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Sample records for anhydrobiotic tardigrade milnesium

  1. Transcriptome survey of the anhydrobiotic tardigrade Milnesium tardigradum in comparison with Hypsibius dujardini and Richtersius coronifer

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    Reuter Dirk

    2010-03-01

    Full Text Available Abstract Background The phenomenon of desiccation tolerance, also called anhydrobiosis, involves the ability of an organism to survive the loss of almost all cellular water without sustaining irreversible damage. Although there are several physiological, morphological and ecological studies on tardigrades, only limited DNA sequence information is available. Therefore, we explored the transcriptome in the active and anhydrobiotic state of the tardigrade Milnesium tardigradum which has extraordinary tolerance to desiccation and freezing. In this study, we present the first overview of the transcriptome of M. tardigradum and its response to desiccation and discuss potential parallels to stress responses in other organisms. Results We sequenced a total of 9984 expressed sequence tags (ESTs from two cDNA libraries from the eutardigrade M. tardigradum in its active and inactive, anhydrobiotic (tun stage. Assembly of these ESTs resulted in 3283 putative unique transcripts, whereof ~50% showed significant sequence similarity to known genes. The resulting unigenes were functionally annotated using the Gene Ontology (GO vocabulary. A GO term enrichment analysis revealed several GOs that were significantly underrepresented in the inactive stage. Furthermore we compared the putative unigenes of M. tardigradum with ESTs from two other eutardigrade species that are available from public sequence databases, namely Richtersius coronifer and Hypsibius dujardini. The processed sequences of the three tardigrade species revealed similar functional content and the M. tardigradum dataset contained additional sequences from tardigrades not present in the other two. Conclusions This study describes novel sequence data from the tardigrade M. tardigradum, which significantly contributes to the available tardigrade sequence data and will help to establish this extraordinary tardigrade as a model for studying anhydrobiosis. Functional comparison of active and anhydrobiotic

  2. The Aquaporin Channel Repertoire of the Tardigrade Milnesium tardigradum.

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    Grohme, Markus A; Mali, Brahim; Wełnicz, Weronika; Michel, Stephanie; Schill, Ralph O; Frohme, Marcus

    2013-01-01

    Limno-terrestrial tardigrades are small invertebrates that are subjected to periodic drought of their micro-environment. They have evolved to cope with these unfavorable conditions by anhydrobiosis, an ametabolic state of low cellular water. During drying and rehydration, tardigrades go through drastic changes in cellular water content. By our transcriptome sequencing effort of the limno-terrestrial tardigrade Milnesium tardigradum and by a combination of cloning and targeted sequence assembly, we identified transcripts encoding eleven putative aquaporins. Analysis of these sequences proposed 2 classical aquaporins, 8 aquaglyceroporins and a single potentially intracellular unorthodox aquaporin. Using quantitative real-time PCR we analyzed aquaporin transcript expression in the anhydrobiotic context. We have identified additional unorthodox aquaporins in various insect genomes and have identified a novel common conserved structural feature in these proteins. Analysis of the genomic organization of insect aquaporin genes revealed several conserved gene clusters.

  3. Towards Decrypting Cryptobiosis—Analyzing Anhydrobiosis in the Tardigrade Milnesium tardigradum Using Transcriptome Sequencing

    OpenAIRE

    Chong Wang; Grohme, Markus A.; Brahim Mali; Schill, Ralph O.; Marcus Frohme

    2014-01-01

    BACKGROUND: Many tardigrade species are capable of anhydrobiosis; however, mechanisms underlying their extreme desiccation resistance remain elusive. This study attempts to quantify the anhydrobiotic transcriptome of the limno-terrestrial tardigrade Milnesium tardigradum. RESULTS: A prerequisite for differential gene expression analysis was the generation of a reference hybrid transcriptome atlas by assembly of Sanger, 454 and Illumina sequence data. The final assembly yielded 79,064 contigs ...

  4. Desiccation tolerance of the tardigrade Milnesium tardigradum collected in Sapporo, Japan, and Bogor, Indonesia.

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    Horikawa, Daiki D; Higashi, Seigo

    2004-08-01

    A tardigrade Milnesium tardigradum showed anhydrobiotic capacity, in which the desiccation tolerance, given by the mean survival rate under desiccation at different relative humidity levels, was significantly higher in the Sapporo (Japan) population than that in the Bogor (Indonesia) population. Accordingly, the surviving tardigrades took a significantly longer time for revival in Bogor than those in Sapporo. The higher tolerance of the Sapporo population is thought to be related to the low relative humidity and low temperature such that the animals experience 41% RH in May and often -10 degrees C or lower in winter.

  5. Proteomic analysis of tardigrades: towards a better understanding of molecular mechanisms by anhydrobiotic organisms.

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    Elham Schokraie

    Full Text Available BACKGROUND: Tardigrades are small, multicellular invertebrates which are able to survive times of unfavourable environmental conditions using their well-known capability to undergo cryptobiosis at any stage of their life cycle. Milnesium tardigradum has become a powerful model system for the analysis of cryptobiosis. While some genetic information is already available for Milnesium tardigradum the proteome is still to be discovered. PRINCIPAL FINDINGS: Here we present to the best of our knowledge the first comprehensive study of Milnesium tardigradum on the protein level. To establish a proteome reference map we developed optimized protocols for protein extraction from tardigrades in the active state and for separation of proteins by high resolution two-dimensional gel electrophoresis. Since only limited sequence information of M. tardigradum on the genome and gene expression level is available to date in public databases we initiated in parallel a tardigrade EST sequencing project to allow for protein identification by electrospray ionization tandem mass spectrometry. 271 out of 606 analyzed protein spots could be identified by searching against the publicly available NCBInr database as well as our newly established tardigrade protein database corresponding to 144 unique proteins. Another 150 spots could be identified in the tardigrade clustered EST database corresponding to 36 unique contigs and ESTs. Proteins with annotated function were further categorized in more detail by their molecular function, biological process and cellular component. For the proteins of unknown function more information could be obtained by performing a protein domain annotation analysis. Our results include proteins like protein member of different heat shock protein families and LEA group 3, which might play important roles in surviving extreme conditions. CONCLUSIONS: The proteome reference map of Milnesium tardigradum provides the basis for further studies in

  6. Two Novel Heat-Soluble Protein Families Abundantly Expressed in an Anhydrobiotic Tardigrade

    OpenAIRE

    Ayami Yamaguchi; Sae Tanaka; Shiho Yamaguchi; Hirokazu Kuwahara; Chizuko Takamura; Shinobu Imajoh-Ohmi; Horikawa, Daiki D.; Atsushi Toyoda; Toshiaki Katayama; Kazuharu Arakawa; Asao Fujiyama; Takeo Kubo; Takekazu Kunieda

    2012-01-01

    Tardigrades are able to tolerate almost complete dehydration by reversibly switching to an ametabolic state. This ability is called anhydrobiosis. In the anhydrobiotic state, tardigrades can withstand various extreme environments including space, but their molecular basis remains largely unknown. Late embryogenesis abundant (LEA) proteins are heat-soluble proteins and can prevent protein-aggregation in dehydrated conditions in other anhydrobiotic organisms, but their relevance to tardigrade a...

  7. Towards decrypting cryptobiosis--analyzing anhydrobiosis in the tardigrade Milnesium tardigradum using transcriptome sequencing.

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    Chong Wang

    Full Text Available BACKGROUND: Many tardigrade species are capable of anhydrobiosis; however, mechanisms underlying their extreme desiccation resistance remain elusive. This study attempts to quantify the anhydrobiotic transcriptome of the limno-terrestrial tardigrade Milnesium tardigradum. RESULTS: A prerequisite for differential gene expression analysis was the generation of a reference hybrid transcriptome atlas by assembly of Sanger, 454 and Illumina sequence data. The final assembly yielded 79,064 contigs (>100 bp after removal of ribosomal RNAs. Around 50% of them could be annotated by SwissProt and NCBI non-redundant protein sequences. Analysis using CEGMA predicted 232 (93.5% out of the 248 highly conserved eukaryotic genes in the assembly. We used this reference transcriptome for mapping and quantifying the expression of transcripts regulated under anhdydrobiosis in a time-series during dehydration and rehydration. 834 of the transcripts were found to be differentially expressed in a single stage (dehydration/inactive tun/rehydration and 184 were overlapping in two stages while 74 were differentially expressed in all three stages. We have found interesting patterns of differentially expressed transcripts that are in concordance with a common hypothesis of metabolic shutdown during anhydrobiosis. This included down-regulation of several proteins of the DNA replication and translational machinery and protein degradation. Among others, heat shock proteins Hsp27 and Hsp30c were up-regulated in response to dehydration and rehydration. In addition, we observed up-regulation of ployubiquitin-B upon rehydration together with a higher expression level of several DNA repair proteins during rehydration than in the dehydration stage. CONCLUSIONS: Most of the transcripts identified to be differentially expressed had distinct cellular function. Our data suggest a concerted molecular adaptation in M. tardigradum that permits extreme forms of ametabolic states such as

  8. Towards Decrypting Cryptobiosis—Analyzing Anhydrobiosis in the Tardigrade Milnesium tardigradum Using Transcriptome Sequencing

    Science.gov (United States)

    Wang, Chong; Grohme, Markus A.; Mali, Brahim; Schill, Ralph O.; Frohme, Marcus

    2014-01-01

    Background Many tardigrade species are capable of anhydrobiosis; however, mechanisms underlying their extreme desiccation resistance remain elusive. This study attempts to quantify the anhydrobiotic transcriptome of the limno-terrestrial tardigrade Milnesium tardigradum. Results A prerequisite for differential gene expression analysis was the generation of a reference hybrid transcriptome atlas by assembly of Sanger, 454 and Illumina sequence data. The final assembly yielded 79,064 contigs (>100 bp) after removal of ribosomal RNAs. Around 50% of them could be annotated by SwissProt and NCBI non-redundant protein sequences. Analysis using CEGMA predicted 232 (93.5%) out of the 248 highly conserved eukaryotic genes in the assembly. We used this reference transcriptome for mapping and quantifying the expression of transcripts regulated under anhdydrobiosis in a time-series during dehydration and rehydration. 834 of the transcripts were found to be differentially expressed in a single stage (dehydration/inactive tun/rehydration) and 184 were overlapping in two stages while 74 were differentially expressed in all three stages. We have found interesting patterns of differentially expressed transcripts that are in concordance with a common hypothesis of metabolic shutdown during anhydrobiosis. This included down-regulation of several proteins of the DNA replication and translational machinery and protein degradation. Among others, heat shock proteins Hsp27 and Hsp30c were up-regulated in response to dehydration and rehydration. In addition, we observed up-regulation of ployubiquitin-B upon rehydration together with a higher expression level of several DNA repair proteins during rehydration than in the dehydration stage. Conclusions Most of the transcripts identified to be differentially expressed had distinct cellular function. Our data suggest a concerted molecular adaptation in M. tardigradum that permits extreme forms of ametabolic states such as anhydrobiosis. It is

  9. Proteomic Analysis of Tardigrades: Towards a Better Understanding of Molecular Mechanisms by Anhydrobiotic Organisms

    OpenAIRE

    Schokraie, Elham; Hotz-Wagenblatt, Agnes; Warnken, Uwe; Mali, Brahim; Frohme, Marcus; Förster, Frank; Dandekar, Thomas; Hengherr, Steffen; Schill, Ralph O.; Schnölzer, Martina

    2010-01-01

    Background Tardigrades are small, multicellular invertebrates which are able to survive times of unfavourable environmental conditions using their well-known capability to undergo cryptobiosis at any stage of their life cycle. Milnesium tardigradum has become a powerful model system for the analysis of cryptobiosis. While some genetic information is already available for Milnesium tardigradum the proteome is still to be discovered. Principal Findings Here we present to the best of our knowled...

  10. Tolerance of anhydrobiotic eggs of the Tardigrade Ramazzottius varieornatus to extreme environments.

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    Horikawa, Daiki D; Yamaguchi, Ayami; Sakashita, Tetsuya; Tanaka, Daisuke; Hamada, Nobuyuki; Yukuhiro, Fumiko; Kuwahara, Hirokazu; Kunieda, Takekazu; Watanabe, Masahiko; Nakahara, Yuichi; Wada, Seiichi; Funayama, Tomoo; Katagiri, Chihiro; Higashi, Seigo; Yokobori, Shin-Ichi; Kuwabara, Mikinori; Rothschild, Lynn J; Okuda, Takashi; Hashimoto, Hirofumi; Kobayashi, Yasuhiko

    2012-04-01

    Tardigrades are tiny (less than 1 mm in length) invertebrate animals that have the potential to survive travel to other planets because of their tolerance to extreme environmental conditions by means of a dry ametabolic state called anhydrobiosis. While the tolerance of adult tardigrades to extreme environments has been reported, there are few reports on the tolerance of their eggs. We examined the ability of hydrated and anhydrobiotic eggs of the tardigrade Ramazzottius varieornatus to hatch after exposure to ionizing irradiation (helium ions), extremely low and high temperatures, and high vacuum. We previously reported that there was a similar pattern of tolerance against ionizing radiation between hydrated and anhydrobiotic adults. In contrast, anhydrobiotic eggs (50% lethal dose; 1690 Gy) were substantially more radioresistant than hydrated ones (50% lethal dose; 509 Gy). Anhydrobiotic eggs also have a broader temperature resistance compared with hydrated ones. Over 70% of the anhydrobiotic eggs treated at either -196°C or +50°C hatched successfully, but all the hydrated eggs failed to hatch. After exposure to high-vacuum conditions (5.3×10(-4) Pa to 6.2×10(-5) Pa), the hatchability of the anhydrobiotic eggs was comparable to that of untreated control eggs.

  11. Novel Mitochondria-Targeted Heat-Soluble Proteins Identified in the Anhydrobiotic Tardigrade Improve Osmotic Tolerance of Human Cells

    OpenAIRE

    Sae Tanaka; Junko Tanaka; Yoshihiro Miwa; Horikawa, Daiki D.; Toshiaki Katayama; Kazuharu Arakawa; Atsushi Toyoda; Takeo Kubo; Takekazu Kunieda

    2015-01-01

    Tardigrades are able to tolerate almost complete dehydration through transition to a metabolically inactive state, called "anhydrobiosis". Late Embryogenesis Abundant (LEA) proteins are heat-soluble proteins involved in the desiccation tolerance of many anhydrobiotic organisms. Tardigrades, Ramazzottius varieornatus, however, express predominantly tardigrade-unique heat-soluble proteins: CAHS (Cytoplasmic Abundant Heat Soluble) and SAHS (Secretory Abundant Heat Soluble) proteins, which are se...

  12. Sequence analysis of the DNA-repair gene rad51 in the tardigrades Milnesium cf. tardigradum, Hypsibius dujardini and Macrobiotus cf. harmsworthi

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    Eliana A. Beltrán-Pardo

    2013-05-01

    Full Text Available Tardigrades are known for being resistant to extreme conditions, including tolerance to ionising and UV radiation in both the hydrated and the dehydrated state. It is known that these factors may cause damage to DNA. It has recently been shown that single and double DNA strand breaks occur when tardigrades are maintained for a long time in the anhydrobiotic state. This may suggest that perhaps tardigrades rely on efficient DNA repair mechanisms. Among all proteins that comprise the DNA repair system, recombinases such as RecA or Rad51 have a very important function: DNA exchange activity. This enzyme is used in the homologous recombination and allows repair of the damaged strand using homologous non-damaged strands as a template. In this study, Rad51 induction was evaluated by western blot in Milnesium cf. tardigradum, after exposure to gamma radiation. The Rad51 protein was highly induced by radiation, when compared to the control. The rad51 genes were searched in three tardigrades: Milnesium cf. tardigradum, Hypsibius dujardini and Macrobiotus cf. harmsworthi. The gene sequences were obtained by preparing and sequencing transcriptome libraries for H. dujardini and M. cf. harmsworthi and designing rad51 degenerate primers specific for M. cf. tardigradum. Comparison of Rad51 putative proteins from tardigrades with other organisms showed that they are highly similar to the corresponding sequence from the nematode Trichinella spiralis. A structure-based sequence alignment from tardigrades and other organisms revealed that putative Rad51 predicted proteins from tardigrades contain the expected motifs for these important recombinases. In a cladogram tree based on this alignment, tardigrades tend to cluster together suggesting that they have selective differences in these genes that make them diverge between species. Predicted Rad51 structures from tardigrades were also compared with crystalline structure of Rad51 in Saccharomyces cerevisiae. These

  13. Two Novel Heat-Soluble Protein Families Abundantly Expressed in an Anhydrobiotic Tardigrade

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    Yamaguchi, Ayami; Tanaka, Sae; Yamaguchi, Shiho; Kuwahara, Hirokazu; Takamura, Chizuko; Imajoh-Ohmi, Shinobu; Horikawa, Daiki D.; Toyoda, Atsushi; Katayama, Toshiaki; Arakawa, Kazuharu; Fujiyama, Asao; Kubo, Takeo; Kunieda, Takekazu

    2012-01-01

    Tardigrades are able to tolerate almost complete dehydration by reversibly switching to an ametabolic state. This ability is called anhydrobiosis. In the anhydrobiotic state, tardigrades can withstand various extreme environments including space, but their molecular basis remains largely unknown. Late embryogenesis abundant (LEA) proteins are heat-soluble proteins and can prevent protein-aggregation in dehydrated conditions in other anhydrobiotic organisms, but their relevance to tardigrade anhydrobiosis is not clarified. In this study, we focused on the heat-soluble property characteristic of LEA proteins and conducted heat-soluble proteomics using an anhydrobiotic tardigrade. Our heat-soluble proteomics identified five abundant heat-soluble proteins. All of them showed no sequence similarity with LEA proteins and formed two novel protein families with distinct subcellular localizations. We named them Cytoplasmic Abundant Heat Soluble (CAHS) and Secretory Abundant Heat Soluble (SAHS) protein families, according to their localization. Both protein families were conserved among tardigrades, but not found in other phyla. Although CAHS protein was intrinsically unstructured and SAHS protein was rich in β-structure in the hydrated condition, proteins in both families changed their conformation to an α-helical structure in water-deficient conditions as LEA proteins do. Two conserved repeats of 19-mer motifs in CAHS proteins were capable to form amphiphilic stripes in α-helices, suggesting their roles as molecular shield in water-deficient condition, though charge distribution pattern in α-helices were different between CAHS and LEA proteins. Tardigrades might have evolved novel protein families with a heat-soluble property and this study revealed a novel repertoire of major heat-soluble proteins in these anhydrobiotic animals. PMID:22937162

  14. Two novel heat-soluble protein families abundantly expressed in an anhydrobiotic tardigrade.

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    Yamaguchi, Ayami; Tanaka, Sae; Yamaguchi, Shiho; Kuwahara, Hirokazu; Takamura, Chizuko; Imajoh-Ohmi, Shinobu; Horikawa, Daiki D; Toyoda, Atsushi; Katayama, Toshiaki; Arakawa, Kazuharu; Fujiyama, Asao; Kubo, Takeo; Kunieda, Takekazu

    2012-01-01

    Tardigrades are able to tolerate almost complete dehydration by reversibly switching to an ametabolic state. This ability is called anhydrobiosis. In the anhydrobiotic state, tardigrades can withstand various extreme environments including space, but their molecular basis remains largely unknown. Late embryogenesis abundant (LEA) proteins are heat-soluble proteins and can prevent protein-aggregation in dehydrated conditions in other anhydrobiotic organisms, but their relevance to tardigrade anhydrobiosis is not clarified. In this study, we focused on the heat-soluble property characteristic of LEA proteins and conducted heat-soluble proteomics using an anhydrobiotic tardigrade. Our heat-soluble proteomics identified five abundant heat-soluble proteins. All of them showed no sequence similarity with LEA proteins and formed two novel protein families with distinct subcellular localizations. We named them Cytoplasmic Abundant Heat Soluble (CAHS) and Secretory Abundant Heat Soluble (SAHS) protein families, according to their localization. Both protein families were conserved among tardigrades, but not found in other phyla. Although CAHS protein was intrinsically unstructured and SAHS protein was rich in β-structure in the hydrated condition, proteins in both families changed their conformation to an α-helical structure in water-deficient conditions as LEA proteins do. Two conserved repeats of 19-mer motifs in CAHS proteins were capable to form amphiphilic stripes in α-helices, suggesting their roles as molecular shield in water-deficient condition, though charge distribution pattern in α-helices were different between CAHS and LEA proteins. Tardigrades might have evolved novel protein families with a heat-soluble property and this study revealed a novel repertoire of major heat-soluble proteins in these anhydrobiotic animals.

  15. Two novel heat-soluble protein families abundantly expressed in an anhydrobiotic tardigrade.

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    Ayami Yamaguchi

    Full Text Available Tardigrades are able to tolerate almost complete dehydration by reversibly switching to an ametabolic state. This ability is called anhydrobiosis. In the anhydrobiotic state, tardigrades can withstand various extreme environments including space, but their molecular basis remains largely unknown. Late embryogenesis abundant (LEA proteins are heat-soluble proteins and can prevent protein-aggregation in dehydrated conditions in other anhydrobiotic organisms, but their relevance to tardigrade anhydrobiosis is not clarified. In this study, we focused on the heat-soluble property characteristic of LEA proteins and conducted heat-soluble proteomics using an anhydrobiotic tardigrade. Our heat-soluble proteomics identified five abundant heat-soluble proteins. All of them showed no sequence similarity with LEA proteins and formed two novel protein families with distinct subcellular localizations. We named them Cytoplasmic Abundant Heat Soluble (CAHS and Secretory Abundant Heat Soluble (SAHS protein families, according to their localization. Both protein families were conserved among tardigrades, but not found in other phyla. Although CAHS protein was intrinsically unstructured and SAHS protein was rich in β-structure in the hydrated condition, proteins in both families changed their conformation to an α-helical structure in water-deficient conditions as LEA proteins do. Two conserved repeats of 19-mer motifs in CAHS proteins were capable to form amphiphilic stripes in α-helices, suggesting their roles as molecular shield in water-deficient condition, though charge distribution pattern in α-helices were different between CAHS and LEA proteins. Tardigrades might have evolved novel protein families with a heat-soluble property and this study revealed a novel repertoire of major heat-soluble proteins in these anhydrobiotic animals.

  16. Comparative proteome analysis of Milnesium tardigradum in early embryonic state versus adults in active and anhydrobiotic state.

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    Elham Schokraie

    Full Text Available Tardigrades have fascinated researchers for more than 300 years because of their extraordinary capability to undergo cryptobiosis and survive extreme environmental conditions. However, the survival mechanisms of tardigrades are still poorly understood mainly due to the absence of detailed knowledge about the proteome and genome of these organisms. Our study was intended to provide a basis for the functional characterization of expressed proteins in different states of tardigrades. High-throughput, high-accuracy proteomics in combination with a newly developed tardigrade specific protein database resulted in the identification of more than 3000 proteins in three different states: early embryonic state and adult animals in active and anhydrobiotic state. This comprehensive proteome resource includes protein families such as chaperones, antioxidants, ribosomal proteins, cytoskeletal proteins, transporters, protein channels, nutrient reservoirs, and developmental proteins. A comparative analysis of protein families in the different states was performed by calculating the exponentially modified protein abundance index which classifies proteins in major and minor components. This is the first step to analyzing the proteins involved in early embryonic development, and furthermore proteins which might play an important role in the transition into the anhydrobiotic state.

  17. Comparative proteome analysis of Milnesium tardigradum in early embryonic state versus adults in active and anhydrobiotic state.

    Science.gov (United States)

    Schokraie, Elham; Warnken, Uwe; Hotz-Wagenblatt, Agnes; Grohme, Markus A; Hengherr, Steffen; Förster, Frank; Schill, Ralph O; Frohme, Marcus; Dandekar, Thomas; Schnölzer, Martina

    2012-01-01

    Tardigrades have fascinated researchers for more than 300 years because of their extraordinary capability to undergo cryptobiosis and survive extreme environmental conditions. However, the survival mechanisms of tardigrades are still poorly understood mainly due to the absence of detailed knowledge about the proteome and genome of these organisms. Our study was intended to provide a basis for the functional characterization of expressed proteins in different states of tardigrades. High-throughput, high-accuracy proteomics in combination with a newly developed tardigrade specific protein database resulted in the identification of more than 3000 proteins in three different states: early embryonic state and adult animals in active and anhydrobiotic state. This comprehensive proteome resource includes protein families such as chaperones, antioxidants, ribosomal proteins, cytoskeletal proteins, transporters, protein channels, nutrient reservoirs, and developmental proteins. A comparative analysis of protein families in the different states was performed by calculating the exponentially modified protein abundance index which classifies proteins in major and minor components. This is the first step to analyzing the proteins involved in early embryonic development, and furthermore proteins which might play an important role in the transition into the anhydrobiotic state.

  18. Suggested Involvement of PP1/PP2A Activity and De Novo Gene Expression in Anhydrobiotic Survival in a Tardigrade, Hypsibius dujardini, by Chemical Genetic Approach

    OpenAIRE

    Koyuki Kondo; Takeo Kubo; Takekazu Kunieda

    2015-01-01

    Upon desiccation, some tardigrades enter an ametabolic dehydrated state called anhydrobiosis and can survive a desiccated environment in this state. For successful transition to anhydrobiosis, some anhydrobiotic tardigrades require pre-incubation under high humidity conditions, a process called preconditioning, prior to exposure to severe desiccation. Although tardigrades are thought to prepare for transition to anhydrobiosis during preconditioning, the molecular mechanisms governing such pro...

  19. Suggested Involvement of PP1/PP2A Activity and De Novo Gene Expression in Anhydrobiotic Survival in a Tardigrade, Hypsibius dujardini, by Chemical Genetic Approach.

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    Koyuki Kondo

    Full Text Available Upon desiccation, some tardigrades enter an ametabolic dehydrated state called anhydrobiosis and can survive a desiccated environment in this state. For successful transition to anhydrobiosis, some anhydrobiotic tardigrades require pre-incubation under high humidity conditions, a process called preconditioning, prior to exposure to severe desiccation. Although tardigrades are thought to prepare for transition to anhydrobiosis during preconditioning, the molecular mechanisms governing such processes remain unknown. In this study, we used chemical genetic approaches to elucidate the regulatory mechanisms of anhydrobiosis in the anhydrobiotic tardigrade, Hypsibius dujardini. We first demonstrated that inhibition of transcription or translation drastically impaired anhydrobiotic survival, suggesting that de novo gene expression is required for successful transition to anhydrobiosis in this tardigrade. We then screened 81 chemicals and identified 5 chemicals that significantly impaired anhydrobiotic survival after severe desiccation, in contrast to little or no effect on survival after high humidity exposure only. In particular, cantharidic acid, a selective inhibitor of protein phosphatase (PP 1 and PP2A, exhibited the most profound inhibitory effects. Another PP1/PP2A inhibitor, okadaic acid, also significantly and specifically impaired anhydrobiotic survival, suggesting that PP1/PP2A activity plays an important role for anhydrobiosis in this species. This is, to our knowledge, the first report of the required activities of signaling molecules for desiccation tolerance in tardigrades. The identified inhibitory chemicals could provide novel clues to elucidate the regulatory mechanisms underlying anhydrobiosis in tardigrades.

  20. Suggested Involvement of PP1/PP2A Activity and De Novo Gene Expression in Anhydrobiotic Survival in a Tardigrade, Hypsibius dujardini, by Chemical Genetic Approach.

    Science.gov (United States)

    Kondo, Koyuki; Kubo, Takeo; Kunieda, Takekazu

    2015-01-01

    Upon desiccation, some tardigrades enter an ametabolic dehydrated state called anhydrobiosis and can survive a desiccated environment in this state. For successful transition to anhydrobiosis, some anhydrobiotic tardigrades require pre-incubation under high humidity conditions, a process called preconditioning, prior to exposure to severe desiccation. Although tardigrades are thought to prepare for transition to anhydrobiosis during preconditioning, the molecular mechanisms governing such processes remain unknown. In this study, we used chemical genetic approaches to elucidate the regulatory mechanisms of anhydrobiosis in the anhydrobiotic tardigrade, Hypsibius dujardini. We first demonstrated that inhibition of transcription or translation drastically impaired anhydrobiotic survival, suggesting that de novo gene expression is required for successful transition to anhydrobiosis in this tardigrade. We then screened 81 chemicals and identified 5 chemicals that significantly impaired anhydrobiotic survival after severe desiccation, in contrast to little or no effect on survival after high humidity exposure only. In particular, cantharidic acid, a selective inhibitor of protein phosphatase (PP) 1 and PP2A, exhibited the most profound inhibitory effects. Another PP1/PP2A inhibitor, okadaic acid, also significantly and specifically impaired anhydrobiotic survival, suggesting that PP1/PP2A activity plays an important role for anhydrobiosis in this species. This is, to our knowledge, the first report of the required activities of signaling molecules for desiccation tolerance in tardigrades. The identified inhibitory chemicals could provide novel clues to elucidate the regulatory mechanisms underlying anhydrobiosis in tardigrades.

  1. Novel mitochondria-targeted heat-soluble proteins identified in the anhydrobiotic Tardigrade improve osmotic tolerance of human cells.

    Science.gov (United States)

    Tanaka, Sae; Tanaka, Junko; Miwa, Yoshihiro; Horikawa, Daiki D; Katayama, Toshiaki; Arakawa, Kazuharu; Toyoda, Atsushi; Kubo, Takeo; Kunieda, Takekazu

    2015-01-01

    Tardigrades are able to tolerate almost complete dehydration through transition to a metabolically inactive state, called "anhydrobiosis". Late Embryogenesis Abundant (LEA) proteins are heat-soluble proteins involved in the desiccation tolerance of many anhydrobiotic organisms. Tardigrades, Ramazzottius varieornatus, however, express predominantly tardigrade-unique heat-soluble proteins: CAHS (Cytoplasmic Abundant Heat Soluble) and SAHS (Secretory Abundant Heat Soluble) proteins, which are secreted or localized in most intracellular compartments, except the mitochondria. Although mitochondrial integrity is crucial to ensure cellular survival, protective molecules for mitochondria have remained elusive. Here, we identified two novel mitochondrial heat-soluble proteins, RvLEAM and MAHS (Mitochondrial Abundant Heat Soluble), as potent mitochondrial protectants from Ramazzottius varieornatus. RvLEAM is a group3 LEA protein and immunohistochemistry confirmed its mitochondrial localization in tardigrade cells. MAHS-green fluorescent protein fusion protein localized in human mitochondria and was heat-soluble in vitro, though no sequence similarity with other known proteins was found, and one region was conserved among tardigrades. Furthermore, we demonstrated that RvLEAM protein as well as MAHS protein improved the hyperosmotic tolerance of human cells. The findings of the present study revealed that tardigrade mitochondria contain at least two types of heat-soluble proteins that might have protective roles in water-deficient environments.

  2. Novel mitochondria-targeted heat-soluble proteins identified in the anhydrobiotic Tardigrade improve osmotic tolerance of human cells.

    Directory of Open Access Journals (Sweden)

    Sae Tanaka

    Full Text Available Tardigrades are able to tolerate almost complete dehydration through transition to a metabolically inactive state, called "anhydrobiosis". Late Embryogenesis Abundant (LEA proteins are heat-soluble proteins involved in the desiccation tolerance of many anhydrobiotic organisms. Tardigrades, Ramazzottius varieornatus, however, express predominantly tardigrade-unique heat-soluble proteins: CAHS (Cytoplasmic Abundant Heat Soluble and SAHS (Secretory Abundant Heat Soluble proteins, which are secreted or localized in most intracellular compartments, except the mitochondria. Although mitochondrial integrity is crucial to ensure cellular survival, protective molecules for mitochondria have remained elusive. Here, we identified two novel mitochondrial heat-soluble proteins, RvLEAM and MAHS (Mitochondrial Abundant Heat Soluble, as potent mitochondrial protectants from Ramazzottius varieornatus. RvLEAM is a group3 LEA protein and immunohistochemistry confirmed its mitochondrial localization in tardigrade cells. MAHS-green fluorescent protein fusion protein localized in human mitochondria and was heat-soluble in vitro, though no sequence similarity with other known proteins was found, and one region was conserved among tardigrades. Furthermore, we demonstrated that RvLEAM protein as well as MAHS protein improved the hyperosmotic tolerance of human cells. The findings of the present study revealed that tardigrade mitochondria contain at least two types of heat-soluble proteins that might have protective roles in water-deficient environments.

  3. Novel Mitochondria-Targeted Heat-Soluble Proteins Identified in the Anhydrobiotic Tardigrade Improve Osmotic Tolerance of Human Cells

    Science.gov (United States)

    Tanaka, Sae; Tanaka, Junko; Miwa, Yoshihiro; Horikawa, Daiki D.; Katayama, Toshiaki; Arakawa, Kazuharu; Toyoda, Atsushi; Kubo, Takeo; Kunieda, Takekazu

    2015-01-01

    Tardigrades are able to tolerate almost complete dehydration through transition to a metabolically inactive state, called “anhydrobiosis”. Late Embryogenesis Abundant (LEA) proteins are heat-soluble proteins involved in the desiccation tolerance of many anhydrobiotic organisms. Tardigrades, Ramazzottius varieornatus, however, express predominantly tardigrade-unique heat-soluble proteins: CAHS (Cytoplasmic Abundant Heat Soluble) and SAHS (Secretory Abundant Heat Soluble) proteins, which are secreted or localized in most intracellular compartments, except the mitochondria. Although mitochondrial integrity is crucial to ensure cellular survival, protective molecules for mitochondria have remained elusive. Here, we identified two novel mitochondrial heat-soluble proteins, RvLEAM and MAHS (Mitochondrial Abundant Heat Soluble), as potent mitochondrial protectants from Ramazzottius varieornatus. RvLEAM is a group3 LEA protein and immunohistochemistry confirmed its mitochondrial localization in tardigrade cells. MAHS-green fluorescent protein fusion protein localized in human mitochondria and was heat-soluble in vitro, though no sequence similarity with other known proteins was found, and one region was conserved among tardigrades. Furthermore, we demonstrated that RvLEAM protein as well as MAHS protein improved the hyperosmotic tolerance of human cells. The findings of the present study revealed that tardigrade mitochondria contain at least two types of heat-soluble proteins that might have protective roles in water-deficient environments. PMID:25675104

  4. High hydrostatic pressure tolerance of four different anhydrobiotic animal species.

    Science.gov (United States)

    Horikawa, Daiki D; Iwata, Ken-Ichi; Kawai, Kiyoshi; Koseki, Shigenobu; Okuda, Takashi; Yamamoto, Kazutaka

    2009-03-01

    High hydrostatic pressure (HHP) can induce physical changes in DNA, proteins, and lipids, causing lethal or sublethal damage to organisms. However, HHP tolerance of animals has not been studied sufficiently. In this study, HHP tolerance of four species of invertebrate anhydrobiotes (the tardigrade Milnesium tardigradum, a nematode species in the family Plectidae, larvae of Polypedilum vanderplanki, and cysts of Artemia franciscana), which have the potential to enter anhydrobiosis upon desiccation, were investigated by exposing them to 1.2 GPa for 20 minutes. This exposure killed the anhydrobiotes in their ordinary hydrated state, but did not affect their survival in the anhydrobiotic state. The results indicated that the hydrated anhydrobiotes were vulnerable to HHP, but that HHP of 1.2 GPa was not sufficient to kill them in anhyrdobiosis.

  5. Effects of ionizing radiation on embryos of the tardigrade Milnesium cf. tardigradum at different stages of development.

    Science.gov (United States)

    Beltrán-Pardo, Eliana; Jönsson, K Ingemar; Wojcik, Andrzej; Haghdoost, Siamak; Harms-Ringdahl, Mats; Bermúdez-Cruz, Rosa M; Bernal Villegas, Jaime E

    2013-01-01

    Tardigrades represent one of the most desiccation and radiation tolerant animals on Earth, and several studies have documented their tolerance in the adult stage. Studies on tolerance during embryological stages are rare, but differential effects of desiccation and freezing on different developmental stages have been reported, as well as dose-dependent effect of gamma irradiation on tardigrade embryos. Here, we report a study evaluating the tolerance of eggs from the eutardigrade Milnesium cf. tardigradum to three doses of gamma radiation (50, 200 and 500 Gy) at the early, middle, and late stage of development. We found that embryos of the middle and late developmental stages were tolerant to all doses, while eggs in the early developmental stage were tolerant only to a dose of 50 Gy, and showed a declining survival with higher dose. We also observed a delay in development of irradiated eggs, suggesting that periods of DNA repair might have taken place after irradiation induced damage. The delay was independent of dose for eggs irradiated in the middle and late stage, possibly indicating a fixed developmental schedule for repair after induced damage. These results show that the tolerance to radiation in tardigrade eggs changes in the course of their development. The mechanisms behind this pattern are unknown, but may relate to changes in mitotic activities over the embryogenesis and/or to activation of response mechanisms to damaged DNA in the course of development.

  6. Effects of ionizing radiation on embryos of the tardigrade Milnesium cf. tardigradum at different stages of development.

    Directory of Open Access Journals (Sweden)

    Eliana Beltrán-Pardo

    Full Text Available Tardigrades represent one of the most desiccation and radiation tolerant animals on Earth, and several studies have documented their tolerance in the adult stage. Studies on tolerance during embryological stages are rare, but differential effects of desiccation and freezing on different developmental stages have been reported, as well as dose-dependent effect of gamma irradiation on tardigrade embryos. Here, we report a study evaluating the tolerance of eggs from the eutardigrade Milnesium cf. tardigradum to three doses of gamma radiation (50, 200 and 500 Gy at the early, middle, and late stage of development. We found that embryos of the middle and late developmental stages were tolerant to all doses, while eggs in the early developmental stage were tolerant only to a dose of 50 Gy, and showed a declining survival with higher dose. We also observed a delay in development of irradiated eggs, suggesting that periods of DNA repair might have taken place after irradiation induced damage. The delay was independent of dose for eggs irradiated in the middle and late stage, possibly indicating a fixed developmental schedule for repair after induced damage. These results show that the tolerance to radiation in tardigrade eggs changes in the course of their development. The mechanisms behind this pattern are unknown, but may relate to changes in mitotic activities over the embryogenesis and/or to activation of response mechanisms to damaged DNA in the course of development.

  7. Two new tardigrade species from Romania (Eutardigrada: Milnesiidae, Macrobiotidae), with some remarks on secondary sex characters in Milnesium dornensis sp. nov.

    Science.gov (United States)

    Ciobanu, Daniel Adrian; Roszkowska, Milena; Kaczmarek, Łukasz

    2015-04-02

    In two moss and lichen samples collected in Romania, two new eutardigrade species were found. Milnesium dornensis sp. nov. belongs to the granulatum group and differs from most of other species in this group mainly by having a different claw configuration ([3-3]-[3-3]) and by some morphometric characters. Minibiotus diversus sp. nov. is very similar to M. gumersindoi Guil & Guidetti, 2005 and M. weglarskae Michalczyk et al., 2005, but differs from these and other congeners by the cuticular pore arrangement and morphometric characters of both adults and eggs. Males and females of the newly described Milnesium species differ not only by the shape and structure of claws I, but also by other morphometric characters. Males of Milnesium dornensis sp. nov. are smaller, more slender, have shorter papillae and relatively longer claws on legs III-IV.

  8. Milnesium berladnicorum sp. n. (Eutardigrada, Apochela, Milnesiidae), a new species of water bear from Romania

    OpenAIRE

    2014-01-01

    Abstract In a lichen sample collected from a tree in Bârlad town (Vaslui County, Romania), a new tardigrade species belonging to the genus Milnesium (granulatum group) was found. Milnesium berladnicorum sp. n. is most similar (in the type of dorsal sculpture) to Milnesium beasleyi Kaczmarek et al., 2012 but differs from it mainly by having a different claw configuration and some morphometric characters. Additionally, the new species differs from other congeners of the granulatum group by the ...

  9. Tardigrade workbench: comparing stress-related proteins, sequence-similar and functional protein clusters as well as RNA elements in tardigrades

    OpenAIRE

    Frohme Marcus; Schnölzer Martina; Engelmann Julia C; Beisser Daniela; Shkumatov Alexander; Liang Chuanguang; Förster Frank; Müller Tobias; Schill Ralph O; Dandekar Thomas

    2009-01-01

    Abstract Background Tardigrades represent an animal phylum with extraordinary resistance to environmental stress. Results To gain insights into their stress-specific adaptation potential, major clusters of related and similar proteins are identified, as well as specific functional clusters delineated comparing all tardigrades and individual species (Milnesium tardigradum, Hypsibius dujardini, Echiniscus testudo, Tulinus stephaniae, Richtersius coronifer) and functional elements in tardigrade ...

  10. Functional protein clusters and regulatory motifs in Hypsibius dujardini und Milnesium tardigradum

    OpenAIRE

    Förster, Frank; Liang, Chunguang; Beisser, Daniela; Frohme, Marcus; Schill, Ralph O.; Dandekar, Thomas

    2009-01-01

    Functional protein clusters and regulatory motifs do not only mediate the unique adaptation of tardigrades against extreme temperature and other harsh environmental conditions, but are important markers to distinguish species and taxonomic units. We show here in detail results of our current comparison between Hypsibius dujardini and Milnesium tardigradum. We found 50 different clusters of sequence similar proteins between both tardigrades of which 10 are tardigrade specific. Proteins of othe...

  11. Tardigrades as a Potential Model Organism in Space Research

    Science.gov (United States)

    Jönsson, K. Ingemar

    2007-10-01

    Exposure of living organisms to open space requires a high level of tolerance to desiccation, cold, and radiation. Among animals, only anhydrobiotic species can fulfill these requirements. The invertebrate phylum Tardigrada includes many anhydrobiotic species, which are adapted to survive in very dry or cold environmental conditions. As a likely by-product of the adaptations for desiccation and freezing, tardigrades also show a very high tolerance to a number of other, unnatural conditions, including exposure to ionizing radiation. This makes tardigrades an interesting candidate for experimental exposure to open space. This paper reviews the tolerances that make tardigrades suitable for astrobiological studies and the reported radiation tolerance in other anhydrobiotic animals. Several studies have shown that tardigrades can survive γ-irradiation well above 1 kilogray, and desiccated and hydrated (active) tardigrades respond similarly to irradiation. Thus, tolerance is not restricted to the dry anhydrobiotic state, and I discuss the possible involvement of an efficient, but yet undocumented, mechanism for DNA repair. Other anhydrobiotic animals (Artemia, Polypedium), when dessicated, show a higher tolerance to γ-irradiation than hydrated animals, possibly due to the presence of high levels of the protective disaccharide trehalose in the dry state. Tardigrades and other anhydrobiotic animals provide a unique opportunity to study the effects of space exposure on metabolically inactive but vital metazoans.

  12. Milnesium berladnicorum sp. n. (Eutardigrada, Apochela, Milnesiidae), a new species of water bear from Romania

    Science.gov (United States)

    Ciobanu, Daniel Adrian; Zawierucha, Krzysztof; Moglan, Ioan; Kaczmarek, Łukasz

    2014-01-01

    Abstract In a lichen sample collected from a tree in Bârlad town (Vaslui County, Romania), a new tardigrade species belonging to the genus Milnesium (granulatum group) was found. Milnesium berladnicorum sp. n. is most similar (in the type of dorsal sculpture) to Milnesium beasleyi Kaczmarek et al., 2012 but differs from it mainly by having a different claw configuration and some morphometric characters. Additionally, the new species differs from other congeners of the granulatum group by the different type of dorsal sculpture, claw configuration and some morphometric characters. PMID:25147467

  13. Milnesium berladnicorum sp. n. (Eutardigrada, Apochela, Milnesiidae), a new species of water bear from Romania.

    Science.gov (United States)

    Ciobanu, Daniel Adrian; Zawierucha, Krzysztof; Moglan, Ioan; Kaczmarek, Lukasz

    2014-01-01

    In a lichen sample collected from a tree in Bârlad town (Vaslui County, Romania), a new tardigrade species belonging to the genus Milnesium (granulatum group) was found. Milnesium berladnicorum sp. n. is most similar (in the type of dorsal sculpture) to Milnesium beasleyi Kaczmarek et al., 2012 but differs from it mainly by having a different claw configuration and some morphometric characters. Additionally, the new species differs from other congeners of the granulatum group by the different type of dorsal sculpture, claw configuration and some morphometric characters.

  14. Milnesium berladnicorum sp. n. (Eutardigrada, Apochela, Milnesiidae, a new species of water bear from Romania

    Directory of Open Access Journals (Sweden)

    Daniel Ciobanu

    2014-07-01

    Full Text Available In a lichen sample collected from a tree in Bârlad town (Vaslui County, Romania, a new tardigrade species belonging to the genus Milnesium (granulatum group was found. Milnesium berladnicorum sp. n. is most similar (in the type of dorsal sculpture to Milnesium beasleyi Kaczmarek et al., 2012 but differs from it mainly bya different claw configuration and some morphometric characters. Additionally, the new species differs from other congeners of the granulatum group by the different type of dorsal sculpture, claw configuration and some morphometric characters.

