134 research outputs found
Resistance to Extreme Stresses by a Newly Discovered Japanese Tardigrade Species, Macrobiotus kyoukenus (Eutardigrada, Macrobiotidae)
No full textSIMPLE SUMMARY: Tardigrades are small micrometazoans able to resist several environmental stresses in any stage of their life cycle. The integrated molecular and morphological analysis of tardigrade specimens collected in Tsukuba (Japan) revealed that this population represents a new species, Macrobiotus kyoukenus sp. nov., belonging to the genus Macrobiotus, one of the most speciose and widespread water bear taxon. The stress resistance capabilities of M. kyoukenus 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 and freezing, and both hydrated and desiccated animals showed a high tolerance to increasing UV radiations. Overall, our findings contribute to the discovery of a larger tardigrade biodiversity in Japan, and the tolerance capabilities of M. kyoukenus sp. nov. show that this new species could become an emerging model for stress resistance studies. ABSTRACT: 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, Macrobiotus kyoukenus sp. nov., belonging to the widespread Macrobiotus hufelandi group. The stress resistance capabilities of M. kyoukenus 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(−2) (UVB) and up to 15.00 kJ m(−2) (UVC), while desiccated specimens persisted to radiations up to 165.12 kJ m(−2) (UVB) and up to 35.00 kJ m(−2) (UVC). Present data contribute to the discovery of a larger tardigrade biodiversity in Japan, and the tolerance capabilities of M. kyoukenus sp. nov. show that it could become a new emerging model for stress resistance studies
TENLAW: Tenancy Law and Housing Policy in Multi-level Europe. National Report for France
No full textOTB ResearchArchitecture and The Built Environmen
TENLAW: Tenancy Law and Housing Policy in Multi-level Europe. Tenant's Rights Brochure for France
No full textOTBArchitecture and The Built Environmen
Juvenile Hormone titre and vitellogenin gene expression related to ovarian development in primary reproductives compared with nymphs and nymphoid reproductives of the termite Reticulitermes speratus
No full textTo elucidate the reproductive cycle of termite queens, incipient colonies of Reticulitemes speratus (Isoptera: Rhinotermitidae) were established under laboratory conditions, and the transition of colony development was observed at 0.5, 1.5, 2.5, 3.5, and 7.5 months (stages I-V, respectively) after colony foundation. Ovarian development, vitellogenin gene expression, and Juvenile Hormone (JH) titres are examined in the queens and in non-physogastric nymphoids collected from natural colonies. A reproductive cycle in queens is observed, in which the oviposition rate is relatively higher during stages I and II, and then decreases during stages III and IV. Vitellogenic oocytes are not observed in the ovary during stages III and IV, and the expression level of the vitellogenin gene is low, suggesting that egg production in queens is repressed during these stages. However, vitellogen gene expression and egg deposition in queens resumes during stage V. Juvenile Hormone levels rise during the transition from nymphs to stage-I queens, and elevated JH titres are observed also during stages III and IV. The decrease in JH titre in queens at stage II precedes the decline in vitellogenesis at stages III and IV. Thus, JH titre and vitellogenesis are correlated in an offset pattern. However, non-physogastric nymphoid reproductives do not have vitellogenic oocytes in their ovaries, and their JH titre is two-fold higher than that of queens, suggesting that elevated JH titre precedes vitellogenesis as in queens
The 21st International Symposium on Chironomidae
No full textThe 21st International Symposium on Chironomidae was originally scheduled for Tsukuba, Japan in July 2021. However, the COVID-19 pandemic is far from ending and Tokyo Summer Olympic Games were postponed to 2021. Many international conferences including the International Congress of Entomology or the Congress of the International Society of Limnology were also reported to next year. The organizing committee wishes to welcome the whole community of chironomid researchers to Tsukuba under safer and the best possible conditions. For this reason, the organizing committee decided to postpone the symposium to summer 2022. As many colleagues agreed, a physical meeting will yield more fruitful exchanges in our field rather than an online symposium. This is also one point that motivated our decision to postpone the 21st International Symposium on Chironomidae to 2022. As soon as the new dates for the Symposium are fixed, we will make a new announcements in the Chironomus Journal, on the Chironomid Home Page and in the Chironomidae list server ([email protected]).
We wish you all good health and look forward to welcome all of you in Tsukuba
The 21st International Symposium on Chironomidae – 2022 online
No full textWe announce that the 21st International Symposium on Chironomidae in 2022 will be held online and provide the following url to the symposium website: https://kinki-convention.jp/isc2022/.
- …
