduced by tearing themselves into a head and tail offspring, in a process called binary fission (1). How was it possible for these animals to generate the forces necessary to rip themselves using only their

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Section: Resultsmentioning

confidence: 84%

Mechanics dictate where and how freshwater planarians fission

Malinowski

Cochet‐Escartin

Kaj

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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“…80,81 The body musculature involves longitudinal, diagonal and circular muscle fibers. 27,82 All planarian organs are embedded in a mesodermal tissue called parenchyma or mesenchyma that consists of several types of nonproliferating cells 83 and only one mitotically active cell type, the neoblast, which is believed to be an adult somatic stem-cell. 6,11,21,[84][85][86][87] Together with their immediate progeny, neoblasts account for approximately 15 percent to 25 percent of all parenchymal cells.…”

Section: Autophagy During Degrowth and Regenerationmentioning

confidence: 99%

Autophagy meets planarians

González‐Estévez

2009

Autophagy

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This review aims to demonstrate the importance of freshwater planarians as model organisms, particularly emphasizing those characteristics of the animal that make them a good model to study autophagy. The aim of this review is to provide a better understanding of autophagy in this model for the nonplanarian reader, and elucidate the relevance of autophagy research in this peculiar model organism. Furthermore, I will try to synthesize the evidence showing the importance of autophagy in planarian body remodeling, and I will discuss some ideas about the role of autophagy in stem cell biology. In light of these new developments, it is likely that the planarian field will make an important contribution to the study of the molecular mechanisms involved in autophagy in the future.

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“…Monoclonal antibodies were produced for different planarian species, such as Dugesia (Girardia) tigrina (Romero et al 1991;Bueno et al 1997), Phagocata vivida (Shirakawa et al 1991;Asano et al 2001) and Dugesia japonica (Asano et al 2001;Orii et al 2002). Physiological regeneration was recently studied in an acoel species (Gschwentner et al 2003).…”

Section: Introductionmentioning

confidence: 99%

Production and characterisation of cell- and tissue-specific monoclonal antibodies for the flatworm Macrostomum sp.

Ladurner

Pfister

Seifarth

et al. 2004

Histochem Cell Biol

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Monoclonal antibodies (mABs) against various cell types of the basal free-living flatworm Macrostomum sp. were produced by immunising Balb/c mice with cell suspensions of disintegrated animals. We identified 360 positive supernatants with specific staining of various tissues, cell types, patterns or structures. Here we report immunocytochemical characterisation, histological stainings and isotyping of 11 mABs specific for muscle cells (MMu-1, MMu-2, MMu-3, MMu-4), digestive and prostate glands (MDr-1 and MDr-2, MPr-1), epidermal cells (MEp-1), the ventral nerve cord including neuron clusters (MNv-1), gastrodermal cells (MDa-1) and spermatids (MSp-1). Confocal microscopy, histological techniques, electron microscopy and immunoblotting were applied to demonstrate stainings in juveniles, adults, starved or well-fed animals. Considering the current lack of specific markers the obtained mABs will be particularly helpful studying embryonic and postembryonic development, pattern formation, cell differentiation, regeneration and reproductive allocation in Macrostomum sp., and possibly other basal flatworms. The small size, ease of culturing, short generation time, transparency and the basal phylogenetic position specify Macrostomum sp. as a suitable model organism for comparative analyses within Platyhelminthes and to Drosophila and C. elegans.

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Anatomy of the Planarian Dugesia japonica I. The Muscular System Revealed by Antisera against Myosin Heavy Chains

Cited by 38 publications

References 22 publications

Mechanics dictate where and how freshwater planarians fission

Mechanics dictate where and how freshwater planarians fission

Autophagy meets planarians

Production and characterisation of cell- and tissue-specific monoclonal antibodies for the flatworm Macrostomum sp.

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