  15. Experiences with dormancy in tardigrades

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    Deborah BOSCHINI

    2004-09-01

    Full Text Available Tardigrades often colonise extreme habitats, in which they survive using both types of dormancy: quiescence and diapause. Together with nematodes and bdelloid rotifers, tardigrades are known to enter quiescence (with several forms of cryptobiosis: anhydrobiosis, cryobiosis, anoxybiosis, osmobiosis at any stage of their life cycle, from egg to adult. Entering anhydrobiosis, tardigrades contract their body into a so-called tun, loosing most of their free and bound water (>95%, synthesizing cell protectants (e.g., trehalose, glycerol, heat shock proteins and strongly reducing or suspending their metabolism. Our research on cryptobiosis focused on some ecological and evolutionary aspects. We evaluated: i the long-term anhydrobiotic survival by comparing quantitative data on recovery from naturally induced desiccation in several species of tardigrades; ii differences in survival patterns between species and populations by experimentally inducing anhydrobiosis and cryobiosis; iii phenotypic factors affecting anhydrobiotic survival. As regards diapause, we considered encystment and eggs. Encystment involves at least the synthesis of new cuticular structures. Morphological changes during cyst formation are more complex than those involved in tun formation. We analyzed more in detail encystment processes, comparing a semiterrestrial with a limnic species. Several inter-specific differences have been identified, other than the production of two types of cysts in the semiterrestrial species. Our analysis of life history traits of a laboratory reared strain of a soil tardigrade revealed a particular hatching phenology that involved the production of both subitaneous and resting eggs. The latter need a cue to hatch (dehydration followed by re-hydration. In addition, the evolutionary meaning of dormancy in tardigrades is discussed.

  16. Appearance of males in a thelytokous strain of Milnesium cf. tardigradum (Tardigrada).

    Science.gov (United States)

    Suzuki, Atsushi C

    2008-08-01

    Tardigrades are generally gonochoristic. Many moss-dwelling species propagate by parthenogenesis, but heterogony has not yet been found. Milnesium tardigradum, a carnivorous tardigrade, also has both sexes, but males are usually rare and many populations appear to have only parthenogenetic reproduction. Since 2000, I have maintained a thelytokous strain of Milnesium cf. tardigradum that originated from one female. Individuals of this strain were thought to be all females, but here I report that males have emerged in this strain at a very low frequency. This is the first report of the appearance of males in parthenogenetic tardigrades. On the first pair of legs of some individuals, I observed the modified claws characteristic of males of this species. It is unknown whether these males can actually function in sexual reproduction; however, they might allow some possibility of genetic exchange among clonal populations. No environmental factors that generate males were determined.

  17. 温度对小斑熊虫Milnesium tardigradum Doyère(缓步动物门,小斑熊虫科)食量和食物消化率的影响%Effect of Temperature on Food Assimilation of Tardigrade Milnesium tardigradum Doyère (Tardigrada, Milnesiidae)

    Institute of Scientific and Technical Information of China (English)

    王立志; 李晓晨

    2006-01-01

    为研究温度对小斑熊虫Milnesium tardigradum食量和食物消化率的影响,以轮虫为食物,将20只小斑熊虫分成两组,每组10只,分别在20℃和5℃下驯化饲养10天,并在各自驯化温度下进行实验观察.对实验结果的方差分析和t-检验表明,小斑熊虫的食量随温度的升高而显著增加,20℃下饲养的个体取食轮虫的个数比5℃下的多0.84个/天;小斑熊虫的食物消化率随温度的升高而显著增加,20℃下的小斑熊虫消化率比5℃下的快24 h.

  18. Transcriptome analysis in tardigrade species reveals specific molecular pathways for stress adaptations

    OpenAIRE

    Frank Förster; Daniela Beisser; Grohme, Markus A.; Chunguang Liang; Brahim Mali; Alexander Matthias Siegl; Engelmann, Julia C.; Shkumatov, Alexander V; Elham Schokraie; Tobias Müller; Martina Schnölzer; Schill, Ralph O.; Marcus Frohme; Thomas Dandekar

    2012-01-01

    Tardigrades have unique stress-adaptations that allow them to survive extremes of cold, heat, radiation and vacuum. To study this, encoded protein clusters and pathways from an ongoing transcriptome study on the tardigrade \\(Milnesium\\) \\(tardigradum\\) were analyzed using bioinformatics tools and compared to expressed sequence tags (ESTs) from \\(Hypsibius\\) \\(dujardini\\), revealing major pathways involved in resistance against extreme environmental conditions. ESTs are available on the Tardig...

  19. Tardigrade workbench: comparing stress-related proteins, sequence-similar and functional protein clusters as well as RNA elements in tardigrades

    Directory of Open Access Journals (Sweden)

    Frohme Marcus

    2009-10-01

    Full Text Available Abstract Background Tardigrades represent an animal phylum with extraordinary resistance to environmental stress. Results To gain insights into their stress-specific adaptation potential, major clusters of related and similar proteins are identified, as well as specific functional clusters delineated comparing all tardigrades and individual species (Milnesium tardigradum, Hypsibius dujardini, Echiniscus testudo, Tulinus stephaniae, Richtersius coronifer and functional elements in tardigrade mRNAs are analysed. We find that 39.3% of the total sequences clustered in 58 clusters of more than 20 proteins. Among these are ten tardigrade specific as well as a number of stress-specific protein clusters. Tardigrade-specific functional adaptations include strong protein, DNA- and redox protection, maintenance and protein recycling. Specific regulatory elements regulate tardigrade mRNA stability such as lox P DICE elements whereas 14 other RNA elements of higher eukaryotes are not found. Further features of tardigrade specific adaption are rapidly identified by sequence and/or pattern search on the web-tool tardigrade analyzer http://waterbear.bioapps.biozentrum.uni-wuerzburg.de. The work-bench offers nucleotide pattern analysis for promotor and regulatory element detection (tardigrade specific; nrdb as well as rapid COG search for function assignments including species-specific repositories of all analysed data. Conclusion Different protein clusters and regulatory elements implicated in tardigrade stress adaptations are analysed including unpublished tardigrade sequences.

  20. Two new species of Milnesium (Tardigrada: Milnesiidae).

    Science.gov (United States)

    Pilato, Giovanni; Sabella, Giorgio; Lisi, Oscar

    2016-07-01

    Two new species of Milnesium are described: Milnesium vorax sp. nov from Sicily and Milnesium tumanovi sp. nov. from Crimea. Milnesium vorax sp. nov. is uncoloured, with eye spots, smooth cuticle, wide buccal tube, stylet supports inserted on the buccal tube at almost 62 % of its length; claws with configuration [2-3]-[3-2]; accessory points present on the main branches. Milnesium tumanovi sp. nov. is also uncoloured, has eye spots, smooth cuticle, and wide buccal tube, but it has the stylet supports inserted on the buccal tube at about 52 % of its length, and claws with configuration [3-3]-[3-3]; the accessory points are present on the main branches.

  1. Comments on the eyes of tardigrades.

    Science.gov (United States)

    Greven, Hartmut

    2007-12-01

    A survey is given on the scarce information on the visual organs (eyes or ocelli) of Tardigrada. Many Eutardigrada and some Arthrotardigrada, namely the Echiniscidae, possess inverse pigment-cup ocelli, which are located in the outer lobe of the brain, and probably are of cerebral origin. Occurrence of such organs in tardigrades, suggested as being eyeless, has never been checked. Depending on the species, response to light (photokinesis) is negative, positive or indifferent, and may change during the ontogeny. The tardigrade eyes of the two eutardigrades examined up to now comprise a single pigment cup cell, one or two microvillous (rhabdomeric) sensory cells and ciliary sensory cell(s). In the eyes of the eutardigrade Milnesium tardigradum the cilia are differentiated in an outer branching segment and an inner (dendritic) segment. Because of the scarcity of information on the tardigrade eyes, their homology with the visual organs of other bilaterians is currently difficult to establish and further comparative studies are needed. Thus, the significance of these eyes for the evolution of arthropod visual systems is unclear yet.

  2. Superoxide Anion Radical Production in the Tardigrade Paramacrobiotus richtersi, the First Electron Paramagnetic Resonance Spin-Trapping Study.

    Science.gov (United States)

    Savic, Aleksandar G; Guidetti, Roberto; Turi, Ana; Pavicevic, Aleksandra; Giovannini, Ilaria; Rebecchi, Lorena; Mojovic, Milos

    2015-01-01

    Anhydrobiosis is an adaptive strategy that allows withstanding almost complete body water loss. It has been developed independently by many organisms belonging to different evolutionary lines, including tardigrades. The loss of water during anhydrobiotic processes leads to oxidative stress. To date, the metabolism of free radicals in tardigrades remained unclear. We present a method for in vivo monitoring of free radical production in tardigrades, based on electron paramagnetic resonance and spin-trap DEPMPO, which provides simultaneous identification of various spin adducts (i.e., different types of free radicals). The spin trap can be easily absorbed in animals, and tardigrades stay alive during the measurements and during 24-h monitoring after the treatment. The results show that hydrated specimens of the tardigrade Paramacrobiotus richtersi produce the pure superoxide anion radical ((•)O2(-)). This is an unexpected result, as all previously examined animals and plants produce both superoxide anion radical and hydroxyl radical ((•)OH) or exclusively hydroxyl radical.

  3. Dry up and survive: the role of antioxidant defences in anhydrobiotic organisms

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    Lorena Rebecchi

    2013-05-01

    tolerance in anhydrobiotic organisms. The action of these molecules emphasises the need for redox balancing in anhydrobiotic organisms including tardigrades and chironomid larvae.

  4. Antioxidant defences in hydrated and desiccated states of the tardigrade Paramacrobiotus richtersi.

    Science.gov (United States)

    Rizzo, Angela M; Negroni, Manuela; Altiero, Tiziana; Montorfano, Gigliola; Corsetto, Paola; Berselli, Patrizia; Berra, Bruno; Guidetti, Roberto; Rebecchi, Lorena

    2010-06-01

    Reactive oxygen species (ROS) are formed in all aerobic organisms, potentially leading to oxidative damage of all biological molecules. A number of defence mechanisms have developed to protect the organism from attack by ROS. Desiccation tolerance is correlated with an increase in the antioxidant potential in several organisms, but the regulation of the antioxidant defence system is complex and its role in desiccation-tolerant organisms is not yet firmly established. To determine if anhydrobiotic tardigrades have an antioxidant defence system, capable of counteracting ROS, we compared the activity of several antioxidant enzymes, the fatty acid composition and Heat shock protein expression in two physiological states (desiccated vs. hydrated) of the tardigrade Paramacrobiotus richtersi. In hydrated tardigrades, superoxide dismutase and catalase show comparable activities, while in desiccated specimens the activity of superoxide dismutase increases. Both glutathione peroxidase and glutathione were induced by desiccation. The percentage of fatty acid composition of polyunsaturated fatty acids and the amount of thiobarbituric acid reactive substances are higher in desiccated animals than in hydrated ones. Lastly, desiccated tardigrades did not differ significantly from the hydrated ones in the relative levels of Hsp70 and Hsp90. These results indicate that the possession of antioxidant metabolism could represent a crucial strategy to avoid damages during desiccation in anhydrobiotic tardigrades.

  5. Analysis of DNA repair and protection in the Tardigrade Ramazzottius varieornatus and Hypsibius dujardini after exposure to UVC radiation.

    Science.gov (United States)

    Horikawa, Daiki D; Cumbers, John; Sakakibara, Iori; Rogoff, Dana; Leuko, Stefan; Harnoto, Raechel; Arakawa, Kazuharu; Katayama, Toshiaki; Kunieda, Takekazu; Toyoda, Atsushi; Fujiyama, Asao; Rothschild, Lynn J

    2013-01-01

    Tardigrades inhabiting terrestrial environments exhibit extraordinary resistance to ionizing radiation and UV radiation although little is known about the mechanisms underlying the resistance. We found that the terrestrial tardigrade Ramazzottius varieornatus is able to tolerate massive doses of UVC irradiation by both being protected from forming UVC-induced thymine dimers in DNA in a desiccated, anhydrobiotic state as well as repairing the dimers that do form in the hydrated animals. In R. varieornatus accumulation of thymine dimers in DNA induced by irradiation with 2.5 kJ/m(2) of UVC radiation disappeared 18 h after the exposure when the animals were exposed to fluorescent light but not in the dark. Much higher UV radiation tolerance was observed in desiccated anhydrobiotic R. varieornatus compared to hydrated specimens of this species. On the other hand, the freshwater tardigrade species Hypsibius dujardini that was used as control, showed much weaker tolerance to UVC radiation than R. varieornatus, and it did not contain a putative phrA gene sequence. The anhydrobiotes of R. varieornatus accumulated much less UVC-induced thymine dimers in DNA than hydrated one. It suggests that anhydrobiosis efficiently avoids DNA damage accumulation in R. varieornatus and confers better UV radiation tolerance on this species. Thus we propose that UV radiation tolerance in tardigrades is due to the both high capacities of DNA damage repair and DNA protection, a two-pronged survival strategy.

  6. Establishment of a Rearing System of the Extremotolerant Tardigrade Ramazzottius varieornatus: A New Model Animal for Astrobiology

    Science.gov (United States)

    Horikawa, Daiki D.; Kunieda, Takekazu; Abe, Wataru; Watanabe, Masahiko; Nakahara, Yuichi; Yukuhiro, Fumiko; Sakashita, Tetsuya; Hamada, Nobuyuki; Wada, Seiichi; Funayama, Tomoo; Katagiri, Chihiro; Kobayashi, Yasuhiko; Higashi, Seigo

    2008-06-01

    Studies on the ability of multicellular organisms to tolerate specific environmental extremes are relatively rare compared to those of unicellular microorganisms in extreme environments. Tardigrades are extremotolerant animals that can enter an ametabolic dry state called anhydrobiosis and have high tolerance to a variety of extreme environmental conditions, particularly while in anhydrobiosis. Although tardigrades have been expected to be a potential model animal for astrobiological studies due to their excellent anhydrobiotic and extremotolerant abilities, few studies of tolerance with cultured tardigrades have been reported, possibly due to the absence of a model species that can be easily maintained under rearing conditions. We report the successful rearing of the herbivorous tardigrade, Ramazzottius varieornatus, by supplying the green alga Chlorella vulgaris as food. The life span was 35 ± 16.4 d, deposited eggs required 5.7 ± 1.1 d to hatch, and animals began to deposit eggs 9 d after hatching. The reared individuals of this species had an anhydrobiotic capacity throughout their life cycle in egg, juvenile, and adult stages. Furthermore, the reared adults in an anhydrobiotic state were tolerant of temperatures of 90°C and -196°C, and exposure to 99.8% acetonitrile or irradiation with 4000 Gy 4He ions. Based on their life history traits and tolerance to extreme stresses, R. varieornatus may be a suitable model for astrobiological studies of multicellular organisms.

  7. Analysis of DNA repair and protection in the Tardigrade Ramazzottius varieornatus and Hypsibius dujardini after exposure to UVC radiation.

    Directory of Open Access Journals (Sweden)

    Daiki D Horikawa

    Full Text Available Tardigrades inhabiting terrestrial environments exhibit extraordinary resistance to ionizing radiation and UV radiation although little is known about the mechanisms underlying the resistance. We found that the terrestrial tardigrade Ramazzottius varieornatus is able to tolerate massive doses of UVC irradiation by both being protected from forming UVC-induced thymine dimers in DNA in a desiccated, anhydrobiotic state as well as repairing the dimers that do form in the hydrated animals. In R. varieornatus accumulation of thymine dimers in DNA induced by irradiation with 2.5 kJ/m(2 of UVC radiation disappeared 18 h after the exposure when the animals were exposed to fluorescent light but not in the dark. Much higher UV radiation tolerance was observed in desiccated anhydrobiotic R. varieornatus compared to hydrated specimens of this species. On the other hand, the freshwater tardigrade species Hypsibius dujardini that was used as control, showed much weaker tolerance to UVC radiation than R. varieornatus, and it did not contain a putative phrA gene sequence. The anhydrobiotes of R. varieornatus accumulated much less UVC-induced thymine dimers in DNA than hydrated one. It suggests that anhydrobiosis efficiently avoids DNA damage accumulation in R. varieornatus and confers better UV radiation tolerance on this species. Thus we propose that UV radiation tolerance in tardigrades is due to the both high capacities of DNA damage repair and DNA protection, a two-pronged survival strategy.

  8. Establishment of a rearing system of the extremotolerant tardigrade Ramazzottius varieornatus: a new model animal for astrobiology.

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    Horikawa, Daiki D; Kunieda, Takekazu; Abe, Wataru; Watanabe, Masahiko; Nakahara, Yuichi; Yukuhiro, Fumiko; Sakashita, Tetsuya; Hamada, Nobuyuki; Wada, Seiichi; Funayama, Tomoo; Katagiri, Chihiro; Kobayashi, Yasuhiko; Higashi, Seigo; Okuda, Takashi

    2008-06-01

    Studies on the ability of multicellular organisms to tolerate specific environmental extremes are relatively rare compared to those of unicellular microorganisms in extreme environments. Tardigrades are extremotolerant animals that can enter an ametabolic dry state called anhydrobiosis and have high tolerance to a variety of extreme environmental conditions, particularly while in anhydrobiosis. Although tardigrades have been expected to be a potential model animal for astrobiological studies due to their excellent anhydrobiotic and extremotolerant abilities, few studies of tolerance with cultured tardigrades have been reported, possibly due to the absence of a model species that can be easily maintained under rearing conditions. We report the successful rearing of the herbivorous tardigrade, Ramazzottius varieornatus, by supplying the green alga Chlorella vulgaris as food. The life span was 35 +/- 16.4 d, deposited eggs required 5.7 +/- 1.1 d to hatch, and animals began to deposit eggs 9 d after hatching. The reared individuals of this species had an anhydrobiotic capacity throughout their life cycle in egg, juvenile, and adult stages. Furthermore, the reared adults in an anhydrobiotic state were tolerant of temperatures of 90 degrees C and -196 degrees C, and exposure to 99.8% acetonitrile or irradiation with 4000 Gy (4)He ions. Based on their life history traits and tolerance to extreme stresses, R. varieornatus may be a suitable model for astrobiological studies of multicellular organisms.

  9. Milnesium minutum and Milnesium sandrae, two new species of Milnesiidae (Tardigrada, Eutardigrada, Apochela).

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    Pilato, Giovanni; Lisi, Oscar

    2016-01-01

    Two new species of Milnesium are described, Milnesium minutum sp. n. from Sicily and Milnesium sandrae sp. n. from the Hawaiian Archipelago. The body size of Milnesium minutum is the smallest of the known species of the genus. The stylet supports are inserted on the buccal tube at 63-66% of its length and the claws have a [3-3]-[3-3] configuration. Milnesium sandrae has stylet supports inserted on the buccal tube at 58-60.5% of its length, a [3-3]-[3-3] claw configuration, and the percent ratio between the secondary claw and primary claw length on legs I-III (78.6%-85.5%) clearly higher than on legs IV (70.5%-71.4%). With the description of these two new species, the number of species in the genus is increased to 31.

  10. Element analysis of the eutardigrades Richtersius coronifer and Milnesium cf. asiaticum using Particle Induced X-ray Emission (PIXE

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    Charlotta Nilsson

    2013-05-01

    Full Text Available Semi-terrestrial tardigrades are well-known for their tolerance to a variety of environmental extremes, including desiccation, freezing and radiation. Despite several attempts to reveal the genetic and molecular mechanisms behind the resilience of tardigrades, it is still unknown how these animals are able to maintain the integrity of their cellular components under severe stress. Quantitative or qualitative changes in molecular compounds (e.g., carbohydrates, proteins are expected, and have been the main line of research towards understanding the tolerance of tardigrades. In radiation tolerant bacteria, a tolerance mechanism based on manganese has been proposed. We evaluate this hypothesis in tardigrades and provide the first data on element composition in desiccated and non-desiccated specimens of two eutardigrade species, Richtersius coronifer and Milnesium cf. asiaticum. A focused 2 MeV proton microbeam was utilised to determine the elemental content, distributions and concentrations, using the ion beam analytical technique particle induced X-ray emission (PIXE. The presence of six elements – phosphorus, sulphur, chlorine, potassium, calcium and iron – were confirmed in all tardigrade specimens, at levels up to a few mg g–1. However, manganese was found in less than 10% of the analysed specimens, and in low amounts, thus our study provides no evidence for the manganese hypothesis. We also show that the distributions and/or concentrations of some elements differ between the two species as well as between the dehydrated and hydrated state. In particular, very low levels of iron were found in dehydrated M. cf. asiaticum. Our analysis shows that the PIXE technique is a useful tool for investigating questions on the distribution of elements both in dehydrated and hydrated tardigrades.

  11. Long-term experimental manipulation of moisture conditions and its impact on moss-living tardigrades

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    Ingemar K. JÖNSSON

    2007-09-01

    Full Text Available The effects of long-term experimentally modified hydration conditions on populations of moss-living tardigrades were investigated in a naturally dry South-Swedish alvar environment at the Island Öland. Carbonite rocks with mosses were collected from rock fences and arranged in three experimental groups: increased dehydration, increased hydration, and control. The total experimental period was 18 months, with treatments applied during two 6 month periods. The density of tardigrade populations was recorded. The total population of tardigrades, all species included, tended to be lower under watering treatment, but the difference was only marginally significant. Populations of Richtersius coronifer and Echiniscus spiniger did not respond to the treatments, while populations of Milnesium tardigradum declined under conditions of increased hydration. The density of eggs in R. coronifer was also lower in the watering treatment. Thus, no positive response to increased hydration was recorded. These results suggest that the tardigrade populations either were not limited by the amount of hydrated periods, or that some other factor(s counteracted the expected positive response to increased hydration. All populations showed a high variability in density among different moss samples, and the rock from which a sample was taken explained a significant part of this variability. This confirms a commonly believed, but seldom quantified, high heterogeneity in density of semi-terrestrial tardigrades, also among seemingly very similar substrates.

  12. Effect of ultra-high pressure on small animals, tardigrades and Artemia

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    Fumihisa Ono

    2016-12-01

    Full Text Available This research shows that small animals, tardigrades (Milnesium tardigradum in tun (dehydrated state and Artemia salina cists (dried eggs can tolerate the very high hydrostatic pressure of 7.5 GPa. It was really surprising that living organisms can survive after exposure to such a high pressure. We extended these studies to the extremely high pressure of 20 GPa by using a Kawai-type octahedral anvil press. After exposure to this pressure for 30 min, the tardigrades were soaked in pure water and investigated under a microscope. Their bodies regained metabolic state and no serious injury could be seen. But they were not alive. A few of Artemia eggs went part of the way to hatching after soaked in sea water, but they never grew any further. Comparing with the case of blue-green alga, these animals are weaker under ultra-high pressure.

  13. Integrated pathway modules using time-course metabolic profiles and EST data from Milnesium tardigradum

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    Beisser Daniela

    2012-06-01

    Full Text Available Abstract Background Tardigrades are multicellular organisms, resistant to extreme environmental changes such as heat, drought, radiation and freezing. They outlast these conditions in an inactive form (tun to escape damage to cellular structures and cell death. Tardigrades are apparently able to prevent or repair such damage and are therefore a crucial model organism for stress tolerance. Cultures of the tardigrade Milnesium tardigradum were dehydrated by removing the surrounding water to induce tun formation. During this process and the subsequent rehydration, metabolites were measured in a time series by GC-MS. Additionally expressed sequence tags are available, especially libraries generated from the active and inactive state. The aim of this integrated analysis is to trace changes in tardigrade metabolism and identify pathways responsible for their extreme resistance against physical stress. Results In this study we propose a novel integrative approach for the analysis of metabolic networks to identify modules of joint shifts on the transcriptomic and metabolic levels. We derive a tardigrade-specific metabolic network represented as an undirected graph with 3,658 nodes (metabolites and 4,378 edges (reactions. Time course metabolite profiles are used to score the network nodes showing a significant change over time. The edges are scored according to information on enzymes from the EST data. Using this combined information, we identify a key subnetwork (functional module of concerted changes in metabolic pathways, specific for de- and rehydration. The module is enriched in reactions showing significant changes in metabolite levels and enzyme abundance during the transition. It resembles the cessation of a measurable metabolism (e.g. glycolysis and amino acid anabolism during the tun formation, the production of storage metabolites and bioprotectants, such as DNA stabilizers, and the generation of amino acids and cellular components from

  14. The genus Milnesium (Eutardigrada: Milnesiidae) in the Sierra Nevada de Santa Marta (Colombia), with the description of Milnesium kogui sp. nov.

    Science.gov (United States)

    Londoño, Rosana; Daza, Anisbeth; Caicedo, Martín; Quiroga, Sigmer; Kaczmarek, Łukasz

    2015-05-06

    A new species, Milnesium kogui sp. nov. is described from the Sierra Nevada de Santa Marta, Colombia. The new species belongs to the tardigradum group and is most similar, by the claw configuration [2-2]-[2-2], to Milnesium dujiangensis and Milnesium katarzynae. Milnesium kogui sp. nov. differs from M. dujiangensis mainly by the presence of primary branches on all legs and from M. katarzynae by the absence of dorsal sculpture. Additionally, in this paper we present a list of all Milnesium species recorded in Colombia including Milnesium cf. barbadosense Meyer & Hinton, 2012 and M. brachyungue Binda & Pilato, 1990, new additions to the recorded fauna of Colombia.

  15. Transcriptome analysis in tardigrade species reveals specific molecular pathways for stress adaptations.

    Science.gov (United States)

    Förster, Frank; Beisser, Daniela; Grohme, Markus A; Liang, Chunguang; Mali, Brahim; Siegl, Alexander Matthias; Engelmann, Julia C; Shkumatov, Alexander V; Schokraie, Elham; Müller, Tobias; Schnölzer, Martina; Schill, Ralph O; Frohme, Marcus; Dandekar, Thomas

    2012-01-01

    Tardigrades have unique stress-adaptations that allow them to survive extremes of cold, heat, radiation and vacuum. To study this, encoded protein clusters and pathways from an ongoing transcriptome study on the tardigrade Milnesium tardigradum were analyzed using bioinformatics tools and compared to expressed sequence tags (ESTs) from Hypsibius dujardini, revealing major pathways involved in resistance against extreme environmental conditions. ESTs are available on the Tardigrade Workbench along with software and databank updates. Our analysis reveals that RNA stability motifs for M. tardigradum are different from typical motifs known from higher animals. M. tardigradum and H. dujardini protein clusters and conserved domains imply metabolic storage pathways for glycogen, glycolipids and specific secondary metabolism as well as stress response pathways (including heat shock proteins, bmh2, and specific repair pathways). Redox-, DNA-, stress- and protein protection pathways complement specific repair capabilities to achieve the strong robustness of M. tardigradum. These pathways are partly conserved in other animals and their manipulation could boost stress adaptation even in human cells. However, the unique combination of resistance and repair pathways make tardigrades and M. tardigradum in particular so highly stress resistant.

  16. Comparison of different protocols for DNA preparation and PCR amplification of mitochondrial genes of tardigrades

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    Ralph O. SCHILL

    2007-09-01

    Full Text Available Phylogenetic relationships and molecular taxonomy within the Tardigrada have been given a lot of attention in recent years. Here I present the first comparison of different protocols for DNA preparation by investigating six commercial available DNA extraction kits and the CTAB method. Successful extraction of DNA from tardigrades depends strongly on the life-stage (embryo, adult, and on the condition of the specimens, respectively on the preservation (anhydrobiotic, ethanol. Although the extraction kits showed differences in the amount of extracted DNA, in all cases fresh tissue of live animals or embryos resulted in the best quality and quantity of DNA. A lesser amount of DNA was extractable from anhydrobiotic animals and embryos and the results of specimens fixed in ethanol were unsatisfactory. All used commercially available DNA extraction kits and PCR cocktails have been focused on vertebrate tissues, blood, cultured cells, bacteria and yeast. However, I used successfully the kits according to the manufacturer’s instruction without changes in the protocols for DNA extraction of tardigrades. Commercial kits provide a simple and convenient way to isolate pure genomic DNA of high-quality from tardigrades. Furthermore I tested eight different Taq polymerase enzymes for PCR amplification of mitochondrial genes of tardigrades. Each of the enzymes resulted in a PCR product, and even if the amount of the PCR products was quite different, it was possible to use it successful for direct sequencing. Summarizing, the successful PCR of the target DNA depends on the purity and quality of the DNA template and for this the species preservation is more critical than the extraction method or the PCR cocktail which can be optimized.

  17. Survival of freezing by hydrated tardigrades inhabiting terrestrial and freshwater habitats.

    Science.gov (United States)

    Guidetti, Roberto; Altiero, Tiziana; Bertolani, Roberto; Grazioso, Pasqualina; Rebecchi, Lorena

    2011-04-01

    The seasonality and unpredictability of environmental conditions at high altitudes and latitudes govern the life cycle patterns of organisms, giving rise to stresses that cause death or development of specific adaptations. Ice formation is a major variable affecting the survival of both freshwater fauna and fauna inhabiting lichens, mosses and leaf litter. Tardigrades occupy a wide range of niches in marine, freshwater and terrestrial environments. The highest number of species is found in terrestrial habitats thanks to their ability to enter anhydrobiosis and cryobiosis. The cryobiotic ability of tardigrade species from polar regions is well known. Consequently, we focused our research on the ability to survive freezing in the active hydrated state using seven tardigrade species differing in phylogenetic position and collected at various altitudes and from different habitats in a temperate area. Specimens were cooled at different cooling rates (from 0.31° C min(-1) to 3.26° C min(-1)). Even though the final survival and the time required by animals to recover to active life were both inversely related to the cooling rate, highly significant interspecific differences were found. Species survival ability ranged from excellent to none. Species living in xeric habitats withstood freezing better than those living in hygrophilous habitats, while true limnic species did not exhibit any cryobiotic ability. The ability to withstand freezing seems linked to the anhydrobiotic ability. The differences in cryptobiotic performance among tardigrade species seem more influenced by selective pressures linked to local adaptation to habitat characteristics than by phylogenetic relationships.

  18. Desiccation tolerance in the tardigrade Richtersius coronifer relies on muscle mediated structural reorganization.

    Science.gov (United States)

    Halberg, Kenneth Agerlin; Jørgensen, Aslak; Møbjerg, Nadja

    2013-01-01

    Life unfolds within a framework of constraining abiotic factors, yet some organisms are adapted to handle large fluctuations in physical and chemical parameters. Tardigrades are microscopic ecdysozoans well known for their ability to endure hostile conditions, such as complete desiccation--a phenomenon called anhydrobiosis. During dehydration, anhydrobiotic animals undergo a series of anatomical changes. Whether this reorganization is an essential regulated event mediated by active controlled processes, or merely a passive result of the dehydration process, has not been clearly determined. Here, we investigate parameters pivotal to the formation of the so-called "tun", a state that in tardigrades and rotifers marks the entrance into anhydrobiosis. Estimation of body volume in the eutardigrade Richtersius coronifer reveals an 87 % reduction in volume from the hydrated active state to the dehydrated tun state, underlining the structural stress associated with entering anhydrobiosis. Survival experiments with pharmacological inhibitors of mitochondrial energy production and muscle contractions show that i) mitochondrial energy production is a prerequisite for surviving desiccation, ii) uncoupling the mitochondria abolishes tun formation, and iii) inhibiting the musculature impairs the ability to form viable tuns. We moreover provide a comparative analysis of the structural changes involved in tun formation, using a combination of cytochemistry, confocal laser scanning microscopy and 3D reconstructions as well as scanning electron microscopy. Our data reveal that the musculature mediates a structural reorganization vital for anhydrobiotic survival, and furthermore that maintaining structural integrity is essential for resumption of life following rehydration.

  19. Desiccation tolerance in the tardigrade Richtersius coronifer relies on muscle mediated structural reorganization.

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    Kenneth Agerlin Halberg

    Full Text Available Life unfolds within a framework of constraining abiotic factors, yet some organisms are adapted to handle large fluctuations in physical and chemical parameters. Tardigrades are microscopic ecdysozoans well known for their ability to endure hostile conditions, such as complete desiccation--a phenomenon called anhydrobiosis. During dehydration, anhydrobiotic animals undergo a series of anatomical changes. Whether this reorganization is an essential regulated event mediated by active controlled processes, or merely a passive result of the dehydration process, has not been clearly determined. Here, we investigate parameters pivotal to the formation of the so-called "tun", a state that in tardigrades and rotifers marks the entrance into anhydrobiosis. Estimation of body volume in the eutardigrade Richtersius coronifer reveals an 87 % reduction in volume from the hydrated active state to the dehydrated tun state, underlining the structural stress associated with entering anhydrobiosis. Survival experiments with pharmacological inhibitors of mitochondrial energy production and muscle contractions show that i mitochondrial energy production is a prerequisite for surviving desiccation, ii uncoupling the mitochondria abolishes tun formation, and iii inhibiting the musculature impairs the ability to form viable tuns. We moreover provide a comparative analysis of the structural changes involved in tun formation, using a combination of cytochemistry, confocal laser scanning microscopy and 3D reconstructions as well as scanning electron microscopy. Our data reveal that the musculature mediates a structural reorganization vital for anhydrobiotic survival, and furthermore that maintaining structural integrity is essential for resumption of life following rehydration.

  20. Nearctic freshwater tardigrades: a review

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    Juliana G. HINTON

    2007-09-01

    Full Text Available The distribution and ecology of limno-terrestrial Tardigrada in the Nearctic realm remain poorly known. This is especially true of freshwater tardigrades (i.e., species found in permanently submerged habitats, which have received much less attention than terrestrial species. We reviewed the literature on Nearctic freshwater tardigrades. Of 204 Nearctic limno-terrestrial tardigrade species, 44 have been collected from sediments and aquatic vegetation of streams, rivers, ponds, lakes, groundwater and cryoconite holes. Of these, 17 are hydrophilous species found exclusively or primarily in aquatic environments. Most of the remainder are probably washed in accidentally from terrestrial substrates. Among the hydrophilous species, five are endemic to the Nearctic realm and three cosmopolitan. Hypsibius dujardini is the most widely-distributed hydrophilous species. There are no regional collections of Nearctic freshwater tardigrades comparable to those for terrestrial species. Aquatic tardigrades are benthic, and are found in sediments and on aquatic vegetation. Hypsibius dujardini and other widespread species are found in both substrates, and there is thus no evidence of substrate specificity. Numerically, tardigrades usually comprise a minor component of benthic invertebrate communities. Nothing is known of their trophic relationships or dispersal in these habitats. The density of Nearctic freshwater tardigrade species peaks in the spring and/or fall. Future research should increase the spatial and temporal scale of study, and employ adequate replication.

  1. The Moss Fauna 1: Tardigrades.

    Science.gov (United States)

    Kinchin, Ian M.

    1987-01-01

    Describes the Tardigrada as a group of animals suitable for close study in project work. Gives reasons for their suitability and an illustrated identification key. Discusses possible investigations into the ecology and physiology of tardigrades. (Author/CW)

  2. On dormancy strategies in tardigrades.

    Science.gov (United States)

    Guidetti, Roberto; Altiero, Tiziana; Rebecchi, Lorena

    2011-05-01

    In this review we analyze the dormancy strategies of metazoans inhabiting "hostile to life" habitats, which have a strong impact on their ecology and in particular on the traits of their life history. Tardigrades are here considered a model animal, being aquatic organisms colonizing terrestrial habitats. Tardigrades evolved a large variety of dormant stages that can be ascribed to diapause (encystment, cyclomorphosis, resting eggs) and cryptobiosis (anhydrobiosis, cryobiosis, anoxibiosis). In tardigrades, diapause and cryptobiosis can occur separately or simultaneously, consequently the adoption of one adaptive strategy is not necessarily an alternative to the adoption of the other. Encystment and cyclomorphosis are characterized by seasonal cyclic changes in morphology and physiology of the animals. They share several common features and their evolution is strictly linked to the molting process. A bet-hedging strategy with different patterns of egg hatching time has been observed in a tardigrade species. Four categories of eggs have been identified: subitaneous, delayed-hatching, abortive and diapause resting eggs, which needs a stimulus to hatch (rehydration after a period of desiccation). Cryptobiotic tardigrades are able to withstand desiccation (anhydrobiosis) and freezing (cryobiosis) at any stage of their life-cycle. This ability involves a complex array of factors working at molecular (bioprotectans), physiological and structural levels. Animal survival and the accumulation of molecular damage are related to the time spent in the cryptobiotic state, to the abiotic parameters during the cryptobiotic state, and to the conditions during initial and final phases of the process. Cryptobiosis evolved independently at least two times in tardigrades, in eutardigrades and in echiniscoids. Within each evolutionary line, the absence of cryptobiotic abilities is more related to selective pressures to local habitat adaptation than to phylogenetic relationships. The

  3. Tardigrades from Peru (South America), with descriptions of three new species of Parachela.

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    Kaczmarek, Lukasz; Cytan, Joanna; Zawierucha, Krzysztof; Diduszko, Dawid; Michalczyk, Lukasz

    2014-04-17

    In four samples of mosses and mosses mixed with lichens collected in the Peruvian region of Cusco, 344 tardigrades, 78 free-laid eggs and six simplexes were found. In total, nine species were identified: Cornechiniscus lobatus, Echiniscus dariae, E. ollantaytamboensis, Isohypsibius condorcanquii sp. nov., Macrobiotus pisacensis sp. nov., Milnesium krzysztofi, Minibiotus intermedius, Paramacrobiotus intii sp. nov. and Pseudechiniscus ramazzottii ramazzottii. Isohypsibius condorcanquii sp. nov. is most similar to I. baldii, but differs mainly by the absence of ventral sculpture, the presence of the oral cavity armature, a different macroplacoid length sequence and a different shape of macroplacoids. The new species also differs from other congeners by a different dorsal sculpture, the absence of cuticular bars under the claws and the absence of eyes. Macrobiotus pisacensis sp. nov. differs from the most similar M. ariekammensis and M. kirghizicus by a different oral cavity armature, the presence of cuticular pores, details of egg morphology and some morphometric characters of both animals and eggs. Paramacrobiotus intii sp. nov. differs from most similar species of the genus by a different type of the oral cavity armature, details of egg morphology and some morphometric characters of both animals and eggs. In addition, we briefly discuss the tardigrade fauna of Peru, and propose a simple and economic system of describing relative lengths of pharyngeal macroplacoids. The system is especially useful in interspecific comparisons and differential diagnoses.

  4. Comparative studies on storage cells in tardigrades during starvation and anhydrobiosis

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    Andy REUNER, Steffen HENGHERR, Franz Brümmer, Ralph O. SCHILL

    2010-04-01

    Full Text Available The impact of starvation and anhydrobiosis on the number and size of the storage cells in the tardigrade species Milnesium tardigradum, Paramacrobiotus tonollii and Macrobiotus sapiens was investigated to gain more insight on the energetic side of anhydrobiosis. Storage cells are free floating cells within the body cavity of tardigrades and are presumed to store and release energy in form of glycogen, protein and fat to maintain a constant nutrient regime for the other tissues. The body size of the animals was not correlated with the size of the storage cells, however, M. tardigradum the largest species analysed also had the largest storage cells. A reduction in the size of the storage cells is apparent in all three species after seven days of starvation. A seven-day period of anhydrobiosis leads to a decrease in cell size in M. tardigradum but not in P. tonollii and M. sapiens. Although M. sapiens was raised on green algae, and M. tardigradum and P. tonollii were fed with rotifers and nematodes this difference in nourishment was not reflected in the response of the storage cells to anhydrobiosis [Current Zoology 56 (2: 259–263, 2010].

  5. Stress gene (hsp70) sequences and quantitative expression in Milnesium tardigradum (Tardigrada) during active and cryptobiotic stages.

    Science.gov (United States)

    Schill, Ralph O; Steinbrück, Günther H B; Köhler, Heinz-R

    2004-04-01

    The eutardigrade Milnesium tardigradum can undergo cryptobiosis, i.e. entry into a reversible ametabolic stage induced by dehydration, cooling and, probably, osmotic and anoxic stress. For the first time in tardigrades, we described partial sequences of three heat-shock protein (hsp70 family) genes and examined gene expression on the way from an active to a cryptobiotic and back to an active stage again. Results showed different patterns of gene expression in the hsp70 isoforms. All three isoforms seem to be true heat-shock proteins since transcription could be clearly enhanced by temperature elevation. Isoform 1 and, at a lower level, isoform 3 do not seem to have a specific function for cryptobiosis. By contrast, transcription of isoform 2 is significantly induced in the transitional stage between the active and the cryptobiotic stage, resulting in a comparatively high mRNA copy number also during cryptobiosis. This pattern of induction implies that isoform 2 is the most relevant hsp70 gene for M. tardigradum individuals entering the cryptobiotic stage.

  6. What can we learn from the toughest animals of the Earth? Water bears (tardigrades) as multicellular model organisms in order to perform scientific preparations for lunar exploration

    Science.gov (United States)

    Guidetti, Roberto; Rizzo, Angela Maria; Altiero, Tiziana; Rebecchi, Lorena

    2012-12-01

    Space missions of long duration required a series of preliminary experiments on living organisms, validated by a substantial phase of ground simulation experiments, in the field of micro- and inter-mediate gravities, radiobiology, and, for planetary explorations, related to risks deriving from regolith and dust exposure. In this review, we present the tardigrades, whose characteristics that recommend them as an emerging model for space biology. They are microscopic animals but are characterized by a complex structural organization similar to that of larger animals; they can be cultured in lab in small facilities, having small size; they are able to produce clonal lineages by means of parthenogenesis; they can completely suspend their metabolism when entering in dormant states (anhydrobiosis induced by dehydration and cryobiosis induced by freezing); desiccated anhydrobiotic tardigrades are able to withstand chemical and physical extremes, but a large tolerance is showed also by active animals; they can be stored in dry state for many years without loss of viability. Tardigrades have already been exposed to space stressors on Low Earth Orbit several times. The relevance of ground-based and space studies on tardigrades rests on the presumption that results could suggest strategies to protect organisms, also humans, when exposed to the space and lunar environments.

  7. The genus Milnesium (Tardigrada: Eutardigrada: Milnesiidae) in the Great Smoky Mountains National Park (North Carolina and Tennessee, USA), with the description of Milnesium bohleberi sp. nov.

    Science.gov (United States)

    Bartels, Paul J; Nelson, Diane R; Kaczmarek, Lukasz; Michalczyk, Lukasz

    2014-06-30

    For many decades the genus Milnesium was thought to consist of a single, cosmopolitan species: Milnesium tardigradum Doyère, 1840. However, recently the genus has been re-evaluated, and numerous new species have been described. Currently, over twenty extant species and one fossil are recognised, and most appear to have very narrow geographic ranges. It is doubtful that M. tardigradum sensu stricto is truly cosmopolitan, but to evaluate this hypothesis, specimens previously identified as M. tardigradum must be re-examined using newly proposed taxonomic characters. As part of the All Taxa Biodiversity Inventory (ATBI) we collected Milnesium specimens from various locations in the Great Smoky Mountains National Park (GSMNP). Two Milnesium species have been evaluated, and one of them, Milnesium bohleberi sp. nov., is new to science. The new species is most similar to M. eurystomum but differs by shorter claws and a shorter, narrower, and more cylindrical buccal tube. The other Milnesium species, very rare in our collection, is morphologically indistinguishable from Milnesium granulatum Ramazzotti 1962, which was previously known only from Chile, Italy and Romania. Based on the recently revised description of M. tardigradum sensu stricto, this nominal species for the genus has not been found in the GSMNP samples. 

  8. Specimens with an Artifact Appearing as 'Three Spines' in Milnesium tardigradum var. trispinosa Rahm, 1931 (Tardigrada).

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    Suzuki, Atsushi C

    2016-08-01

    Milnesium tardigradum trispinosa Rahm, 1931 is characterized by its three spines at the posterior end of the animal, but has never been reported since its original description. Among mounted specimens of Milnesium sp. from Japan and M. tardigradum s. s. from France, several cases with these 'three spines' were observed. In these samples, the character was formed by an artifact of the fixation process. Images of these specimens show such a striking similarity to Milnesium tardigradum trispinosa that this taxon must be considered as having been erroneously established as a result of misinterpretation of an artifact and no longer valid.

