Radiation tolerance in the tardigrade<i>Milnesium tardigradum</i>

Horikawa, Daiki D.; Sakashita, Tetsuya; Katagiri, Chiaki; Watanabe, Masahiko; Kikawada, Takahiro; Nakahara, Yuko; Hamada, Nobuyuki; Wada, Seiichi; Funayama, Tomoo; Higashi, Seigo; Kobayashi, Yasuhiko; Okuda, Takashi; Kuwabara, Mikinori

doi:10.1080/09553000600972956

Cited by 178 publications

(142 citation statements)

References 13 publications

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“…Our data show the link between tps presence and trehalose production, as the gene was found in the same Richtersius coronifer population (previously cited as Adorybiotus coronifer) in which Westh and Ramløv (1991) first detected the synthesis of trehalose during the desiccation process. Moreover, our data support the possibility that the trehalose biosynthesis pathway can be functional in Milnesium tardigradum, as shown by the presence of trehalose found by Horikawa et al (2006) and Jönsson & Persson (2010). The absence of trehalose in M. tardigradum found by Hengherr et al (2008) could be due to the fact that the trehalose level in M. tardigradum is very low (Horikawa et al 2006;Jönsson & Persson 2010) and Hengherr et al (2008) may have underestimated its presence.…”

Section: Discussionsupporting

confidence: 54%

“…Trehalose was not detectable in one desiccation tolerant population (Hengherr et al 2008), a datum confirmed by further analyses on proteome and transcriptome Schokraie et al 2010), which did not evidence any transcripts of genes involved in trehalose biosynthesis. On the other hand, in other studies on different desiccation tolerant populations of the same species, trehalose was detected (Horikawa et al 2006;Jönsson & Persson 2010).…”

Section: Introductionmentioning

confidence: 97%

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Identification of the trehalose-6-phosphate synthase (tps) gene in desiccation tolerant and intolerant tardigrades

Cesari

Altiero

Rebecchi

2012

Italian Journal of Zoology

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The non-reducing disaccharide trehalose is one of the molecules involved in anhydrobiosis, acting as bioprotectant of cells exposed to desiccation. The main biosynthesis pathway of trehalose involves a glycosyl-transferase, trehalose-6-phosphate synthase (TPS), encoded by a gene (tps) whose presence and characterization has been studied in different metazoans. The tps gene is here identified for the first time in Tardigrada in twelve species belonging to both Heterotardigrada and Eutardigrada. The tps gene is found in all semiterrestrial and anhydrobiotic species examined, correlating trehalose presence with anhydrobiotic ability. In contrast, tps is not detected in two limnic and desiccation intolerant species. The surprising presence of tps in another limnic and desiccation intolerant species, Dactylobiotus parthenogeneticus, allows us to infer that in tardigrades trehalose could be produced and involved, not just in anhydrobiosis, but also in the regulation of other biological functions, such as encystment. The analysis of nucleotide tps sequences shows a very high conservation of the gene inside the phylum Tardigrada, while amino acid sequences further support the relationship between Tardigrada and Pancrustacea.

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Section: Discussionsupporting

confidence: 54%

Section: Introductionmentioning

confidence: 97%

Identification of the trehalose-6-phosphate synthase (tps) gene in desiccation tolerant and intolerant tardigrades

Cesari

Altiero

Rebecchi

2012

Italian Journal of Zoology

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“…However, DNA may be the sensitive target of spores exposed to ultrahigh shock pressures (Moeller et al 2008). As another extreme example, tardigrades, which are among the most desiccation and radiation-tolerant animals, have been shown to survive extreme levels of ionizing radiation (Horikawa et al 2006), temperatures of −273°C (Becquerel 1950) and the vacuum of space (Jönsson et al 2008). Whereas microgravity and radiation had no effect on the survival nor DNA integrity of active tardigrades (Rebecchi et al 2009), after being exposed to the space environment for 12 days, tardigrades molted and females laid eggs (Rebecchi et al 2009).…”

Section: Discussionmentioning

confidence: 99%

PCR-based analysis of microbial communities during the EuroGeoMars campaign at Mars Desert Research Station, Utah

