Resistance to Extreme Stresses by a Newly Discovered Japanese Tardigrade Species, <i>Macrobiotus kyoukenus</i> (Eutardigrada, Macrobiotidae)

Tardigrades are small micrometazoans able to resist several environmental stresses in any stage of their life cycle. An integrated analysis of tardigrade specimens collected in Tsukuba (Japan) revealed a peculiar morphology and a new sensory field in the cloaca. Molecular taxonomy and phylogenetic a...

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Main Authors: Michele Cesari, Ilaria Giovannini, Tiziana Altiero, Roberto Guidetti, Richard Cornette, Takahiro Kikawada, Lorena Rebecchi
Format: Article
Language:English
Published: MDPI AG 2022-07-01
Series:Insects
Subjects:
Online Access:https://www.mdpi.com/2075-4450/13/7/634
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author Michele Cesari
Ilaria Giovannini
Tiziana Altiero
Roberto Guidetti
Richard Cornette
Takahiro Kikawada
Lorena Rebecchi
author_facet Michele Cesari
Ilaria Giovannini
Tiziana Altiero
Roberto Guidetti
Richard Cornette
Takahiro Kikawada
Lorena Rebecchi
author_sort Michele Cesari
collection DOAJ
description Tardigrades are small micrometazoans able to resist several environmental stresses in any stage of their life cycle. An integrated analysis of tardigrade specimens collected in Tsukuba (Japan) revealed a peculiar morphology and a new sensory field in the cloaca. Molecular taxonomy and phylogenetic analysis on different genes (COI, ITS2, 18S and 28S) confirmed that this population is a new species, <i>Macrobiotus kyoukenus</i> sp. nov., belonging to the widespread <i>Macrobiotus hufelandi</i> group. The stress resistance capabilities of <i>M. kyoukenus</i> sp. nov. have been tested by submitting animals to extreme desiccation, rapid freezing, and high levels of ultraviolet radiations (UVB and UVC). Animals were able to survive desiccation (survivorship 95.71 ± 7.07%) and freezing up to −80 °C (82.33 ± 17.11%). Both hydrated and desiccated animals showed a high tolerance to increasing UV radiations: hydrated animals survived to doses up to 152.22 kJ m<sup>−2</sup> (UVB) and up to 15.00 kJ m<sup>−2</sup> (UVC), while desiccated specimens persisted to radiations up to 165.12 kJ m<sup>−2</sup> (UVB) and up to 35.00 kJ m<sup>−2</sup> (UVC). Present data contribute to the discovery of a larger tardigrade biodiversity in Japan, and the tolerance capabilities of <i>M. kyoukenus</i> sp. nov. show that it could become a new emerging model for stress resistance studies.
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spelling doaj.art-75f84d683d8c46c6bb305a8426b5a7872023-12-03T15:11:52ZengMDPI AGInsects2075-44502022-07-0113763410.3390/insects13070634Resistance to Extreme Stresses by a Newly Discovered Japanese Tardigrade Species, <i>Macrobiotus kyoukenus</i> (Eutardigrada, Macrobiotidae)Michele Cesari0Ilaria Giovannini1Tiziana Altiero2Roberto Guidetti3Richard Cornette4Takahiro Kikawada5Lorena Rebecchi6Department of Life Sciences, University of Modena and Reggio Emilia, Via G. Campi 213/d, 41125 Modena, ItalyDepartment of Life Sciences, University of Modena and Reggio Emilia, Via G. Campi 213/d, 41125 Modena, ItalyDepartment of Education and Humanities, University of Modena and Reggio Emilia, Viale Timavo, 93, 42121 Reggio Emilia, ItalyDepartment of Life Sciences, University of Modena and Reggio Emilia, Via G. Campi 213/d, 41125 Modena, ItalyDivision of Biomaterial Sciences, National Institute of Agrobiological Sciences, NARO, 1-2 Owashi, Tsukuba 305-0851, Ibaraki, JapanDivision of Biomaterial Sciences, National Institute of Agrobiological Sciences, NARO, 1-2 Owashi, Tsukuba 305-0851, Ibaraki, JapanDepartment of Life Sciences, University of Modena and Reggio Emilia, Via G. Campi 213/d, 41125 Modena, ItalyTardigrades are small micrometazoans able to resist several environmental stresses in any stage of their life cycle. An integrated analysis of tardigrade specimens collected in Tsukuba (Japan) revealed a peculiar morphology and a new sensory field in the cloaca. Molecular taxonomy and phylogenetic analysis on different genes (COI, ITS2, 18S and 28S) confirmed that this population is a new species, <i>Macrobiotus kyoukenus</i> sp. nov., belonging to the widespread <i>Macrobiotus hufelandi</i> group. The stress resistance capabilities of <i>M. kyoukenus</i> sp. nov. have been tested by submitting animals to extreme desiccation, rapid freezing, and high levels of ultraviolet radiations (UVB and UVC). Animals were able to survive desiccation (survivorship 95.71 ± 7.07%) and freezing up to −80 °C (82.33 ± 17.11%). Both hydrated and desiccated animals showed a high tolerance to increasing UV radiations: hydrated animals survived to doses up to 152.22 kJ m<sup>−2</sup> (UVB) and up to 15.00 kJ m<sup>−2</sup> (UVC), while desiccated specimens persisted to radiations up to 165.12 kJ m<sup>−2</sup> (UVB) and up to 35.00 kJ m<sup>−2</sup> (UVC). Present data contribute to the discovery of a larger tardigrade biodiversity in Japan, and the tolerance capabilities of <i>M. kyoukenus</i> sp. nov. show that it could become a new emerging model for stress resistance studies.https://www.mdpi.com/2075-4450/13/7/634integrated taxonomyphylogenyultraviolet resistancedesiccation tolerancefreezing tolerancesensory field
spellingShingle Michele Cesari
Ilaria Giovannini
Tiziana Altiero
Roberto Guidetti
Richard Cornette
Takahiro Kikawada
Lorena Rebecchi
Resistance to Extreme Stresses by a Newly Discovered Japanese Tardigrade Species, <i>Macrobiotus kyoukenus</i> (Eutardigrada, Macrobiotidae)
Insects
integrated taxonomy
phylogeny
ultraviolet resistance
desiccation tolerance
freezing tolerance
sensory field
title Resistance to Extreme Stresses by a Newly Discovered Japanese Tardigrade Species, <i>Macrobiotus kyoukenus</i> (Eutardigrada, Macrobiotidae)
title_full Resistance to Extreme Stresses by a Newly Discovered Japanese Tardigrade Species, <i>Macrobiotus kyoukenus</i> (Eutardigrada, Macrobiotidae)
title_fullStr Resistance to Extreme Stresses by a Newly Discovered Japanese Tardigrade Species, <i>Macrobiotus kyoukenus</i> (Eutardigrada, Macrobiotidae)
title_full_unstemmed Resistance to Extreme Stresses by a Newly Discovered Japanese Tardigrade Species, <i>Macrobiotus kyoukenus</i> (Eutardigrada, Macrobiotidae)
title_short Resistance to Extreme Stresses by a Newly Discovered Japanese Tardigrade Species, <i>Macrobiotus kyoukenus</i> (Eutardigrada, Macrobiotidae)
title_sort resistance to extreme stresses by a newly discovered japanese tardigrade species i macrobiotus kyoukenus i eutardigrada macrobiotidae
topic integrated taxonomy
phylogeny
ultraviolet resistance
desiccation tolerance
freezing tolerance
sensory field
url https://www.mdpi.com/2075-4450/13/7/634
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