  9. Extremotolerant tardigrade genome and improved radiotolerance of human cultured cells by tardigrade-unique protein.

    OpenAIRE

    Hashimoto, Takuma; Horikawa, Daiki D.; Saito, Yuki; Kuwahara, Hirokazu; Kozuka-Hata, Hiroko; Shin-I, Tadasu; Minakuchi, Yohei; Ohishi, Kazuko; Motoyama, Ayuko; Aizu, Tomoyuki; Enomoto, Atsushi; Kondo, Koyuki; Tanaka, Sae; Hara, Yuichiro; Koshikawa, Shigeyuki

    2016-01-01

    Tardigrades, also known as water bears, are small aquatic animals. Some tardigrade species tolerate almost complete dehydration and exhibit extraordinary tolerance to various physical extremes in the dehydrated state. Here we determine a high-quality genome sequence of Ramazzottius varieornatus, one of the most stress-tolerant tardigrade species. Precise gene repertoire analyses reveal the presence of a small proportion (1.2% or less) of putative foreign genes, loss of gene pathways that prom...

  10. Extremotolerant tardigrade genome and improved radiotolerance of human cultured cells by tardigrade-unique protein

    OpenAIRE

    Hashimoto, Takuma; Horikawa, Daiki D.; Saito, Yuki; Kuwahara, Hirokazu; Kozuka-Hata, Hiroko; Shin-I, Tadasu; Minakuchi, Yohei; Ohishi, Kazuko; Motoyama, Ayuko; Aizu, Tomoyuki; Enomoto, Atsushi; Kondo, Koyuki; Tanaka, Sae; Hara, Yuichiro; Koshikawa, Shigeyuki

    2016-01-01

    Tardigrades, also known as water bears, are small aquatic animals. Some tardigrade species tolerate almost complete dehydration and exhibit extraordinary tolerance to various physical extremes in the dehydrated state. Here we determine a high-quality genome sequence of Ramazzottius varieornatus, one of the most stress-tolerant tardigrade species. Precise gene repertoire analyses reveal the presence of a small proportion (1.2% or less) of putative foreign genes, loss of gene pathways that prom...

  11. A model study for tardigrade identification

    OpenAIRE

    Bertolani, Roberto; Lorena REBECCHI; Cesari, Michele

    2010-01-01

    Using tardigrades from a single moss sample as a case study, we propose a new method for tardigrade species identification, which is often problematic, due to the low number of morphological characters. Identification at generic level was carried out on adults, while morphological analyses were performed on animals (LM) and eggs (LM and SEM), including hologenophores, vouchers used also for molecular analysis of COI mtDNA. This multi-approach method revealed the presence of ...

  12. Tardigrades Use Intrinsically Disordered Proteins to Survive Desiccation.

    Science.gov (United States)

    Boothby, Thomas C; Tapia, Hugo; Brozena, Alexandra H; Piszkiewicz, Samantha; Smith, Austin E; Giovannini, Ilaria; Rebecchi, Lorena; Pielak, Gary J; Koshland, Doug; Goldstein, Bob

    2017-03-16

    Tardigrades are microscopic animals that survive a remarkable array of stresses, including desiccation. How tardigrades survive desiccation has remained a mystery for more than 250 years. Trehalose, a disaccharide essential for several organisms to survive drying, is detected at low levels or not at all in some tardigrade species, indicating that tardigrades possess potentially novel mechanisms for surviving desiccation. Here we show that tardigrade-specific intrinsically disordered proteins (TDPs) are essential for desiccation tolerance. TDP genes are constitutively expressed at high levels or induced during desiccation in multiple tardigrade species. TDPs are required for tardigrade desiccation tolerance, and these genes are sufficient to increase desiccation tolerance when expressed in heterologous systems. TDPs form non-crystalline amorphous solids (vitrify) upon desiccation, and this vitrified state mirrors their protective capabilities. Our study identifies TDPs as functional mediators of tardigrade desiccation tolerance, expanding our knowledge of the roles and diversity of disordered proteins involved in stress tolerance.

  13. Extremotolerant tardigrade genome and improved radiotolerance of human cultured cells by tardigrade-unique protein.

    Science.gov (United States)

    Hashimoto, Takuma; Horikawa, Daiki D; Saito, Yuki; Kuwahara, Hirokazu; Kozuka-Hata, Hiroko; Shin-I, Tadasu; Minakuchi, Yohei; Ohishi, Kazuko; Motoyama, Ayuko; Aizu, Tomoyuki; Enomoto, Atsushi; Kondo, Koyuki; Tanaka, Sae; Hara, Yuichiro; Koshikawa, Shigeyuki; Sagara, Hiroshi; Miura, Toru; Yokobori, Shin-Ichi; Miyagawa, Kiyoshi; Suzuki, Yutaka; Kubo, Takeo; Oyama, Masaaki; Kohara, Yuji; Fujiyama, Asao; Arakawa, Kazuharu; Katayama, Toshiaki; Toyoda, Atsushi; Kunieda, Takekazu

    2016-09-20

    Tardigrades, also known as water bears, are small aquatic animals. Some tardigrade species tolerate almost complete dehydration and exhibit extraordinary tolerance to various physical extremes in the dehydrated state. Here we determine a high-quality genome sequence of Ramazzottius varieornatus, one of the most stress-tolerant tardigrade species. Precise gene repertoire analyses reveal the presence of a small proportion (1.2% or less) of putative foreign genes, loss of gene pathways that promote stress damage, expansion of gene families related to ameliorating damage, and evolution and high expression of novel tardigrade-unique proteins. Minor changes in the gene expression profiles during dehydration and rehydration suggest constitutive expression of tolerance-related genes. Using human cultured cells, we demonstrate that a tardigrade-unique DNA-associating protein suppresses X-ray-induced DNA damage by ∼40% and improves radiotolerance. These findings indicate the relevance of tardigrade-unique proteins to tolerability and tardigrades could be a bountiful source of new protection genes and mechanisms.

  14. Extremotolerant tardigrade genome and improved radiotolerance of human cultured cells by tardigrade-unique protein

    Science.gov (United States)

    Hashimoto, Takuma; Horikawa, Daiki D.; Saito, Yuki; Kuwahara, Hirokazu; Kozuka-Hata, Hiroko; Shin-I, Tadasu; Minakuchi, Yohei; Ohishi, Kazuko; Motoyama, Ayuko; Aizu, Tomoyuki; Enomoto, Atsushi; Kondo, Koyuki; Tanaka, Sae; Hara, Yuichiro; Koshikawa, Shigeyuki; Sagara, Hiroshi; Miura, Toru; Yokobori, Shin-ichi; Miyagawa, Kiyoshi; Suzuki, Yutaka; Kubo, Takeo; Oyama, Masaaki; Kohara, Yuji; Fujiyama, Asao; Arakawa, Kazuharu; Katayama, Toshiaki; Toyoda, Atsushi; Kunieda, Takekazu

    2016-01-01

    Tardigrades, also known as water bears, are small aquatic animals. Some tardigrade species tolerate almost complete dehydration and exhibit extraordinary tolerance to various physical extremes in the dehydrated state. Here we determine a high-quality genome sequence of Ramazzottius varieornatus, one of the most stress-tolerant tardigrade species. Precise gene repertoire analyses reveal the presence of a small proportion (1.2% or less) of putative foreign genes, loss of gene pathways that promote stress damage, expansion of gene families related to ameliorating damage, and evolution and high expression of novel tardigrade-unique proteins. Minor changes in the gene expression profiles during dehydration and rehydration suggest constitutive expression of tolerance-related genes. Using human cultured cells, we demonstrate that a tardigrade-unique DNA-associating protein suppresses X-ray-induced DNA damage by ∼40% and improves radiotolerance. These findings indicate the relevance of tardigrade-unique proteins to tolerability and tardigrades could be a bountiful source of new protection genes and mechanisms. PMID:27649274

  15. Species diversity and morphometrics of tardigrades from a medium-size city in the Neotropical Region: Santa Rosa (La Pampa, Argentina

    Directory of Open Access Journals (Sweden)

    Peluffo, J. R.

    2007-06-01

    Full Text Available Tardigrade diversity was studied in a medium-sized city in the Neotropical Region: Santa Rosa (La Pampa, Argentina. Samples were collected between February 1999 and January 2000 from lichens and mosses growing on sidewalk trees of the urban and periurban area. Five species of tardigrades were found, i.e., Echiniscus rufoviridis du Bois-Reymond Marcus, 1944, Macrobiotus areolatus Murray, 1907, Ramazzottius oberhaeuseri (Doyère, 1840, Milnesium cf. tardigradum and a non-described species of Macrobiotus. Only one species, M. cf. tardigradum, was found in areas with high levels of vehicle traffic. Results are compared with those from cities in the Nearctic and Palearctic regions. Measurements and pt index values (percentage ratios between the length of the structure considered and the buccal tube length are provided for M. areolatus, R. oberhaeuseri and M. cf. tardigradum. Amongst the characters considered, the pt index for the stylet support insertion shows the least intraspecific variation. This character is also independent from body length and buccal-tube length.

  16. Movement behaviour and video tracking of Milnesium tardigradum Doyère, 1840 (Eutardigrada, Apochela)

    NARCIS (Netherlands)

    Shcherbakov, D.; Schill, R.O.; Brümmer, F.; Blum, M.

    2010-01-01

    Tardigrades or ‘water-bears’ live in moist environments with a high degree of gaseous exchange. In tardigrades, locomotion is essential, e.g. for feeding, to find sexual partners and to adjust the level of hydration by moving to wetter or dryer environments. Here we report on the movement behaviour

  17. Integrated pathway modules using time-course metabolic profiles and EST data from Milnesium tardigradum

    NARCIS (Netherlands)

    Beisser, D.; Grohme, M.; Kopka, J.; Frohme, M.; Schill, R.O.; Hengherr, S.; Dandekar, T.; Klau, G.W.; Dittrich, M.; Müller, T.

    2012-01-01

    Background Tardigrades are multicellular organisms, resistant to extreme environmental changes such as heat, drought, radiation and freezing. They outlast these conditions in an inactive form (tun) to escape damage to cellular structures and cell death. Tardigrades are apparently able to prevent o

  18. Genome sequencing of a single tardigrade Hypsibius dujardini individual

    OpenAIRE

    Arakawa, Kazuharu; Yoshida, Yuki; Tomita, Masaru

    2016-01-01

    Tardigrades are ubiquitous microscopic animals that play an important role in the study of metazoan phylogeny. Most terrestrial tardigrades can withstand extreme environments by entering an ametabolic desiccated state termed anhydrobiosis. Due to their small size and the non-axenic nature of laboratory cultures, molecular studies of tardigrades are prone to contamination. To minimize the possibility of microbial contaminations and to obtain high-quality genomic information, we have developed ...

  19. Radiation tolerance in water bears.

    Science.gov (United States)

    Horikawa, D. D.; Sakashita, T.; Katagiri, C.; Watanabe, M.; Nakahara, Y.; Okuda, T.; Hamada, N.; Wada, S.; Funayama, T.; Kobayashi, Y.

    Tardigrades water bears are tiny invertebrates forming a phylum and inhabit various environments on the earth Terrestrial tardigrades enter a form called as anhydrobiosis when the surrounding water disappears Anhyydrobiosis is defined as an ametabolic dry state and followed by recovering their activity when rehydrated Anhydrobiotic tardigrades show incredible tolerance to a variety of extreme environmental conditions such as temperatures -273 r C to 151 r C vacuum high pressure 600 MPa and chemicals that include alcohols and methyl bromide In these views there have been some discussions about their potential for surviving outer space In the present study we demonstrated the survival limit not merely against gamma-rays but against heavy ions in the tardigrade Milnesium tardigradum in order to evaluate the effects of radiations on them The animals were exposure to 500 to 7000 Gy of gamma-rays or 500 to 8000 Gy of heavy ions 4 He in their hydrated or anhydrobiotic state The results showed that both of hydrated and anhydrobiotic animals have high radio-tolerance median lethal dose LD50 48 h of gamma-rays or heavy ions in M tardigradum was more than 4000 Gy indicating that this species is categorized into the most radio-tolerant animals We suggest that tardigrades will be suitable model animals for extremophilic multicellular organisms and may provide a survival strategy in extraterrestrial environments

  20. Genome sequencing of a single tardigrade Hypsibius dujardini individual.

    Science.gov (United States)

    Arakawa, Kazuharu; Yoshida, Yuki; Tomita, Masaru

    2016-08-16

    Tardigrades are ubiquitous microscopic animals that play an important role in the study of metazoan phylogeny. Most terrestrial tardigrades can withstand extreme environments by entering an ametabolic desiccated state termed anhydrobiosis. Due to their small size and the non-axenic nature of laboratory cultures, molecular studies of tardigrades are prone to contamination. To minimize the possibility of microbial contaminations and to obtain high-quality genomic information, we have developed an ultra-low input library sequencing protocol to enable the genome sequencing of a single tardigrade Hypsibius dujardini individual. Here, we describe the details of our sequencing data and the ultra-low input library preparation methodologies.

  1. Tardigrades in Space Research - Past and Future

    Science.gov (United States)

    Weronika, Erdmann; Łukasz, Kaczmarek

    2016-10-01

    To survive exposure to space conditions, organisms should have certain characteristics including a high tolerance for freezing, radiation and desiccation. The organisms with the best chance for survival under such conditions are extremophiles, like some species of Bacteria and Archea, Rotifera, several species of Nematoda, some of the arthropods and Tardigrada (water bears). There is no denying that tardigrades are one of the toughest animals on our planet and are the most unique in the extremophiles group. Tardigrada are very small animals (50 to 2,100 μm in length), and they inhabit great number of Earth environments. Ever since it was proven that tardigrades have high resistance to the different kinds of stress factors associated with cosmic journeys, combined with their relatively complex structure and their relative ease of observation, they have become a perfect model organism for space research. This taxon is now the focus of astrobiologists from around the world. Therefore, this paper presents a short review of the space research performed on tardigrades as well as some considerations for further studies.

  2. Tardigrades of Sweden; an updated check-list.

    Science.gov (United States)

    Guidetti, Roberto; Jönsson, K Ingemar; Kristensen, Reinhardt Møbjerg

    2015-07-07

    Tardigrades occur worldwide and in a variety of ecosystems and habitats representing an important component of the micrometazoan biodiversity. Several studies documenting the occurrence of tardigrades in Sweden have been published since the first reports in early 1900, but no comprehensive summary of these studies have been published. We compiled the available information on recorded tardigrades from Sweden, using material from published studies and museum and university collections. In total, our review document 101 species of tardigrades that have been recorded from Sweden (an updated checklist of tardigrades from Sweden will be available online), of which 14 species are new records for the country. The highest number of species was recorded in the northernmost province of Lappland and the more southern provinces of Uppland and Skåne, while much lower species numbers are reported from the middle part of Sweden. This pattern probably represents biased sampling activities of biologists rather than real differences in biodiversity of tardigrades. In view of the few studies that have been made on tardigrade biodiversity in Sweden, the relatively high number of tardigrade species recorded, representing almost a tenth of the species recorded worldwide, indicates that many more species remain to be found. In this respect, more studies of the marine ecosystems along the Swedish west coast and the long Baltic Sea coastline would be of particular interest.

  3. Osmotic stress tolerance in semi-terrestrial tardigrades

    DEFF Research Database (Denmark)

    Heidemann, Nanna W T; Smith, Daniel K.; Hygum, Thomas L.;

    2016-01-01

    Little is known about ionic and osmotic stress tolerance in tardigrades. Here, we examine salt stress tolerance in Ramazzottius oberhaeuseri and Echiniscus testudo from Nivå (Denmark) and address whether limno-terrestrial tardigrades can enter a state of quiescence (osmobiosis) in the face of hig...

  4. Osmotic stress tolerance in semi-terrestrial tardigrades

    DEFF Research Database (Denmark)

    Heidemann, Nanna W T; Smith, Daniel K.; Hygum, Thomas L.;

    2016-01-01

    Little is known about ionic and osmotic stress tolerance in tardigrades. Here, we examine salt stress tolerance in Ramazzottius oberhaeuseri and Echiniscus testudo from Nivå (Denmark) and address whether limno-terrestrial tardigrades can enter a state of quiescence (osmobiosis) in the face of high...

  5. Experimental taxonomy exposes ontogenetic variability and elucidates the taxonomic value of claw configuration in Milnesium Doyère, 1840 (Tardigrada: Eutardigrada: Apochela)

    NARCIS (Netherlands)

    Witold Morek, W.; Gąsiorek, P.; Stec, D.; Blagden, B.; Michalczyk, Ł

    2016-01-01

    In this paper we describe a new apochelan species, Milnesium variefidum sp. nov. from Scotland and provide novel morphological and molecular data for Milnesium berladnicorum Ciobanu et al., 2014. The new species differs from the most similar M. berladnicorum by the presence of developmental dimorphi

  6. New records of marine tardigrades from Brazil

    Directory of Open Access Journals (Sweden)

    Clélia Márcia Cavalcanti Da Rocha

    2013-05-01

    Full Text Available In studies developed in the mid- and infralittoral of Cupe Beach (Pernambuco, in the shallow infralittoral of Saint Peter and Saint Paul Archipelago, and in the continental shelf of northeastern Brazil, we recorded for the first time in Brazilian waters specimens of Archechiniscus marci, Batillipes lesteri, Florarctus hulingsi, Halechiniscus tuleari, Angursa lingua, Raiarctus aureolatus, Actinarctus doryphorus doryphorus, Tanarctus dendriticus, Tanarctus velatus, Neoarctus sp. and Neostygarctus sp., as well as six other species that had been previously recorded in the region. Hence, the number of marine tardigrade taxa recorded in Brazil was increased to twenty-seven.

  7. Tardigrades: In the Classroom, Laboratory, and on the Internet.

    Science.gov (United States)

    Miller, William R.; Case, Steve B.

    1998-01-01

    Details the development of the Tardigrade Survey, focusing on the questions related to how to present projects. Recommends challenging high school students in ways that stimulate their interest in the investigatory approach. (DDR)

  8. 3-Dimensional reconstruction of fluorescent structures in tardigrades

    Directory of Open Access Journals (Sweden)

    Franz BRÜMMER

    2007-09-01

    Full Text Available Tardigrades are microscopic animals, thus brightfield microscopy is a well established method for tardigrade observation. Modern techniques in functional genetics like fluorescence in situ hybridisation or fluorescently labelled expression markers demand high resolution fluorescence microscopy. Nevertheless tardigrades are still considered to be difficult objects for fluorescence techniques as they are covered by an opaque and diffracting cuticle. We show a modern technique of structured light illumination that enables us to acquire thin optical sections and consequently to reconstruct 3-dimensional structures in tardigrades with a high spatial resolution in all 3 dimensions. This technique is evaluated on taxonomically valuable internal as well as external structures of eutardigrades: the bucco-pharyngeal apparatus and the claws. The 3-dimensional reconstructions allow the measurement of distances in all 3 dimensions.

  9. Dehydration-Specific Induction of Hydrophilic Protein Genes in the Anhydrobiotic Nematode Aphelenchus avenae

    OpenAIRE

    2004-01-01

    Some organisms can survive exposure to extreme desiccation by entering a state of suspended animation known as anhydrobiosis. The free-living nematode Aphelenchus avenae can be induced to enter the anhydrobiotic state by exposure to a moderate reduction in relative humidity. During this preconditioning period, the nematode accumulates large amounts of the disaccharide trehalose, which is thought to be necessary, but not sufficient, for successful anhydrobiosis. To identify other adaptations t...

  10. Survival in extreme environments – on the current knowledge of adaptations in tardigrades

    DEFF Research Database (Denmark)

    Møbjerg, Nadja; Halberg, Kenneth Agerlin; Jørgensen, Aslak

    2011-01-01

    of the tardigrades and highlight species that are currently used as models for physiological and molecular investigations. Tardigrades are uniquely adapted to a range of environmental extremes. Cryptobiosis, currently referred to as a reversible ametabolic state induced by e.g. desiccation, is common especially...... to below )20 C, presumably relying on efficient DNA repair mechanisms and osmoregulation. This review summarizes the current knowledge on adaptations found among tardigrades, and presents new data on tardigrade cell numbers and osmoregulation....

  11. Two new tardigrade species from Sicily.

    Science.gov (United States)

    Pilato, Giovanni; Sabella, Giorgio; Lisi, Oscar

    2014-01-14

    Two new species of tardigrades are described from Sicilian moss samples: Macrobiotus insuetus sp. nov. and Diphascon (Diphascon) procerum sp. nov.        Macrobiotus insuetus sp. nov. is a species of the harmsworthi-group characterized by both posterior and anterior claws of the hind legs, which are different in shape from those of the first three leg pairs. The IV claws have extended basal tract where the branches are joined and the secondary branch breaks at near right angle to the primary branch and is clearly shorter than the main branch and the secondary branch of claws I-III. The eggs are not areolated and have conical processes with a reticular ornamentation.        Diphascon (D.) procerum sp. nov. has a delicate cuticular ornamentation of very small tubercles, almost dots; two macroplacoids and septulum are present; thin accessory points are present on the main branches of the slender claws; lunules are absent but the base of the external claws of the hind legs are enlarged and slightly indented; a cuticular bar is present near the internal claw of the first three leg pairs and two cuticular bars are present on the hind legs between the base of the claws and near the base of the anterior claw. 

  12. Myoanatomy of the marine tardigrade Halobiotus crispae (Eutardigrada: Hypsibiidae)

    DEFF Research Database (Denmark)

    Halberg, Kenneth Agerlin; Persson, Dennis; Møbjerg, Nadja;

    2009-01-01

    The muscular architecture of Halobiotus crispae (Eutardigrada: Hypsibiidae) was examined by means of fluorescent-coupled phalloidin in combination with confocal laser scanning microscopy and computer-aided three-dimensional reconstruction, in addition to light microscopy (Nomarski), scanning elec...... for the use of muscular architecture in elucidating tardigrade phylogeny....

  13. Neural development in the tardigrade Hypsibius dujardini based on anti-acetylated α-tubulin immunolabeling

    OpenAIRE

    Gross, Vladimir; Mayer, Georg

    2015-01-01

    Background The tardigrades (water bears) are a cosmopolitan group of microscopic ecdysozoans found in a variety of aquatic and temporarily wet environments. They are members of the Panarthropoda (Tardigrada + Onychophora + Arthropoda), although their exact position within this group remains contested. Studies of embryonic development in tardigrades have been scarce and have yielded contradictory data. Therefore, we investigated the development of the nervous system in embryos of the tardigrad...

  14. Evidence for extensive horizontal gene transfer from the draft genome of a tardigrade

    OpenAIRE

    Boothby, Thomas C; Tenlen, Jennifer R.; Smith, Frank W.; Wang, Jeremy R; Patanella, Kiera A.; Osborne Nishimura, Erin; Tintori, Sophia C.; Li, Qing; Jones, Corbin D.; Yandell, Mark; Messina, David N.; Glasscock, Jarret; Goldstein, Bob

    2015-01-01

    Despite fascinating scientists for over 200 years, little at the molecular level is known about tardigrades, microscopic animals resistant to extreme stresses. We present the genome of a tardigrade. Approximately one-sixth of the genes in the tardigrade genome were found to have been acquired through horizontal transfer, a proportion nearly double the proportion of previous known cases of extreme horizontal gene transfer (HGT) in animals. Foreign genes have impacted the composition of the tar...

  15. No evidence for extensive horizontal gene transfer in the genome of the tardigrade Hypsibius dujardini

    OpenAIRE

    Koutsovoulos, Georgios; Kumar, Sujai; Laetsch, Dominik R.; Stevens, Lewis; Daub, Jennifer; Conlon, Claire; Maroon, Habib; Thomas, Fran; Aboobaker, Aziz A.; Blaxter, Mark

    2016-01-01

    Tardigrades, also known as moss piglets or water bears, are renowned for their ability to withstand extreme environmental challenges. A recently published analysis of the genome of the tardigrade Hypsibius dujardini by Boothby et al. concluded that horizontal acquisition of genes from bacterial and other sources might be key to cryptobiosis in tardigrades. We independently sequenced the genome of H. dujardini and detected a low level of horizontal gene transfer. We show that the extensive hor...

  16. Dehydration-specific induction of hydrophilic protein genes in the anhydrobiotic nematode Aphelenchus avenae.

    Science.gov (United States)

    Browne, John A; Dolan, Katharine M; Tyson, Trevor; Goyal, Kshamata; Tunnacliffe, Alan; Burnell, Ann M

    2004-08-01

    Some organisms can survive exposure to extreme desiccation by entering a state of suspended animation known as anhydrobiosis. The free-living nematode Aphelenchus avenae can be induced to enter the anhydrobiotic state by exposure to a moderate reduction in relative humidity. During this preconditioning period, the nematode accumulates large amounts of the disaccharide trehalose, which is thought to be necessary, but not sufficient, for successful anhydrobiosis. To identify other adaptations that are required for anhydrobiosis, we developed a novel SL1-based mRNA differential display technique to clone genes that are upregulated by dehydration in A. avenae. Three such genes, Aav-lea-1, Aav-ahn-1, and Aav-glx-1, encode, respectively, a late embryogenesis abundant (LEA) group 3 protein, a novel protein that we named anhydrin, and the antioxidant enzyme glutaredoxin. Strikingly, the predicted LEA and anhydrin proteins are highly hydrophilic and lack significant secondary structure in the hydrated state. The dehydration-induced upregulation of Aav-lea-1 and Aav-ahn-1 was confirmed by Northern hybridization and quantitative PCR experiments. Both genes were also upregulated by an osmotic upshift, but not by cold, heat, or oxidative stress. Experiments to investigate the relationship between mRNA levels and protein expression for these genes are in progress. LEA proteins occur commonly in plants, accumulating during seed maturation and desiccation stress; the presence of a gene encoding an LEA protein in an anhydrobiotic nematode suggests that some mechanisms of coping with water loss are conserved between plants and animals.

  17. Ground Testing of the EMCS Seed Cassette for Biocompatibility with the Tardigrade, Hypsibius dujardini

    Science.gov (United States)

    Reinsch, Sigrid; Myers, Zachary Alan; DeSimone, Julia Carol; Freeman, John L.; Steele, Marianne K.; Sun, Gwo-Shing; Heathcote, David

    2014-01-01

    The European Modular Cultivation System, EMCS, was developed by ESA for plant experiments. We performed ground testing to determine whether ARC EMCS seed cassettes could be adapted for use with tardigrades for future spaceflight experiments. Tardigrades (water bears) are small invertebrates that enter the tun state in response to desiccation or other environmental stresses. Tardigrade tuns have suspended metabolism and have been shown to be survive exposure to space vacuum, high pressure, temperature and other stresses. For spaceflight experiments using the EMCS, the organisms ideally must be able to survive desiccation and storage in the cassette at ambient temperature for several weeks prior to the initiation of the experiment by the infusion of water to the cassette during spaceflight. The ability of tardigrades to survive extremes by entering the tun state make them ideal candidates for growth experiments in the EMCS cassettes. The growth substratum in the cassettes is a gridded polyether sulfone (PES) membrane. A blotter beneath the PES membrane contains dried growth medium. The goals of our study were to (1) determine whether tardigrades survive and reproduce on PES membranes, (2) develop a consistent method for dehydration of the tardigrades with high recovery rates upon rehydration, (3) to determine an appropriate food source for the tardigrades that can also be dehydrated/rehydrated and (4) successful mock rehydration experiment in cassettes with appropriate food source. We present results that show successful multigenerational growth of tardigrades on PES membranes with a variety of wet food sources. We have successfully performed a mock rehydration with tardigrades and at least one candidate food, protonema of the moss Polytrichum, that supports multigenerational growth and whose spores germinate quickly enough to match tardigrade feeding patterns post rehydration. Our results indicate that experiments on the ISS using the tardigrade, Hypsibius dujardini

  18. Molecular and morphological analysis of an Antarctic tardigrade, Acutuncus antarcticus

    Directory of Open Access Journals (Sweden)

    Hiroshi Kagoshima

    2013-03-01

    Full Text Available We isolated a species of tardigrade from moss samples collected from Langhovde and Skarvsnes, near Syowa station, East Antarctic, from which we cultured a parthenogenetic strain in Petri dishes with co-occurring cyanobacteria or green algae. This culture was maintained at both 4 and 10ºC, though the latter proved more suitable for growth. Eggs were laid free, rather than in exuviae. We isolated the 18S rRNA sequences from this tardigrade, identical to that of Acutuncus antarcticus from King George island, South Shetland islands. Morphological analyses via both light and scanning electron microscopy also show general agreement with characteristics of A. antarcticus: dorsal and ventral apophyses for the insertion of stylet muscles and dorsal longitudinal thickening on the anterior part of buccal tube; presence of pharyngeal apophyses, two macroplacoids and absence of a microplacoid; the surface structure of egg; and claw shape. Peribuccal lamellae were absent, but six oval swellings surrounded the mouth opening. An additional study of moss pillars from lake Hotoke-ike, Skarvsnes, proved the existence of the same tardigrade taxon living at the bottom of the lake.

  19. Tardigrades of Alaska: distribution patterns, diversity and species richness

    Directory of Open Access Journals (Sweden)

    Carl Johansson

    2013-05-01

    Full Text Available During the summer of 2010, a biotic survey of tardigrades was conducted along a latitudinal transect in central Alaska from the Kenai Peninsula, via Fairbanks and the Arctic Circle to the coastal plain. Work was centred at the Toolik and Bonanza Creek Long Term Ecological Research Network sites and supplemented by opportunistic collections from the Kenai Peninsula and Anchorage areas. The 235 samples collected at 20 sites over 10 degrees of latitude yielded 1463 tardigrades representing two classes, three orders, 10 families, 23 genera and 73 species from 142 positive samples. A total of 50 species are new to Alaska, increasing the state's known species richness to 84. Several environmental metrics, such as pH, substrate, elevation, location and habitat were measured, recorded and analysed along the latitudinal gradient. Contrary to expectations, pH did not appear to be a predictor of tardigrade abundance or distribution. Density and species richness were relatively consistent across sites. However, the assemblages were highly variable within and between sites at only 14–20% similarity. We detected no correlation between species diversity and latitudinal or environmental gradients, though this may be affected by a high (59.9% occurrence of single-species samples (containing individuals of only one species. Estimates of species richness were calculated for Alaska (118 and the Arctic (172. Our efforts increased the number of known species in Alaska to 84, and those results led us to question the validity of the estimate numbers.

  20. Brain anatomy of the marine tardigrade Actinarctus doryphorus (Arthrotardigrada).

    Science.gov (United States)

    Persson, Dennis K; Halberg, Kenneth A; Jørgensen, Aslak; Møbjerg, Nadja; Kristensen, Reinhardt M

    2014-02-01

    Knowledge of tardigrade brain structure is important for resolving the phylogenetic relationships of Tardigrada. Here, we present new insight into the morphology of the brain in a marine arthrotardigrade, Actinarctus doryphorus, based on transmission electron microscopy, supported by scanning electron microscopy, conventional light microscopy as well as confocal laser scanning microscopy. Arthrotardigrades contain a large number of plesiomorphic characters and likely represent ancestral tardigrades. They often have segmented body outlines and each trunk segment, with its paired set of legs, may have up to five sensory appendages. Noticeably, the head carries numerous cephalic appendages that are structurally equivalent to the sensory appendages of the trunk segments. Our data reveal that the brain of A. doryphorus is partitioned into three paired lobes, and that these lobes exhibit a more pronounced separation as compared to that of eutardigrades. The first brain lobe in A. doryphorus is located anteriodorsally, with the second lobe just below it in an anterioventral position. Both of these two paired lobes are located anterior to the buccal tube. The third pair of brain lobes are situated posterioventrally to the first two lobes, and flank the buccal tube. In addition, A. doryphorus possesses a subpharyngeal ganglion, which is connected with the first of the four ventral trunk ganglia. The first and second brain lobes in A. doryphorus innervate the clavae and cirri of the head. The innervations of these structures indicate a homology between, respectively, the clavae and cirri of A. doryphorus and the temporalia and papilla cephalica of eutardigrades. The third brain lobes innervate the buccal lamella and the stylets as described for eutardigrades. Collectively, these findings suggest that the head region of extant tardigrades is the result of cephalization of multiple segments. Our results on the brain anatomy of Actinarctus doryphorus support the monophyly of

  1. Looking at tardigrades in a new light: using epifluorescence to interpret structure.

    Science.gov (United States)

    Perry, E S; Miller, W R; Lindsay, S

    2015-02-01

    The use of epifluorescence microscopy coupled with ultraviolet (UV) autofluorescence is suggested as a means to view and interpret tardigrade structures. Endogenous fluorochromes are a known component of tardigrade cuticle, claws and bucco-pharyngeal apparatus. By imaging the autofluorescence from tardigrades, it is possible to document these structures in detail, including the subdivisions and boundaries of echiniscid (heterotardigrade) plates and the nature and spatial relationships of the texture (pores, granules, papillae and tubercles) on the various plates. This allows the determination of taxonomic features not easily seen with other microscopic techniques.

  2. The Tardigrada Register: a comprehensive online data repository for tardigrade taxonomy

    Directory of Open Access Journals (Sweden)

    Łukasz Michalczyk

    2013-05-01

    Full Text Available In this paper we present the Tardigrada Register (www.tardigrada.net/register: a free, comprehensive, and standardised online data repository for tardigrade taxonomy. We outline key problems of the modern tardigrade systematics and we propose the Register as a potential solution to some of them. We then describe the idea, structure and works of the service and discuss challenges it may face. However, most importantly, we hope to convince fellow Tardigradologists that sharing their data via the Register will benefit the entire community of the contemporary and future tardigrade researchers.

  3. Neutron Dose and Sub-Kelvin Resistance of the Tardigrade: Ramazzottius Varieoranatus

    Science.gov (United States)

    Kletetschka, G.; Horikawa, D.; Parsons, A.; Bodnarik, J.; Chervenak, J.

    2010-04-01

    Tardigrades have never been exposed to neutron/gamma radiation. They were also never cooled down to temperatures less than 1 K. We will show the survival data of these conditions and discuss the survival mechanisms.

  4. Novel origin of lamin-derived cytoplasmic intermediate filaments in tardigrades.

    Science.gov (United States)

    Hering, Lars; Bouameur, Jamal-Eddine; Reichelt, Julian; Magin, Thomas M; Mayer, Georg

    2016-02-03

    Intermediate filament (IF) proteins, including nuclear lamins and cytoplasmic IF proteins, are essential cytoskeletal components of bilaterian cells. Despite their important role in protecting tissues against mechanical force, no cytoplasmic IF proteins have been convincingly identified in arthropods. Here we show that the ancestral cytoplasmic IF protein gene was lost in the entire panarthropod (onychophoran + tardigrade + arthropod) rather than arthropod lineage and that nuclear, lamin-derived proteins instead acquired new cytoplasmic roles at least three times independently in collembolans, copepods, and tardigrades. Transcriptomic and genomic data revealed three IF protein genes in the tardigrade Hypsibius dujardini, one of which (cytotardin) occurs exclusively in the cytoplasm of epidermal and foregut epithelia, where it forms belt-like filaments around each epithelial cell. These results suggest that a lamin derivative has been co-opted to enhance tissue stability in tardigrades, a function otherwise served by cytoplasmic IF proteins in all other bilaterians.

  5. A short review on tardigrades – some lesser known taxa of polyextremophilic invertebrates

    Directory of Open Access Journals (Sweden)

    Andrea Gagyi-Palffy

    2011-06-01

    Full Text Available Tardigrades are polyextremophilic small organisms capable to survive in a variety of extremeconditions. By reversibly suspending their metabolism (cryptobiosis – tun state tardigrades can dry orfreeze and, thus, survive the extreme conditions like very high or low pressure and temperatures,changes in salinity, lack of oxygen, lack of water, some noxious chemicals, boiling alcohol, even thevacuum of the outer space. Despite their peculiar morphology and amazing diversity of habitats,relatively little is known about these organisms. Tardigrades are considered some lesser known taxa.Studying tardigrades can teach us about the evolution of life on our planet, can help us understand whatextremophilic evolution and adaptation means and they can show us what forms of life may develop onother planets.

  6. A zoogeographic study of the limnoterrestrial tardigrade fauna on the Faroe islands

    DEFF Research Database (Denmark)

    Var Trygvadottir, Birna; Kristensen, Reinhardt Møbjerg

    2013-01-01

    The Faroe islands (62 degrees N, 7 degrees W) are an archipelago of 18 small islands situated in the northeast Atlantic ocean between Iceland and the Shetland islands. A zoogeographic investigation (2001-2004) of the limnoterrestrial tardigrade fauna of these islands revealed 48 limnoterrestrial......), Greenland (West and East), Scotland, England and with Newfoundland. On the basis of presence/absence data of the tardigrade species from the different countries a cluster analysis was computed, based on Bray-Curtis similarities, and a dendrogram was constructed. The interesting results show that the Faroese...... tardigrade fauna is mostly similar with Iceland, which could be expected, but more surprising it is also very similar to the tardigrade fauna on Disko island (West Greenland). Several of the reported species exhibit a boreo-alpine disjunction (i.e. species only found in northern latitudes and in high...

  7. The Tardigrada Register: a comprehensive online data repository for tardigrade taxonomy

    OpenAIRE

    Łukasz Michalczyk; Łukasz Kaczmarek

    2013-01-01

    In this paper we present the Tardigrada Register (www.tardigrada.net/register): a free, comprehensive, and standardised online data repository for tardigrade taxonomy. We outline key problems of the modern tardigrade systematics and we propose the Register as a potential solution to some of them. We then describe the idea, structure and works of the service and discuss challenges it may face. However, most importantly, we hope to convince fellow Tardigradologists that sharing their data via t...

  8. Neural markers reveal a one-segmented head in tardigrades (water bears.

    Directory of Open Access Journals (Sweden)

    Georg Mayer

    Full Text Available BACKGROUND: While recent neuroanatomical and gene expression studies have clarified the alignment of cephalic segments in arthropods and onychophorans, the identity of head segments in tardigrades remains controversial. In particular, it is unclear whether the tardigrade head and its enclosed brain comprises one, or several segments, or a non-segmental structure. To clarify this, we applied a variety of histochemical and immunocytochemical markers to specimens of the tardigrade Macrobiotus cf. harmsworthi and the onychophoran Euperipatoides rowelli. METHODOLOGY/PRINCIPAL FINDINGS: Our immunolabelling against serotonin, FMRFamide and α-tubulin reveals that the tardigrade brain is a dorsal, bilaterally symmetric structure that resembles the brain of onychophorans and arthropods rather than a circumoesophageal ring typical of cycloneuralians (nematodes and allies. A suboesophageal ganglion is clearly lacking. Our data further reveal a hitherto unknown, unpaired stomatogastric ganglion in Macrobiotus cf. harmsworthi, which innervates the ectodermal oesophagus and the endodermal midgut and is associated with the second leg-bearing segment. In contrast, the oesophagus of the onychophoran E. rowelli possesses no immunoreactive neurons, whereas scattered bipolar, serotonin-like immunoreactive cell bodies are found in the midgut wall. Furthermore, our results show that the onychophoran pharynx is innervated by a medullary loop nerve accompanied by monopolar, serotonin-like immunoreactive cell bodies. CONCLUSIONS/SIGNIFICANCE: A comparison of the nervous system innervating the foregut and midgut structures in tardigrades and onychophorans to that of arthropods indicates that the stomatogastric ganglion is a potential synapomorphy of Tardigrada and Arthropoda. Its association with the second leg-bearing segment in tardigrades suggests that the second trunk ganglion is a homologue of the arthropod tritocerebrum, whereas the first ganglion corresponds to

  9. Survival in extreme environments - on the current knowledge of adaptations in tardigrades.

    Science.gov (United States)

    Møbjerg, N; Halberg, K A; Jørgensen, A; Persson, D; Bjørn, M; Ramløv, H; Kristensen, R M

    2011-07-01

    Tardigrades are microscopic animals found worldwide in aquatic as well as terrestrial ecosystems. They belong to the invertebrate superclade Ecdysozoa, as do the two major invertebrate model organisms: Caenorhabditis elegans and Drosophila melanogaster. We present a brief description of the tardigrades and highlight species that are currently used as models for physiological and molecular investigations. Tardigrades are uniquely adapted to a range of environmental extremes. Cryptobiosis, currently referred to as a reversible ametabolic state induced by e.g. desiccation, is common especially among limno-terrestrial species. It has been shown that the entry and exit of cryptobiosis may involve synthesis of bioprotectants in the form of selective carbohydrates and proteins as well as high levels of antioxidant enzymes and other free radical scavengers. However, at present a general scheme of mechanisms explaining this phenomenon is lacking. Importantly, recent research has shown that tardigrades even in their active states may be extremely tolerant to environmental stress, handling extreme levels of ionizing radiation, large fluctuation in external salinity and avoiding freezing by supercooling to below -20 °C, presumably relying on efficient DNA repair mechanisms and osmoregulation. This review summarizes the current knowledge on adaptations found among tardigrades, and presents new data on tardigrade cell numbers and osmoregulation.

  10. A zoogeographic study of the limnoterrestrial tardigrade fauna on the Faroe islands

    Directory of Open Access Journals (Sweden)

    Birna Vár Trygvadóttir

    2013-05-01

    Full Text Available The Faroe islands (62°N, 7°W are an archipelago of 18 small islands situated in the northeast Atlantic ocean between Iceland and the Shetland islands. A zoogeographic investigation (2001-2004 of the limnoterrestrial tardigrade fauna of these islands revealed 48 limnoterrestrial species and subspecies and one marine species, of which 29 were new records for the Faroe islands. Among the findings were three species in the recently described genus belonging to the family Eohypsibiidae. A faunistic comparison was also done with Iceland, Svalbard islands, Disko island (Greenland, Greenland (West and East, Scotland, England and with Newfoundland. On the basis of presence/absence data of the tardigrade species from the different countries a cluster analysis was computed, based on Bray-Curtis similarities, and a dendrogram was constructed. The interesting results show that the Faroese tardigrade fauna is mostly similar with Iceland, which could be expected, but more surprising it is also very similar to the tardigrade fauna on Disko island (West Greenland. Several of the reported species exhibit a boreo-alpine disjunction (i.e. species only found in northern latitudes and in high altitudes farther south. These facts could indicate that the tardigrade fauna on the islands is very ancient and could have survived glaciation periods in refuges such as nunataks which occurred on the Faroes during glaciation periods. This study also includes a closer inspection of the altitudinal distribution of the tardigrade species found compared with similar data from Poland.

  11. Further studies on the marine tardigrade fauna from Sardinia (Italy

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    Cristiana DE LEONARDIS

    2007-09-01

    Full Text Available An investigation on the taxonomy and ecology of marine tardigrades was carried out in different intertidal and subtidal sites along the coasts of Sardinia (Italy. Particle size analysis of sediments revealed medium or medium-fine intertidal sands and coarse subtidal sands, the latter mainly formed by coralligenous debris. The systematic study was particularly relevant, leading to the identification of 25 species, of which 9 are new records for Sardinia, and 2 are new to science. With these new findings, the total number of species for Sardinia adds up to 47. The species found belong to the families Halechiniscidae (16 species; abundance 2 to 263 ind. 10 cm-2, Batillipedidae (6 species; abundance 2 to 574 ind. 10 cm-2 and Stygarctidae (3 species; abundance 0 to 13 ind. 10 cm-2. The present data confirm the existence of a remarkable diversity, both of intertidal and subtidal tardigrade fauna. Generally, the prevalently siliceous intertidal sands host a few number of species (sometimes with many individuals, while the subtidal sediments, which were mainly calcareous, show a higher number of species often with low density. In fact, in the intertidal sediments only 11 species were found, 5 belonging to Halechiniscidae and 6 to Batillipedidae. In the subtidal sediments, there was a much wider variety; Halechiniscidae showed the highest number of species (16, compared to the remaining families, while Stygarctidae, which were present only in subtidal sediments, accounted only for 3 species. In the intertidal zone the highest value of the diversity index (H' was 2.1 and in the subtidal zone it was 3.3.

  12. The Compact Body Plan of Tardigrades Evolved by the Loss of a Large Body Region.

    Science.gov (United States)

    Smith, Frank W; Boothby, Thomas C; Giovannini, Ilaria; Rebecchi, Lorena; Jockusch, Elizabeth L; Goldstein, Bob

    2016-01-25

    The superphylum Panarthropoda (Arthropoda, Onychophora, and Tardigrada) exhibits a remarkable diversity of segment morphologies, enabling these animals to occupy diverse ecological niches. The molecular identities of these segments are specified by Hox genes and other axis patterning genes during development [1, 2]. Comparisons of molecular segment identities between arthropod and onychophoran species have yielded important insights into the origins and diversification of their body plans [3-9]. However, the relationship of the segments of tardigrades to those of arthropods and onychophorans has remained enigmatic [10, 11], limiting our understanding of early panarthropod body plan diversification. Here, we reveal molecular identities for all of the segments of a tardigrade. Based on our analysis, we conclude that tardigrades have lost a large intermediate region of the body axis-a region corresponding to the entire thorax and most of the abdomen of insects-and that they have lost the Hox genes that originally specified this region. Our data suggest that nearly the entire tardigrade body axis is homologous to just the head region of arthropods. Based on our results, we reconstruct a last common ancestor of Panarthropoda that had a relatively elongate body plan like most arthropods and onychophorans, rather than a compact, tardigrade-like body plan. These results demonstrate that the body plan of an animal phylum can originate by the loss of a large part of the body.