Thiel

Ehrenfreund

Foing

et al. 2011

International Journal of Astrobiology

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Abstract:The search for evidence of past or present life on Mars will require the detection of markers that indicate the presence of life. Because deoxyribonucleic acid (DNA) is found in all known living organisms, it is considered to be a 'biosignature' of life. The main function of DNA is the long-term storage of genetic information, which is passed on from generation to generation as hereditary material. The Polymerase Chain Reaction (PCR) is a revolutionary technique which allows a single fragment or a small number of fragments of a DNA molecule to be amplified millions of times, making it possible to detect minimal traces of DNA. The compactness of the contemporary PCR instruments makes routine sample analysis possible with a minimum amount of laboratory space. Furthermore the technique is effective, robust and straightforward. Our goal was to establish a routine for the detection of DNA from micro-organisms using the PCR technique during the EuroGeoMars simulation campaign. This took place at the Mars Society's Mars Desert Research Station (MDRS) in Utah in February 2009 (organized with the support of the International Lunar Exploration Working Group (ILEWG), NASA Ames and the European Space Research and Technology Centre (ESTEC)). During the MDRS simulation, we showed that it is possible to establish a minimal molecular biology lab in the habitat for the immediate on-site analysis of samples by PCR after sample collection. Soil and water samples were taken at different locations and soil depths. The sample analysis was started immediately after the crew returned to the habitat laboratory. DNA was isolated from micro-organisms and used as a template for PCR analysis of the highly conserved ribosomal DNA to identify representatives of the different groups of micro-organisms (bacteria, archaea and eukarya). The PCR products were visualized by agarose gel electrophoresis and documented by transillumination and digital imaging. The microbial diversity in the collected samples was analysed with respect to sampling depth and the presence or absence of vegetation. For the first time, we have demonstrated that it is possible to perform direct on-site DNA analysis by PCR at MDRS, a simulated planetary habitat in an extreme environment that serves as a model for preparation and optimization of techniques to be used for future Mars exploration.

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“…To survive drought, which occurs frequently in the habitat of moss-dwelling tardigrades, they enter a so-called tun state (Baumann 1922) and show strong resistance to physical extremes, including high and low temperatures (Ramløv and Westh 1992;Sømme 1996;Ramløv and Westh 2001;Hengherr et al 2009), high pressure (Seki and Toyoshima 1998), vacuum and ionising irradiation (Horikawa et al 2006;Jönsson et al 2008). In the anhydrobiotic state, their metabolism is barely measurable (Pigoń and Węglarska 1955).…”

Section: Introductionmentioning

confidence: 99%

Stress response in tardigrades: differential gene expression of molecular chaperones

Reuner

Hengherr

Mali

et al. 2010

Cell Stress and Chaperones

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Semi-terrestrial tardigrades exhibit a remarkable tolerance to desiccation by entering a state called anhydrobiosis. In this state, they show a strong resistance against several kinds of physical extremes. Because of the probable importance of stress proteins during the phases of dehydration and rehydration, the relative abundance of transcripts coding for two α-crystallin heat-shock proteins (MtsHsp17.2 and Mt-sHsp19.5), as well for the heat-shock proteins Mt-sHsp10, Mt-Hsp60, Mt-Hsp70 and Mt-Hsp90, were analysed in active and anhydrobiotic tardigrades of the species Milnesium tardigradum. They were also analysed in the transitional stage (I) of dehydration, the transitional stage (II) of rehydration and in heat-shocked specimens. A variable pattern of expression was detected, with most candidates being downregulated. Gene transcripts of one Mt-hsp70 isoform in the transitional stage I and Mt-hsp90 in the anhydrobiotic stage were significantly upregulated. A high gene expression (778.6-fold) was found for the small α-crystallin heat-shock protein gene Mt-sHsp17.2 after heat shock. We discuss the limited role of the stress-gene expression in the transitional stages between the active and anhydrobiotic tardigrades and other mechanisms which allow tardigrades to survive desiccation.

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Radiation tolerance in the tardigradeMilnesium tardigradum

Abstract: M. tardigradum survives high doses of ionizing radiation in both hydrated and anhydrobiotic states, but irradiation with >1000 Gy makes them sterile.

Cited by 178 publications

References 13 publications

Identification of the trehalose-6-phosphate synthase (tps) gene in desiccation tolerant and intolerant tardigrades

Identification of the trehalose-6-phosphate synthase (tps) gene in desiccation tolerant and intolerant tardigrades

PCR-based analysis of microbial communities during the EuroGeoMars campaign at Mars Desert Research Station, Utah

Stress response in tardigrades: differential gene expression of molecular chaperones

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