  13. A DNA barcoding approach in the study of tardigrades

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    Michele Cesari

    2013-05-01

    Full Text Available DNA barcoding is a technique proposed by Hebert and co-workers in 2003 for discriminating species through analysis of a single gene barcode locus. It aims to obtain a better taxonomic resolution than that achieved through morphological studies, and to avoid the decline in taxonomic knowledge. Today DNA barcoding is a global enterprise, and the implementation of the idea has seen a rapid rise (more than 1900 papers published to date on different organisms. Nonetheless, controversy still arises regarding barcoding and taxonomy. It is important to note that DNA barcoding does not focus on building a tree-of-life or on doing DNA taxonomy, even though sometimes it has been used for these purposes. DNA barcoding rather focuses on producing a universal molecular identification key based on strong taxonomic knowledge that should be included in the barcode reference library. In the phylum Tardigrada, DNA barcoding represents a recent approach to species identification and to help in solving taxonomic problems, especially considering the diminutive size of these animals and the paucity of morphological characters useful for taxonomy. In the framework of the MoDNA Project (Morphology and DNA, carried out by our research group in collaboration with several colleagues, we are combining the study of a fragment of the mitochondrial cytochrome c oxidase subunit I gene (cox1 with morphological data, in a wide sense (cuticular structures, chromosomes, data on sex ratio and reproduction, to form an integrative taxonomy approach for tardigrade species identification. We believe that without verified reference sequences from voucher specimens that have been authenticated by qualified taxonomists, there is no reliable library for newly generated sequences with which to be compared. Methods and protocols for standardized results are focused on obtaining tight correspondence between tardigrade morphology (and egg shell morphology, when useful, possibly both light and

  14. First record of cysts in the tidal tardigrade Echiniscoides sigismundi

    Science.gov (United States)

    Clausen, Lykke K. B.; Andersen, Kasper N.; Hygum, Thomas L.; Jørgensen, Aslak; Møbjerg, Nadja

    2014-12-01

    Tardigrades are microscopic metazoans that withstand environmental extremes by entering dormant states, such as cryptobiosis (latent life). In addition, they may also form cysts. Here, we present the first report of cyst formation in a marine heterotardigrade, i.e., Echiniscoides sigismundi, which constitutes a cryptic species complex present worldwide in tidal zones. The cysts were initially discovered during experimental series constructed to investigate osmotic stress tolerance. The animals, which eventually formed cysts, showed signs of an imminent molt at the beginning of experimentation. We use the term "cyst" for stages, where a total of three or more cuticles have been synthesized. Our observations show that encystment in E. sigismundi involves synthesizing of at least two new cuticle layers. Legs with discharged claws are present in connection with the first outer cuticle, as well as the second cuticular layer. In the most developed cyst, a third cuticle lacking claws seems to surround the animal, which is delineated by a fourth cuticle. Many features are shared with the well-studied cysts of eutardigrades. The cysts of E. sigismundi, however, lack pigmentation and have an extra set of claws, and the animal inside retains buccopharyngeal sclerified parts, until discharging the third cuticle. The finding of cysts in a marine heterotardigrade is novel and confirms that encystment also occurs within this major evolutionary lineage.

  15. Tolerance to Gamma Radiation in the Tardigrade Hypsibius dujardini from Embryo to Adult Correlate Inversely with Cellular Proliferation.

    Science.gov (United States)

    Beltrán-Pardo, Eliana; Jönsson, K Ingemar; Harms-Ringdahl, Mats; Haghdoost, Siamak; Wojcik, Andrzej

    2015-01-01

    Tardigrades are highly tolerant to desiccation and ionizing radiation but the mechanisms of this tolerance are not well understood. In this paper, we report studies on dose responses of adults and eggs of the tardigrade Hypsibius dujardini exposed to gamma radiation. In adults the LD50/48h for survival was estimated at ~ 4200 Gy, and doses higher than 100 Gy reduced both fertility and hatchability of laid eggs drastically. We also evaluated the effect of radiation (doses 50 Gy, 200 Gy, 500 Gy) on eggs in the early and late embryonic stage of development, and observed a reduced hatchability in the early stage, while no effect was found in the late stage of development. Survival of juveniles from irradiated eggs was highly affected by a 500 Gy dose, both in the early and the late stage. Juveniles hatched from eggs irradiated at 50 Gy and 200 Gy developed into adults and produced offspring, but their fertility was reduced compared to the controls. Finally we measured the effect of low temperature during irradiation at 4000 Gy and 4500 Gy on survival in adult tardigrades, and observed a slight delay in the expressed mortality when tardigrades were irradiated on ice. Since H. dujardini is a freshwater tardigrade with lower tolerance to desiccation compared to limno-terrestrial tardigrades, the high radiation tolerance in adults, similar to limno-terrestrial tardigrades, is unexpected and seems to challenge the idea that desiccation and radiation tolerance rely on the same molecular mechanisms. We suggest that the higher radiation tolerance in adults and late stage embryos of H. dujardini (and in other studied tardigrades) compared to early stage embryos may partly be due to limited mitotic activity, since tardigrades have a low degree of somatic cell division (eutely), and dividing cells are known to be more sensitive to radiation.

  16. Tolerance to Gamma Radiation in the Tardigrade Hypsibius dujardini from Embryo to Adult Correlate Inversely with Cellular Proliferation.

    Directory of Open Access Journals (Sweden)

    Eliana Beltrán-Pardo

    Full Text Available Tardigrades are highly tolerant to desiccation and ionizing radiation but the mechanisms of this tolerance are not well understood. In this paper, we report studies on dose responses of adults and eggs of the tardigrade Hypsibius dujardini exposed to gamma radiation. In adults the LD50/48h for survival was estimated at ~ 4200 Gy, and doses higher than 100 Gy reduced both fertility and hatchability of laid eggs drastically. We also evaluated the effect of radiation (doses 50 Gy, 200 Gy, 500 Gy on eggs in the early and late embryonic stage of development, and observed a reduced hatchability in the early stage, while no effect was found in the late stage of development. Survival of juveniles from irradiated eggs was highly affected by a 500 Gy dose, both in the early and the late stage. Juveniles hatched from eggs irradiated at 50 Gy and 200 Gy developed into adults and produced offspring, but their fertility was reduced compared to the controls. Finally we measured the effect of low temperature during irradiation at 4000 Gy and 4500 Gy on survival in adult tardigrades, and observed a slight delay in the expressed mortality when tardigrades were irradiated on ice. Since H. dujardini is a freshwater tardigrade with lower tolerance to desiccation compared to limno-terrestrial tardigrades, the high radiation tolerance in adults, similar to limno-terrestrial tardigrades, is unexpected and seems to challenge the idea that desiccation and radiation tolerance rely on the same molecular mechanisms. We suggest that the higher radiation tolerance in adults and late stage embryos of H. dujardini (and in other studied tardigrades compared to early stage embryos may partly be due to limited mitotic activity, since tardigrades have a low degree of somatic cell division (eutely, and dividing cells are known to be more sensitive to radiation.

  17. A zoogeographic study of the limnoterrestrial tardigrade fauna on the Faroe islands

    DEFF Research Database (Denmark)

    Var Trygvadottir, Birna; Kristensen, Reinhardt Møbjerg

    2013-01-01

    ), Greenland (West and East), Scotland, England and with Newfoundland. On the basis of presence/absence data of the tardigrade species from the different countries a cluster analysis was computed, based on Bray-Curtis similarities, and a dendrogram was constructed. The interesting results show that the Faroese...

  18. Genetic diversity in the parthenogenetic reproducing tardigrade Echiniscus testudo (Heterotardigrada: Echiniscoidea)

    DEFF Research Database (Denmark)

    Jørgensen, A.; Faurby, S.; Krog Persson, D.

    2013-01-01

    Little is known about the genetic structure of microscopic animals from mosses and lichens. A few studies have investigated the geographic variation in tardigrades from mosses, but so far no study has investigated the intra-population or local clonal lineage variation. Echiniscus testudo (Echinis...

  19. Florarctus antillensis, a new Tardigrade from the coraL sand of Curaçao

    NARCIS (Netherlands)

    Land, van der J.

    1968-01-01

    Recently DELAMARE DEBOUTTEVILLE & RENAUD-MORNANT (1965) described two new species of marine tardigrades, Florarctus heimi and F. salvati, for which they erected a new genus. The representatives of this remarkable genus are characterized by the possession of large, aliform expansions of the body, str

  20. RNA interference can be used to disrupt gene function in tardigrades.

    Science.gov (United States)

    Tenlen, Jennifer R; McCaskill, Shaina; Goldstein, Bob

    2013-05-01

    How morphological diversity arises is a key question in evolutionary developmental biology. As a long-term approach to address this question, we are developing the water bear Hypsibius dujardini (Phylum Tardigrada) as a model system. We expect that using a close relative of two well-studied models, Drosophila (Phylum Arthropoda) and Caenorhabditis elegans (Phylum Nematoda), will facilitate identifying genetic pathways relevant to understanding the evolution of development. Tardigrades are also valuable research subjects for investigating how organisms and biological materials can survive extreme conditions. Methods to disrupt gene activity are essential to each of these efforts, but no such method yet exists for the Phylum Tardigrada. We developed a protocol to disrupt tardigrade gene functions by double-stranded RNA-mediated RNA interference (RNAi). We showed that targeting tardigrade homologs of essential developmental genes by RNAi produced embryonic lethality, whereas targeting green fluorescent protein did not. Disruption of gene functions appears to be relatively specific by two criteria: targeting distinct genes resulted in distinct phenotypes that were consistent with predicted gene functions and by RT-PCR, RNAi reduced the level of a target mRNA and not a control mRNA. These studies represent the first evidence that gene functions can be disrupted by RNAi in the phylum Tardigrada. Our results form a platform for dissecting tardigrade gene functions for understanding the evolution of developmental mechanisms and survival in extreme environments.

  1. Novel origin of lamin-derived cytoplasmic intermediate filaments in tardigrades

    Science.gov (United States)

    Hering, Lars; Bouameur, Jamal-Eddine; Reichelt, Julian; Magin, Thomas M; Mayer, Georg

    2016-01-01

    Intermediate filament (IF) proteins, including nuclear lamins and cytoplasmic IF proteins, are essential cytoskeletal components of bilaterian cells. Despite their important role in protecting tissues against mechanical force, no cytoplasmic IF proteins have been convincingly identified in arthropods. Here we show that the ancestral cytoplasmic IF protein gene was lost in the entire panarthropod (onychophoran + tardigrade + arthropod) rather than arthropod lineage and that nuclear, lamin-derived proteins instead acquired new cytoplasmic roles at least three times independently in collembolans, copepods, and tardigrades. Transcriptomic and genomic data revealed three IF protein genes in the tardigrade Hypsibius dujardini, one of which (cytotardin) occurs exclusively in the cytoplasm of epidermal and foregut epithelia, where it forms belt-like filaments around each epithelial cell. These results suggest that a lamin derivative has been co-opted to enhance tissue stability in tardigrades, a function otherwise served by cytoplasmic IF proteins in all other bilaterians. DOI: http://dx.doi.org/10.7554/eLife.11117.001 PMID:26840051

  2. Evidence for extensive horizontal gene transfer from the draft genome of a tardigrade.

    Science.gov (United States)

    Boothby, Thomas C; Tenlen, Jennifer R; Smith, Frank W; Wang, Jeremy R; Patanella, Kiera A; Nishimura, Erin Osborne; Tintori, Sophia C; Li, Qing; Jones, Corbin D; Yandell, Mark; Messina, David N; Glasscock, Jarret; Goldstein, Bob

    2015-12-29

    Horizontal gene transfer (HGT), or the transfer of genes between species, has been recognized recently as more pervasive than previously suspected. Here, we report evidence for an unprecedented degree of HGT into an animal genome, based on a draft genome of a tardigrade, Hypsibius dujardini. Tardigrades are microscopic eight-legged animals that are famous for their ability to survive extreme conditions. Genome sequencing, direct confirmation of physical linkage, and phylogenetic analysis revealed that a large fraction of the H. dujardini genome is derived from diverse bacteria as well as plants, fungi, and Archaea. We estimate that approximately one-sixth of tardigrade genes entered by HGT, nearly double the fraction found in the most extreme cases of HGT into animals known to date. Foreign genes have supplemented, expanded, and even replaced some metazoan gene families within the tardigrade genome. Our results demonstrate that an unexpectedly large fraction of an animal genome can be derived from foreign sources. We speculate that animals that can survive extremes may be particularly prone to acquiring foreign genes.

  3. Evidence for extensive horizontal gene transfer from the draft genome of a tardigrade

    Science.gov (United States)

    Boothby, Thomas C.; Tenlen, Jennifer R.; Smith, Frank W.; Wang, Jeremy R.; Patanella, Kiera A.; Osborne Nishimura, Erin; Tintori, Sophia C.; Li, Qing; Jones, Corbin D.; Yandell, Mark; Glasscock, Jarret; Goldstein, Bob

    2015-01-01

    Horizontal gene transfer (HGT), or the transfer of genes between species, has been recognized recently as more pervasive than previously suspected. Here, we report evidence for an unprecedented degree of HGT into an animal genome, based on a draft genome of a tardigrade, Hypsibius dujardini. Tardigrades are microscopic eight-legged animals that are famous for their ability to survive extreme conditions. Genome sequencing, direct confirmation of physical linkage, and phylogenetic analysis revealed that a large fraction of the H. dujardini genome is derived from diverse bacteria as well as plants, fungi, and Archaea. We estimate that approximately one-sixth of tardigrade genes entered by HGT, nearly double the fraction found in the most extreme cases of HGT into animals known to date. Foreign genes have supplemented, expanded, and even replaced some metazoan gene families within the tardigrade genome. Our results demonstrate that an unexpectedly large fraction of an animal genome can be derived from foreign sources. We speculate that animals that can survive extremes may be particularly prone to acquiring foreign genes. PMID:26598659

  4. Expression profiling and cross-species RNA interference (RNAi of desiccation-induced transcripts in the anhydrobiotic nematode Aphelenchus avenae

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    Culleton Bridget A

    2010-01-01

    Full Text Available Abstract Background Some organisms can survive extreme desiccation by entering a state of suspended animation known as anhydrobiosis. The free-living mycophagous nematode Aphelenchus avenae can be induced to enter anhydrobiosis by pre-exposure to moderate reductions in relative humidity (RH prior to extreme desiccation. This preconditioning phase is thought to allow modification of the transcriptome by activation of genes required for desiccation tolerance. Results To identify such genes, a panel of expressed sequence tags (ESTs enriched for sequences upregulated in A. avenae during preconditioning was created. A subset of 30 genes with significant matches in databases, together with a number of apparently novel sequences, were chosen for further study. Several of the recognisable genes are associated with water stress, encoding, for example, two new hydrophilic proteins related to the late embryogenesis abundant (LEA protein family. Expression studies confirmed EST panel members to be upregulated by evaporative water loss, and the majority of genes was also induced by osmotic stress and cold, but rather fewer by heat. We attempted to use RNA interference (RNAi to demonstrate the importance of this gene set for anhydrobiosis, but found A. avenae to be recalcitrant with the techniques used. Instead, therefore, we developed a cross-species RNAi procedure using A. avenae sequences in another anhydrobiotic nematode, Panagrolaimus superbus, which is amenable to gene silencing. Of 20 A. avenae ESTs screened, a significant reduction in survival of desiccation in treated P. superbus populations was observed with two sequences, one of which was novel, while the other encoded a glutathione peroxidase. To confirm a role for glutathione peroxidases in anhydrobiosis, RNAi with cognate sequences from P. superbus was performed and was also shown to reduce desiccation tolerance in this species. Conclusions This study has identified and characterised the

  5. Comparative Investigation of Copper Tolerance and Identification of Putative Tolerance Related Genes in Tardigrades

    Science.gov (United States)

    Hygum, Thomas L.; Fobian, Dannie; Kamilari, Maria; Jørgensen, Aslak; Schiøtt, Morten; Grosell, Martin; Møbjerg, Nadja

    2017-01-01

    Tardigrades are microscopic aquatic animals renowned for their tolerance toward extreme environmental conditions. The current study is the first to investigate their tolerance toward heavy metals and we present a novel tardigrade toxicant tolerance assay based on activity assessments as a measure of survival. Specifically, we compare tolerance toward copper in four species representing different evolutionary lineages, habitats and adaptation strategies, i.e., a marine heterotardigrade, Echiniscoides sigismundi, a limno-terrestrial heterotardigrade, Echiniscus testudo, a limno-terrestrial eutardigrade, Ramazzottius oberhaeuseri, and a marine eutardigrade, Halobiotus crispae. The latter was sampled at a time of year, when the population is predominantly represented by aberrant P1 cysts, while the other species were in normal active states prior to exposure. Based on volume measurements and a general relation between body mass and copper tolerance, expected tardigrade EC50 values were estimated at 0.5–2 μg l−1. Following 24 h of exposure, tolerance was high with no apparent link to lineage or habitat. EC50s (95% CI), 24 h after exposure, were estimated at 178 (168–186) and 310 (295–328) μg l−1, respectively, for E. sigismundi and R. oberhaeuseri, whereas E. testudo and H. crispae were less affected. Highest tolerance was observed in H. crispae with a mean ± s.e.m. activity of 77 ± 2% (n = 3) 24 h after removal from ~3 mg l−1 copper, suggesting that tardigrade cysts have increased tolerance toward toxicants. In order to identify putative tolerance related genes, an E. sigismundi transcriptome was searched for key enzymes involved in osmoregulation, antioxidant defense and copper metabolism. We found high expression of Na/K ATPase and carbonic anhydrase, known targets for copper. Our transcriptome, furthermore, revealed high expression of antioxidant enzymes, copper transporters, ATOX1, and a Cu-ATPase. In summary, our results indicate that tardigrades

  6. The impact of fire on terrestrial tardigrade biodiversity: a first case-study from Portugal

    Directory of Open Access Journals (Sweden)

    Filipe Vicente

    2013-05-01

    Full Text Available Currently, loss of habitat is the greatest threat to biodiversity, yet little is known about its effect on microscopic animal taxa, such as Tardigrada. One of the causes of habitat destruction is forest fire, both natural and anthropogenic. The latter is commonly used in agriculture to kill insect pests, as a soil preparation, or conservation to create habitat mosaics. In Portugal, 42% of fire frequency is anthropogenic. There is no consensus on the impact of fires on biodiversity, with studies pointing towards different conclusions. Different methods and target taxonomic study groups may partly explain this paradigm. This study is the first into possible effects of habitat destruction on tardigrade populations, in which we analysed the taxonomic and genetic variations of tardigrades from a fire affected location in a Portuguese natural park. Sampling was performed over a 10-year period, from 2000 to 2010. The location was affected by a small fire in 1998 and a big fire in 2003. A total of 11 species from nine separate genera was recorded, from which 19 cox1 haplotypes were identified. Our data suggest a negative effect of a forest fire on tardigrade populations. Taxonomic and genetic richness, as well as abundance show lower levels in the years after a fire, compared with the preceding years. Additionally, the population recovered visibly faster after the small fire than after the bigger one. This is consistent with larger fires destroying larger forest areas, leaving fewer animals at a farther distance available for re-colonisation. Most species found before the main fire are also found after it, indicating these tardigrades have a high recolonisation capability. However, only three of all recorded haplotypes were found both pre and post the main fire, which indicates genetic diversity loss as a direct consequence of fire. Therefore, we conclude that habitat destruction by means of forest fire has a detrimental effect on tardigrade

  7. The tardigrade Hypsibius dujardini, a new model for studying the evolution of development.

    Science.gov (United States)

    Gabriel, Willow N; McNuff, Robert; Patel, Sapna K; Gregory, T Ryan; Jeck, William R; Jones, Corbin D; Goldstein, Bob

    2007-12-15

    Studying development in diverse taxa can address a central issue in evolutionary biology: how morphological diversity arises through the evolution of developmental mechanisms. Two of the best-studied developmental model organisms, the arthropod Drosophila and the nematode Caenorhabditis elegans, have been found to belong to a single protostome superclade, the Ecdysozoa. This finding suggests that a closely related ecdysozoan phylum could serve as a valuable model for studying how developmental mechanisms evolve in ways that can produce diverse body plans. Tardigrades, also called water bears, make up a phylum of microscopic ecdysozoan animals. Tardigrades share many characteristics with C. elegans and Drosophila that could make them useful laboratory models, but long-term culturing of tardigrades historically has been a challenge, and there have been few studies of tardigrade development. Here, we show that the tardigrade Hypsibius dujardini can be cultured continuously for decades and can be cryopreserved. We report that H. dujardini has a compact genome, a little smaller than that of C. elegans or Drosophila, and that sequence evolution has occurred at a typical rate. H. dujardini has a short generation time, 13-14 days at room temperature. We have found that the embryos of H. dujardini have a stereotyped cleavage pattern with asymmetric cell divisions, nuclear migrations, and cell migrations occurring in reproducible patterns. We present a cell lineage of the early embryo and an embryonic staging series. We expect that these data can serve as a platform for using H. dujardini as a model for studying the evolution of developmental mechanisms.

  8. Recovery and reproduction of an Antarctic tardigrade retrieved from a moss sample frozen for over 30 years.

    Science.gov (United States)

    Tsujimoto, Megumu; Imura, Satoshi; Kanda, Hiroshi

    2016-02-01

    Long-term survival has been one of the most studied of the extraordinary physiological characteristics of cryptobiosis in micrometazoans such as nematodes, tardigrades and rotifers. In the available studies of long-term survival of micrometazoans, instances of survival have been the primary observation, and recovery conditions of animals or subsequent reproduction are generally not reported. We therefore documented recovery conditions and reproduction immediately following revival of tardigrades retrieved from a frozen moss sample collected in Antarctica in 1983 and stored at -20 °C for 30.5 years. We recorded recovery of two individuals and development of a separate egg of the Antarctic tardigrade, Acutuncus antarcticus, providing the longest records of survival for tardigrades as animals or eggs. One of the two resuscitated individuals and the hatchling successfully reproduced repeatedly after their recovery from long-term cryptobiosis. This considerable extension of the known length of long-term survival of tardigrades recorded in our study is interpreted as being associated with the minimum oxidative damage likely to have resulted from storage under stable frozen conditions. The long recovery times of the revived tardigrades observed is suggestive of the requirement for repair of damage accrued over 30 years of cryptobiosis. Further more detailed studies will improve understanding of mechanisms and conditions underlying the long-term survival of cryptobiotic organisms.

  9. Tardigrade eggs and exuviae in Antarctic lake sediments: insights into Holocene dynamics and origins of the fauna

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    Sandra J. MCINNES

    2007-09-01

    Full Text Available The preservation of tardigrade eggs and exuviae in Antarctic lake sediments provided an opportunity to assess post-glacial colonisation and Holocene tardigrade dynamics on the southern continent. Tardigrade eggs were recovered from five lakes, two from the maritime Antarctic and three from continental Antarctica. Eggs were identified from the following species: Dactylobiotus cf. ambiguus, Macrobiotus furciger, Macrobiotus blocki, Minibiotus weinerorum and Acutuncus antarcticus. Other, unornamented eggs were also observed. The preservation of some of these eggs in exuviae allowed identification to at least genus. Significant variations were observed in egg abundance within the sediment of each lake, and in one lake a species (Dactylobiotus cf. ambiguus became locally extinct, probably as the result of penguin-associated eutrophication. Tardigrades generally did not become abundant for a considerable period after the lakes’ formation. The presence of an in-part endemic fauna is consistent with slow colonisation from Antarctic sources rather than wind transport from extra-continental sites. Tardigrade eggs appear to be abundant in high-latitude lake sediments, and greater use could be made of these records when evaluating tardigrade dynamics during the Holocene.

  10. Tardigrades living in extreme environments have naturally selected prerequisites useful to space conquer

    Science.gov (United States)

    Guidetti, Roberto; Tiziana, Altiero; Cesari, Michele; Rizzo, Angela Maria; Bertolani, Roberto; Galletta, Giuseppe; Dalessandro, Maurizio; Rebecchi, Lorena

    Extreme habitats are highly selective and can host only living organisms possessing specific adaptations to stressors. Among extreme habitats, space environment has particular charac-teristics of radiations, vacuum, microgravity and temperature, which induce rapid changes in living systems. Consequently, the response of multicellular complex organisms, able to colo-nize extreme environments, to space stresses can give very useful information on the ability to withstand a single stress or stress combinations. This knowledge on changes in living systems in space, with their similarity to the ageing processes, offers the opportunity to improve human life both on Earth and in space. Even though experimentation in space has often been carried out using unicellular organisms, multicellular organisms are very relevant in order to develop the appropriate countermeasures to avoid the risks imposed by environmental space in humans. The little attention received by multicellular organisms is probably due, other than to difficul-ties in the manipulation of biological materials in space, to the presence of only few organisms with the potential to tolerate environmental space stresses. Among them, tardigrades are small invertebrates representing an attractive animal model to study adaptive strategies for surviving extreme environments, including space environment. Tardigrades are little known microscopic aquatic animals (250-800 m in body length) distributed in different environments (from the deep sea to high mountains and deserts all over the world), and frequently inhabiting very unstable and unpredictable habitats (e.g. interstices of mosses, lichens, leaf litter, freshwater ponds, cryoconite holes). Their ability to live in the extreme environments is related to a wide variety of their life histories and adaptive strategies. A widespread and crucial strategy is cryptobiosis, a form of quiescence. It includes strategies such as anhydrobiosis and cryobiosis, characterized by

  11. The tardigrade cuticle. I. Fine structure and the distribution of lipids.

    Science.gov (United States)

    Wright, J C

    1988-01-01

    Fine structure and lipid distribution are studied in cuticles of five tardigrade species using TEM and SEM. Double osmication using partitioning methods reveals a substantial lipid component in the intracuticle and in irregular granular regions within the procuticle. These results are substantiated by the loss of osmiophily following lipid extraction with chloroform and methanol. Other lipid components are revealed by osmication following unmasking of lipo-protein complexes with thymol. These occur in the outer epicuticle and in the trilaminar layer lying between the epi- and intracuticles. Anhydrous fixation of dehydrated tardigrades (tuns) reveals dense, superficial masses of osmiophilic material, apparently concentrated lumps of the surface mucopolysaccharide ('flocculent coat'). However, cryo-SEMs of tuns reveal similar dense aggregations which apparently exude from pores (not visible) and are removed by chloroform. These results suggest extruded lipids since the flocculent coat is unaffected by chloroform; likely functions of such lipids are discussed.

  12. First evidence of epithelial transport in tardigrades: a comparative investigation of organic anion transport.

    Science.gov (United States)

    Halberg, Kenneth Agerlin; Møbjerg, Nadja

    2012-02-01

    We investigated transport of the organic anion Chlorophenol Red (CPR) in the tardigrade Halobiotus crispae using a new method for quantifying non-fluorescent dyes. We compared the results acquired from the tardigrade with CPR transport data obtained from Malpighian tubules of the desert locust Schistocerca gregaria. CPR accumulated in the midgut lumen of H. crispae, indicating that organic anion transport takes place here. Our results show that CPR transport is inhibited by the mitochondrial un-coupler DNP (1 mmol l(-1); 81% reduction), the Na(+)/K(+)-ATPase inhibitor ouabain (10 mmol l(-1); 21% reduction) and the vacuolar H(+)-ATPase inhibitor bafilomycin (5 μmol l(-1); 21% reduction), and by the organic anions PAH (10 mmol l(-1); 44% reduction) and probenecid (10 mmol l(-1); 61% reduction, concentration-dependent inhibition). Transport by locust Malpighian tubules exhibits a similar pharmacological profile, albeit with markedly higher concentrations of CPR being reached in S. gregaria. Immunolocalization of the Na(+)/K(+)-ATPase α-subunit in S. gregaria revealed that this transporter is abundantly expressed and localized to the basal cell membranes. Immunolocalization data could not be obtained from H. crispae. Our results indicate that organic anion secretion by the tardigrade midgut is transporter mediated with likely candidates for the basolateral entry step being members of the Oat and/or Oatp transporter families. From our results, we cautiously suggest that apical H(+) and possibly basal Na(+)/K(+) pumps provide the driving force for the transport; the exact coupling between electrochemical gradients generated by the pumps and transport of ions, as well as the nature of the apical exit step, are unknown. This study is, to our knowledge, the first to show active epithelial transport in tardigrades.

  13. Tardigrades from Taiwan, with the description of a new species of Doryphoribius (Tardigrada, Hypsibiidae).

    Science.gov (United States)

    Li, Xiaochen; Li, Hongqun

    2008-05-01

    A total of eleven species of tardigrades from Taiwan are reported in this article. They belong to two classes, three orders, four families, and ten genera. Ten species are new records for Taiwan and one is new to science. Doryphoribius taiwanus sp. nov. is similar to Dor. mariae , but differs from it by larger body size, by conspicuous tubercles on the lateral side and dorsal sides of the body, by lacking gibbosities and undulations, by a narrower buccal tube, and by longer claws.

  14. RNA interference can be used to disrupt gene function in tardigrades

    OpenAIRE

    Tenlen, Jennifer R.; McCaskill, Shaina; Goldstein, Bob

    2012-01-01

    How morphological diversity arises is a key question in evolutionary developmental biology. As a long-term approach to address this question, we are developing the water bear Hypsibius dujardini (Phylum Tardigrada) as a model system. We expect that using a close relative of two well-studied models, Drosophila (Phylum Arthropoda) and Caenorhabditis elegans (Phylum Nematoda), will facilitate identifying genetic pathways relevant to understanding the evolution of development. Tardigrades are als...

  15. Space flight effects on antioxidant molecules in dry tardigrades: the TARDIKISS experiment.

    Science.gov (United States)

    Rizzo, Angela Maria; Altiero, Tiziana; Corsetto, Paola Antonia; Montorfano, Gigliola; Guidetti, Roberto; Rebecchi, Lorena

    2015-01-01

    The TARDIKISS (Tardigrades in Space) experiment was part of the Biokon in Space (BIOKIS) payload, a set of multidisciplinary experiments performed during the DAMA (Dark Matter) mission organized by Italian Space Agency and Italian Air Force in 2011. This mission supported the execution of experiments in short duration (16 days) taking the advantage of the microgravity environment on board of the Space Shuttle Endeavour (its last mission STS-134) docked to the International Space Station. TARDIKISS was composed of three sample sets: one flight sample and two ground control samples. These samples provided the biological material used to test as space stressors, including microgravity, affected animal survivability, life cycle, DNA integrity, and pathways of molecules working as antioxidants. In this paper we compared the molecular pathways of some antioxidant molecules, thiobarbituric acid reactive substances, and fatty acid composition between flight and control samples in two tardigrade species, namely, Paramacrobiotus richtersi and Ramazzottius oberhaeuseri. In both species, the activities of ROS scavenging enzymes, the total content of glutathione, and the fatty acids composition between flight and control samples showed few significant differences. TARDIKISS experiment, together with a previous space experiment (TARSE), further confirms that both desiccated and hydrated tardigrades represent useful animal tool for space research.

  16. No evidence for extensive horizontal gene transfer in the genome of the tardigrade Hypsibius dujardini.

    Science.gov (United States)

    Koutsovoulos, Georgios; Kumar, Sujai; Laetsch, Dominik R; Stevens, Lewis; Daub, Jennifer; Conlon, Claire; Maroon, Habib; Thomas, Fran; Aboobaker, Aziz A; Blaxter, Mark

    2016-05-03

    Tardigrades are meiofaunal ecdysozoans that are key to understanding the origins of Arthropoda. Many species of Tardigrada can survive extreme conditions through cryptobiosis. In a recent paper [Boothby TC, et al. (2015) Proc Natl Acad Sci USA 112(52):15976-15981], the authors concluded that the tardigrade Hypsibius dujardini had an unprecedented proportion (17%) of genes originating through functional horizontal gene transfer (fHGT) and speculated that fHGT was likely formative in the evolution of cryptobiosis. We independently sequenced the genome of H. dujardini As expected from whole-organism DNA sampling, our raw data contained reads from nontarget genomes. Filtering using metagenomics approaches generated a draft H. dujardini genome assembly of 135 Mb with superior assembly metrics to the previously published assembly. Additional microbial contamination likely remains. We found no support for extensive fHGT. Among 23,021 gene predictions we identified 0.2% strong candidates for fHGT from bacteria and 0.2% strong candidates for fHGT from nonmetazoan eukaryotes. Cross-comparison of assemblies showed that the overwhelming majority of HGT candidates in the Boothby et al. genome derived from contaminants. We conclude that fHGT into H. dujardini accounts for at most 1-2% of genes and that the proposal that one-sixth of tardigrade genes originate from functional HGT events is an artifact of undetected contamination.

  17. Stress response of a boreo-alpine species of tardigrade, Borealibius zetlandicus (Eutardigrada, Hypsibiidae

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    Michele CESARI

    2009-02-01

    Full Text Available Invertebrates living in extreme environments as well as those living under unpredictable habitat conditions must be able to survive severe environmental stresses bound to their habitats. Tardigrades represent a good animal model to analyze responses evolved by organisms to overcome extreme environmental stresses or to colonize extreme environments because they respond to desiccation or freezing in their habitats by entering cryptobiosis. The responses to environmental stresses have been evaluated almost exclusively in terrestrial tardigrades, while very little is known about the ability of limnic species to tolerate those stresses. This study evaluates the responses of the limnic boreo-alpine species Borealibius zetlandicus, under lab conditions, to stresses imposed by desiccation and temperature variation (freezing and heating. Our results indicate that active specimens are able to freeze, confirming the cryobiotic ability of this species. There is a negative correlation between survival and cooling rates. In contrast, no specimens of B. zetlandicus are able to survive desiccation. With regard to thermal tolerance, the animals show a high ability to resist heat-shock (LT50 = 33.0 ± 0.5 °C for a short time. This wide tolerance to different environmental parameters could be the reason for the wide distribution of the species. Due to the disjunct distribution of the species and to the potential presence of cryptic tardigrade species that could have different ecological and physiological responses, we decided to characterize the population studied from a molecular point of view by investigating its COI mtDNA sequences.

  18. Space Flight Effects on Antioxidant Molecules in Dry Tardigrades: The TARDIKISS Experiment

    Directory of Open Access Journals (Sweden)

    Angela Maria Rizzo

    2015-01-01

    Full Text Available The TARDIKISS (Tardigrades in Space experiment was part of the Biokon in Space (BIOKIS payload, a set of multidisciplinary experiments performed during the DAMA (Dark Matter mission organized by Italian Space Agency and Italian Air Force in 2011. This mission supported the execution of experiments in short duration (16 days taking the advantage of the microgravity environment on board of the Space Shuttle Endeavour (its last mission STS-134 docked to the International Space Station. TARDIKISS was composed of three sample sets: one flight sample and two ground control samples. These samples provided the biological material used to test as space stressors, including microgravity, affected animal survivability, life cycle, DNA integrity, and pathways of molecules working as antioxidants. In this paper we compared the molecular pathways of some antioxidant molecules, thiobarbituric acid reactive substances, and fatty acid composition between flight and control samples in two tardigrade species, namely, Paramacrobiotus richtersi and Ramazzottius oberhaeuseri. In both species, the activities of ROS scavenging enzymes, the total content of glutathione, and the fatty acids composition between flight and control samples showed few significant differences. TARDIKISS experiment, together with a previous space experiment (TARSE, further confirms that both desiccated and hydrated tardigrades represent useful animal tool for space research.

  19. Nature, source and function of pigments in tardigrades: in vivo raman imaging of carotenoids in Echiniscus blumi.

    Science.gov (United States)

    Bonifacio, Alois; Guidetti, Roberto; Altiero, Tiziana; Sergo, Valter; Rebecchi, Lorena

    2012-01-01

    Tardigrades are microscopic aquatic animals with remarkable abilities to withstand harsh physical conditions such as dehydration or exposure to harmful highly energetic radiation. The mechanisms responsible for such robustness are presently little known, but protection against oxidative stresses is thought to play a role. Despite the fact that many tardigrade species are variously pigmented, scarce information is available about this characteristic. By applying Raman micro-spectroscopy on living specimens, pigments in the tardigrade Echiniscus blumi are identified as carotenoids, and their distribution within the animal body is visualized. The dietary origin of these pigments is demonstrated, as well as their presence in the eggs and in eye-spots of these animals, together with their absence in the outer layer of the animal (i.e., cuticle and epidermis). Using in-vivo semi-quantitative Raman micro-spectroscopy, a decrease in carotenoid content is detected after inducing oxidative stress, demonstrating that this approach can be used for studying the role of carotenoids in oxidative stress-related processes in tardigrades. This approach could be thus used in further investigations to test several hypotheses concerning the function of these carotenoids in tardigrades as photo-protective pigments against ionizing radiations or as antioxidants defending these organisms against the oxidative stress occurring during desiccation processes.

  20. Water bears in the Anthropocene: a comparison of urban and woodland tardigrade (Phylum Tardigrada communities in Southwestern Louisiana, USA

    Directory of Open Access Journals (Sweden)

    Harry A. Meyer

    2013-05-01

    Full Text Available Humans have had such a profound effect on global ecosystems, including biodiversity, that Anthropocene is being increasingly used as a chronological term to mark the period of greatest human impact. No areas show the effect of human impact on the environment more than cities, which often have novel combinations of species in unique communities. Tardigrades (Phylum Tardigrada have often been collected in cities, but studies dedicated to urban tardigrade biodiversity are few, and those comparing urban diversity with nearby rural or natural sites even fewer. In this paper we compare the diversity and abundance of tardigrade species in Lake Charles with a nearby forested nonurban site, Sam Houston Jones State Park (SHJSP. Although tardigrade density did not differ significantly between Lake Charles and SHJSP, species richness and diversity were greater in SHJSP (17 species, H1=3.01 than in Lake Charles (8 species, H1=1.30. All but one species found in Lake Charles also occurred in SHJSP. The number of species found in Lake Charles lies within the range (5-10 found in previous urban surveys. All tardigrade studies comparing urban with nearby nonurban habitats have found lower species richness in cities.

  1. Nature, source and function of pigments in tardigrades: in vivo raman imaging of carotenoids in Echiniscus blumi.

    Directory of Open Access Journals (Sweden)

    Alois Bonifacio

    Full Text Available Tardigrades are microscopic aquatic animals with remarkable abilities to withstand harsh physical conditions such as dehydration or exposure to harmful highly energetic radiation. The mechanisms responsible for such robustness are presently little known, but protection against oxidative stresses is thought to play a role. Despite the fact that many tardigrade species are variously pigmented, scarce information is available about this characteristic. By applying Raman micro-spectroscopy on living specimens, pigments in the tardigrade Echiniscus blumi are identified as carotenoids, and their distribution within the animal body is visualized. The dietary origin of these pigments is demonstrated, as well as their presence in the eggs and in eye-spots of these animals, together with their absence in the outer layer of the animal (i.e., cuticle and epidermis. Using in-vivo semi-quantitative Raman micro-spectroscopy, a decrease in carotenoid content is detected after inducing oxidative stress, demonstrating that this approach can be used for studying the role of carotenoids in oxidative stress-related processes in tardigrades. This approach could be thus used in further investigations to test several hypotheses concerning the function of these carotenoids in tardigrades as photo-protective pigments against ionizing radiations or as antioxidants defending these organisms against the oxidative stress occurring during desiccation processes.

  2. Tardigrade Resistance to Space Effects: first results of experiments on the LIFE-TARSE mission on FOTON-M3 (September 2007).

    Science.gov (United States)

    Rebecchi, Lorena; Altiero, Tiziana; Guidetti, Roberto; Cesari, Michele; Bertolani, Roberto; Negroni, Manuela; Rizzo, Angela M

    2009-01-01

    The Tardigrade Resistance to Space Effects (TARSE) project, part of the mission LIFE on FOTON-M3, analyzed the effects of the space environment on desiccated and active tardigrades. Four experiments were conducted in which the eutardigrade Macrobiotus richtersi was used as a model species. Desiccated (in leaf litter or on paper) and hydrated tardigrades (fed or starved) were flown on FOTON-M3 for 12 days in September 2007, which, for the first time, allowed for a comparison of the effects of the space environment on desiccated and on active animals. In this paper, we report the experimental design of the TARSE project and data on tardigrade survival. In addition, data on survival, genomic DNA integrity, Hsp70 and Hsp90 expressions, antioxidant enzyme contents and activities, and life history traits were compared between hydrated starved tardigrades flown in space and those maintained on Earth as a control. Microgravity and radiation had no effect on survival or DNA integrity of active tardigrades. Hsp expressions between the animals in space and the control animals on Earth were similar. Spaceflight induced an increase of glutathione content and its related enzymatic activities. Catalase and superoxide dismutase decreased with spaceflight, and thiobarbituric acid reactive substances did not change. During the flight mission, tardigrades molted, and females laid eggs. Several eggs hatched, and the newborns exhibited normal morphology and behavior.

  3. Tardigrade Resistance to Space Effects: First Results of Experiments on the LIFE-TARSE Mission on FOTON-M3 (September 2007)

    Science.gov (United States)

    Rebecchi, Lorena; Altiero, Tiziana; Guidetti, Roberto; Cesari, Michele; Bertolani, Roberto; Negroni, Manuela; Rizzo, Angela M.

    2009-08-01

    The Tardigrade Resistance to Space Effects (TARSE) project, part of the mission LIFE on FOTON-M3, analyzed the effects of the space environment on desiccated and active tardigrades. Four experiments were conducted in which the eutardigrade Macrobiotus richtersi was used as a model species. Desiccated (in leaf litter or on paper) and hydrated tardigrades (fed or starved) were flown on FOTON-M3 for 12 days in September 2007, which, for the first time, allowed for a comparison of the effects of the space environment on desiccated and on active animals. In this paper, we report the experimental design of the TARSE project and data on tardigrade survival. In addition, data on survival, genomic DNA integrity, Hsp70 and Hsp90 expressions, antioxidant enzyme contents and activities, and life history traits were compared between hydrated starved tardigrades flown in space and those maintained on Earth as a control. Microgravity and radiation had no effect on survival or DNA integrity of active tardigrades. Hsp expressions between the animals in space and the control animals on Earth were similar. Spaceflight induced an increase of glutathione content and its related enzymatic activities. Catalase and superoxide dismutase decreased with spaceflight, and thiobarbituric acid reactive substances did not change. During the flight mission, tardigrades molted, and females laid eggs. Several eggs hatched, and the newborns exhibited normal morphology and behavior.

  4. Genetic diversity in the parthenogenetic reproducing tardigrade Echiniscus testudo (Heterotardigrada: Echiniscoidea

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    Aslak Jørgensen

    2013-04-01

    Full Text Available Little is known about the genetic structure of microscopic animals from mosses and lichens. A few studies have investigated the geographic variation in tardigrades from mosses, but so far no study has investigated the intra-population or local clonal lineage variation. Echiniscus testudo (Echiniscoidea: Echiniscidae belongs to a large cosmopolitan genus of terrestrial tardigrades comprising more than 150 species. It is a common tardigrade in mosses in the temperate part of the Northern hemisphere, and is highly tolerant of desiccation and freezing. In a previous study, we reported a maximum of 1.28% sequence variation (uncorrected p-distance in cytochrome c oxidase subunit I (COI haplotypes between clonal lineages covering a large geographical area. However, in this previous study we used pooled specimens to constitute a sample, and the genetic diversity from single specimens within a locality therefore remains unknown. Accordingly, the present study investigates the COI sequence variation and haplotype diversity between single specimens of E. testudo collected at three Danish localities, separated by 80 m and 186 km. A total of 10 COI haplotypes were found in the present study (Et2, Et3, Et9, Et12-Et18; only three of these were previously reported (Et2, Et3 and Et9. The uncorrected COI sequence diversity ranged between 0-2.07%, with haplotype Et18 having the highest genetic difference. The second most variable haplotypes (Et14, Et15, and Et17 all showed a maximum diversity of 1.19% compared to the other haplotypes. No general pattern of haplotype distribution was evident. Our data suggest that E. testudo has dispersed across the Baltic sea as haplotypes Et3, Et13 and Et14 are present at all three localities. The most likely dispersal mode is passive wind dispersal in the cryptobiotic tun stage. The current study emphasises that numerous sequences from single specimens are needed to describe the genetic diversity within single moss cushions.

  5. Segmental expression of Pax3/7 and engrailed homologs in tardigrade development.

    Science.gov (United States)

    Gabriel, Willow N; Goldstein, Bob

    2007-06-01

    How morphological diversity arises through evolution of gene sequence is a major question in biology. In Drosophila, the genetic basis for body patterning and morphological segmentation has been studied intensively. It is clear that some of the genes in the Drosophila segmentation program are functioning similarly in certain other taxa, although many questions remain about when these gene functions arose and which taxa use these genes similarly to establish diverse body plans. Tardigrades are an outgroup to arthropods in the Ecdysozoa and, as such, can provide insight into how gene functions have evolved among the arthropods and their close relatives. We developed immunostaining methods for tardigrade embryos, and we used cross-reactive antibodies to investigate the expression of homologs of the pair-rule gene paired (Pax3/7) and the segment polarity gene engrailed in the tardigrade Hypsibius dujardini. We find that in H. dujardini embryos, Pax3/7 protein localizes not in a pair-rule pattern but in a segmentally iterated pattern, after the segments are established, in regions of the embryo where neurons later arise. Engrailed protein localizes in the posterior ectoderm of each segment before ectodermal segmentation is apparent. Together with previous results from others, our data support the conclusions that the pair-rule function of Pax3/7 is specific to the arthropods, that some of the ancient functions of Pax3/7 and Engrailed in ancestral bilaterians may have been in neurogenesis, and that Engrailed may have a function in establishing morphological boundaries between segments that is conserved at least among the Panarthropoda.

  6. Evaluation of cryoanalysis as a tool for analyzing elemental distribution in "live" tardigrades using micro-PIXE

    Science.gov (United States)

    Nilsson, E. J. C.; Pallon, J.; Przybylowicz, W. J.; Wang, Y. D.; Jönsson, K. I.

    2014-08-01

    Although heavy on labor and equipment, thus not often applied, cryoanalysis of frozen hydrated biological specimens can provide information that better reflects the living state of the organism, compared with analysis in the freeze-dried state. In this paper we report a study where the cryoanalysis facility with cryosectioning capabilities at Materials Research Department, iThemba LABS, South Africa was employed to evaluate the usefulness of combining three ion beam analytical methods (μPIXE, RBS and STIM) to analyze a biological target where a better elemental compositional description is needed - the tardigrade. Imaging as well as quantification results are of interest. In a previous study, the element composition and redistribution of elements in the desiccated and active states of two tardigrade species was investigated. This study included analysis of both whole and sectioned tardigrades, and the aim was to analyze each specimen twice; first frozen hydrated and later freeze-dried. The combination of the three analytical techniques proved useful: elements from C to Rb in the tardigrades could be determined and certain differences in distribution of elements between the frozen hydrated and the freeze-dried states were observed. RBS on frozen hydrated specimens provided knowledge of matrix elements.

  7. Evaluation of cryoanalysis as a tool for analyzing elemental distribution in “live” tardigrades using micro-PIXE

    Energy Technology Data Exchange (ETDEWEB)

    Nilsson, E.J.C., E-mail: charlotta.nilsson@nuclear.lu.se [Division of Nuclear Physics, Department of Physics, Lund University, Box 118, SE-221 00 Lund (Sweden); Pallon, J., E-mail: jan.pallon@nuclear.lu.se [Division of Nuclear Physics, Department of Physics, Lund University, Box 118, SE-221 00 Lund (Sweden); Przybylowicz, W.J., E-mail: przybylowicz@tlabs.ac.za [Materials Research Department, iThemba LABS, National Research Foundation, P.O. Box 722, Somerset West 7129 (South Africa); AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, Al. A. Mickiewicza 30, 30-059 Krakow (Poland); Wang, Y.D., E-mail: yaodongw@hotmail.com [Materials Research Department, iThemba LABS, National Research Foundation, P.O. Box 722, Somerset West 7129 (South Africa); Jönsson, K.I., E-mail: ingemar.jonsson@hkr.se [School of Education and Environment, Kristianstad University, SE-291 88 Kristianstad (Sweden); Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, SE-106 91 Stockholm (Sweden)

    2014-08-01

    Although heavy on labor and equipment, thus not often applied, cryoanalysis of frozen hydrated biological specimens can provide information that better reflects the living state of the organism, compared with analysis in the freeze-dried state. In this paper we report a study where the cryoanalysis facility with cryosectioning capabilities at Materials Research Department, iThemba LABS, South Africa was employed to evaluate the usefulness of combining three ion beam analytical methods (μPIXE, RBS and STIM) to analyze a biological target where a better elemental compositional description is needed – the tardigrade. Imaging as well as quantification results are of interest. In a previous study, the element composition and redistribution of elements in the desiccated and active states of two tardigrade species was investigated. This study included analysis of both whole and sectioned tardigrades, and the aim was to analyze each specimen twice; first frozen hydrated and later freeze-dried. The combination of the three analytical techniques proved useful: elements from C to Rb in the tardigrades could be determined and certain differences in distribution of elements between the frozen hydrated and the freeze-dried states were observed. RBS on frozen hydrated specimens provided knowledge of matrix elements.

  8. The tardigrade fauna of Australian marine caves: with descriptions of nine new species of Arthrotardigrada.

    Science.gov (United States)

    Jørgensen, Aslak; Boesgaard, Tom M; Møbjerg, Nadja; Kristensen, Reinhardt M

    2014-05-28

    Marine caves are known to support a rich macrofauna; however, few studies have focused on meiofauna. Marine cave meiofaunal tardigrades have been reported from Japan and the Mediterranean Sea and a preliminary list of species including a redescription of Actinarctus neretinus Grimaldi de Zio, D'Addabbo Gallo, Morone De Lucia, Vaccarella and Grimaldi, 1982 was reported from Fish Rock Cave and Jim's Cave on the coast of Australia. This study is the fourth in a series describing the unique meiofauna in two Australian submarine caves located off the coast of New South Wales, describing nine new species.        Only 67 tardigrades were collected from the two caves, yet these contained a high diversity of at least 16 different species which are quite different in the two caves. The fauna includes nine arthrotardigrade genera: Actinarctus, Batillipes, Dipodarctus, Halechiniscus, Raiarctus, Styraconyx, Tanarctus, Tholoarctus, and Wingstrandarctus. This fauna is different from that reported for the high energy beaches along the East Coast of Australia.        We describe nine new species comprising a single batillipedid and eight halechiniscids: Batillipes solitarius nov. sp., Dipodarctus australiensis nov. sp., Dipodarctus susannae nov. sp., Raiarctus jesperi nov. sp., Raiarctus katrinae nov. sp., Tanarctus hirsutospinosus nov. sp., Tholoarctus oleseni nov. sp., Wingstrandarctus stinae nov. sp. and Wingstrandarctus unsculptus nov. sp.

  9. Life-history traits in the tardigrade species Paramacrobiotus kenianus and Paramacrobiotus palaui

    Directory of Open Access Journals (Sweden)

    Ralph O. Schill

    2013-05-01

    Full Text Available Although tardigrades have been studied for a long time, little is still known about their life-history traits. In the present study, two populations of the parthenogenetic African tardigrade species Paramacrobiotus kenianus, and the parthenogenetic species Paramacrobiotus palaui from the pacific islands of Palau were examined and analysed related to their life-history traits under laboratory conditions. The longevity in days (mean±SD do not vary between the P. kenianus population (I (125±35 and (II (141±54, but P. palaui showed a significant shorter longevity (97±31. A recorded maximum age of 212 days was reached by P. kenianus population (II. P. kenianus population (I laid 138±71 eggs (mean±SD and population (II 124±78 eggs (mean±SD during their life, whereas P. palaui laid only 42±54 eggs (mean±SD. While the hatching time was similar in all species, starting after 6 to 9 days, the hatching rate in P. kenianus population (I was 33%, compared with 51% of population (II and 54% of P. palaui.

  10. Neuroanatomy of Halobiotus crispae (Eutardigrada: Hypsibiidae): Tardigrade brain structure supports the clade Panarthropoda.

    Science.gov (United States)

    Persson, Dennis K; Halberg, Kenneth A; Jørgensen, Aslak; Møbjerg, Nadja; Kristensen, Reinhardt M

    2012-11-01

    The position of Tardigrada in the animal tree of life is a subject that has received much attention, but still remains controversial. Whereas some think tardigrades should be categorized as cycloneuralians, most authors argue in favor of a phylogenetic position within Panarthropoda as a sister group to Arthropoda or Arthropoda + Onychophora. Thus far, neither molecular nor morphological investigations have provided conclusive results as to the tardigrade sister group relationships. In this article, we present a detailed description of the nervous system of the eutardigrade Halobiotus crispae, using immunostainings, confocal laser scanning microscopy, and computer-aided three-dimensional reconstructions supported by transmission electron microscopy. We report details regarding the structure of the brain as well as the ganglia of the ventral nerve cord. In contrast to the newest investigation, we find transverse commissures in the ventral ganglia, and our data suggest that the brain is partitioned into at least three lobes. Additionally, we can confirm the existence of a subpharyngeal ganglion previously called subesophagal ganglion. According to our results, the original suggestion of a brain comprised of at least three parts cannot be rejected, and the data presented supports a sister group relationship of Tardigrada to 1) Arthropoda or 2) Onychophora or 3) Arthropoda + Onychophora.

  11. Response of soil nematodes, rotifers and tardigrades to three levels of season-long sulfur dioxide exposures

    Energy Technology Data Exchange (ETDEWEB)

    Leetham, J.W.; McNary, T.J.; Dodd, J.L.; Lauenroth, W.K.

    1982-05-01

    Soil nematode, rotifer, and tardigrade populations were sampled in field plots of native northern mixed prairie in southeastern Montana from 1977 to 1979. The field plots were exposed to season-long fumigation with controlled low-levels of SO/sub 2/ throughout the growing seasons (April-October). Two field sites were used, one fumigated for five seasons (1975-1979) and the other for four (1976-1979). Seasonal average SO/sub 2/ concentrations ranged from control (< 1 pphm) to approximately 7 pphm. Soil fauna were sampled by taking soil cores and extracting them by the Baermann wet funnel technique.Total counts were made for tardigrades and rotifers while nematodes were divided into three groups - stylet bearers (Tylenchida-Dorylimida), non-stylet bearers, and the predatory Mononchida. Consistent trends of substantial reductions in tardigrade populations occurred in all treated plots in all years; however, statistical significance was achieved only in 1979 when sample size and individual core size were substantially increased. Tardigrades were found to be restricted almost completely to the surface two centimeters of the soil profile. Significant population reductions in the treated plots of both sites were found for non-stylet bearing nematodes in 1977 only. Stylet bearing types and predaceous Mononchida appeared unaffected by the SO/sub 2/ as were the soil rotifers, although slight but consistent trends of reduction in rotifers occurred in the highest treatments in 1977 and 1978. Both nematodes and rotifers were distributed primarily in the 0 to 10 cm layer of the soil profile but not restricted to the soil surface as much as the tardigrades. Implications of the responses to SO/sub 2/ and vertical distributions of the three groups are discussed.

  12. New tardigrade records for the Baltic states with a description of Minibiotus formosus sp. n. (Eutardigrada, Macrobiotidae).

    Science.gov (United States)

    Zawierucha, Krzysztof; Dziamięcki, Jakub; Jakubowska, Natalia; Michalczyk, Lukasz; Kaczmarek, Lukasz

    2014-01-01

    In sixteen moss, lichen and mixed (moss/lichen) samples, collected from Estonia, Latvia and Lithuania, 291 specimens, 48 simplexes, including one exuvium with 6 eggs, and 8 free-laid eggs of eutardigrades were found. In total, 17 species, together with one new to science, were identified (all are new records for the Baltic states): Astatumen bartosi, Diphascon (Adropion) prorsirostre, D. (Diphascon) bullatum, D. (D.) pingue pingue, D. (D.) recamieri, D. (D.) rugosum, Hypsibius convergens, H. dujardini, H. cf. scabropygus, Isohypsibius ronsisvallei, I. sattleri, Macrobiotus harmsworthi harmsworthi, M. hufelandi hufelandi, Milnesium asiaticum, Milnesium tardigradum tardigradum, Minibiotus formosus sp. n. and Paramacrobiotus richtersi. The new species is most similar to Minibiotus gumersindoi, but differs from it mainly by the presence of two types of cuticular pores, the absence of a triangular or pentagonal arrangement of pores above a single large pore on legs, the presence of granulation on all legs and a different macroplacoid length sequence. In this paper we also provide photographs and morphometrics of H. cf. scabropygus.

  13. New tardigrade records for the Baltic states with a description of Minibiotus formosus sp. n. (Eutardigrada, Macrobiotidae

    Directory of Open Access Journals (Sweden)

    Krzysztof Zawierucha

    2014-05-01

    Full Text Available In sixteen moss, lichen and mixed (moss/lichen samples, collected from Estonia, Latvia and Lithuania, 291 specimens, 48 simplexes, including one exuvium with 6 eggs, and 8 free-laid eggs of eutardigrades were found. In total, 17 species, together with one new to science, were identified (all are new records for the Baltic states: Astatumen bartosi, Diphascon (Adropion prorsirostre, D. (Diphascon bullatum, D. (D. pingue pingue, D. (D. recamieri, D. (D. rugosum, Hypsibius convergens, H. dujardini, H. cf. scabropygus, Isohypsibius ronsisvallei, I. sattleri, Macrobiotus harmsworthi harmsworthi, M. hufelandi hufelandi, Milnesium asiaticum, Milnesium tardigradum tardigradum, Minibiotus formosus sp. n. and Paramacrobiotus richtersi. The new species is most similar to Minibiotus gumersindoi, but differs from it mainly by the presence of two types of cuticular pores, the absence of a triangular or pentagonal arrangement of pores above a single large pore on legs, the presence of granulation on all legs and a different macroplacoid length sequence. In this paper we also provide photographs and morphometrics of H. cf. scabropygus.

  14. A new tardigrade Doryphoribius maasaimarensis sp. nov. (Eutardigrada: Hypsibiidae) from Kenya.

    Science.gov (United States)

    Fontoura, Paulo; Lisi, Oscar; Pilato, Giovanni

    2013-01-01

    A new tardigrade, Doryphoribius maasaimarensis sp. nov., is described from a moss sample collected in Masai Mara Game Reserve, Kenya. The new species is characterized by having a reticulate dorsal cuticle with small tubercles; nine transverse rows of dorsal gibbosities (configuration IX:4-6-4-6-4-6-4-4-2); pharyngeal bulb with two macroplacoids and no microplacoid; claws with short and thin accessory points; small, smooth lunules under the claws. The new species is most similar to Doryphoribius zyxiglobus (Horning, Schuster & Grigarick, 1978). Both exhibit two macroplacoids, similar cuticular pattern and the same configuration of gibbosities. However, in Doryphoribius maasaimarensis sp. nov. the cuticular tubercles are less close, buccal tube slightly longer with respect to the body length, more gradual curvature of the buccal tube, different claws shape and thinner accessory points.

  15. The impact of tourists on Antarctic tardigrades: an ordination-based model

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    Sandra J. McInnes

    2013-05-01

    Full Text Available Tardigrades are important members of the Antarctic biota yet little is known about their role in the soil fauna or whether they are affected by anthropogenic factors. The German Federal Environment Agency commissioned research to assess the impact of human activities on soil meiofauna at 14 localities along the Antarctic peninsula during the 2009/2010 and 2010/2011 austral summers. We used ordination techniques to re-assess the block-sampling design used to compare areas of high and low human impact, to identify which of the sampled variables were biologically relevant and/or demonstrated an anthropogenic significance. We found the most significant differences between locations, reflecting local habitat and vegetation factor, rather than within-location anthropogenic impact. We noted no evidence of exotic imports but report on new maritime Antarctic sample sites and habitats.

  16. Population dynamics and vertical distribution of enchytraeids and tardigrades in response to deforestation

    Science.gov (United States)

    Uhía, E.; Briones, M. J. I.

    2002-12-01

    In order to increase our present knowledge of the potential impacts of deforestation on the soil ecosystem, we investigated the responses of enchytraeid and tardigrade populations to tree harvesting. The study was conducted in an area of ca. 10 ha located at an altitude of approximately 450 m in the surroundings of the University campus (Vigo, Pontevedra, Spain). Pine forest ( Pinus pinaster Aiton), with an average density of 400 trees/ha ranging between 10 and 20 years of age, and some young oaks ( Quercus robur L.) were covering the area. At the end of the summer 1995, approximately 50% of the area was harvested. Soil and animal samples were taken from May 1996 to April 1997 at monthly intervals in both forested and deforested areas. Removal of the trees resulted in a significant effect on enchytraeid population numbers and their response was species-dependent in terms of changes in both population numbers and vertical distribution. Higher mortality rates of enchytraeids were recorded in the absence of trees. August seemed to have been critical for survival of all enchytraeid species as no individuals were found in that month and only a few recovered in the following month. Only Cognettia sphagnetorum showed vertical migration in order to avoid adverse conditions. Tardigrades were more abundant in the deforested areas; their ability to enter in a resistant stage could have enabled them to overcome adverse environmental conditions. It is concluded that harvesting of the trees has changed the soil environment and that differences in moisture and temperature conditions are not sufficient to explain the observed differences. The forest soils contained more organic matter than those in the deforested area and therefore differences in the amount and/or quality of the organic matter could be one of the possible explanations for the observed changes in enchytraeid abundance when the forest is removed.

  17. Arginine kinase from the Tardigrade, Macrobiotus occidentalis: molecular cloning, phylogenetic analysis and enzymatic properties.

    Science.gov (United States)

    Uda, Kouji; Ishida, Mikako; Matsui, Tohru; Suzuki, Tomohiko

    2010-10-01

    Arginine kinase (AK), which catalyzes the reversible transfer of phosphate from ATP to arginine to yield phosphoarginine and ADP, is widely distributed throughout the invertebrates. We determined the cDNA sequence of AK from the tardigrade (water bear) Macrobiotus occidentalis, cloned the sequence into pET30b plasmid, and expressed it in Escherichia coli as a 6x His-tag—fused protein. The cDNA is 1377 bp, has an open reading frame of 1080 bp, and has 5′- and 3′-untranslated regions of 116 and 297 bp, respectively. The open reading frame encodes a 359-amino acid protein containing the 12 residues considered necessary for substrate binding in Limulus AK. This is the first AK sequence from a tardigrade. From fragmented and non-annotated sequences available from DNA databases, we assembled 46 complete AK sequences: 26 from arthropods (including 19 from Insecta), 11 from nematodes, 4 from mollusks, 2 from cnidarians and 2 from onychophorans. No onychophoran sequences have been reported previously. The phylogenetic trees of 104 AKs indicated clearly that Macrobiotus AK (from the phylum Tardigrada) shows close affinity with Epiperipatus and Euperipatoides AKs (from the phylum Onychophora), and therefore forms a sister group with the arthropod AKs. Recombinant 6x His-tagged Macrobiotus AK was successfully expressed as a soluble protein, and the kinetic constants (K(m), K(d), V(ma) and k(cat)) were determined for the forward reaction. Comparison of these kinetic constants with those of AKs from other sources (arthropods, mollusks and nematodes) indicated that Macrobiotus AK is unique in that it has the highest values for k(cat) and K(d)K(m) (indicative of synergistic substrate binding) of all characterized AKs.

  18. An evaluation of species richness estimators for tardigrades of the Great Smoky Mountains National Park, Tennessee and North Carolina, USA

    Directory of Open Access Journals (Sweden)

    Diane R. NELSON

    2007-09-01

    Full Text Available For the past 5 years we have been conducting a large-scale, multi-habitat inventory of the tardigrades in the Great Smoky Mountains National Park (U.S.A. as part of the All Taxa Biodiversity Inventory (ATBI (see www.dlia.org. In terrestrial habitats, we collected moss, lichen, and soil samples from 19 permanent ATBI plots, representing all major land cover types within the park. Each ATBI plot is 100 × 100 m. In each plot, when available, 16 moss samples, 16 lichen samples, and 4 soil samples were collected in paper bags and air dried in the laboratory. Specimens were isolated with LudoxAM centrifugation, and for each sample up to 50 adults plus eggs were individually mounted on microscope slides in Hoyer's medium and identified using phase contrast and DIC microscopy. Additional collections were made in the limestone caves of the Cades Cove region of the park, bird nests, and 13 different streams. To date (1-Jun-06, 589 samples have been collected, and of these 401 have been analyzed, yielding a total of 8133 identifiable tardigrades or, in some cases, species groups. A total of 73 species have been found in the park, 14 of which we believe are new to science. Seven species richness estimators have been developed to predict total species richness (see EstimateS 7.5 software, viceroy.eeb.uconn.edu/estimates, and these were evaluated by comparing predictions from half of our data to the actual numbers from the total database. The results of this comparison indicate that different estimators work best in different habitats. Using the best estimators in each habitat, EstimateS 7.5 indicates that a total of 96 species are likely to occur throughout the park. Thus, Great Smoky Mountains National Park tardigrade diversity represents 10% of the world's known tardigrade fauna.

  19. A long-term study of population dynamics of tardigrades in the moss Rhytidiadelphus squarrosus (Hedw. Warnst

    Directory of Open Access Journals (Sweden)

    Rolf SCHUSTER

    2007-09-01

    Full Text Available Variation of abundance, dominance and diversity of tardigrades were studied over a period of 54 months in a carpet of the moss Rhytidiadelphus squarrosus that covered a lawn in the Black Forest (Germany. Altogether 19,909 individuals belonging to 24 species were extracted from the moss. Macrobiotus hufelandi (56%, Macrobiotus richtersi (18% and Diphascon pingue (12% were the most abundant and dominant species. Dominances of the other species varied between 0.01 to 2.15%. Generally, species diversity (Shannon-Index and evenness was highest during the winter. A temporal variation in numbers with a decline in winter and an increase in spring until fall was seen in M. hufelandi, D. pingue and less clear in M. richtersi. Three species (Diphascon rugosum, Hypsibius dujardini, Hypsibius cfr. convergens showed a cyclic variation with clear peaks in wintertime. The moist season favoured species that were considered as hygrophilous in the literature, whereas the relatively dry sunny seasons promoted the relative increase of euryhygric species. The composition of the tardigrade community was strikingly robust over the years. Fourteen species were always present during the entire period of investigation. However, changes in the species composition over the years, and cyclical temporal presence of certain species stress the significance of long-term studies to estimate species richness in a given habitat. Application of the Spearman rank correlation test to the data set of the whole study period showed different correlations between the mean number of tardigrades as well as the mean number of individuals of selected species (dominance >1 and rainfall, humidity and temperature. Correlations confirmed some of the ecological dependences of tardigrade species known from literature. Conflicting classifications suggest dependence from other variables or perhaps presence of ecotypes.

  20. Analysis of the Opsin Repertoire in the Tardigrade Hypsibius dujardini Provides Insights into the Evolution of Opsin Genes in Panarthropoda

    OpenAIRE

    Hering, Lars; Mayer, Georg

    2014-01-01

    Screening of a deeply sequenced transcriptome using Illumina sequencing as well as the genome of the tardigrade Hypsibius dujardini revealed a set of five opsin genes. To clarify the phylogenetic position of these genes and to elucidate the evolutionary history of opsins in Panarthropoda (Onychophora + Tardigrada + Arthropoda), we reconstructed the phylogeny of broadly sampled metazoan opsin genes using maximum likelihood and Bayesian inference methods in conjunction with carefully selected s...

  1. Tolerance to gamma-irradiation in eggs of the tardigrade Richtersius coronifer depends on stage of development

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    Ingemar Jönsson

    2013-05-01

    Full Text Available Tardigrades are known as one of the most radiation tolerant animals on Earth, and several studies on tolerance in adult tardigrades have been published. In contrast, very few studies on radiation tolerance of embryonic stages have been reported. Here we report a study on tolerance to gamma irradiation in eggs of the eutardigrade Richtersius coronifer. Irradiation of eggs collected directly from a natural substrate (moss showed a clear dose-response, with a steep decline in hatchability at doses up to 0.4 kGy followed by a relatively constant hatchability around 25% up to 2 kGy, and a decline to ca. 5% at 4 kGy above which no eggs hatched. Analysis of the time required for eggs to hatch after irradiation (residual development time showed that hatching of eggs after exposure to high doses of gamma radiation was associated with short residual development time. Since short residual development time means that the egg was irradiated at a late developmental stage, this suggests that eggs were more tolerant to radiation late in development. This was also confirmed in another experiment in which stage of development at irradiation was controlled. No eggs irradiated at the early developmental stage hatched, and only one egg at middle stage hatched, while eggs irradiated in the late stage hatched at a rate indistinguishable from controls. This suggests that the eggs are more sensitive to radiation in the early stages of development, or that tolerance to radiation is acquired only late in development, shortly before the eggs hatch, hypotheses that are not mutually exclusive. Our study emphasizes the importance of considering specific cell cycle phases and developmental stages in studies of tolerance to radiation in tardigrades, and the potential importance of embryonic studies in revealing the mechanisms behind the radiation tolerance of tardigrades and other cryptobiotic animals.

  2. A molecular study of the tardigrade Echiniscus testudo (Echiniscidae reveals low DNA sequence diversity over a large geographical area

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    Aslak JØRGENSEN

    2007-09-01

    Full Text Available In the present study we investigate the genetic diversity within the asexually reproducing tardigrade Echiniscus testudo. The present study is the first to sample a tardigrade species for comparison of DNA sequence diversity between widely separated samples. Echiniscus testudo was sampled at 13 localities spanning three continents. DNA sequences of the mitochondrial COI gene and the nuclear ITS2 sequence were used to investigate the genetic diversity and phylogeographic structure of the various asexual lineages. Terrestrial tardigrades with the capability of entering a cryptobiotic state are assumed to have a high passive dispersal potential through airborne transport. Our results show moderate (ITS2 to high (COI haplotype diversity and low sequence diversity that indicate evolution of haplotypes within distinct asexual lineages and a high dispersal potential. No isolation by distance was detected by Mantel tests. Different phylogeny inference methods (neighbor-joining, maximum parsimony, maximum likelihood and Bayesian inference revealed little topological resolution, but minimum spanning networks showed some phylogeographic patterns. The COI and ITS2 minimum spanning networks show patterns that indicate dispersal of several haplotypes from founding populations. In conclusion our data show a low genetic diversity and a relatively high haplotype diversity indicating that E. testudo is a young species with a high dispersal potential.

  3. Aquatic tardigrades in the Great Smoky Mountains National Park, North Carolina and Tennessee, U.S.A., with the description of a new species of Thulinius (Tardigrada, Isohypsibiidae).

    Science.gov (United States)

    Bertolani, Roberto; Bartels, Paul J; Guidetti, Roberto; Cesari, Michele; Nelson, Diane R

    2014-02-05

    As part of the All Taxa Biodiversity Inventory (http://www.dlia.org), an extensive survey of tardigrades has been conducted in the Great Smoky Mountains National Park (GSMNP) in Tennessee and North Carolina, U.S.A., by Bartels and Nelson. Freshwater tardigrades include three species in the aquatic genus Thulinius (Eutardigrada, Isohypsibiidae). A new species, Thulinius romanoi, described from stream sediment, is distinguished from all other congeners by having a sculptured cuticle. In addition, the presence of Thulinius augusti (Murray, 1907) was verified by combined morphological and molecular analysis, and nine specimens of a third species, Thulinius cf. saltursus, were also found. Thulinius augusti is a new record for the United States. Thulinius saltursus (Schuster, Toftner & Grigarick, 1978) was previously recorded in California and Ohio, but our specimens vary slightly in morphology. The list of tardigrades from streams in the GSMNP was updated to a total of 44 species, 22 of which were predominantly or exclusively aquatic.

  4. Mesobiotus philippinicus sp. nov., the first limnoterrestrial tardigrade from the Philippines.

    Science.gov (United States)

    Mapalo, Marc A; Stec, Daniel; Mirano-Bascos, Denise; Michalczyk, Łukasz

    2016-06-20

    The limnoterrestrial tardigrade fauna of the Philippines is completely unknown. In this paper, we describe the first ever limnoterrestrial water bear species from this southeast Asian country, Mesobiotus philippinicus sp. nov., found in a moss sample collected in Quezon City. Apart from morphometrics and imaging in light microscopy, we also analysed the new species under scanning electron microscope and sequenced four DNA markers differing in mutation rates, three nuclear (18S rRNA, 28S rRNA, and ITS-2) and one mitochondrial (COI). This allowed not only a detailed description but also provided barcodes to aid future species identification. The new species belongs to the harmsworthi group and is most similar to M. diffusus (Binda & Pilato, 1987), M. pseudocoronatus (Pilato et al., 2006), M. montanus (Murray, 1910) and M. mottai (Binda & Pilato, 1994), but differs from these species by whorled egg processes and dimensions of some morphometric traits. The 28S rRNA, ITS-2 and COI sequences presented in this paper are the first published DNA sequences for the genus Mesobiotus.

  5. Analysis of the opsin repertoire in the tardigrade Hypsibius dujardini provides insights into the evolution of opsin genes in panarthropoda.

    Science.gov (United States)

    Hering, Lars; Mayer, Georg

    2014-09-04

    Screening of a deeply sequenced transcriptome using Illumina sequencing as well as the genome of the tardigrade Hypsibius dujardini revealed a set of five opsin genes. To clarify the phylogenetic position of these genes and to elucidate the evolutionary history of opsins in Panarthropoda (Onychophora + Tardigrada + Arthropoda), we reconstructed the phylogeny of broadly sampled metazoan opsin genes using maximum likelihood and Bayesian inference methods in conjunction with carefully selected substitution models. According to our findings, the opsin repertoire of H. dujardini comprises representatives of all three major bilaterian opsin clades, including one r-opsin, three c-opsins, and a Group 4 opsin (neuropsin/opsin-5). The identification of the tardigrade ortholog of neuropsin/opsin-5 is the first record of this opsin type in a protostome, but our screening of available metazoan genomes revealed that it is also present in other protostomes. Our opsin phylogeny further suggests that two r-opsins, including an "arthropsin," were present in the last common ancestor of Panarthropoda. Although both r-opsin lineages were retained in Onychophora and Arthropoda, the arthropsin was lost in Tardigrada. The single (most likely visual) r-opsin found in H. dujardini supports the hypothesis of monochromatic vision in the panarthropod ancestor, whereas two duplications of the ancestral panarthropod c-opsin have led to three c-opsins in tardigrades. Although the early-branching nodes are unstable within the metazoans, our findings suggest that the last common ancestor of Bilateria possessed six opsins: Two r-opsins, one c-opsin, and three Group 4 opsins, one of which (Go opsin) was lost in the ecdysozoan lineage.

  6. Diversity and distribution of tardigrades (Bilateria, Tardigrada from the Iberian Peninsula, Balearic Islands and Chafarinas Islands

    Directory of Open Access Journals (Sweden)

    Guil, Noemí

    2002-12-01

    Full Text Available Bibliographical information on the Tardigrada from Iberian Peninsula, Balearic Islands and Chafarinas Islands is compiled herein. 118 species are listed from the studied area. The first records of six Tardigrada species, Dactylobiotus parthenogeneticus, Dactylobiotus selenicus, Murrayon dianeae, Diphascon (Diphascon nodulosum (first time in Europe, Diphascon (Diphascon pingue and Isohypsibius marcellinoi that had not previously been found in the area are included. Bibliography data are analysed. After the analysis, it is concluded that more intensive, extensive and within more diverse habitats sampling effort should significantly increase the knowledge of tardigrade diversity in the studied area.

    En este artículo hemos recopilado la información existente en la bibliografía acerca del phylum Tardigrada en la Península Ibérica, Islas Baleares e Islas Chafarinas. La lista de especies del phylum Tardigrada incluye 118 especies en el área de estudio. Además, incluimos seis especies encontradas por primera vez en el área de estudio: Dactylobiotus parthenogeneticus, Dactylobiotus selenicus, Murrayon dianeae, Diphascon (Diphascon nodulosum (por primera vez encontrado en Europa, Diphascon (Diphascon pingue e Isohypsibius marcellinoi. En base al análisis realizado con los datos recopilados de la bibliografía, podemos concluir que un pequeño aumento en el esfuerzo de muestreo (intensivo, extensivo y aumentando la diversidad de hábitats recolectados se traduce en un aumento significativo de la diversidad del phylum en el área estudiada.

  7. Distribution of Calcium and Chitin in the Tardigrade Feeding Apparatus in Relation to its Function and Morphology.

    Science.gov (United States)

    Guidetti, Roberto; Bonifacio, Alois; Altiero, Tiziana; Bertolani, Roberto; Rebecchi, Lorena

    2015-08-01

    The cuticular portion of the tardigrade feeding apparatus is a complex structure that can be schematically divided into four parts: a buccal ring, a buccal tube, a stylet system (formed by two piercing stylets, each within a stylet coat, and two stylet supports), and the lining of a myoepithelial sucking pharynx. To better understand the function and evolution of the feeding apparatus, the morpho-functional traits and chemical composition of the structures forming the feeding apparatuses of eight different species of tardigrades were analyzed. These eight species are representative of almost all main phylogenetic lineages of the phylum. The calcium and chitin in the feeding apparatus were examined by light microscopy, scanning electron microscopy, confocal laser scanning microscopy, energy dispersive X-ray spectroscopy, and Raman microspectroscopy (Raman). In all species, the feeding apparatus had been subjected to biomineralization due to CaCO3 encrustations organized in the crystalline form of aragonite. Aragonite and chitin are present in different concentrations in the feeding apparatus according to the structures and species considered. Generally, where the structures are rigid there is more aragonite than chitin, and vice versa. The buccal tube and piercing stylets are rich in calcium, with the piercing stylets apparently composed exclusively of aragonite. In eutardigrades, chitin is in higher concentration in the structures subject to higher mechanical stresses, such as the crests of the buccal crown and the condyles of the stylet furca.

  8. Survival of the Tardigrade Hypsibius Dujardini during Hypervelocity Impact Events up to 5.49 km s-1

    Science.gov (United States)

    Pasini, D.

    2014-04-01

    Studies have previously been conducted to verify the survivability of living cells during hypervelocity impact events to test the panspermia and lithopanspermia hypotheses [1, 2]. It has been demonstrated that bacteria survive impacts up to 5.4 km s-1 (approx. shock pressure 30 GPa) - albeit with a low probability of survival [1], whilst larger, more complex, objects (such as seeds) break up at ~1 km s-1 [2]. The survivability of yeast spores in impacts up to 7.4 km s-1 has also recently been shown [3]. Previous work by the authors demonstrated the survivability of Nannochloropsis Oculata Phytoplankton, a eukaryotic photosynthesizing autotroph found in the 'euphotic zone' (sunlit surface layers of oceans [4]), at impact velocities up to 6.07 km s-1 [5]. Other groups have also reported that lichens are able to survive shocks in similar pressure ranges [6]. However, whilst many simple single celled organisms have now been shown to survive such impacts (and the associated pressures) as those encountered during the migration of material from one planet to another [1, 3, 5], complex multicellular organisms have either largely not been tested or, those that have been, have not survived the process [2]. Hypsibius dujardini, like most species of tardigrade, are complex organisms composed of approximately 40,000 cells [7]. When humidity decreases they enter a highly dehydrated state known as a 'tun' and can survive extreme temperatures (as low as - 253°C or as high as 151°C), as well as exposure to Xrays and the vacuum of space [7]. Here we test the shock survivability of Hypsibius dujardini by firing a nylon projectile onto a frozen sample of water containing frozen tardigrades using a light gas gun (LGG) [8]. The recovered ice and water were then analysed under an optical microscope to check the viability of any remnant organisms that may have survived impact, and the pressures generated.

  9. Tardigrada of Xinjiang Uygur Autonomous Region, China

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    William R. MILLER

    2007-09-01

    Full Text Available Relatively little is known of the Tardigrada fauna of China, and there are no previous tardigrade records for Xinjiang Uygur Autonomous Region, China's largest administrative division. Moss specimens of the Missouri Botanical Garden Herbarium (St. Louis, U.S.A. were used as a source of tardigrades from this region. Of the 270 moss specimens sampled, 78 yielded tardigrades. Species found were Bryodelphax asiaticus, Cornechiniscus holmeni, Echiniscus blumi, Echiniscus canadensis, Echiniscus granulatus, Echiniscus testudo, Echiniscus trisetosus, Macrobiotus alekseevi, Macrobiotus mauccii, Milnesium asiaticum, Milnesium longiungue, and Milnesium tardigradum. Of the species found, the Heterotardigrada are better represented, which is probably a reflection of the higher altitudes at which the samples were taken and the arid environment of the region; the species found are primarily ones considered to be xerophilic or montane. Seven species new to China are reported.

  10. A P2X receptor from the tardigrade species Hypsibius dujardini with fast kinetics and sensitivity to zinc and copper

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    Blaxter Mark L

    2009-01-01

    Full Text Available Abstract Background Orthologs of the vertebrate ATP gated P2X channels have been identified in Dictyostelium and green algae, demonstrating that the emergence of ionotropic purinergic signalling was an early event in eukaryotic evolution. However, the genomes of a number of animals including Drosophila melanogaster and Caenorhabditis elegans, both members of the Ecdysozoa superphylum, lack P2X-like proteins, whilst other species such as the flatworm Schistosoma mansoni have P2X proteins making it unclear as to what stages in evolution P2X receptors were lost. Here we describe the functional characterisation of a P2X receptor (HdP2X from the tardigrade Hypsibius dujardini demonstrating that purinergic signalling is preserved in some ecdysozoa. Results ATP (EC50 ~44.5 μM evoked transient inward currents in HdP2X with millisecond rates of activation and desensitisation. HdP2X is antagonised by pyridoxal-phosphate-6-azophenyl-2',4' disulfonic acid (IC50 15.0 μM and suramin (IC50 22.6 μM and zinc and copper inhibit ATP-evoked currents with IC50 values of 62.8 μM and 19.9 μM respectively. Site-directed mutagenesis showed that unlike vertebrate P2X receptors, extracellular histidines do not play a major role in coordinating metal binding in HdP2X. However, H306 was identified as playing a minor role in the actions of copper but not zinc. Ivermectin potentiated responses to ATP with no effect on the rates of current activation or decay. Conclusion The presence of a P2X receptor in a tardigrade species suggests that both nematodes and arthropods lost their P2X genes independently, as both traditional and molecular phylogenies place the divergence between Nematoda and Arthropoda before their divergence from Tardigrada. The phylogenetic analysis performed in our study also clearly demonstrates that the emergence of the family of seven P2X channels in human and other mammalian species was a relatively recent evolutionary event that occurred subsequent

  11. Comparative analysis of the tardigrade feeding apparatus: adaptive convergence and evolutionary pattern of the piercing stylet system

    Directory of Open Access Journals (Sweden)

    Roberto Guidetti

    2013-03-01

    Full Text Available A thorough analysis of the cuticular parts of tardigrade feeding apparatuses was performed in order to provide a more complete understanding of their evolution and their potential homologies with other animal phyla (e.g. Cycloneuralia and Arthropoda. The buccal- pharyngeal apparatuses of eight species belonging to both Eutardigrada and Heterotardigrada were studied using light and scanning electron microscopy. This study supports and completes a previous study on the relationships between form and function in the buccalpharyngeal apparatus of eutardigrades. The common sclerified structures of the tardigrade buccal-pharyngeal apparatus are: a buccal ring connected to a straight buccal tube, a buccal crown, longitudinal thickenings within the pharynx, and a stylet system composed of piercing stylets within stylet coats, and stylet supports. Specifically, heterotardigrades (Echiniscoidea have a narrow buccal tube; long piercing stylets, each with a longitudinal groove, that cross one another before exiting the mouth; pharyngeal bars and secondary longitudinal thickenings within the pharynx. In contrast, eutardigrades have stylets which are shorter than the buccal tube; Parachela have pharyngeal apophyses and placoids within the pharynx, while Apochela lack a buccal crown and cuticular thickenings within the pharynx, the buccal tube is very wide, and the short stylets are associated with triangular-shaped stylet supports. In both classes, when the piercing stylet tips emerge from the mouth to pierce food, the buccal tube opening is almost completely obstructed, which may hinder food uptake. In heterotardigrades, the crossing of the piercing stylets may further decrease food uptake, however this disadvantage may have been reduced in echiniscids by the evolution of a long buccal tube and long stylets able to run more parallel to the buccal tube. In contrast, eutardigrades evolved different strategies. In the order Apochela and in several

  12. 中国陆地-淡水缓步动物分类组成研究%Taxonomic Composition of the Chinese Terrestrial - Freshwater Tardigrades

    Institute of Scientific and Technical Information of China (English)

    高晓燕; 李晓晨; 王立志

    2012-01-01

    简要介绍了缓步动物门的系统分类研究进展,初步分析了中国陆地-淡水缓步动物分类组成.全世界已描述发表的缓步动物种类约1000种,隶属3纲、5目、13科、70余属.中国的缓步动物共计161种,隶属2纲、3目、5科、20属.%The Tardigrada systematics was briefly reviewed, and the taxonomic composition of Chinese terrestrial-freshwater tardigrades was primarily analyzed. About 1 000 species have been described, belonging to 3 classes, 5 orders, 13 families, and over 70 genera. A total of 161 species, belonging to 2 classes, 3 orders, 5 families, and 20 genera, have been reported from China.

  13. Tolerance to X-rays and Heavy Ions (Fe, He) in the Tardigrade Richtersius coronifer and the Bdelloid Rotifer Mniobia russeola

    Science.gov (United States)

    Jønsson, K. Ingemar; Wojcik, Andrzej

    2017-02-01

    The aim of this study was to analyze tolerance to heavy ions in desiccated animals of the eutardigrade Richtersius coronifer and the bdelloid rotifer Mniobia russeola within the STARLIFE project. Both species were exposed to iron (Fe) and helium (He) ions at the Heavy Ion Medical Accelerator in Chiba (HIMAC) in Chiba, Japan, and to X-rays at the German Aerospace Center (DLR) in Cologne, Germany. Results show no effect of Fe and He on viability up to 7 days post-rehydration in both R. coronifer and M. russeola, while X-rays tended to reduce viability in R. coronifer at the highest doses. Mean egg production rate tended to decline with higher doses in R. coronifer for all radiation types, but the pattern was not statistically confirmed. In M. russeola, there was no such tendency for a dose response in egg production rate. These results confirm the previously reported high tolerance to high linear energy transfer (LET) radiation in tardigrades and show for the first time that bdelloid rotifers are also very tolerant to high-LET radiation. These animal phyla represent the most desiccation- and radiation-tolerant animals on Earth and provide excellent eukaryotic models for astrobiological research.

  14. 中国东部武夷山风景区苔藓中的缓步动物%TARDIGRADES FROM SOME MOSSES OF WUYI MOUNTAIN SCENERIES IN EAST CHINA

    Institute of Scientific and Technical Information of China (English)

    杨潼

    2008-01-01

    记述了采自中国东部福建省武夷山风景区苔藓中的缓步动物11种,包括:日本棘影熊虫 Echiniscus japonicusMorikawa,1951中国东部新纪录种;结痂棘影熊虫 Echiniscus scabrospinesus Fontoura,1982中国东部新纪录种;华美假棘影熊虫 Pseudechiniscus facettalis Petersen,1951中国东部新纪录种;迟缓小斑熊虫 Milnesium tardigradum(Doyère,1840);埃卡门大生熊虫 Macrobiotus ariekammensis Weglarska,1965 中国东部新纪录种;节值大生熊虫,模式亚种 Macrobiotus harmswodsrthiharmsworthi Murray,1907;华丽大生熊虫 Macrobiotus richtersi,1911;陆栖大生熊虫 Macrobiotus terricola Mihelcic,1949;异常拉玛熊虫 Ramazzottius anomalus(Ramazzotti,1962)中国新纪录种;肥曲拉玛熊虫 Ramazzottius oberhaeuseri(Doyère,1840);黄色具矛熊虫 Doryphoribius flavus(Iharos,1966)中国东部新纪录种.所有的标本均保存于中国科学院水生生物研究所.

  15. TARDIGRADES FROM SOME MOSSES OF SHENNONG FRAME STATE FOREST PARK IN CHINA%中国神农架国家森林公园苔藓中的缓步动物

    Institute of Scientific and Technical Information of China (English)

    杨潼

    2007-01-01

    记述了采自湖北省西部神农架国家森林公园苔藓中的缓步动物12种,包括:日本棘影熊虫Echiniscus japonicus Morikawa,1951;双粒棘影熊虫Echiniscus bigranulatus Richters,1907中国新纪录种;华美假棘影熊虫Pseudechiniscus facettalis Petersen,1951;于猪假棘影熊虫Pseudechiniscus suillus(Ehrenberg,1853);迟缓小斑熊虫Milnesium tardigradum(Doyère,1840);隐匿大生熊虫Macrobiotus adelges Dastych,1977;锦葵大生熊虫Macrobiotus hibiscus Barros,1942中国新纪录种;胡芬大生熊虫Macrobiotus hufelandi Schultze,1833;华丽大生熊虫Macrobiotus richtersi Murray,1911;陆栖大生熊虫Macrobiotus terricola Mihel(c)I(c),1949;水生趾生熊虫Dactylobiotus aquatilis Yang,1999;金猴等高熊虫Isohypsibius jinhouensis sp. Nov..所有的标本均保存于中国科学院水生生物研究所.

  16. Induction of Hsp70 by desiccation, ionising radiation and heat-shock in the eutardigrade Richtersius coronifer.

    Science.gov (United States)

    Jönsson, K Ingemar; Schill, Ralph O

    2007-04-01

    The physiology and biochemistry behind the extreme tolerance to desiccation shown by the so-called anhydrobiotic animals represents an exciting challenge to biology. The current knowledge suggests that both carbohydrates and proteins are often involved in protecting the dry cell from damage, or in the repair of induced damage. Tardigrades belong to the most desiccation-tolerant multicellular organisms, but very little research has been reported on the biochemistry behind desiccation tolerance in this group. We quantified the induction of the heat-shock protein Hsp70, a very wide-spread stress protein, in response to desiccation, ionising radiation, and heating, in the anhydrobiotic tardigrade Richtersius coronifer using an immuno-westernblot method. Elevated levels of Hsp70 were recorded after treatment of both heat and ionising radiation, and also in rehydrated tardigrades after a period of desiccation. In contrast, tardigrades in the desiccated (dry) state had reduced Hsp70 levels compared to the non-treated control group. Our results suggest that Hsp70 may be involved in the physiological and biochemical system underlying desiccation (and radiation) tolerance in tardigrades, and that its role may be connected to repair processes after desiccation rather than to biochemical stabilization in the dry state.

  17. Terrestrial and freshwater Tardigrada of the Americas.

    Science.gov (United States)

    Meyer, Harry A

    2013-12-16

    This paper provides a comprehensive list of the freshwater and terrestrial tardigrade fauna reported from the Americas (North America, South America, Central America and the West Indies), their distribution in the Americas, and the substrates from which they have been reported. Data were obtained from 316 published references. Authors' identifications were accepted at face value unless subsequently amended. Taxa were assigned to sub-national units (states, provinces, etc.). Many areas, in particular large portions of Central America and the West Indies, have no reported tardigrade fauna.        The presence of 54 genera and 380 species has been reported for the Americas; 245 species have been collected in the Nearctic ecozone and 251 in the Neotropical ecozone. Among the tardigrade species found in the Americas, 52 are currently considered cosmopolitan, while 153 species have known distributions restricted to the Americas. Based on recent taxonomic revision of the genus Milnesium, the vast majority of records of M. tardigradum in the Americas should now be reassigned to Milnesium tardigradum sensu lato, either because the provided description differs from M. tardigradum sensu stricto or because insufficient description is provided to make a determination; the remainder should be considered Milnesium cf. tardigradum.        Most terrestrial tardigrade sampling in the Americas has focused on cryptogams (mosses, lichens and liverworts); 90% of the species have been collected in such substrates. The proportion of species collected in other habitats is lower: 14% in leaf litter, 20% in soil, and 24% in aquatic samples (in other terrestrial substrates the proportion never exceeds 5%). Most freshwater tardigrades have been collected from aquatic vegetation and sediment. For nine species in the Americas no substrates have been reported. 

  18. Experimentally Induced Repeated Anhydrobiosis in the Eutardigrade Richtersius coronifer

    Science.gov (United States)

    2016-01-01

    Tardigrades represent one of the main animal groups with anhydrobiotic capacity at any stage of their life cycle. The ability of tardigrades to survive repeated cycles of anhydrobiosis has rarely been studied but is of interest to understand the factors constraining anhydrobiotic survival. The main objective of this study was to investigate the patterns of survival of the eutardigrade Richtersius coronifer under repeated cycles of desiccation, and the potential effect of repeated desiccation on size, shape and number of storage cells. We also analyzed potential change in body size, gut content and frequency of mitotic storage cells. Specimens were kept under non-cultured conditions and desiccated under controlled relative humidity. After each desiccation cycle 10 specimens were selected for analysis of morphometric characteristics and mitosis. The study demonstrates that tardigrades may survive up to 6 repeated desiccations, with declining survival rates with increased number of desiccations. We found a significantly higher proportion of animals that were unable to contract properly into a tun stage during the desiccation process at the 5th and 6th desiccations. Also total number of storage cells declined at the 5th and 6th desiccations, while no effect on storage cell size was observed. The frequency of mitotic storage cells tended to decline with higher number of desiccation cycles. Our study shows that the number of consecutive cycles of anhydrobiosis that R. coronifer may undergo is limited, with increased inability for tun formation and energetic constraints as possible causal factors. PMID:27828978

  19. The structure of the desiccated Richtersius coronifer (Richters, 1903).

    Science.gov (United States)

    Czerneková, Michaela; Jönsson, K Ingemar; Chajec, Lukasz; Student, Sebastian; Poprawa, Izabela

    2017-05-01

    Tun formation is an essential morphological adaptation for entering the anhydrobiotic state in tardigrades, but its internal structure has rarely been investigated. We present the structure and ultrastructure of organs and cells in desiccated Richtersius coronifer by transmission and scanning electron microscopy, confocal microscopy, and histochemical methods. A 3D reconstruction of the body organization of the tun stage is also presented. The tun formation during anhydrobiosis of tardigrades is a process of anterior-posterior body contraction, which relocates some organs such as the pharyngeal bulb. The cuticle is composed of epicuticle, intracuticle and procuticle; flocculent coat; and trilaminate layer. Moulting does not seem to restrict the tun formation, as evidenced from tardigrade tuns that were in the process of moulting. The storage cells of desiccated specimens filled up the free inner space and surrounded internal organs, such as the ovary and digestive system, which were contracted. All cells (epidermal cells, storage cells, ovary cells, cells of the digestive system) underwent shrinkage, and their cytoplasm was electron dense. Lipids and polysaccharides dominated among reserve material of storage cells, while the amount of protein was small. The basic morphology of specific cell types and organelles did not differ between active and anhydrobiotic R. coronifer.

  20. Phylogenetic position of the enigmatic clawless eutardigrade genus Apodibius Dastych, 1983 (Tardigrada), based on 18S and 28S rRNA sequence data from its type species A. confusus.

    Science.gov (United States)

    Dabert, Miroslawa; Dastych, Hieronymus; Hohberg, Karin; Dabert, Jacek

    2014-01-01

    The systematics of Eutardigrada, the largest lineage among the three classes of the phylum Tardigrada, is based mainly on the morphology of the leg claws and of the buccal apparatus. However, three members of the rarely recorded and poorly known limno-terrestrial eutardigrade genus Apodibius have no claws on their strongly reduced legs, a unique character among all tardigrades. This absence of all claws makes the systematic position of Apodibius one of the most enigmatic among the whole class. Until now all known associates of the genus Apodibius have been located in the incertae sedis species group or, quite recently, included into the Necopinatidae family. In the present study, phylogenetic analyses of 18S and 28S rRNA sequence data from 31 tardigrade species representing four parachelan superfamilies (Isohypsibioidea, Hypsibioidea, Macrobiotoidea, Eohypsibioidea), the apochelan Milnesium tardigradum, and the type species of the genus Apodibius, A. confusus, indicated close relationship of the Apodibius with tardigrade species recently included in the superfamily Isohypsibioidea. This result was well-supported and consistent across all markers (separate 18S rRNA, 28S rRNA, and combined 18S rRNA+28S rRNA datasets) and methods (MP, ML) applied.

  1. Inorganic ion composition in Tardigrada: cryptobionts contain a large fraction of unidentified organic solutes.

    Science.gov (United States)

    Halberg, Kenneth Agerlin; Larsen, Kristine Wulff; Jørgensen, Aslak; Ramløv, Hans; Møbjerg, Nadja

    2013-04-01

    Many species of tardigrades are known to tolerate extreme environmental stress, yet detailed knowledge of the mechanisms underlying the remarkable adaptations of tardigrades is still lacking, as are answers to many questions regarding their basic biology. Here, we present data on the inorganic ion composition and total osmotic concentration of five different species of tardigrades (Echiniscus testudo, Milnesium tardigradum, Richtersius coronifer, Macrobiotus cf. hufelandi and Halobiotus crispae) using high-performance liquid chromatography and nanoliter osmometry. Quantification of the ionic content indicates that Na(+) and Cl(-) are the principal inorganic ions in tardigrade fluids, albeit other ions, i.e. K(+), NH4(+), Ca(2+), Mg(2+), F(-), SO4(2-) and PO4(3-) were also detected. In limno-terrestrial tardigrades, the respective ions are concentrated by a large factor compared with that of the external medium (Na(+), ×70-800; K(+), ×20-90; Ca(2+) and Mg(2+), ×30-200; F(-), ×160-1040, Cl(-), ×20-50; PO4(3-), ×700-2800; SO4(2-), ×30-150). In contrast, in the marine species H. crispae, Na(+), Cl(-) and SO4(2-) are almost in ionic equilibrium with (brackish) salt water, while K(+), Ca(2+), Mg(2+) and F(-) are only slightly concentrated (×2-10). An anion deficit of ~120 mEq l(-1) in M. tardigradum and H. crispae indicates the presence of unidentified ionic components in these species. Body fluid osmolality ranges from 361±49 mOsm kg(-1) in R. coronifer to 961±43 mOsm kg(-1) in H. crispae. Concentrations of most inorganic ions are largely identical between active and dehydrated groups of R. coronifer, suggesting that this tardigrade does not lose large quantities of inorganic ions during dehydration. The large osmotic and ionic gradients maintained by both limno-terrestrial and marine species are indicative of a powerful ion-retentive mechanism in Tardigrada. Moreover, our data indicate that cryptobiotic tardigrades contain a large fraction of unidentified

  2. The alpha,alpha-(1-->1) linkage of trehalose is key to anhydrobiotic preservation.

    Science.gov (United States)

    Albertorio, Fernando; Chapa, Vanessa A; Chen, Xin; Diaz, Arnaldo J; Cremer, Paul S

    2007-08-29

    This study compares the efficacy of six disaccharides and glucose for the preservation of solid supported lipid bilayers (SLBs) upon exposure to air. Disaccharide molecules containing an alpha,alpha-(1-->1) linkage, such as alpha,alpha-trehalose and alpha,alpha-galacto-trehalose, were found to be effective at retaining bilayer structure in the absence of water. These sugars are known to crystallize in a clam shell conformation. Other saccharides, which are found to crystallize in more open structures, did not preserve the SLB structure during the drying process. These included the nonreducing sugar, sucrose, as well as maltose, lactose, and the monosaccharide, glucose. In fact, even close analogs to alpha,alpha-trehalose, such as alpha,beta-trehalose, which connects its glucopyranose rings via a (1-->1) linkage in an axial, equatorial fashion, permitted nearly complete delamination and destruction of supported bilayers upon exposure to air. Lipids with covalently attached sugar molecules such as ganglioside GM1, lactosyl phosphatidylethanolamine, and glucosylcerebroside were also ineffective at preserving bilayer structure. The liquid crystalline-to-gel phase transition temperature of supported phospholipid bilayers was tested in the presence of sugars in a final set of experiments. Only alpha,alpha-trehalose and alpha,alpha-galacto-trehalose depressed the phase transition temperature, whereas the introduction of other sugar molecules into the bulk solution caused the phase transition temperature of the bilayer to increase. These results point to the importance of the axial-axial linkage of disaccharides for preserving SLB structure.

  3. A new peritrichous Ciliate as a symphoriont on a Tardigrade

    NARCIS (Netherlands)

    Land, van der J.

    1964-01-01

    INTRODUCTION On 24 September 1962 a number of Tardigrada was obtained from a sample of lichens from the French Alps. The lichens had been collected Figs. 1, 2. Pyxidium tardigradum n. sp. on Hypsibius oberhaeuseri (Doy.). on 27 June 1961 from a rock in the department Haute Savoie and had been preser

  4. Tardigrada from a sub-Andean forest in the Sierra Nevada de Santa Marta (Colombia) with the description of Itaquascon pilatoi sp. nov.

    Science.gov (United States)

    Lisi, Oscar; Londoño, Rosana; Quiroga, Sigmer

    2014-07-29

    Currently only 32 species of limno-terrestrial tardigrades have been reported in the literature for Colombia. Our study focused on both heterotardigrades and eutardigrades, which were extracted from eight samples of bryophytes and lichens collected in a sub-Andean forest transect in the Sierra Nevada de Santa Marta, Colombia. Fourteen species were found, six of which are new records for Colombia: Echiniscus madonnae Michalczyk & Kaczmarek, 2006, Echiniscus virginicus Riggin, 1962, Milnesium krzysztofi Kaczmarek & Michalczyk, 2007, Doryphoribius amazzonicus Lisi, 2011, Isohypsibius sattleri (Richters, 1902) and Diphascon higginsi Binda, 1971; and one new to science. Itaquascon pilatoi sp. nov., is characterized by having smooth cuticle, no eyes, buccal tube almost as long as the pharyngeal tube, well developed, obvious stylet furcae with long branches, slender claws, no lunules and no cuticular bars on the legs. The new species differs from I. umbellinae Barros, 1939, the most similar species, in having the stylet supports inserted precisely at the border between buccal and pharyngeal tube, more slender claws and more pronounced length differential between the external and internal claws of each leg. The total number of Colombian limno-terrestrial tardigrade species is raised to 37. 

  5. Distribution and diversity of Tardigrada along altitudinal gradients in the Hornsund, Spitsbergen (Arctic

    Directory of Open Access Journals (Sweden)

    Krzysztof Zawierucha

    2015-02-01

    Full Text Available Two transects were established and sampled along altitudinal gradients on the slopes of Ariekammen (77°01′N; 15°31′E and Rotjesfjellet (77°00′N; 15°22′E in Hornsund, Spitsbergen. In total 59 moss, lichen, liverwort and mixed moss–lichen samples were collected and 33 tardigrade species of Hetero- and Eutardigrada were found. The α diversity ranged from 1 to 8 per sample; the estimated number of species based on all analysed samples was 52±17 for the Chao 2 estimator and 41 for the incidence-based coverage estimator. According to the results of detrended canonical correspondence analysis, altitude and type of substratum were the most important factors influencing tardigrade communities in the investigated area. Macrobiotus crenulatus, M. hufelandi hufelandi and Hypsibius pallidus dominated in the lower elevations, whereas Echiniscus wendti and E. merokensis merokensis prevailed in samples from higher plots. Macrobiotus islandicus islandicus was collected most often from mosses collected from rock whereas Isohypsibius coulsoni from mosses collected from soil. Analyses of covariance were employed to test for differences in species richness between the transects in relation to altitude. Contrary to expectations, there were significant differences in species richness between the transects, but richness was not significantly related to altitude. Interestingly, significant effects of colonies of seabirds, little auk (Alle alle, on the tardigrades communities were detected. Additionally, in one of the samples first ever males of Milnesium asiaticum were found. Their measurements and microphotographs are provided herein.

  6. Membrane behavior as influenced by partitioning of amphiphiles during drying: a comparative study in anhydrobiotic plant systems.

    Science.gov (United States)

    Golovina, Elena A; Hoekstra, Folkert A

    2002-03-01

    During cellular desiccation, reduction in volume can in principle cause amphiphilic compounds to partition from the cytoplasm into membranes, with structural perturbance as the result. Here, we studied the effect of partitioning of endogenous amphiphiles on membrane surface dynamics in desiccation-tolerant and -intolerant, higher and lower plant systems, using electron paramagnetic resonance (EPR) spin probe techniques. Labeling cells with the amphiphilic spin probe perdeuterated TEMPONE (PDT) enabled partitioning into the various phases to be followed. During drying, PDT molecules preferentially partitioned from the aqueous cytoplasm into the membrane surface and, at advanced stages of water loss, also into oil bodies. There was no specific partition behavior that could be correlated with lower/higher plants or with desiccation-tolerance. In vivo labeling with 5-doxylstearate (5-DS) enabled membrane surface fluidity to be characterized. In hydrated plants, the 5-DS spectra contained an immobile and a fluid component. The characteristics of the immobile component could not be specifically correlated with either lower or higher plants, or with desiccation tolerance. The relative contribution of the fluid component to the 5-DS spectra was higher in lower plants than in higher plants, but considerably decreased with drying in all desiccation-tolerant organisms. In contrast, the proportion of the fluid component in desiccation-sensitive wheat seedling root was higher than that in desiccation-tolerant wheat axis and considerably increased at the onset of water loss. We suggest that partitioning of amphipaths fluidize the membrane surface, but that in desiccation-tolerant systems the membranes are protected from excessive fluidization.

  7. Membrane behavior as influenced by partitioning of amphiphiles during drying : a comparative study in anhydrobiotic plant systems

    NARCIS (Netherlands)

    Golovina, E.A.; Hoekstra, F.A.

    2002-01-01

    During cellular desiccation, reduction in volume can in principle cause amphiphilic compounds to partition from the cytoplasm into membranes, with structural perturbance as the result. Here, we studied the effect of partitioning of endogenous amphiphiles on membrane surface dynamics in desiccation-t

  8. Bioinformatic prediction of arthropod/nematode-like peptides in non-arthropod, non-nematode members of the Ecdysozoa.

    Science.gov (United States)

    Christie, Andrew E; Nolan, Daniel H; Garcia, Zachery A; McCoole, Matthew D; Harmon, Sarah M; Congdon-Jones, Benjamin; Ohno, Paul; Hartline, Niko; Congdon, Clare Bates; Baer, Kevin N; Lenz, Petra H

    2011-02-01

    The Onychophora, Priapulida and Tardigrada, along with the Arthropoda, Nematoda and several other small phyla, form the superphylum Ecdysozoa. Numerous peptidomic studies have been undertaken for both the arthropods and nematodes, resulting in the identification of many peptides from each group. In contrast, little is known about the peptides used as paracrines/hormones by species from the other ecdysozoan taxa. Here, transcriptome mining and bioinformatic peptide prediction were used to identify peptides in members of the Onychophora, Priapulida and Tardigrada, the only non-arthropod, non-nematode members of the Ecdysozoa for which there are publicly accessible expressed sequence tags (ESTs). The extant ESTs for each phylum were queried using 106 arthropod/nematode peptide precursors. Transcripts encoding calcitonin-like diuretic hormone and pigment-dispersing hormone (PDH) were identified for the onychophoran Peripatopsis sedgwicki, with transcripts encoding C-type allatostatin (C-AST) and FMRFamide-like peptide identified for the priapulid Priapulus caudatus. For the Tardigrada, transcripts encoding members of the A-type allatostatin, C-AST, insect kinin, orcokinin, PDH and tachykinin-related peptide families were identified, all but one from Hypsibius dujardini (the exception being a Milnesium tardigradum orcokinin-encoding transcript). The proteins deduced from these ESTs resulted in the prediction of 48 novel peptides, six onychophoran, eight priapulid and 34 tardigrade, which are the first described from these phyla.

  9. Germ cell cluster organization and oogenesis in the tardigrade Dactylobiotus parthenogeneticus Bertolani, 1982 (Eutardigrada, Murrayidae).

    Science.gov (United States)

    Poprawa, Izabela; Hyra, Marta; Rost-Roszkowska, Magdalena Maria

    2015-07-01

    Germ cell cluster organization and the process of oogenesis in Dactylobiotus parthenogeneticus have been described using transmission electron microscopy and light microscopy. The reproductive system of D. parthenogeneticus is composed of a single, sac-like, meroistic ovary and a single oviduct that opens into the cloaca. Two zones can be distinguished in the ovary: a small germarium that is filled with oogonia and a vitellarium that is filled with germ cell clusters. The germ cell cluster, which has the form of a modified rosette, consists of eight cells that are interconnected by stable cytoplasmic bridges. The cell that has the highest number of stable cytoplasmic bridges (four bridges) finally develops into the oocyte, while the remaining cells become trophocytes. Vitellogenesis of a mixed type occurs in D. parthenogeneticus. One part of the yolk material is produced inside the oocyte (autosynthesis), while the second part is synthesized in the trophocytes and transported to the oocyte through the cytoplasmic bridges. The eggs are covered with two envelopes: a thin vitelline envelope and a three-layered chorion. The surface of the chorion forms small conical processes, the shape of which is characteristic for the species that was examined. In our paper, we present the first report on the rosette type of germ cell clusters in Parachela.

  10. A new tardigrade, Mutaparadoxipus duodigifinis gen. nov., sp. nov. (Heterotardigrada: Arthrotardigrada), from the Southeastern United States.

    Science.gov (United States)

    Gross, Vladimir; Miller, William R; Hochberg, Rick

    2014-07-10

    A new genus and species of Arthrotardigrada is described from Florida, USA based on its unique adhesive pad/claw combinations. Mutaparadoxipus duodigifinis gen. nov., sp. nov., is characterized by well-developed, ventral secondary clavae that are adjacent to the mouth, pointed lateral and caudal alae, seminal receptacles with coiled ducts opening lateral to the gonopore, and all legs with digits bearing proximal adhesive pads. Distal claws are present on digits I-III of legs I-III, but are missing from digit IV. On leg IV, distal claws are present only on digits II & III. A single accessory point is present on claws II & III only. This is the fourth species discovered to date with proximal adhesive pads, increasing support for a clade of adhesive-padded arthrotardigrades, and is likely the sister taxon of Paradoxipus orzeliscoides. The incomplete set of claws may represent an evolutionary step in a progressive loss of claws hypothesized to have occurred within the Halechiniscidae. The subfamily Orzeliscinae is amended as a result.

  11. Tolerance to Ammonia of Thulinius ruffoi (Bertolani, 1981), a Tardigrade Isolated from a Sewage Treatment Plant.

    Science.gov (United States)

    Sobczyk, Mateusz; Michno, Klaudia; Kosztyła, Paulina; Stec, Daniel; Michalczyk, Łukasz

    2015-12-01

    The acute toxicity of ammonia on Thulinius ruffoi (Bertolani, 1981), a eutardigrade isolated from a small waste water treatment plant (WWTP) in Poland, was estimated. Our results show that no active individuals survived a 24 h exposure to solutions equal to or higher than 125 mg/L of total ammonia nitrogen (NH3-N + NH4 (+)-N), which, under the conditions in our experiment, was equivalent to 1.17 mg/L of un-ionised ammonia (NH3). The LC50 concentration of total ammonia nitrogen was equal to 52 mg/L (or 0.65 mg/L un-ionised ammonia). Given that the norms for the concentration of ammonia in treated waters leaving WWTPs are usually several times lower than the LC50 for T. ruffoi, this species does not seem to be a good bioindicator candidate for WWTPs. In this paper we also note that various ecotoxicological studies use different methodological approaches and we suggest that a more uniform methodology may aid interspecific comparisons of LC50 values.

  12. Characterization of cyclomorphic stages in the marine tardigrade Halobiotus crispae

    DEFF Research Database (Denmark)

    Halberg, Kenneth Agerlin; Mortensen, Hans Ramløv; Westh, Peter

    2008-01-01

    experience large changes in total body volume, yet exhibit a regulatory volume decrease/increase over a 48 h period. Hemolymph osmolality was measured by melting point depression in a nanoliter osmometer. In animals kept at 20 ppt the hemolymph osmotic pressure was 926 ± 29 mOsm/kg (n = 6). This value...

  13. Published records of limno-terrestrial tardigrades (Tardigrada: Heterotardigrada, Eutardigrada from Vrachanski Balkan Nature Park

    Directory of Open Access Journals (Sweden)

    DILIAN GEORGIEV

    2016-05-01

    Full Text Available The following 6 species were reported for the area by Iharos (1961: Echiniscus testudo, Ramazzottius oberhaeuseri, Hypsibius convergens, Macrobiotus hufelandi, Minibiotus intermedius, Paramacrobiotus richtersi. Specimens from the Macrobiotus hufelandi species group were recorded and during present study from one locality.

  14. New records of marine tardigrades from Moorea, French Polynesia, with the description of Styraconyx turbinarium sp. nov. (Arthrotardigrada, Halechiniscidae).

    Science.gov (United States)

    Bartels, Paul J; Fontoura, Paulo; Nelson, Diane R

    2015-05-05

    Five marine arthrotardigrade species are recorded from Moorea, Society Islands, French Polynesia. Four were collected from coral sand; two, Dipodarctus anaholiensis Pollock, 1995 and Florarctus kwoni Chang & Rho, 1997, are new records for the region, and two, Halechiniscus perfectus Schulz, 1955 and Styraconyx kristenseni kristenseni Renaud-Mornant, 1981, have been previously reported. The fifth, a new species Styraconyx turbinarium sp. nov., is described and was collected from the drifting brown alga Turbinaria ornata. The new species is characterized by the presence of peduncles on all digits, an elongate primary clava, and the lateral cirrus A arising from a common pedestal and enveloped by a common membrane extending almost to the claval tip. The new species differs from the most similar species, Styraconyx tyrrhenus D'Addabbo Gallo, Morone De Lucia & de Zio Grimaldi, 1989, by having longer and differently shaped primary clavae which are elongated in the new species and club-shaped in S. tyrrhenus. By having a dorsal cuticle that is coarsely punctated but without folds or other ornamentations, the new species can be easily distinguished from S. craticulus (Pollock, 1983), a species with similar primary clavae, but with cuticular dorsal folds ornamented with a grid-like pattern.

  15. Ovary organization and oogenesis in the tardigrade Macrobiotus polonicus Pilato, Kaczmarek, Michalczyk & Lisi, 2003 (Eutardigrada, Macrobiotidae): ultrastructural and histochemical analysis.

    Science.gov (United States)

    Poprawa, Izabela; Schlechte-Wełnicz, Weronika; Hyra, Marta

    2015-05-01

    The female reproductive system, the process of oogenesis, and the morphology of the egg capsule of Macrobiotus polonicus were analyzed using transmission and scanning electron microscopy and histochemical methods. The female reproductive system of Macrobiotus polonicus consists of a single ovary and a single oviduct that opens into the cloaca. The seminal receptacle filled with sperm cells is present. The ovary is divided into two parts: a germarium that is filled with oogonia and a vitellarium that is filled with branched clusters of the germ cells. Meroistic oogenesis occurs in the species that was examined. The yolk material is synthesized by the oocyte (autosynthesis) and by the trophocytes and is transported to the oocyte through cytoplasmic bridges. The process of the formation of the egg envelopes starts in the late vitellogenesis. The egg capsule is composed of two envelopes-the vitelline envelope and the three-layered chorion. The vitelline envelope is of the primary type while the chorion is of a secondary type. The surface of the chorion is covered with conical processes that terminate with a strongly indented terminal disc.

  16. The deep sea elements of the Faroe Bank tardigrade fauna with a description of two new species

    Directory of Open Access Journals (Sweden)

    Jesper GULDBERG HANSEN

    2007-09-01

    Full Text Available Two new marine Tardigrada species are described from the calcareous sediments at the steep slope of the Faroe Bank in the North Atlantic Ocean. Parmursa torquata sp. nov. can be distinguished mainly by small cylindrical secondary clavae, and the presence of caudal and cephalic vesicles, and a large ventral plate. Coronarctus verrucatus sp. nov. is characterised by its unique cuticular sculpture, with numerous small wart-like excrescences, regularly distributed all over the body. These new records from the relatively shallow water of the Faroe Bank (200-260 m further widen the range of Parmursa and Coronarctus distribution and diversity, especially regarding the genus Parmursa, which to date has remained monospecific.

  17. Progress of Research on Diversity of Tardigrades%缓步动物多样性的研究进展

    Institute of Scientific and Technical Information of China (English)

    王立志

    2010-01-01

    缓步动物遗传多样性的研究包括染色体染色技术、核基因和线粒体基因的序列分析以及细胞色素c基因分析几个方面.其包括3纲、5目、13科、100多属,约1 000种.不同生境中的缓步动物种群密度具有明显的差异.目前,缓步动物群落多样性的研究主要集中在海拔对缓步动物群落的影响方面.本文按照缓步动物生态学前沿研究的发展趋势,结合我国的研究现状,简要概述了其在遗传、物种和生态系统多样性方面的研究进展与成就,并对今后的研究提出几点建议.

  18. 缓步动物应用前景初探%Primary Discussion on Application Prospect of Tardigrade

    Institute of Scientific and Technical Information of China (English)

    陈玉祥; 肖欣

    2010-01-01

    简要介绍了缓步动物的生物学习性,展望了缓步动物在科学研究、医疗和商业等方面的应用前景,重点讨论了缓步动物作为模式动物及其在生物材料保存和航天工程领域的应用价值.

  19. Resistance to Extreme Stresses in the Tardigrada: Experiments on Earth and in Space and Astrobiological Perspectives

    Science.gov (United States)

    Rebecchi, L.; Altiero, T.; Guidetti, R.; Cesari, M.; Rizzo, A. M.; Bertolani, R.

    2010-04-01

    The ability of tardigrades to enter cryptobiosis al-lows them to resist to extreme stresses: very low or high temperatures, chemicals, high pressure, ionizing and UV radiations This has lead to propose tardigrades as suitable model in space research.

  20. Anhydrobiosis and Freezing-Tolerance

    DEFF Research Database (Denmark)

    McGill, Lorraine; Shannon, Adam; Pisani, Davide

    2015-01-01

    Anhydrobiotic animals can survive the loss of both free and bound water from their cells. While in this state they are also resistant to freezing. This physiology adapts anhydrobiotes to harsh environments and it aids their dispersal. Panagrolaimus davidi, a bacterial feeding anhydrobiotic nematode...... isolated from Ross Island Antarctica, can survive intracellular ice formation when fully hydrated. A capacity to survive freezing while fully hydrated has also been observed in some other Antarctic nematodes. We experimentally determined the anhydrobiotic and freezing-tolerance phenotypes of 24...... of the davidi and the superbus clades were anhydrobiotic and also possessed robust freezing tolerance, along with a capacity to inhibit the growth and recrystallization of ice crystals. Unlike other endemic Antarctic nematodes, the life history traits of P. davidi do not show evidence of an evolved response...

  1. 江西省缓步动物四个新纪录种记述%Four New Records of Tardigrada for Tardigrade Fauna of Jiangxi Province

    Institute of Scientific and Technical Information of China (English)

    郁笛

    2006-01-01

    本文报道了江西省缓步动物4个新记录种:双裂角棘影熊虫Cornechiniscus lobatus Ramazzotti,1943(异缓步纲,棘影熊虫科),节值大生熊虫Macrobiotus harmsworthi Murray, 1907(真缓步纲,大生熊虫科),胡氏大生熊虫Macrobiotus hufelandi Schultze, 1833 (大生熊虫科)和杜氏高生熊虫Hypsibius dujardini Doyére, 1840(高生熊虫科).

  2. Two new records of Tardigrades from Anhui province%安徽省缓步动物两新纪录种记述

    Institute of Scientific and Technical Information of China (English)

    熊成香; 王怡婷; 王大勇

    2008-01-01

    记述了安徽省缓步动物两新纪录种,分别是:Macrobiotus adelges Dastych, 1977和Macrobiotus richtersi Murray 1911,此两种均属于真缓步纲(Eutardigrada)并爪目(Parachela)大生科(Macrobiotidae)大生属(Macrobiotus),在安徽省属首次发现.

  3. Advancement of DNA Barcoding in Taxonomy of Tardigrade%DNA条形编码技术在缓步动物分类中的研究进展

    Institute of Scientific and Technical Information of China (English)

    肖欣; 李晓晨

    2010-01-01

    缓步动物是一种十分微小的水生无脊椎动物,用传统的形态分类学方法对其进行物种鉴定难度较大.DNA条形编码技术是近几年用于物种分类、鉴定等研究的一种新兴的分子学技术.

  4. Comparison of tardigrade community structure along altitude gradient%不同海拔缓步动物群落结构的比较

    Institute of Scientific and Technical Information of China (English)

    刘莹; 李晓晨

    2006-01-01

    为研究海拔对缓步动物群落结构的影响,对地处秦岭北坡的南五台山缓步动物群落进行了初步调查研究.调查设置3个样区、45个样方,共采集缓步动物919个,个体密度平均816.89个·m-2,隶属缓步动物门2纲2目3科7属11种.其中Macrobiotus hufelandi和M.harmsworthi共占总采量的92.93%,为优势类群.采用Simpson指数、Shannon-Wiener信息指数、Pielou均匀度指数和修正的Hill指数来计算各生境缓步动物群落结构特点.研究表明,海拔对缓步动物群落结构有一定的影响.随着海拔的下降其物种的个体数量、群落优势类群的数量和优势物种数都呈下降趋势;物种多样性的变化趋势为中海拔地区>低海拔地区>高海拔地区,而群落优势度的变化趋势完全相反;不同海拔样区的群落相似性较低.

  5. Science Notes.

    Science.gov (United States)

    Thurman, Shirley; And Others

    1988-01-01

    Describes 36 science activities. Topics include: osmosis, fermentation, anhydrobiotic organisms, breathing monitors, trypsin, weeds, amyloplasts, electrolysis, polarimeters, ethene ripening of fruit, colorimetry, diffusion, redox reactions, equilibria, acid-base relationships, electricity, power, resonance, measurement, parallax, amplifiers,…

  6. Anhydrobiosis and freezing-tolerance: adaptations that facilitate the establishment of Panagrolaimus nematodes in polar habitats.

    Directory of Open Access Journals (Sweden)

    Lorraine M McGill

    Full Text Available Anhydrobiotic animals can survive the loss of both free and bound water from their cells. While in this state they are also resistant to freezing. This physiology adapts anhydrobiotes to harsh environments and it aids their dispersal. Panagrolaimus davidi, a bacterial feeding anhydrobiotic nematode isolated from Ross Island Antarctica, can survive intracellular ice formation when fully hydrated. A capacity to survive freezing while fully hydrated has also been observed in some other Antarctic nematodes. We experimentally determined the anhydrobiotic and freezing-tolerance phenotypes of 24 Panagrolaimus strains from tropical, temperate, continental and polar habitats and we analysed their phylogenetic relationships. We found that several other Panagrolaimus isolates can also survive freezing when fully hydrated and that tissue extracts from these freezing-tolerant nematodes can inhibit the growth of ice crystals. We show that P. davidi belongs to a clade of anhydrobiotic and freezing-tolerant panagrolaimids containing strains from temperate and continental regions and that P. superbus, an early colonizer at Surtsey island, Iceland after its volcanic formation, is closely related to a species from Pennsylvania, USA. Ancestral state reconstructions show that anhydrobiosis evolved deep in the phylogeny of Panagrolaimus. The early-diverging Panagrolaimus lineages are strongly anhydrobiotic but weakly freezing-tolerant, suggesting that freezing tolerance is most likely a derived trait. The common ancestors of the davidi and the superbus clades were anhydrobiotic and also possessed robust freezing tolerance, along with a capacity to inhibit the growth and recrystallization of ice crystals. Unlike other endemic Antarctic nematodes, the life history traits of P. davidi do not show evidence of an evolved response to polar conditions. Thus we suggest that the colonization of Antarctica by P. davidi and of Surtsey by P. superbus may be examples of recent

  7. Anhydrobiosis and freezing-tolerance: adaptations that facilitate the establishment of Panagrolaimus nematodes in polar habitats.

    Science.gov (United States)

    McGill, Lorraine M; Shannon, Adam J; Pisani, Davide; Félix, Marie-Anne; Ramløv, Hans; Dix, Ilona; Wharton, David A; Burnell, Ann M

    2015-01-01

    Anhydrobiotic animals can survive the loss of both free and bound water from their cells. While in this state they are also resistant to freezing. This physiology adapts anhydrobiotes to harsh environments and it aids their dispersal. Panagrolaimus davidi, a bacterial feeding anhydrobiotic nematode isolated from Ross Island Antarctica, can survive intracellular ice formation when fully hydrated. A capacity to survive freezing while fully hydrated has also been observed in some other Antarctic nematodes. We experimentally determined the anhydrobiotic and freezing-tolerance phenotypes of 24 Panagrolaimus strains from tropical, temperate, continental and polar habitats and we analysed their phylogenetic relationships. We found that several other Panagrolaimus isolates can also survive freezing when fully hydrated and that tissue extracts from these freezing-tolerant nematodes can inhibit the growth of ice crystals. We show that P. davidi belongs to a clade of anhydrobiotic and freezing-tolerant panagrolaimids containing strains from temperate and continental regions and that P. superbus, an early colonizer at Surtsey island, Iceland after its volcanic formation, is closely related to a species from Pennsylvania, USA. Ancestral state reconstructions show that anhydrobiosis evolved deep in the phylogeny of Panagrolaimus. The early-diverging Panagrolaimus lineages are strongly anhydrobiotic but weakly freezing-tolerant, suggesting that freezing tolerance is most likely a derived trait. The common ancestors of the davidi and the superbus clades were anhydrobiotic and also possessed robust freezing tolerance, along with a capacity to inhibit the growth and recrystallization of ice crystals. Unlike other endemic Antarctic nematodes, the life history traits of P. davidi do not show evidence of an evolved response to polar conditions. Thus we suggest that the colonization of Antarctica by P. davidi and of Surtsey by P. superbus may be examples of recent "ecological fitting

  8. Neuroanatomy of Tardigrada

    DEFF Research Database (Denmark)

    Persson, Dennis Krog

    The organization of the tardigrade nervous system is important for inference of phylogenetic relationships; however, there is some uncertainties regarding the structure and even existence of certain nervous structures. Therefore, a detailed description of the tardigrade neuroanatomy, and especial...... and papilla cephalica of H. crispae. Furthermore, the organisation of the brain strengthens the position of tardigrada in Panarthropoda, and provides evidence of a cephalisation of several anterior segments in the tardigrade ancestor....

  9. The Shock Response of Space Bears: The Ability of Life to Survive Some of the Most Extreme Environments Known to Man

    Science.gov (United States)

    Painter, Jonathon; Leighs, James; Appleby-Thomas, Gareth; Hazael, Rachael; McMillan, Paul; Kristensen, Reinhardt

    2013-06-01

    There have been many recent discoveries of life forms living in environments previously thought to be completely uninhabitable. One particularly interesting discovery of this na- ture is the space bear or tardigrade. The name space bear is a colloquialism applied to the tardigrades because of a recent investigation which saw them being exposed to the vacuum of space and intense solar radiation, and surviving. Tardigrades have the ability to dehy- drate themselves, entering a state called cryptobiosis. This state enables them to survive in the vacuum of space. A single stage gas gun has been employed to uniaxially shock load and subsequently recover tardigrades in both regular and cryptobiotic states. Loading histories were calculated via hydrocode modelling. Survival data is presented comparing shocked and control samples for tardigrades both in normal and cryptobiotic states.

  10. G-Equivalent Acceleration Tolerance in the Eutardigrade Species Hypsibius dujardini

    Science.gov (United States)

    Vasanthan, Tarushika; Alejaldre, Lorea; Hider, Jessica; Patel, Shreya; Husain, Nabiha; Umapathisivam, Bavithra; Stone, Jonathon

    2017-01-01

    Tardigrades are microscopic organisms renowned for their ability to survive extreme environmental conditions. Tardigrade extreme-tolerance research has centered on the ability to withstand desiccation, low and high temperatures, and high hydrostatic pressure and radiation levels. Tardigrade tolerance to hypergravity, however, has yet to be described. We used the eutardigrade species Hypsibius dujardini to investigate short-term tolerance to g-equivalent accelerations (i.e., mimicking g-forces). Data obtained from specimens centrifuged between 3421g and 16,060g for 1 min inclusively reveal tolerance in an acceleration-dependent relation, with lower survivorship and egg production at higher accelerations. This is the first study to demonstrate tardigrade potential for tolerance to hypergravity and describe expected effects on tardigrade survival and reproduction. These findings will prove to be useful in lithopanspermia research (i.e., viable spread in meteoritic rocks).

  11. Two New Recorded Species of Tardigrades (Tardigrada, Macrobiotidae, Hypsibiidae) from China%中国缓步动物2新纪录种(缓步动物门,大生熊虫科,高生熊虫科)记述

    Institute of Scientific and Technical Information of China (English)

    刘莹

    2008-01-01

    本文记述了缓步动物门2新纪录种,阿瑞科姆大生熊虫Macrobiotus ariekammensis Wêglarska, 1965和帕氏双相熊虫Diphascon patanei Binda & Pilato, 1971.阿瑞科姆大生熊虫模式标本爪无附棘,但中国标本有.帕氏双相熊虫模式标本的吸咽较来自中国标本的吸咽要短圆一些,前者吸咽的长宽比是1.21~1.25∶1,而后者的吸咽平均长宽比为1.47∶1.

  12. 缓步动物条形码及7种缓步动物系统发育研究%A Primary Study on Barcoding and Phylogeny of 7 Species of Tardigrades

    Institute of Scientific and Technical Information of China (English)

    王广明

    2011-01-01

    缓步动物属于微小水生无脊椎动物,以隐生现象著称.该实验对4种缓步动物11个个体的CO Ⅰ基因序列进行提取测定和分析,并与GenBank中下栽的6种缓步动物19条CO Ⅰ基因序列进行比对分析,用贝叶斯法(BI)构建系统发育树,研究了共计7种缓步动物30个个体之间的系统发育关系.研究发现,缓步动物在DNA分子层面的分类与形态学分类结果基本一致,表明CO Ⅰ基因可用于研究缓步动物系统分类及系统发育方面的问题.

  13. Surface enhanced Raman scattering on Tardigrada--towards monitoring and imaging molecular structures in live cryptobiotic organisms.

    Science.gov (United States)

    Kneipp, Harald; Møbjerg, Nadja; Jørgensen, Aslak; Bohr, Henrik G; Hélix-Nielsen, Claus; Kneipp, Janina; Kneipp, Katrin

    2013-10-01

    Tardigrades are microscopic metazoans which are able to survive extreme physical and chemical conditions by entering a stress tolerant state called cryptobiosis. At present, the molecular mechanisms behind cryptobiosis are still poorly understood. We show that surface enhanced Raman scattering supported by plasmonic gold nanoparticles can measure molecular constituents and their local distribution in live tardigrades. Surface enhanced Raman signatures allow to differentiate between two species and indicate molecular structural differences between tardigrades in water and in a dry state. This opens new avenues for exploring cryptobiosis by studying molecular changes in live cryptobiotic organisms.

  14. Osmoregulation with Focus on Fluid and Solute Dynamics in Tardigradia

    DEFF Research Database (Denmark)

    Halberg, Kenneth Agerlin

    , with the main focus being on fluid and solute dynamics in Tardigrada. For example, the inorganic ion composition of several species was investigated, which revealed that tardigrades contain roughly similar relative contributions of inorganic ions to total osmotic concentration, when compared to closely related...... animal groups. Moreover, it was inferred that cryptobiotic tardigrades (species able to enter a state of latent life) contain a large fraction of organic osmolytes. The mechanisms of organic anion transport in a marine species of tardigrade was investigated pharmacologically, and compared...... to that of insects. These data showed that organic anion transport is localized to the midgut epithelium and that the transport is both active and transporter mediated with a pharmacological profile similar to that of insects. Tardigrades survive in a variety of osmotic environments (semi-terrestrial, limnic...

  15. Inorganic ion composition in Tardigrada

    DEFF Research Database (Denmark)

    Halberg, Kenneth Agerlin; Larsen, Kristine Wulff; Jørgensen, Aslak;

    2013-01-01

    Many species of tardigrades are known to tolerate extreme environmental stress, yet detailed knowledge of the mechanisms underlying the remarkable adaptations of tardigrades is still lacking, as are answers to many questions regarding their basic biology. Here, we present data on the inorganic ion...... indicates that Na(+) and Cl(-) are the principle inorganic ions in tardigrade fluids, albeit other ions, i.e. K(+), NH(4)(+), Ca(2+), Mg(2+), F(-), SO(4)(2-) and PO(4)(3-) were also detected. In limno-terrestrial tardigrades, the respective ions are concentrated by a large factor compared......+) and F(-) are only slightly concentrated (×2-10). An anion deficit of ~120 mEq 1(-1) in M. tardigradum and H. crispae indicates the presence of unidentified ionic components in these species. Body fluid osmolality ranges from 361±49 mOsm kg(-1) in R. coronifer to 961±43 mOsm kg(-1) in H. crispae...

  16. Diversity and distribution of Tardigrada in Arctic cryoconite holes

    Directory of Open Access Journals (Sweden)

    Krzysztof Zawierucha

    2016-06-01

    Full Text Available Despite the fact that glaciers and ice sheets have been monitored for more than a century, knowledge on the glacial biota remains poor. Cryoconite holes are water-filled reservoirs on a glacier’s surface and one of the most extreme ecosystems for micro-invertebrates. Tardigrada, also known as water bears, are a common inhabitant of cryoconite holes. In this paper we present novel data on the morphology, diversity, distribution and role in food web of tardigrades on Arctic glaciers. From 33 sampled cryoconite holes of 6 glaciers on Spitsbergen, in 25 tardigrades were found and identified. Five taxa of Tardigrada (Eutardigrada were found in the samples, they are: Hypsibius dujardini, Hypsibius sp. A, Isohypsibius sp. A., Pilatobius recamieri, and one species of Ramazzottiidae. H. dujardini and P. recamieri were previously known from tundra in the Svalbard archipelago. Despite the number of studies on Arctic tundra ecosystems, Hypsibius sp. A, one species of Ramazzottiidae and Isohypsibius sp. A are known only from cryoconite holes. Tardigrade found in this study do not falsify the hypothesis that glaciers and ice sheets are a viable biome (characteristic for biome organisms assemblages - tardigrades. Diagnosis of Hypsibius sp. A, Isohypsibius sp. A, and species of Ramazzottiidae with discussion on the status of taxa, is provided. To check what analytes are associated with the presence of tardigrades in High Arctic glacier chemical analyses were carried out on samples taken from the Buchan Glacier. pH values and the chemical composition of anions and cations from cryoconite hole water from the Buchan Glacier are also presented. The current study on the Spitsbergen glaciers clearly indicates that tardigrade species richness in cryoconite holes is lower than tardigrade species richness in Arctic tundra ecosystems, but consists of unique cryoconite hole species. As cryoconite tardigrades may feed on bacteria as well as algae, they are primary

  17. Limno-terrestrial Tardigrada of the Nearctic Realm

    Directory of Open Access Journals (Sweden)

    Juliana G. HINTON

    2007-09-01

    Full Text Available We examined all available records of limno-terrestrial tardigrade distribution in the Nearctic realm (Greenland, Canada, Alaska, the continental United States of America, and northern Mexico, both to compare this fauna with other realms and to investigate distribution within North America. We included only those records in which tardigrades had been identified to species. Of 204 Nearctic limno-terrestrial tardigrade species, 38 were cosmopolitan, while 55 were unique to the Nearctic realm. The Nearctic tardigrade fauna is most similar to the Palearctic, with 135 species in common, 39 of which have not been reported elsewhere. The Nearctic realm shares 82 species with the Neotropical realm, only 10 which are not also Palearctic. These data are consistent with the geological history of the three realms, and indicate a distinction between Laurasian and Gondwanan tardigrade faunas. Although little is known about limno-terrestrial tardigrade distribution in much of North America, there are several excellent regional or local surveys. Many species are distributed widely throughout the continent, but 30.0% of Nearctic species have been reported from a single site. Cluster analysis of the fauna of 11 Nearctic regions shows that the Arctic and sub-Arctic fauna constitute a regional fauna distinct from the rest of the continent. Ecological analysis is hampered by inconsistent reporting of tardigrade substrate, though available data suggest little substrate specificity in terrestrial tardigrades. Most species are found in both mosses and lichens. Many are also present in soil and leaf litter, but few are found only in these substrates.

  18. Notes on the cryptobiotic capability of the marine arthrotardigrades Styraconyx haploceros (Halechiniscidae) and Batillipes pennaki (Batillipedidae) from the tidal zone in Roscoff, France

    DEFF Research Database (Denmark)

    Jørgensen, Aslak; Møbjerg, Nadja

    2015-01-01

    AbstractTardigrades are well known for their ability to survive extreme conditions such as desiccation and freezing by entering cryptobiosis, a state in which metabolism becomes immeasurable. Within tardigrades, cryptobiosis has been investigated almost entirely in eutardigrades and echiniscoidea...... and distilled water for extended periods. Batillipes pennaki, which lives in sandy sediments, is vulnerable to both desiccation and distilled water, and can only survive extreme conditions for brief periods of time....

  19. Meiofaunal Richness in Highly Acidic Hot Springs in Unzen-Amakusa National Park, Japan, Including the First Rediscovery Attempt for Mesotardigrada.

    Science.gov (United States)

    Suzuki, Atsushi C; Kagoshima, Hiroshi; Chilton, Glen; Grothman, Gary T; Johansson, Carl; Tsujimoto, Megumu

    2017-02-01

    Extreme environments sometimes support surprisingly high meiofaunal diversity. We sampled runoff from the acidic hot springs of Unzen, Japan. This is the type locality of Thermozodium esakii Rahm, 1937, the only tardigrade in the class Mesotardigrada, which remains contentious in the absence of corroboration or supporting specimens. Our sampling revealed at least three species of arthropods, four rotifers, and five nematodes living in the hot (ca. 40°C) and acidic (ca. pH 2.5) water, but no tardigrades.

  20. The coastal marine Tardigrada of the Americas.

    Science.gov (United States)

    Miller, William R; Perry, Emma S

    2016-06-20

    The Western Hemisphere or the New World, also known as the Americas (North, Central and South America, associated islands and included seas) have historically been divided into two Realms, the Nearctic and Neotropical based on terrestrial biogeography. The coasts of these two terrestrial realms are bordered by six marine realms, 14 marine provinces and 67 marine ecoregions. From current literature, a comprehensive list of the marine tardigrade fauna from the Americas is presented. Data on marine tardigrades were obtained from 385 published Records of the Occurrence (RoO) of a species, their location, tidal zone, and the substrates from which they were reported. Authors' identifications were accepted at face value unless subsequently amended. Thirty genera and 82 species or subspecies are reported from the Americas; 49 species are documented from margins of the terrestrial Nearctic realm (North America) and 48 from terrestrial Neotropical realm (South America) with only 17 species occurring in both. We define cosmopolitan distribution for marine tardigrades as occurring in or on the margins of five of the seven oceans, only two species of marine tardigrade meets this standard. From the Americas 39 species have been described as new to science, 32 species appear restricted to the hemisphere. Taxa were assigned to marine ecoregions based on adjacent geopolitical units (country, states, provinces, etc.) described in published records. Although tardigrades have been reported from all six marine realms, they are only known from 21 of the 67 ecoregions. Most marine tardigrade sampling in the Americas has focused on near shore substrate (sand, mud, barnacles); for some species no substrates have been reported. The west coasts of both continents have little or no data about tardigrade presence.

  1. THE TARDIGRADES FROM SOME MOSSES OF LIJIANG COUNTY IN YUNNAN PROVINCE(HETEROTARDIGRADA: ECHINISCIDAE; EUTARDIGRADA: PARACHELA:MACROBIOTIDAE, HYPSIBIIDAE)%云南省丽江苔藓中缓步动物(异缓步纲:棘节目:棘影熊虫科;真缓步纲:近爪目:大生熊虫科,高生熊虫科)

    Institute of Scientific and Technical Information of China (English)

    杨潼

    2002-01-01

    记述了采自云南省丽江县的缓步动物13种,包括:安哥拉棘影熊虫Echiniscus angolensis da Cunha et al.,凹口棘影熊虫Echiniscus cavagnaroi Schuster, 米吉棘影熊虫Echiniscus migiurtinus Franceschi,华美假棘影熊虫 Pseudechiniscus facettalis Petersen,丽江苔小猪熊虫Bryodelphax lijiangensis sp. nov., 隐匿大生熊虫Macrobiotus adelges Dastych,云杉大生熊虫Macrobiotus yunshanensis sp.nov.,华丽大生熊虫Macrobiotus richtersi J.Murr.,双甲高生熊虫Hypsibius biscuitiformis Bartol,锐齿高生熊虫Hypsibius runae Bartol,棒形双相熊虫Diphascon clavatum (Bartol),云南等高熊虫Isohypsibius yunnanensis sp.nov.,隆肿等高熊虫Isohypsibius tuberculatus (Plate).本文所用标本均保存在中国科学院水生生物研究所.

  2. Introduction to the Proceedings

    Directory of Open Access Journals (Sweden)

    Lorena Rebecchi

    2007-09-01

    Full Text Available The Tenth International Symposium on Tardigrada took place in Catania, Italy from 18th to 23rd June 2006 and was held in the Auditorium of Benedettini, a fascinating historic building in Catania's downtown. There were seventy-one participants at the Symposium, representing fourteen countries. The Symposium provided a unique opportunity both to review the progress of tardigrade studies and to allow all delegates to meet and to discuss topics of common interest. The Symposium included thirty-four lectures and thirty-one poster presentations on a wide variety of topics in tardigrade biology. They included systematics, morphological and molecular phylogeny, faunal studies, biogeography, ecology, survival strategies, and modern molecular methodologies in tardigrade research. The twenty-four papers appearing in this special issue of the Journal of Limnology represent most of the contributors present in Catania.

  3. Osmoregulation with Focus on Fluid and Solute Dynamics in Tardigradia

    DEFF Research Database (Denmark)

    Halberg, Kenneth Agerlin

    a continuous traffic of compounds in and out of the organism. These demands appear to be in fundamental contradiction however cells and animals achieve so-called “steady-state” by means of an array of transport proteins, which provide a stringent control on the exchange of water and solutes across body......, with the main focus being on fluid and solute dynamics in Tardigrada. For example, the inorganic ion composition of several species was investigated, which revealed that tardigrades contain roughly similar relative contributions of inorganic ions to total osmotic concentration, when compared to closely related...... animal groups. Moreover, it was inferred that cryptobiotic tardigrades (species able to enter a state of latent life) contain a large fraction of organic osmolytes. The mechanisms of organic anion transport in a marine species of tardigrade was investigated pharmacologically, and compared...

  4. Tolerance to gamma radiation in the marine heterotardigrade, Echiniscoides sigismundi

    DEFF Research Database (Denmark)

    Jönsson, K. Ingemar; Hygum, Thomas Lunde; Andersen, Kasper Nørgaard;

    2016-01-01

    Tardigrades belong to the most radiation tolerant animals on Earth, as documented by a number of studies using both low-LET and high-LET ionizing radiation. Previous studies have focused on semi-terrestrial species, which are also very tolerant to desiccation. The predominant view on the reason...... for the high radiation tolerance among these semi-terrestrial species is that it relies on molecular mechanisms that evolved as adaptations for surviving dehydration. In this study we report the first study on radiation tolerance in a marine tardigrade, Echiniscoides sigismundi. Adult specimens in the hydrated...... active state were exposed to doses of gamma radiation from 100 to 5000 Gy. The results showed little effect of radiation at 100 and 500 Gy but a clear decline in activity at 1000 Gy and higher. The highest dose survived was 4000 Gy, at which ca. 8% of the tardigrades were active 7 days after irradiation...

  5. Tolerance to Gamma Radiation in the Marine Heterotardigrade, Echiniscoides sigismundi

    Science.gov (United States)

    Hygum, Thomas L.; Andersen, Kasper N.; Clausen, Lykke K. B.; Møbjerg, Nadja

    2016-01-01

    Tardigrades belong to the most radiation tolerant animals on Earth, as documented by a number of studies using both low-LET and high-LET ionizing radiation. Previous studies have focused on semi-terrestrial species, which are also very tolerant to desiccation. The predominant view on the reason for the high radiation tolerance among these semi-terrestrial species is that it relies on molecular mechanisms that evolved as adaptations for surviving dehydration. In this study we report the first study on radiation tolerance in a marine tardigrade, Echiniscoides sigismundi. Adult specimens in the hydrated active state were exposed to doses of gamma radiation from 100 to 5000 Gy. The results showed little effect of radiation at 100 and 500 Gy but a clear decline in activity at 1000 Gy and higher. The highest dose survived was 4000 Gy, at which ca. 8% of the tardigrades were active 7 days after irradiation. LD50 in the first 7 days after irradiation was in the range of 1100–1600 Gy. Compared to previous studies on radiation tolerance in semi-terrestrial and limnic tardigrades, Echiniscoides sigismundi seems to have a lower tolerance. However, the species still fits into the category of tardigrades that have high tolerance to both desiccation and radiation, supporting the hypothesis that radiation tolerance is a by-product of adaptive mechanisms to survive desiccation. More studies on radiation tolerance in tardigrade species adapted to permanently wet conditions, both marine and freshwater, are needed to obtain a more comprehensive picture of the patterns of radiation tolerance. PMID:27997621

  6. Tardigrada of Ireland: a review of records and an updated checklist of species including a new addition to the Irish fauna

    Directory of Open Access Journals (Sweden)

    Erica DeMilio

    2016-09-01

    Full Text Available The phylum Tardigrada was not recorded in Ireland until the Clare Island Survey of 1909–1911, with only rare subsequent reports on Irish tardigrade species. In recent decades, significant taxonomic revision has occurred within Tardigrada. This has resulted in the need for a review of all known historical records from Ireland and Northern Ireland in order to produce an updated checklist of valid taxa. The new checklist includes fifty-one tardigrade species and subspecies including a new addition to the Irish fauna reported herein, Echiniscus quadrispinosus quadrispinosus Richters, 1902 from Newtown, Ballyvaughan, Co. Clare.

  7. Tardigrada of Ireland: a review of records and an updated checklist of species including a new addition to the Irish fauna.

    Science.gov (United States)

    DeMilio, Erica; Lawton, Colin; Marley, Nigel J

    2016-01-01

    The phylum Tardigrada was not recorded in Ireland until the Clare Island Survey of 1909-1911, with only rare subsequent reports on Irish tardigrade species. In recent decades, significant taxonomic revision has occurred within Tardigrada. This has resulted in the need for a review of all known historical records from Ireland and Northern Ireland in order to produce an updated checklist of valid taxa. The new checklist includes fifty-one tardigrade species and subspecies including a new addition to the Irish fauna reported herein, Echiniscus quadrispinosus quadrispinosus Richters, 1902 from Newtown, Ballyvaughan, Co. Clare.

  8. The Zoogeography of Marine Tardigrada.

    Science.gov (United States)

    Kaczmarek, Łukasz; Bartels, Paul J; Roszkowska, Milena; Nelson, Diane R

    2015-11-02

    This monograph describes the global records of marine water bears (Phylum Tardigrada). We provide a comprehensive list of marine tardigrades recorded from around the world, providing an up-to-date taxonomy and a complete bibliography accompanied by geographic co-ordinates, habitat, substrate and biogeographic comments. A link is provided to an on-line interactive map where all occurrences for each species are shown. In total we list 197 taxa and their 2240 records from 39 oceans and seas and 18 Major Fishing Areas (FAO). It is hoped this work will serve as a reference point and background for further zoogeographic and taxonomic studies on marine tardigrades.

  9. Surface enhanced raman scattering on tardigrada - Towards monitoring and imaging molecular structures in live cryptobiotic organisms

    DEFF Research Database (Denmark)

    Kneipp, Harald; Møbjerg, Nadja; Jørgensen, Aslak

    2013-01-01

    Tardigrades are microscopic metazoans which are able to survive extreme physical and chemical conditions by entering a stress tolerant state called cryptobiosis. At present, the molecular mechanisms behind cryptobiosis are still poorly understood. We show that surface enhanced Raman scattering su....... This opens new avenues for exploring cryptobiosis by studying molecular changes in live cryptobiotic organisms....

  10. A new Batillipedidae (Tardigrada, Arthrotardigrada) from Argentina.

    Science.gov (United States)

    Menechella, Agustín G; Bulnes, Verónica N; Cazzaniga, Néstor J

    2015-10-16

    A new species of marine tardigrade, Batillipes acuticauda sp. n., has been found in midlittoral sand sediments collected at Monte Hermoso beach (Buenos Aires province, Argentina). The new species differs from all other members of Batillipedidae by its combination of caudal apparatus, lateral processes and toe patterns. It is the first description of an arthrotardigrade from Argentina.

  11. Inorganic ion composition in Tardigrada

    DEFF Research Database (Denmark)

    Halberg, Kenneth Agerlin; Larsen, Kristine Wulff; Jørgensen, Aslak

    2013-01-01

    are indicative of a powerful ion-retentive mechanism in Tardigrada. Moreover, our data indicate that cryptobiotic tardigrades contain a large fraction of unidentified organic osmolytes, the identification of which is expected to provide increased insight into the phenomenon of cryptobiosis....

  12. Distribution of limnoterrestrial Tardigrada in Georgia and the Gulf Coast states of the United States of America with ecological remarks

    Directory of Open Access Journals (Sweden)

    Harry A. MEYER

    2007-09-01

    Full Text Available This report is an effort to improve understanding of the distribution of limnoterrestrial tardigrades in Georgia and the states along the Gulf Coast of the United States of America. We collected 14 species of tardigrades from cryptogams (mosses, lichens, and liverworts and leaf litter in a statewide survey of Louisiana and reviewed all publications and theses reporting tardigrade distributions in the Gulf Coast states. Statewide surveys have been also conducted in Alabama, Florida, and Texas, while sampling in Mississippi and Georgia has been more localized. Currently 51 species have been identified in the region: 19 in Texas, 16 in Louisiana, 10 in Mississippi, 33 in Alabama, 3 in Georgia, and 15 in Florida. These tardigrades have been collected from cryptogams (mosses, lichens, and liverworts on trees and rocks, from soil and leaf litter, and from freshwater. Twenty species are widely distributed in the region (i.e., found in ≥ 2 non-contiguous states, while 27 have been found in only one state. Eighteen species are probably cosmopolitan. Seven species, widespread in the Gulf Coast states but unknown elsewhere in the Nearctic Region – Echiniscus kofordi, Echiniscus cavagnaroi, Parexapodibius pilatoi, Hexapodibius christenberryae, Biserovus bindae, Minibiotus fallax and a new Macrobiotus cf. hufelandi – may represent a distinctive regional fauna in cryptogams.

  13. Annotated zoogeography of non-marine Tardigrada. Part I: Central America.

    Science.gov (United States)

    Kaczmarek, Łukasz; Michalczyk, Łukasz; McInnes, Sandra J

    2014-02-05

    Dividing the world into nine regions, this first paper describes literature records of the limno-terrestrial tardigrades (Tardigrada) reported from Central America. Updating previously published species lists we have revised the taxonomy and provided additional habitat, geographic co-ordinates, and biogeographic comments. It is hoped this work will serve as a reference point and background for further zoogeographic studies.

  14. Current status of the tardigrada: evolution and ecology.

    Science.gov (United States)

    Nelson, Diane R

    2002-07-01

    The Tardigrada are bilaterally symmetrical micrometazoans with four pairs of lobopod legs terminating in claws or sucking disks. They occupy a diversity of niches in marine, freshwater, and terrestrial environments throughout the world. Some have a cosmopolitan distribution, while others are endemic. About 900 species have been described thus far, but many more species are expected as additional habitats are investigated. Most are less than 1 mm in body length and are opaque or translucent, exhibiting colors such as brown, green, orange, yellow, red, or pink in the cuticle and/or gut. Marine species are more variable in body shape and overall appearance and generally exhibit low population density with high species diversity. Reproductive modes include sexual reproduction and parthenogenesis, but much remains to be known about development. Tardigrades have a hemocoel-type of fluid-filled body cavity, a complete digestive tract, and a lobed dorsal brain with a ventral nerve cord with fused ganglia. Recent molecular analyses and additional morphological studies of the nervous system have confirmed the phylogenetic position of tardigrades as a sister group of the arthropods. The ability of tardigrades to undergo cryptobiosis has long intrigued scientists. Although tardigrades are active only when surrounded by a film of water, they can enter latent states in response to desiccation (anhydrobiosis), temperature (cryobiosis), low oxygen (anoxybiosis), and salinity changes (osmobiosis). Cryptobiotic states aid in dispersal.

  15. The diversity of Indian Ocean Heterotardigrada

    Directory of Open Access Journals (Sweden)

    Roberto SANDULLI

    2007-09-01

    Full Text Available Information about Indian Ocean tardigrades is quite scarce and in most cases refers to species in coastal coralline sediment and occasionally in abyssal mud. The present data concern species found in the intertidal sand of Coco and La Digue Islands in the Seychelles, previously unsampled for tardigrades, as well as species in subtidal sediment found at depths ranging between 1 and 60 m off the shores of the Maldive Atolls. These sediments are all very similar and consist of heterogeneous coralline sand, moderately or scarcely sorted. Sixteen species (three new to science were found in the Seychelles, belonging to Renaudarctidae, Stygarctidae, Halechiniscidae, Batillipedidae and Echiniscoididae. Diversity and evenness data are also interesting, with maximum values of H' = 2.59 and of J = 0.97. In the Maldives 25 species were found (two new to science belonging to Neostygarctidae, Stygarctidae, Halechiniscidae and Batillipedidae. Such a number of species, despite the low percentage of tardigrade fauna (only 0.6% of the total meiofauna, contributes to the high values of both diversity and evenness, with H' ranging between 1.5 and 2.6 and J between 0.6 and 1. The Indian Ocean tardigrade fauna currently numbers 31 species of Arthrotardigrada and 2 species of Echiniscoidida. In the present study, Arthrotardigrada are the most abundant and all the families are present except Neoarctidae. Halechiniscidae is present with all the sub-families (except Euclavartinae, thus contributing to the high diversity values. Furthermore, 18 species, representing more than 50% of the total marine tardigrade fauna, are new records for the Indian Ocean, including five species new to science.

  16. Area, depth and elevation of cryoconite holes in the Arctic do not influence Tardigrada densities

    Directory of Open Access Journals (Sweden)

    Zawierucha Krzysztof

    2016-06-01

    Full Text Available Water bears (Tardigrada are known as one of the most extremophile animals in the world. They inhabit environments from the deepest parts of the oceans up to the highest mountains. One of the most extreme and still poorly studied habitats which tardigrades inhabit are cryoconite holes. We analysed the relation between area, depth, elevation and tardigrades densities in cryoconite holes on four glaciers on Spitsbergen. The mean (±SD of cryoconite area was 1287.21±2400.8 cm2, while the depth was on average 10.8±11.2 cm, the elevation 172.6±109.66 m a.s.l., and tardigrade density 24.9±33.0 individuals per gram of wet material (n = 38. The densities of tardigrades on Hans Glacier reached values of up to 168 ind. cm3, 104 ind. g−1 wet weight, and 275 ind. g−1 dry weight. The densities of tardigrades of the three glaciers in Billefjorden were up to 82 ind. cm2, 326 ind. g−1 wet weight and 624 ind. g−1 dry weight. Surprisingly, although the model included area, depth and elevation as independent variables, it cannot explain Tardigrada density in cryoconite holes. We propose that due to the rapid melting of the glacier surface in the Arctic, the constant flushing of cryoconite sediments, and inter-hole water-sediment mixing, the functioning of these ecosystems is disrupted. We conclude that cryoconite holes are dynamic ecosystems for microinvertebrates in the Arctic.

  17. Partial mitochondrial gene arrangements support a close relationship between Tardigrada and Arthropoda.

    Science.gov (United States)

    Ryu, Shi Hyun; Lee, Ji Min; Jang, Kuem-Hee; Choi, Eun Hwa; Park, Shin Ju; Chang, Cheon Young; Kim, Won; Hwang, Ui Wook

    2007-12-31

    Regions (about 3.7-3.8 kb) of the mitochondrial genomes (rrnL-cox1) of two tardigrades, a heterotardigrade, Batillipes pennaki, and a eutardigrade, Pseudobiotus spinifer, were sequenced and characterized. The gene order in Batillipes was rrnL-V-rrnS-Q-I-M-nad2-W-C-Y-cox1, and in Pseudobiotus it was rrnL-V-rrnS-Q-M-nad2-W-C-Y-cox1. With the exception of the trnI gene, the two tardigrade regions have the same gene content and order. Their gene orders are strikingly similar to that of the chelicerate Limulus polyphemus (rrnL-V-rrnS-CR-I-Q-M-nad2-W-C-Y-cox1), which is considered to be ancestral for arthropods. Although the tardigrades do not have a distinct control region (CR) within this segment, the trnI gene in Pseudobiotus is located between rrnL-trnL1 and trnL2-nad1, and the trnI gene in Batillipes is located between trnQ and trnM. In addition, the 106-bp region between trnQ and trnM in Batillipes not only contains two plausible trnI genes with opposite orientations, but also exhibits some CR-like characteristics. The mitochondrial gene arrangements of 183 other protostomes were compared. 60 (52.2%) of the 115 arthropods examined have the M-nad2-W-C-Y-cox1 arrangement, and 88 (76.5%) the M-nad2-W arrangement, as found in the tardigrades. In contrast, no such arrangement was seen in the 70 non-arthropod protostomes studied. These are the first non-sequence molecular data that support the close relationship of tardigrades and arthropods.

  18. New records of tardigrades(Tardigrada) from Taiwan%台湾缓步动物(缓步动物门)新纪录种记述

    Institute of Scientific and Technical Information of China (English)

    阴环; 李晓晨

    2011-01-01

    报道了采自台湾的缓步动物(缓步动物门)的7个新纪录种.这些缓步动物属于2纲、3目、4科、5属,它们是翠绿棘甲熊虫Echiniscus viridisMurray、苏氏假棘甲熊虫Pseudechiniscus suillus(Ehrenberg)、凯氏米氏熊虫Milnesium katarzynae Kaczmarek et al.、山地大生熊虫Macrobiotus montanus Murray、瑞氏大生熊虫Macrobiotus richtersi Murray、吉伯具矛熊虫Doryphoribius%Seven new record species of tardigrades(Phylum Tardigrada) from Taiwan are reported.They belong to two classes,three orders,four families and five genera.They are Echiniscus viridis Murray,Pseudechiniscus suillus(Ehrenberg),Milnesium katarzynae Kaczmarek,Michalczyk Beasley,Macrobiotus montanus Murray,Macrobiotus richtersi Murray,Doryphoribius gibber Beasley Pilato,and Doryphoribius zappalai Pilato.A key to Taiwanese species of the tardirada is also given.

  19. Cryptobiosis: a new theoretical perspective.

    Science.gov (United States)

    Neuman, Yair

    2006-10-01

    The tardigrade is a microscopic creature that under environmental stress conditions undergoes cryptobiosis [Feofilova, E.P., 2003. Deceleration of vital activity as a universal biochemical mechanism ensuring adaptation of microorganisms to stress factors: A review. Appl. Biochem. Microbiol. 39, 1-18; Nelson, D.R., 2002. Current status of the tardigrada: Evolution and ecology. Integrative Comp. Biol. 42, 652-659]-a temporary metabolic depression-which is considered to be a third state between life and death [Clegg, J.S., 2001. Cryptobiosis-a peculiar state of biological organization. Comp. Biochem. Physiol. Part B 128, 613-624]. In contrast with death, cryptobiosis is a reversible state, and as soon as environmental conditions change, the tardigrade "returns to life." Cryptobiosis in general, and among the tardigrade in particular, is a phenomenon poorly understood [Guppy, M., 2004. The biochemistry of metabolic depression: a history of perceptions. Comp. Biochem. Physiol. Part B 139, 435-442; Schill, R.O., et al., 2004. Stress gene (hsp70) sequences and quantitative expression in Milensium tardigradum (Tardigrade) during active and cryptobiotic stages. J. Exp. Biol. 207, 1607-1613; Watanabe, M., et al., 2002. Mechanisn allowing an insect to survive complete dehydration and extreme temperatures. J. Exp. Biol. 205, 2799-2802; Wright, J.C., 2001. Cryptobiosis 300 years on from van Leuwenhoek: what have we learned about tardigrades? Zool. Anz. 240, 563-582]. Moreover, the ability of the tardigrade to bootstrap itself and to return to life seems paradoxical like the legendary Baron von Munchausen who pulled himself out of the swamp by grabbing his own hair. Two theoretical obstacles prevent us from advancing our knowledge of cryptobiosis. First, we lack appropriate theoretical understanding of reversible processes of biological computation in living systems. Second, we lack appropriate theoretical understanding of bootstrapping in living systems. In this short opinion

  20. Strong environmental tolerance of Artemia under very high pressure

    Science.gov (United States)

    Minami, K.; Ono, F.; Mori, Y.; Takarabe, K.; Saigusa, M.; Matsushima, Y.; Saini, N. L.; Yamashita, M.

    2010-03-01

    It was shown by the present authors group that a tardigrade in its tun-state can survive after exposed to 7.5 GPa for 13 hours. We have extended this experiment to other tiny animals searching for lives under extreme conditions of high hydrostatic pressure. Artemia, a kind of planktons, in its dried egg-state have strong environmental tolerance. Dozens of Artemia eggs were sealed in a small Teflon capsule together with a liquid pressure medium, and exposed to the high hydrostatic pressure of 7.5 GPa. After the pressure was released, they were soaked in seawater to observe hatching rate. It was proved that 80-90% of the Artemia eggs were alive and hatched into Nauplii after exposed to the maximum pressure of 7.5 GPa for up to 48 hours. Comparing with Tardigrades, Artemia are four-times stronger against high pressure.

  1. Segmentation in Tardigrada and diversification of segmental patterns in Panarthropoda.

    Science.gov (United States)

    Smith, Frank W; Goldstein, Bob

    2016-10-31

    The origin and diversification of segmented metazoan body plans has fascinated biologists for over a century. The superphylum Panarthropoda includes three phyla of segmented animals-Euarthropoda, Onychophora, and Tardigrada. This superphylum includes representatives with relatively simple and representatives with relatively complex segmented body plans. At one extreme of this continuum, euarthropods exhibit an incredible diversity of serially homologous segments. Furthermore, distinct tagmosis patterns are exhibited by different classes of euarthropods. At the other extreme, all tardigrades share a simple segmented body plan that consists of a head and four leg-bearing segments. The modular body plans of panarthropods make them a tractable model for understanding diversification of animal body plans more generally. Here we review results of recent morphological and developmental studies of tardigrade segmentation. These results complement investigations of segmentation processes in other panarthropods and paleontological studies to illuminate the earliest steps in the evolution of panarthropod body plans.

  2. An attempt to revisit the global biogeography of limno-terrestrial Tardigrada

    Directory of Open Access Journals (Sweden)

    Philip J.A. PUGH

    2007-09-01

    Full Text Available The major increase in distribution records of limno-terrestrial tardigrades over the last ten years has enabled us to reassess the global biogeography of the Tardigrada using cluster analysis, principal components analysis and parsimony analysis of endemism (PAE. Although the new clustergram topology shows a close correlation with those we originally presented in 1998, the PAE outputs warrant a radical reinterpretation of the results as they imply that the Laurasian fauna is derived and the Gondwanan groups basal. The distribution of endemic tardigrade genera and families provides some support for this argument though the findings should be viewed with some caution as PAE has its detractors and has not been previously applied on a 'global' scale.

  3. New records of Mexican Tardigrada Nuevos registros de Tardigrada mexicanos

    Directory of Open Access Journals (Sweden)

    Łukasz Kaczmarek

    2011-12-01

    Full Text Available In 9 moss samples collected from Mexico, 6 tardigrade species, including 4 new records for the country, were found. The new records raise the number of known Mexican water bear species to forty-one. We provide a full list of the known Mexican tardigrade species and discuss some biogeographical and taxonomic issues.En 9 muestras de musgo recolectadas en México, se encontraron 6 especies de tardígrados, incluyendo 4 nuevos registros para el país. Los nuevos registros incrementaron a 41 el número de especies de tardígrados mexicanos conocidos. Se proporciona una lista completa de tardígrados mexicanos conocidos y se discuten algunas cuestiones biogeográficas y taxonómicas.

  4. Modulating Radiation Resistance: Novel Protection Paradigms Based on Defenses against Ionizing Radiation in the Extrempohile Deinococcus radiodurans

    Science.gov (United States)

    2013-07-01

    cyanobacteria , lichens, alpine yeast, and tardigrades. 4.3 Knowns and Unknowns of Deinococcus Mn2+ Complexes It is worth reminding the reader...from radiation-induced damage and uncouple it from genome damage and organism killing. The Mn(2+) complex preserved antigenic structures in aqueous...PLoS ONE, 5(9), e12570. 10. K. S. Makarova, MICHAEL J. DALY (2010) Comparative genomics of stress response systems in Deinococcus bacteria

  5. Annotated zoogeography of non-marine Tardigrada. Part II: South America.

    Science.gov (United States)

    Kaczmarek, Łukasz; Michalczyk, Łukasz; Mcinnes, Sandra J

    2015-02-25

    This paper is the second monograph of nine that describes the global records of limno-terrestrial water bears (Tardigrada). Here, we provide a comprehensive list of non-marine tardigrades recorded from South America, providing an updated and revised taxonomy accompanied by geographic co-ordinates, habitat, and biogeographic comments. It is hoped this work will serve as a reference point and background for further zoogeographical and taxonomical studies.

  6. Annotated zoogeography of non-marine Tardigrada. Part III: North America and Greenland.

    Science.gov (United States)

    Kaczmarek, Łukasz; Michalczyk, Łukasz; McInnes, Sandra J

    2016-12-01

    This paper is the third monograph of the series that describes the global records of limno-terrestrial water bears (Tardigrada). Here, we provide a comprehensive list of non-marine tardigrades recorded from the North America, providing an updated and revised taxonomy accompanied by geographic co-ordinates, habitat, and biogeographic comments. It is hoped this work will serve as a reference point and background for further zoogeographical and taxonomical studies.

  7. Neuroanatomy of Halobiotus crispae (Eutardigrada: Hypsibiidae)

    DEFF Research Database (Denmark)

    Persson, Dennis; Halberg, Kenneth; Jørgensen, Aslak

    2012-01-01

    The position of Tardigrada in the animal tree of life is a subject that has received much attention, but still remains controversial. Whereas some think tardigrades should be categorized as cycloneuralians, most authors argue in favor of a phylogenetic position within Panarthropoda as a sister...... of a brain comprised of at least three parts cannot be rejected, and the data presented supports a sister group relationship of Tardigrada to 1) Arthropoda or 2) Onychophora or 3) Arthropoda + Onychophora....

  8. Simulated Space Radiation: Impact of Four Different Types of High-Dose Ionizing Radiation on the Lichen Xanthoria elegans

    Science.gov (United States)

    Brandt, Annette; Meeßen, Joachim; Jänicke, Reiner U.; Raguse, Marina; Ott, Sieglinde

    2017-02-01

    This study addresses the viability of the lichen Xanthoria elegans after high-dose ionizing irradiation in the frame of the STARLIFE campaign. The first set of experiments was intended to resemble several types of galactic cosmic radiation (GCR) as present beyond the magnetic shield of Earth. In the second set of experiments, γ radiation up to 113 kGy was applied to test the limit of lichen resistance to ionizing radiation. Entire thalli of Xanthoria elegans were irradiated in the anhydrobiotic state. After STARLIFE 1, the metabolic activity of both symbionts was quantified by live/dead staining with confocal laser scanning microscopy. The photosynthetic activity was measured after the respective irradiation to assess the ability of the symbiotic green algae to restore photosynthesis after irradiation. The STARLIFE campaign complements the results of the LIFE experiments at the EXPOSE-E facility on the International Space Station by testing the model organism Xanthoria elegans on its resistance to hazardous radiation that might be accumulated during long-term space exposure. In addition, the photosynthetic activity of metabolically active lichen was investigated after X-ray irradiation up to 100 Gy (3.3 Gy/min). Since previous astrobiological experiments were mostly performed with anhydrobiotic lichen, these experiments will broaden our knowledge on the correlation of physiological state and astrobiological stressors.

  9. Molecular phylogeny of Arthrotardigrada (Tardigrada).

    Science.gov (United States)

    Jørgensen, Aslak; Faurby, Søren; Hansen, Jesper G; Møbjerg, Nadja; Kristensen, Reinhardt M

    2010-03-01

    Tardigrades are microscopic ecdysozoans with a worldwide distribution covering marine, limnic and terrestrial habitats. They are regarded as a neglected phylum with regard to studies of their phylogeny. During the last decade molecular data have been included in the investigation of tardigrades. However, the marine arthrotardigrades are still poorly sampled due to their relative rarity, difficult identification and minute size even for tardigrades. In the present study, we have sampled various arthrotardigrades and sequenced the 18S and partial 28S ribosomal subunits. The phylogenetic analyses based on Bayesian inference and maximum parsimony inferred Heterotardigrada (Arthrotardigrada+Echiniscoidea) and Eutardigrada to be monophyletic. Arthrotardigrada was inferred to be paraphyletic as the monophyletic Echiniscoidea is included within the arthrotardigrades. The phylogenetic positions of Stygarctidae and Batillipedidae are poorly resolved with low branch support. The Halechiniscidae is inferred to be polyphyletic as the currently recognized Styraconyxinae is not part of the family. Archechiniscus is the sister-group to the Halechiniscidae and Orzeliscus is placed as one of the basal halechiniscids. The phylogeny of the included eutardigrade taxa resembles the current molecular phylogenies. The genetic diversity within Arthrotardigrada is much larger (18S 15.1-26.5%, 28S 7.2-20.7%) than within Eutardigrada (18S 1.0-12.6%, 28S 1.3-8.2%). This can be explained by higher substitution rates in the arthrotardigrades or by a much younger evolutionary age of the sampled eutardigrades.

  10. Current knowledge of the Tardigrada of Svalbard with the first records of water bears from Nordaustlandet (High Arctic

    Directory of Open Access Journals (Sweden)

    Krzysztof Zawierucha

    2013-11-01

    Full Text Available The first investigations of the tardigrades of Svalbard took place in the early 20th century and 30 papers on the subject have been published to date. In this article, we summarize available information on the distribution of tardigrades in this Arctic archipelago with remarks on the dubious species and records. Additionally, we examined 28 new moss, lichen and soil samples collected from the islands of Nordaustlandet, Edgeøya and Prins Karls Forland. These samples yielded 324 specimens, 15 exuvia and 132 free-laid eggs belonging to 16 limnoterrestrial species (Heterotardigrada and Eutardigrada. These include five first records of water bears from Nordaustlandet, eight new records for Edgeøya and four for Prince Karls Forland. The most dense population of tardigrades was found in a sample with 253 specimens/10 g of dry material and the least dense population in a sample with three specimens/10 g of dry material. The most frequently recorded species in samples collected in this study were Testechiniscus spitsbergensis Scourfield, 1897, Macrobiotus harmsworthi harmsworthi Murray, 1907, and M. islandicus islandicus Richters, 1904. This article also provides the first ever scanning electron microscope photomicrographs of Tenuibiotus voronkovi Tumanov, 2007.

  11. Evaluación de la diversidad en comunidades de tardígrados (Ecdysozoa: Tardigrada en hábitats urbano y rural de la ciudad de Salta (Argentina

    Directory of Open Access Journals (Sweden)

    Andrea González-Reyes

    Full Text Available RESÚMEN Este trabajo se realizó bajo la hipótesis de que existe una pérdida creciente de diversidad en las comunidades de tardígrados, desde las áreas rurales hacia las urbanas, incrementando la homogenización de sus comunidades producto de la urbanización. Para la ciudad de Salta, se tomaron muestras en áreas con tránsito vehicular alto y muestras en áreas rurales circundantes. Se identificaron en total ocho especies/morfoespecies. El inventario tuvo una completitud mayor al 94%. La comunidad rural fue más diversa y estructuralmente más uniforme que la comunidad urbana. Macrobiotus hufelandi Schultze, 1834 resultó especie indicadora y Milnesium sp. como detectora para el hábitat urbano, mientras que Paramacrobiotus areolatus Murray, 1907 resultó indicadora para el hábitat rural.

  12. TWO NEW SPECIES AND THREE NEW RECORDS OF THE TARDIGRADA (HETERO TARDIGRADA, ECHINISCIDAE; EUTARDIGRADA, MILNESIIDAE, MACROBIOTI DAE, HYPSIBIIDAE)%中国缓步动物门二新种及三新纪录种和亚种(异缓步纲,棘影熊虫科;真缓步纲,小斑熊虫科,大生熊虫科,高生熊虫科)

    Institute of Scientific and Technical Information of China (English)

    杨潼

    2003-01-01

    记述采自河南省洛阳市、湖北省京山县和四川省都江堰市的缓步动物门2新种及3新纪录种和亚种:异缓步纲棘影熊虫科的四棘棘影熊虫,新纪录Echiniscus quadrispinosus Richters,1902;真缓步纲小斑熊虫科的都江小斑熊虫,新种Milnesium dujiangensis sp.nov.,大生熊虫科的节值大生熊虫戴冠亚种,新纪录Macrobiotus harmsworthicoronatus Barros,1942;高生熊虫科的大指等高熊虫,新纪录Isohypsibius macrodactylus(Maucci,1978)和京山等高熊虫,新种Isohypsibius jingshanensis sp.nov..

  13. Multiple Roles of Photosynthetic and Sunscreen Pigments in Cyanobacteria Focusing on the Oxidative Stress

    Directory of Open Access Journals (Sweden)

    Seiichi Matsugo

    2013-05-01

    Full Text Available Cyanobacteria have two types of sunscreen pigments, scytonemin and mycosporine-like amino acids (MAAs. These secondary metabolites are thought to play multiple roles against several environmental stresses such as UV radiation and desiccation. Not only the large molar absorption coefficients of these sunscreen pigments, but also their antioxidative properties may be necessary for the protection of biological molecules against the oxidative damages induced by UV radiation. The antioxidant activity and vitrification property of these pigments are thought to be requisite for the desiccation and rehydration processes in anhydrobiotes. In this review, the multiple roles of photosynthetic pigments and sunscreen pigments on stress resistance, especially from the viewpoint of their structures, biosynthetic pathway, and in vitro studies of their antioxidant activity, will be discussed.

  14. Glass-forming property of hydroxyectoine is the cause of its superior function as a desiccation protectant

    Science.gov (United States)

    Tanne, Christoph; Golovina, Elena A.; Hoekstra, Folkert A.; Meffert, Andrea; Galinski, Erwin A.

    2014-01-01

    We were able to demonstrate that hydroxyectoine, in contrast to ectoine, is a good glass-forming compound. Fourier transform infrared and spin label electron spin resonance studies of dry ectoine and hydroxyectoine have shown that the superior glass-forming properties of hydroxyectoine result from stronger intermolecular H-bonds with the OH group of hydroxyectoine. Spin probe experiments have also shown that better molecular immobilization in dry hydroxyectoine provides better redox stability of the molecules embedded in this dry matrix. With a glass transition temperature of 87°C (vs. 47°C for ectoine) hydroxyectoine displays remarkable desiccation protection properties, on a par with sucrose and trehalose. This explains its accumulation in response to increased salinity and elevated temperature by halophiles such as Halomonas elongata and its successful application in ``anhydrobiotic engineering'' of both enzymes and whole cells. PMID:24772110

  15. Glass-forming property of hydroxyectoine is the cause of its superior function as a desiccation protectant

    Directory of Open Access Journals (Sweden)

    Erwin Arno Galinski

    2014-04-01

    Full Text Available We were able to demonstrate that hydroxyectoine, in contrast to ectoine, is a good glass-forming compound. Fourier transform infrared (FTIR and spin label electron spin resonance (ESR studies of dry ectoine and hydroxyectoine have shown that the superior glass-forming properties of hydroxyectoine result from stronger intermolecular H-bonds with the OH group of hydroxyectoine. Spin probe experiments have also shown that better molecular immobilization in dry hydroxyectoine provides better redox stability of the molecules embedded in this dry matrix. With a glass transition temperature of 87 0C (vs. 47 0C for ectoine hydroxyectoine displays remarkable desiccation protection properties, on a par with sucrose and trehalose. This explains its accumulation in response to increased salinity and elevated temperature by halophiles such as Halomonas elongata and its successful application in anhydrobiotic engineering of both enzymes and whole cells.

  16. Study of the Boson Peak and Fragility of Bioprotectant Glass-Forming Mixtures by Neutron Scattering

    Directory of Open Access Journals (Sweden)

    F. Migliardo

    2013-01-01

    Full Text Available The biological relevance of trehalose, glycerol, and their mixtures in several anhydrobiotic and cryobiotic organisms has recently promoted both experimental and simulation studies. In addition, these systems are employed in different industrial fields, such as pharmaceutical and cosmetic industries, as additives in mixtures for cryopreservation and in several formulations. This review article shows an overview of Inelastic Neutron Scattering (INS data, collected at different temperature values by the OSIRIS time-of-flight spectrometer at the ISIS Facility (Rutherford Appleton Laboratory, Oxford, UK and by the IN4 and IN6 spectrometers at the Institut Laue Langevin (ILL, Grenoble, France, on trehalose/glycerol mixtures as a function of the glycerol content. The data analysis allows determining the Boson peak behavior and discussing the findings in terms of fragility in relation to the bioprotective action of trehalose and glycerol.

  17. Structural and dynamical characteristics of trehalose and sucrose matrices at different hydration levels as probed by FTIR and high-field EPR.

    Science.gov (United States)

    Malferrari, M; Nalepa, A; Venturoli, G; Francia, F; Lubitz, W; Möbius, K; Savitsky, A

    2014-06-07

    Some organisms can survive complete dehydration and high temperatures by adopting an anhydrobiotic state in which the intracellular medium contains large amounts of disaccharides, particularly trehalose and sucrose. Trehalose is most effective also in protecting isolated in vitro biostructures. In an attempt to clarify the molecular mechanisms of disaccharide bioprotection, we compared the structure and dynamics of sucrose and trehalose matrices at different hydration levels by means of high-field W-band EPR and FTIR spectroscopy. The hydration state of the samples was characterized by FTIR spectroscopy and the structural organization was probed by EPR using a nitroxide radical dissolved in the respective matrices. Analysis of the EPR spectra showed that the structure and dynamics of the dehydrated matrices as well as their evolution upon re-hydration differ substantially between trehalose and sucrose. The dehydrated trehalose matrix is homogeneous in terms of distribution of the residual water and spin-probe molecules. In contrast, dehydrated sucrose forms a heterogeneous matrix. It is comprised of sucrose polycrystalline clusters and several bulk water domains. The amorphous form was found only in 30% (volume) of the sucrose matrix. Re-hydration leads to a structural homogenization of the sucrose matrix, whilst in the trehalose matrix several domains develop differing in the local water/radical content and radical mobility. The molecular model of the matrices provides an explanation for the different protein-matrix dynamical coupling observed in dried ternary sucrose and trehalose matrices, and accounts for the superior efficacy of trehalose as a bioprotectant. Furthermore, for bacterial photosynthetic reaction centers it is shown that at low water content the protein-matrix coupling is modulated by the sugar/protein molar ratio in sucrose matrices only. This effect is suggested to be related to the preference for sucrose, rather than trehalose, as a

  18. EF-hand proteins and the regulation of actin-myosin interaction in the eutardigrade Hypsibius klebelsbergi (tardigrada).

    Science.gov (United States)

    Prasath, Thiruketheeswaran; Greven, Hartmut; D'Haese, Jochen

    2012-06-01

    Many tardigrade species resist harsh environmental conditions by entering anhydrobiosis or cryobiosis. Desiccation as well as freeze resistance probably leads to changes of the ionic balance that includes the intracellular calcium concentration. In order to search for protein modifications affecting the calcium homoeostasis, we studied the regulatory system controlling actin-myosin interaction of the eutardigrade Hypsibius klebelsbergi and identified full-length cDNA clones for troponin C (TnC, 824 bp), calmodulin (CaM, 1,407 bp), essential myosin light chain (eMLC, 1,015 bp), and regulatory myosin light chain (rMLC, 984 bp) from a cDNA library. All four proteins belong to the EF-hand superfamily typified by a calcium coordinating helix-loop-helix motif. Further, we cloned and obtained recombinant TnC and both MLCs. CaM and TnC revealed four and two potential calcium-binding domains, respectively. Gel mobility shift assays demonstrated calcium-induced conformational transition of TnC. From both MLCs, only the rMLC showed one potential N-terminal EF-hand domain. Additionally, sequence properties suggest phosphorylation of this myosin light chain. Based on our results, we suggest a dual-regulated system at least in somatic muscles for tardigrades with a calcium-dependent tropomyosin-troponin complex bound to the actin filaments and a phosphorylation of the rMLC turning on and off both actin and myosin. Our results indicate no special modifications of the molecular structure and function of the EF-hand proteins in tardigrades. Phylogenetic trees of 131 TnCs, 96 rMLCs, and 62 eMLCs indicate affinities to Ecdysozoa, but also to some other taxa suggesting that our results reflect the complex evolution of these proteins rather than phylogenetic relationships.

  19. A congruent solution to arthropod phylogeny: phylogenomics, microRNAs and morphology support monophyletic Mandibulata

    Science.gov (United States)

    Rota-Stabelli, Omar; Campbell, Lahcen; Brinkmann, Henner; Edgecombe, Gregory D.; Longhorn, Stuart J.; Peterson, Kevin J.; Pisani, Davide; Philippe, Hervé; Telford, Maximilian J.

    2011-01-01

    While a unique origin of the euarthropods is well established, relationships between the four euarthropod classes—chelicerates, myriapods, crustaceans and hexapods—are less clear. Unsolved questions include the position of myriapods, the monophyletic origin of chelicerates, and the validity of the close relationship of euarthropods to tardigrades and onychophorans. Morphology predicts that myriapods, insects and crustaceans form a monophyletic group, the Mandibulata, which has been contradicted by many molecular studies that support an alternative Myriochelata hypothesis (Myriapoda plus Chelicerata). Because of the conflicting insights from published molecular datasets, evidence from nuclear-coding genes needs corroboration from independent data to define the relationships among major nodes in the euarthropod tree. Here, we address this issue by analysing two independent molecular datasets: a phylogenomic dataset of 198 protein-coding genes including new sequences for myriapods, and novel microRNA complements sampled from all major arthropod lineages. Our phylogenomic analyses strongly support Mandibulata, and show that Myriochelata is a tree-reconstruction artefact caused by saturation and long-branch attraction. The analysis of the microRNA dataset corroborates the Mandibulata, showing that the microRNAs miR-965 and miR-282 are present and expressed in all mandibulate species sampled, but not in the chelicerates. Mandibulata is further supported by the phylogenetic analysis of a comprehensive morphological dataset covering living and fossil arthropods, and including recently proposed, putative apomorphies of Myriochelata. Our phylogenomic analyses also provide strong support for the inclusion of pycnogonids in a monophyletic Chelicerata, a paraphyletic Cycloneuralia, and a common origin of Arthropoda (tardigrades, onychophorans and arthropods), suggesting that previous phylogenies grouping tardigrades and nematodes may also have been subject to tree

  20. The oxygen consumption rates of different life stages of the endoparasitic nematode

    Directory of Open Access Journals (Sweden)

    Willie van Aardt

    2010-01-01

    Full Text Available The oxygen consumption rates of different life stages of the endoparasitic nematode, Pratylenchus zeae (Nematoda: Tylenchida during non- and post-anhydrobiosisPratylenchus zeae, widely distributed in tropical and subtropical regions, is an endoparasite in roots of maize and other crop plants. The nematode is attracted to plant roots by CO2 and root exudates and feeds primarily on cells of the root cortex, making channels and openings where the eggs are deposited, with the result that secondary infection occurs due to bacteria and fungi. Nothing is known about the respiration physiology of this nematode and how it manages to survive during dry seasons. To measure the oxygen consumption rate (VO2 of individual P. zeae (less than half a millimeter long, a special measuring technique namely Cartesian diver micro-respirometry was applied. The Cartesian divers were machined from Perspex, and proved to be more accurate to measure VO2 compared with heavier glass divers used in similar experiments on free living nematodes. An accuracy of better than one nanoliter of oxygen consumed per hour was achieved with a single P. zeae inside the diver. Cartesian diver micro-respirometry measurements are based in principle on the manometric changes that occur in a fl otation tube in a manometer set-up when oxygen is consumed by P. zeae and CO2 from the animal is chemically absorbed. VO2 was measured for eggs (length: < 0.05 mm, larvae (length: 0.36 mm and adults (length: 0.47 mm before induction to anhydrobiosis. P. zeae from infected maize roots were extracted and exposed aseptically to in vitro maize root cultures in a grow cabinet at 50 % to 60% relative humidity at 28 ºC using eggs, larvae and adults. VO2 was also measured for post-anhydrobiotic eggs, larvae and adults by taking 50 individuals, eggs and larvae from the culture and placing them in Petri-dishes with 1% agar/water to dry out for 11 days at 28 ºC and 50% relative humidity. The VO2 was measured

  1. Neostygarctus lovedeluxe n. sp. from the Miyako Islands, Japan: the first record of Neostygarctidae (Heterotardigrada: Arthrotardigrada) from the Pacific.

    Science.gov (United States)

    Fujimoto, Shinta; Miyazaki, Katsumi

    2013-05-01

    A new species of the previously monospecific marine tardigrade family Neostygarctidae is described. Neostygarctus lovedeluxe n. sp. was found from a submarine cave in Miyako Islands, Japan. This is the first record of Neostygarctidae from the Pacific. The new species is easily distinguished from the previously known N. acanthophorus by its number of dorsal spines, as N. lovedeluxe has two spines each on the three dorsal body plates in contrast to one in N. acanthophorus. Furthermore the morphology of the two clawed juvenile is reported for the first time in Neostygarctidae, providing new insights into the common sequence in some ontogenic traits.

  2. Tow New Records of Isohypsibius (Tardigrada,Hypsibiidae) in Shaanxi Province%陕西省等高属(缓步动物,高生熊虫科)两个新纪录种记述

    Institute of Scientific and Technical Information of China (English)

    刘莹; 王立志; 薛静

    2011-01-01

    Two records of tardigrades are described in Shaanxi Province.They are Isohypsibius sattleri Richters,1902(Eutardigrada,Hypsibiidae) and Isohypsibius marcellinoi Binda Pilato,1971(Eutardigrada,Hypsibiidae).%记述了陕西省2个缓步动物新纪录种,它们是赛氏等高熊虫Isohypsibius sattleri Richters,1902(真缓步纲,高生熊虫科)和马氏等高熊虫Isohypsibius marcellinoi Binda&Pilato,1971(真缓步纲,高生熊虫科)。

  3. Two New Records of Macrobiotus (Tardigrada,Macrobiotidae) in Shaanxi Province%陕西省大生属(缓步动物,大生熊虫科)两个新纪录种记述

    Institute of Scientific and Technical Information of China (English)

    杜祥云; 王立志; 刘艳

    2012-01-01

    记述了陕西省2个缓步动物新纪录种,它们是球蚜大生熊虫Macrobiotus adelges Dastych,1977(真缓步纲,大生熊虫科)和阿瑞科姆大生熊虫Macrobiotus ariekammensis Wêglarska,1965(真缓步纲,大生熊虫科)。%Two records of tardigrades are described from Shaanxi Province in this article.They are Macrobiotus adelges Dastych,1977 and Macrobiotus ariekammensis Wêglarska,1965.Both species belong to genus Macrobiotus,family Macrobiotidae,order Parachela and class Eutardigrada.

  4. Two New Records of Macrobiotus (Tardigrada, Macrobiotidae) in Guangxi Zhuang Autonomous Region%广西壮族自治区大生属(缓步动物,大生熊虫科)两个新纪录种记述

    Institute of Scientific and Technical Information of China (English)

    刘莹; 王立志

    2013-01-01

    记述了广西壮族自治区2个缓步动物新纪录种,即毛氏大生熊虫[Macrobiotus mauccii Pilato,1974(真缓步纲,大生熊虫科)]和胡氏大生熊虫[Macrobiotus hufelandi Schultze,1833(真缓步纲,大生熊虫科)].%Two records of tardigrades in Guangxi Zhuang Autonomous Region were described,which were Macrobiotus mauccii Pilato,1974 and Macrobiotus hufelandi Schultze,1833.Both species belonged to genus Macrobiotus,family Macrobiotidae,order Parachela and class Eutardigrada.

  5. Evolution of the AKH/corazonin/ACP/GnRH receptor superfamily and their ligands in the Protostomia

    DEFF Research Database (Denmark)

    Hauser, Frank; Grimmelikhuijzen, Cornelis

    2014-01-01

    In this review we trace the evolutionary connections between GnRH receptors from vertebrates and the receptors for adipokinetic hormone (AKH), AKH/corazonin-related peptide (ACP), and corazonin from arthropods. We conclude that these G protein-coupled receptors (GPCRs) are closely related and have...... limpet Lottia gigantea (pQIHFSPTWGSamide), the oyster Crassostrea gigas (pQVSFSTNWGSamide), and the freshwater pearl mussel Hyriopsis cumingii (pQISFSTNWGSamide). We also found AKHs in the tardigrade Hysibius dujardini (pQLSFTGWGHamide), the rotifer Brachionus calycifloros (p...

  6. 中国棘甲熊虫属缓步动物——新记录种%A Newly Record of Genus Echiniscus Schultze from China

    Institute of Scientific and Technical Information of China (English)

    叶添彬; 孙西寨; 乔鹏海

    2012-01-01

    记述了中国缓步动物一种新记录种(Echiniscus Perarmatus Murray,1907).该种属于异缓步纲(Heterotardigrada Marcus)棘甲目(Echiniscoidea Marcus)棘甲科(Echiniscidae Thulin)棘甲熊虫属(Echiniscus Schultze),在国内属于首次发现.%One new record Echiniscus perarmatus Murray of Tardigrades from China in 1907 was described. It belongs to class Heterotaedigrs da, order Echiniscoidea family Echiniscus schultze. It was first found in China.

  7. Strong environmental tolerance of moss Venturiella under very high pressure

    Science.gov (United States)

    Ono, F.; Mori, Y.; Takarabe, K.; Nishihira, N.; Shindo, A.; Saigusa, M.; Matsushima, Y.; Saini, N. L.; Yamashita, M.

    2010-03-01

    It was shown by the present authors group that tardigrade can survive under high pressure of 7.5 GPa. In the case of land plants, however, no result of such experiment has been reported. We have extended our experiments to moss searching for lives under very high pressure. Spore placentas of moss Venturiella were sealed in a small Teflon capsule together with a liquid pressure medium. The capsule was put in the center of a pyrophillite cube, and the maximum pressure of 7.5 GPa was applied using a two-stage cubic anvil press. The pressure was kept constant at the maximum pressure for12, 24, 72 and 144 hours. After the pressure was released, the spores were seeded on a ager medium, and incubated for one week and more longer at 25°C with white light of 2000 lux. It was proved that 70-90% of the spores were alive and germinated after exposed to the maximum pressure of 7.5 GPa for up to 72 hours. However, after exposed to 7.5 GPa for 6 days, only 4 individuals in a hundred were germinated. The pressure tolerance of moss Venturiella is found to be stronger than a small animal, tardigrade.

  8. The past, the present and the future of eutardigrade taxonomy

    Directory of Open Access Journals (Sweden)

    Giovanni Pilato

    2013-03-01

    Full Text Available The Author first recalls the past of eutardigrade taxonomy and indicates the main factors that for a long time restrained its progress. One consequence of a superficial analysis is that very wide individual variability has been erroneously attributed to many species, and this has become the main problem for tardigrade taxonomists. The situation began to change after 1969 because of the first attempts to eliminate the above mentioned problems. Novelties gave impetus to the revision of tardigrade taxonomy, and genuine systematics, finally based on phylogenetics, became popular. Today the morphological characters are considered more in depth and studies utilising DNA sequences are more in fashion; they are surely useful and allow the distinction of morphologically very similar species. However, in the author’s opinion, this progress will be possible only if the molecular studies are always associated with careful morphological studies, which, in the meantime, will be more and more detailed also thanks to the use of the Scanning Electron Microscopy (SEM.

  9. DNA barcoding in Tardigrada: the first case study on Macrobiotus macrocalix Bertolani & Rebecchi 1993 (Eutardigrada, Macrobiotidae).

    Science.gov (United States)

    Cesari, Michele; Bertolani, Roberto; Rebecchi, Lorena; Guidetti, Roberto

    2009-05-01

    Morphological and molecular studies on a tardigrade species have been carried out to verify the possibility of using a DNA barcoding approach for species identification in this phylum. Macrobiotus macrocalix Bertolani & Rebecchi, 1993 was chosen as the test species since it belongs to a group of species in which the taxonomy is quite problematic. Animals and eggs belonging to three Italian and one Swedish populations have been investigated. Both morphological and molecular analyses show that all the populations belong to the same species. The low genetic distances recorded among the studied populations (0.3-1.0%) and the high genetic distance (15.9-16.3%) between these populations and a closely related species confirm the possibility of identifying a specimen of this species by its cytochrome oxidase subunit I sequence. Data from other authors support our results indicating that DNA barcoding can be applied to tardigrades. With our protocols, we have obtained voucher specimens that enable us to show a correspondence between morphology and molecular data.

  10. The 18S rDNA sequences support polyphyly of the Hypsibiidae (Eutardigrada

    Directory of Open Access Journals (Sweden)

    Hartmut GREVEN

    2007-09-01

    Full Text Available To extend data on 18S rDNA gene phylogeny within the Eutardigrada and to provide additional information on unclear taxonomic status of a glacier tardigrade Hypsibius klebelsbergi, gene sequences from seven tardigrade species of the family Hypsibiidae (Hypsibius klebelsbergi, Hypsibius cf. convergens 1, Hypsibius cf. convergens 2, Hypsibius scabropygus, Hebensuncus conjungens, Isohypsibius cambrensis, Isohypsibius granulifer were analysed together with previously published sequences from ten further eutardigrade species or species groups. Three distinctly separated clades within the Hypsibiidae, 1 the Ramazzottius - Hebesuncus clade, 2 the Isohypsibius clade (Isohypsibius, Halobiotus, Thulinius, and 3 the Hypsibius clade (Hypsibius spp. have been obtained in each of four phylogenetic trees recovered by Maximum Parsimony, Neighbour Joining, Minimum Evolution and UPGMA. Hybsibius klebelsbergi has been located always within the Hypsibius clade. The detailed sister group relationship was not resolved adequately, but there is robust support for a sister group relationship between the Hypsibius clade and the remaining clades. We cannot exclude that the Ramazzottius - Hebesuncus clade is a sister group of the Macrobiotus clade. Our findings suggest polyphyly of the Hypsibiidae, and thus multiple evolutions of some structures currently applied as diagnostic characters (e.g., claws, buccal apophyses.

  11. Determinants and taxonomic consequences of extreme egg shell variability in Ramazzottius subanomalus (Biserov, 1985) (Tardigrada).

    Science.gov (United States)

    Stec, Daniel; Morek, Witold; Gąsiorek, Piotr; Kaczmarek, Łukasz; Michalczyk, Łukasz

    2016-12-15

    Nearly a half of known eutardigrade species lay ornamented eggs. The ornamentation is thought to provide attachment of the egg to the substrate and protection for the developing embryo, but from the taxonomic point of view chorion morphology may also provide key characters for species differentiation and identification, especially between closely related taxa. Nonetheless, despite the evolutionary and taxonomic importance of the egg shell, the determinants of its morphology are very poorly, if at all, understood. Here, we combine morphological, molecular and experimental approaches in an attempt to separate the genetic and environmental factors that shape egg chorion morphology in Ramazzottius subanomalus (Biserov, 1985). Our integrative study, based on a population of R. subanomalus isolated from a single moss sample, revealed (1) remarkable variation in egg shell morphology, but (2) relatively little variation in animal morphometric traits, and (3) genetic differentiation, expressed as two ITS-2 haplotypes, but no parallel polymorphism in COI. Although animals did not differ morphometrically between the haplotypes, eggs laid by haplotype 1 and 2 females exhibited highly statistically significant differences in all measured traits. The study demonstrates, for the first time, a correlation between phenotypic and genetic variability within a tardigrade species. The revealed congruence between genetic and morphological traits might be viewed as an example of incipient speciation that illustrates early evolutionary steps leading to species complexes that differ primarily in terms of egg shell morphology. Moreover, our data confirm the value of the ITS-2 fragment in distinguishing very closely related tardigrade lineages.

  12. A transcriptome approach to ecdysozoan phylogeny.

    Science.gov (United States)

    Borner, Janus; Rehm, Peter; Schill, Ralph O; Ebersberger, Ingo; Burmester, Thorsten

    2014-11-01

    The monophyly of Ecdysozoa, which comprise molting phyla, has received strong support from several lines of evidence. However, the internal relationships of Ecdysozoa are still contended. We generated expressed sequence tags from a priapulid (penis worm), a kinorhynch (mud dragon), a tardigrade (water bear) and five chelicerate taxa by 454 transcriptome sequencing. A multigene alignment was assembled from 63 taxa, which comprised after matrix optimization 24,249 amino acid positions with high data density (2.6% gaps, 19.1% missing data). Phylogenetic analyses employing various models support the monophyly of Ecdysozoa. A clade combining Priapulida and Kinorhyncha (i.e. Scalidophora) was recovered as the earliest branch among Ecdysozoa. We conclude that Cycloneuralia, a taxon erected to combine Priapulida, Kinorhyncha and Nematoda (and others), are paraphyletic. Rather Arthropoda (including Onychophora) are allied with Nematoda and Tardigrada. Within Arthropoda, we found strong support for most clades, including monophyletic Mandibulata and Pancrustacea. The phylogeny within the Euchelicerata remained largely unresolved. There is conflicting evidence on the position of tardigrades: While Bayesian and maximum likelihood analyses of only slowly evolving genes recovered Tardigrada as a sister group to Arthropoda, analyses of the full data set, and of subsets containing genes evolving at fast and intermediate rates identified a clade of Tardigrada and Nematoda. Notably, the latter topology is also supported by the analyses of indel patterns.

  13. Strong environmental tolerance of moss Venturiella under very high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Ono, F; Mori, Y; Takarabe, K [Department of Applied Science, Okayama University of Science, 1-1 Ridaicho, Okayama 700-0005 (Japan); Nishihira, N; Shindo, A [Okayama Ichinomiya High School, Okayama 700-0005 (Japan); Saigusa, M [Department of Biology, Okayama University, 3-1-1 Tsushima-Naka, Okayama 700-8530 (Japan); Matsushima, Y [Department of Physics, Okayama University, 3-1-1 Tsushima-Naka, Okayama 700-8530 (Japan); Saini, N L [Dipartimento di Fisica, Universita di Roma ' La Sapienza' , Piazzale Aldo Moro 2, 00185 Rome (Italy); Yamashita, M, E-mail: fumihisa@das.ous.ac.j [Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510 (Japan)

    2010-03-01

    It was shown by the present authors group that tardigrade can survive under high pressure of 7.5 GPa. In the case of land plants, however, no result of such experiment has been reported. We have extended our experiments to moss searching for lives under very high pressure. Spore placentas of moss Venturiella were sealed in a small Teflon capsule together with a liquid pressure medium. The capsule was put in the center of a pyrophillite cube, and the maximum pressure of 7.5 GPa was applied using a two-stage cubic anvil press. The pressure was kept constant at the maximum pressure for12, 24, 72 and 144 hours. After the pressure was released, the spores were seeded on a ager medium, and incubated for one week and more longer at 25{sup 0}C with white light of 2000 lux. It was proved that 70-90% of the spores were alive and germinated after exposed to the maximum pressure of 7.5 GPa for up to 72 hours. However, after exposed to 7.5 GPa for 6 days, only 4 individuals in a hundred were germinated. The pressure tolerance of moss Venturiella is found to be stronger than a small animal, tardigrade.

  14. Preliminary Investigation on Tardigrada Fauna of Qinghai Province%青海省缓步动物区系初步调查

    Institute of Scientific and Technical Information of China (English)

    姜丽琼; 王立志

    2008-01-01

    记述了青海省发现的14种缓步动物,它们属于2纲、3目、4科、10属.2种(叉状大生熊虫Macrobiotus furciger Murray,1906和马氏等高熊虫Isohypsibius marcellinoi Binda & Pilato,1971)是中国新纪录种,12种(叶状角棘影熊虫Cornechiniscus lobatus Ramazzotti,1943、加拿大棘影熊虫Echiniscus canadensis Murray,1910、文氏棘影熊虫Echiniscus wendti Richters, 1903、小刻面假棘影熊虫Pseudechiniscus facettalis Petersen,1951、缓步米氏熊虫Milnesium tardigradum Doyére,1840、哈氏大生熊虫Macrobiotus hamsworthi Murray,1907、胡氏大生熊虫Macrobiotus hufelandi Schultze,1833、瑞氏大生熊虫Macrobiotus richtersi Murray, 1911、介小生熊虫Minibiotus intermedius Palte,1889、苏格兰双相熊虫Diphascon scoticum Murray,1905、黄色腹矛熊虫Doryphoribius flavus Iharos,1966和杜氏高生熊虫Hypsibius dujardini Doyére,1840)是青海省新纪录种.本文系青海省对该类动物的首次报道.

  15. One New Record Species of Pseudechiniscus from Shaanxi%陕西省假棘甲熊虫属一新纪录种

    Institute of Scientific and Technical Information of China (English)

    于浩; 赵彦禹; 孙西寨

    2011-01-01

    [目的] 为我国缓步动物区系研究提供资料.[方法] 从陕西省汉中市西乡县采集苔藓标本,将标本在蒸馏水中浸泡12 h后挑出熊虫,制片、观察、拍照并测量虫体各部位长度,鉴定其种类.[结果] 该虫体表橙红色,有侧丝A、头乳突及口须;肩板分为2部分,假隔板明显;身体背部分布着大量由较大颗粒状突起组成的网状刻饰物;后肢基部外侧有乳突.经鉴定,采集到的熊虫标本属于朱氏假棘甲熊虫.[结论] 该研究报道了陕西省缓步动物—新纪录种Pseudechiniscus juanitae Barros.%[Objective] The aim was to provide the reference for studying tardigrada fuuna. [Method]The lichens samples were collected from Xixiang County , Hanzhong City of Shaanxi Province, the tardigrades were picked nut after 12 h of the samples were soaked in the distilled water , and their species were identified according to the results of slice production, observation, photograph and the length of each part of their body. [ Result ] The body surface of the tardigrades shows salmon pink, and they have lateral filament A, cephalic papilla and lentaculum; the scapular plate is divided into 2 parts, and the fake baffle is obvious; dorsal part was decorated by reticular sculpture; there was papilla on the lateral side of the hind legs. The results of identification showed that the samples of the tardigrade were Pseudechiniscus juanttae de Barros. [Conclusion] The study reports one new record species (Pseudechiniscus juarulae Barros) of tardigrada from Shaanxi.

  16. Assessing meiofaunal variation among individuals utilising morphological and molecular approaches: an example using the Tardigrada

    Directory of Open Access Journals (Sweden)

    Linse Katrin

    2008-04-01

    Full Text Available Abstract Background Meiofauna – multicellular animals captured between sieve size 45 μm and 1000 μm – are a fundamental component of terrestrial, and marine benthic ecosystems, forming an integral element of food webs, and playing a critical roll in nutrient recycling. Most phyla have meiofaunal representatives and studies of these taxa impact on a wide variety of sub-disciplines as well as having social and economic implications. However, studies of variation in meiofauna are presented with several important challenges. Isolating individuals from a sample substrate is a time consuming process, and identification requires increasingly scarce taxonomic expertise. Finding suitable morphological characters in many of these organisms is often difficult even for experts. Molecular markers are extremely useful for identifying variation in morphologically conserved organisms. However, for many species markers need to be developed de novo, while DNA can often only be extracted from pooled samples in order to obtain sufficient quantity and quality. Importantly, multiple independent markers are required to reconcile gene evolution with species evolution. In this primarily methodological paper we provide a proof of principle of a novel and effective protocol for the isolation of meiofauna from an environmental sample. We also go on to illustrate examples of the implications arising from subsequent screening for genetic variation at the level of the individual using ribosomal, mitochondrial and single copy nuclear markers. Results To isolate individual tardigrades from their habitat substrate we used a non-toxic density gradient media that did not interfere with downstream biochemical processes. Using a simple DNA release technique and nested polymerase chain reaction with universal primers we were able amplify multi-copy and, to some extent, single copy genes from individual tardigrades. Maximum likelihood trees from ribosomal 18S, mitochondrial

  17. The evolution of the Ecdysozoa.

    Science.gov (United States)

    Telford, Maximilian J; Bourlat, Sarah J; Economou, Andrew; Papillon, Daniel; Rota-Stabelli, Omar

    2008-04-27

    Ecdysozoa is a clade composed of eight phyla: the arthropods, tardigrades and onychophorans that share segmentation and appendages and the nematodes, nematomorphs, priapulids, kinorhynchs and loriciferans, which are worms with an anterior proboscis or introvert. Ecdysozoa contains the vast majority of animal species and there is a great diversity of body plans among both living and fossil members. The monophyly of the clade has been called into question by some workers based on analyses of whole genome datasets. We review the evidence that now conclusively supports the unique origin of these phyla. Relationships within Ecdysozoa are also controversial and we discuss the molecular and morphological evidence for a number of monophyletic groups within this superphylum.

  18. Zur Biologie des marinen Heterotardigraden Tetrakentron synaptae

    Science.gov (United States)

    Kristensen, R. M.

    1980-06-01

    The life cycle of Tetrakentron synaptae Cuénot, 1892, a tardigrade closely associated with the sea cucumber Leptosynapta galliennei Herapath, was investigated in the littoral zone at Roscoff (France). Eggs and juveniles were found only in June and July, adults only from May to October. There are vagile males and stationary dwarf males. The dorsoventrally flattened body, an enlarged slimy epicuticle in females and dwarf males, the full set of claws also in juveniles, and the anus, which is in a dorsocaudal position, are indicative for an epizoic, sessile life. There is strong evidence that T. synaptae punctures the cells of L. galliennei and sucks out their content, which is indicative of parasitism.

  19. Tardigrada of the Caribbean island of Dominica (West Indies

    Directory of Open Access Journals (Sweden)

    Juliana G. Hinton

    2013-05-01

    Full Text Available In June 2009 we surveyed the terrestrial Tardigrada of Dominica, the most northerly of the Windward islands of the Lesser Antilles in the Caribbean sea. Out of 112 moss, lichen, liverwort and leaf litter samples, 35 had tardigrades, representing 10 genera and 25 species or species groups. This survey increases the number of species reported from Dominica from 3 to 25, more than the total recorded from any other West Indian island. Twelve species found in Dominica are cosmopolitan or belong to cosmopolitan species groups. Eight species are new to the fauna of the West Indies, one is new to the fauna of the Americas, and at least one is endemic to Dominica.

  20. A NEW SUBSPECIES OF THE GENUS DIPHASCON AND TWO NEW RECORDS OF TARDIGRADA (EUTARDIGRADA, HYPSIBIIDAE, MACROBIOTIDAE) FROM CHINA%中国缓步动物门一新亚种及两新纪录种记述

    Institute of Scientific and Technical Information of China (English)

    李晓晨; 刘莹

    2005-01-01

    报道了我国缓步动物门1新亚种Diphascon(Adropion)scoticum qinlingensis subsp.nov.和中国2新纪录Rictersius coronifer ( Richters, 1903) (Eutardigrada, Macrobiotidae)和 Diphascon scoticum Murray, 1905 (Eutardigrada, Hypsibiidae).新亚种主要以爪的主枝基部极度收缩区别于世界其他产地的标本(指名亚种).新亚种和新纪录均采自秦岭山区.%A new subspecies of Diphascon scoticum Murray, 1905 and two new records of tardigrades were described and reported. The new subspecies, D. s. qinlingensis subsp. nov. , differs from the nominate subspecies mainly by the constricted common basal tract. The new subspecies and the two new record species Richtersius coronifer (Richters, 1903) (Eutardigrada, Macrobiotidae) and Diphascon scoticum (Eutardigrada, Hypsibiidae) were collected from Qinling mountains, China.

  1. Elongation factor-2: a useful gene for arthropod phylogenetics.

    Science.gov (United States)

    Regier, J C; Shultz, J W

    2001-07-01

    Robust resolution of controversial higher-level groupings within Arthropoda requires additional sources of characters. Toward this end, elongation factor-2 sequences (1899 nucleotides) were generated from 17 arthropod taxa (5 chelicerates, 6 crustaceans, 3 hexapods, 3 myriapods) plus an onychophoran and a tardigrade as outgroups. Likelihood and parsimony analyses of nucleotide and amino acid data sets consistently recovered Myriapoda and major chelicerate groups with high bootstrap support. Crustacea + Hexapoda (= Pancrustacea) was recovered with moderate support, whereas the conflicting group Myriapoda + Hexapoda (= Atelocerata) was never recovered and bootstrap values were always protein-encoding, nuclear gene (in addition to RNA polymerase II) to support Pancrustacea over Atelocerata. Atelocerata is widely cited in morphology-based analyses, and the discrepancy between results derived from molecular and morphological data deserves greater attention.

  2. Tolerance of budding yeast Saccharomyces cerevisiae to ultra high pressure

    Science.gov (United States)

    Shibata, M.; Torigoe, M.; Matsumoto, Y.; Yamamoto, M.; Takizawa, N.; Hada, Y.; Mori, Y.; Takarabe, K.; Ono, F.

    2014-05-01

    Our studies on the tolerance of plants and animals against very high pressure of several GPa have been extended to a smaller sized fungus, the budding yeast Saccharomyces cerevisiae. Several pieces of budding yeast (dry yeast) were sealed in a small teflon capsule with a liquid pressure medium fluorinate, and exposed to 7.5 GPa by using a cubic anvil press. The pressure was kept constant for various duration of time from 2 to 24 h. After the pressure was released, the specimens were brought out from the teflon capsule, and they were cultivated on a potato dextrose agar. It was found that the budding yeast exposed to 7.5 GPa for up to 6 h showed multiplication. However, those exposed to 7.5 GPa for longer than 12 h were found dead. The high pressure tolerance of budding yeast is a little weaker than that of tardigrades.

  3. Welcome by Professor Giovanni Pilato

    Directory of Open Access Journals (Sweden)

    Giovanni PILATO

    2007-09-01

    Full Text Available Dear Friends, I am very glad to have you in Catania for our Tenth International Symposium and to see again some old friends, some of whom I first met at the first Symposium in Pallanza (more than thirty years ago, and I am glad to see many young colleagues who have chosen to study such an interesting animal group and who represent the future of tardigrade research (even if old men like me have no intention of retiring just yet. I have seen with great satisfaction the flourishing of diversified research: Morphology, Systematics, Ecology, Biology, new Methodologies, especially the extraordinary property of cryptobiosis, are studied by many tardigradologists, and the molecular surveys are no longer sporadic.

  4. 根结线虫生防资源概况及进展

    Institute of Scientific and Technical Information of China (English)

    祝明亮; 李天飞; 张克勤; 夏振远

    2004-01-01

    根结线虫(Meloidogyne spp.)作为农业生产上的一类重要病原物,其生物防治受到了人们的日益重视.根结线虫生防天敌资源包括食线虫菌物(Nematophagous fungi)、专性寄生细菌(0bligate endoparasidc bacteria)、根际细菌(Rhizobacteria)、放线菌(Actinomycetes)、病毒(Viruses)、立克次氏体(Rickettsia)、原生动物(Protozoa)、水熊(Tardigrade)、扁虫(Turbellarians)、螨类(Mites)、跳虫(Collembola)、Enchytraids以及捕食性线虫(Predaciousnematodes)等,对它们进行了简要概述.

  5. The phylogeny of Arthrotardigrada

    DEFF Research Database (Denmark)

    Hansen, Jesper Guldberg

    2011-01-01

    The order Arthrotardigrada, or water bears, constitutes a small group of 160 species of marine, microscopical invertebrates, within the phylum Tardigrada. Although the position of tardigrades in the Animal Kingdom has received much attention focusing on the metazoan phylogeny, the phylogenetic...... arthrotardigrade phylogeny based on combined morphological and molecular data. As a first step to reach this goal, detailed examinations of more than 100 species and thorough revisions of various arthrotardigrade genera were conducted to uncover their taxonomic diversity and morphological disparity, generating new...... and Faroestygarctus nov. gen. belonging to the families Coronarctidae, Halechiniscidae (Euclavarctinae, Florarctinae), Renaudarctidae and Stygarctidae (Megastygarctidinae, Stygarctinae). In addition, diagnostic characters are given for 8 species of Archechiniscus and 3 species of Florarctinae nov. gen. Phylogenies...

  6. Nuclear magnetic resonance spectroscopy of single subnanoliter ova

    CERN Document Server

    Grisi, Marco; Guidetti, Roberto; Harris, Nicola; Boero, Giovanni

    2015-01-01

    Nuclear magnetic resonance (NMR) spectroscopy is, in principle, a promising candidate to study the intracellular chemistry of single microscopic living entities. However, due to sensitivity limitations, NMR experiments were reported only on very few and relatively large single cells down to a minimum volume of 10 nl. Here we show NMR spectroscopy of single ova at volume scales (0.1 and 0.5 nl) where life development begins for a broad variety of animals, humans included. We demonstrate that the sensitivity achieved by miniaturized inductive NMR probes (few pmol of 1H nuclei in some hours at 7 T) is sufficient to observe chemical heterogeneities among subnanoliter ova of tardigrades. Such sensitivities should allow to non-invasively monitor variations of concentrated intracellular compounds, such as glutathione, in single mammalian zygotes.

  7. A Cambrian micro-lobopodian and the evolution of arthropod locomotion and reproduction

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The evolutionary success of arthropods, the most abundant and diverse animal group, is mainly based on their segmented body and jointed appendages, features that had evolved most likely already before the Cambrian. The first arthropod-like animals, the lobopodians from the Early Cambrian, were unsclerotized and worm-like, and they had unjointed tubular legs. Here we describe the first three-dimensionally preserved Cambrian lobopodian. The material presented of Orstenotubulus evamuellerae gen. et sp. nov. is the smallest and youngest of a lobopodian known. O. evamuellerae shows strikingly detailed similarities to Recent tardigrades and/or onychophorans in its cellular-structured cuticle and the telescopic spines. It also shows similarities to other, longer known lobopodians, but which are ten times as large as the new form. These similarities include the finely annulated body and legs, which is characteristic also for Recent onychophorans, and paired humps continuing into spines situated dorsally to the leg insertions, a feature lacking in the extant forms. The morphology of O. evamuellerae not only elucidates our knowledge about lobopodians, but also aids in a clearer picture of the early evolution of arthropods. An example is the single ventral gonopore between a limb pair of O. evamuellerae, which indicates that a single gonopore, as developed in onychophorans, tardigrades, pentastomids, myriapods and insects, might represent the plesiomorphic state for Arthropoda, while the paired state in chelicerates and crustaceans was convergently achieved. Concerning life habits, the lateral orientation of the limbs and their anchoring spines of the new lobopodian imply that early arthropods were crawlers rather than walkers.

  8. Evolution of pigment-dispersing factor neuropeptides in Panarthropoda: Insights from Onychophora (velvet worms) and Tardigrada (water bears).

    Science.gov (United States)

    Mayer, Georg; Hering, Lars; Stosch, Juliane M; Stevenson, Paul A; Dircksen, Heinrich

    2015-09-01

    Pigment-dispersing factor (PDF) denotes a conserved family of homologous neuropeptides present in several invertebrate groups, including mollusks, nematodes, insects, and crustaceans (referred to here as pigment-dispersing hormone [PDH]). With regard to their encoding genes (pdf, pdh), insects possess only one, nematodes two, and decapod crustaceans up to three, but their phylogenetic relationship is unknown. To shed light on the origin and diversification of pdf/pdh homologs in Panarthropoda (Onychophora + Tardigrada + Arthropoda) and other molting animals (Ecdysozoa), we analyzed the transcriptomes of five distantly related onychophorans and a representative tardigrade and searched for putative pdf homologs in publically available genomes of other protostomes. This revealed only one pdf homolog in several mollusk and annelid species; two in Onychophora, Priapulida, and Nematoda; and three in Tardigrada. Phylogenetic analyses suggest that the last common ancestor of Panarthropoda possessed two pdf homologs, one of which was lost in the arthropod or arthropod/tardigrade lineage, followed by subsequent duplications of the remaining homolog in some taxa. Immunolocalization of PDF-like peptides in six onychophoran species, by using a broadly reactive antibody that recognizes PDF/PDH peptides in numerous species, revealed an elaborate system of neurons and fibers in their central and peripheral nervous systems. Large varicose projections in the heart suggest that the PDF neuropeptides functioned as both circulating hormones and locally released transmitters in the last common ancestor of Onychophora and Arthropoda. The lack of PDF-like-immunoreactive somata associated with the onychophoran optic ganglion conforms to the hypothesis that onychophoran eyes are homologous to the arthropod median ocelli.

  9. Ultrastructure of the digestive system of Ramazzottius tribulosus and Macrobiotus richtersi (Eutardigrada in relationship with diet

    Directory of Open Access Journals (Sweden)

    Alexandra M. AVDONINA

    2007-09-01

    Full Text Available The ultrastructure of the digestive system of tardigrades was already described in some species, but it has never been studied in relationship to diet. We performed ultrastructural analyses of the midgut and hindgut of phytophagous Ramazzottius tribulosus and zoophagous Macrobiotus richtersi. In addition, the foregut of R. tribulosus was analyzed. New ultrastructural details have been observed. Among them are: (a distinct transverse pillar-like structures, lacking in electron-dense and compact cuticle of the buccal tube; (b a hole or groups of holes sometimes present in the buccal tube; (c a large cavity within each of the salivary glands where secreted mucus accumulates; and (d already found in zoophagous Isohypsibius prosostomus, one valve, formed by folds of the pharynx and located at the transition from pharynx to esophagus. In both analyzed species the increase of midgut surface is identified by two orders of folds of the gut wall and by microvilli. In R. tribulosus there are many first-order folds and few second-order folds, whereas in M. richtersi the opposite pattern is found. A peritrophic membrane and microvilli with a well developed glycocalyx are found only in the midgut lumen of R. tribulosus. The density of microvilli and the ratio between the real surface with microvilli and the hypothetical surface without microvilli is lower in zoophagous M. richtersi and I. prosostomus than in phytophagous R. tribulosus. All of these data represent an indirect indication of differences in digestive physiology between phytophagous and zoophagous tardigrade species. The shape of the hindgut is similar in both species and the lumen of the hindgut looks like a heartshaped cavity with some narrow cell evaginations.

  10. Anhydrobiosis in bacteria: From physiology to applications

    Indian Academy of Sciences (India)

    Armando Hernández García

    2011-12-01

    Anhydrobiosis is a phenomenon related to the partial or total desiccation of living organisms, keeping their vital functions after rehydration. The desiccated state in prokaryotes has been widely studied, mainly due to the broad spectrum of the anhydrobiosis applications. In this review, we present the basic theoretical concepts related to anhydrobiosis, focusing on bacterial species. An update about desiccation tolerance in bacteria is given; and the general mechanisms of desiccation tolerance and desiccation damage are described. In addition, we show how the study of anhydrobiosis in prokaryotes has established the theoretical and practical basis for the development of the drying technologies. With regard to the desiccation tolerance in bacteria, although many mechanisms remain undiscovered at the molecular level, important research about the physiology of the anhydrobiotic state and its applications has been performed, and here we provide the most recent information about this subject. On the other hand, the most widely used drying technologies and their particular applications in several fields are described (e.g. medicine, agriculture and food industry). Finally, topics on the stability of desiccated bacterial cells are treated, concluding with the necessity of focusing the research on the mathematical modelling of the desiccated state in bacteria.

  11. Gene expression changes in diapause or quiescent potato cyst nematode, Globodera pallida, eggs after hydration or exposure to tomato root diffusate

    Directory of Open Access Journals (Sweden)

    Juan Emilio Palomares-Rius

    2016-02-01

    Full Text Available Plant-parasitic nematodes (PPN need to be adapted to survive in the absence of a suitable host or in hostile environmental conditions. Various forms of developmental arrest including hatching inhibition and dauer stages are used by PPN in order to survive these conditions and spread to other areas. Potato cyst nematodes (PCN (Globodera pallida and G. rostochiensis are frequently in an anhydrobiotic state, with unhatched nematode persisting for extended periods of time inside the cyst in the absence of the host. This paper shows fundamental changes in the response of quiescent and diapaused eggs of G. pallida to hydration and following exposure to tomato root diffusate (RD using microarray gene expression analysis encompassing a broad set of genes. For the quiescent eggs, 547 genes showed differential expression following hydration vs. hydratation and RD (H-RD treatment whereas 708 genes showed differential regulation for the diapaused eggs following these treatments. The comparison between hydrated quiescent and diapaused eggs showed marked differences, with 2,380 genes that were differentially regulated compared with 987 genes following H-RD. Hydrated quiescent and diapaused eggs were markedly different indicating differences in adaptation for long-term survival. Transport activity is highly up-regulated following H-RD and few genes were coincident between both kinds of eggs. With the quiescent eggs, the majority of genes were related to ion transport (mainly sodium, while the diapaused eggs showed a major diversity of transporters (amino acid transport, ion transport, acetylcholine or other molecules.

  12. Late embryogenesis abundant proteins protect human hepatoma cells during acute desiccation.

    Science.gov (United States)

    Li, Shumin; Chakraborty, Nilay; Borcar, Apurva; Menze, Michael A; Toner, Mehmet; Hand, Steven C

    2012-12-18

    Expression of late embryogenesis abundant (LEA) proteins is highly correlated with desiccation tolerance in anhydrobiotic animals, selected land plants, and bacteria. Genes encoding two LEA proteins, one localized to the cytoplasm/nucleus (AfrLEA2) and one targeted to mitochondria (AfrLEA3m), were stably transfected into human HepG2 cells. A trehalose transporter was used for intracellular loading of this disaccharide. Cells were rapidly and uniformly desiccated to low water content (spin-drying technique. Immediately on rehydration, control cells without LEA proteins or trehalose exhibited 0% membrane integrity, compared with 98% in cells loaded with trehalose and expressing AfrLEA2 or AfrLEA3m; surprisingly, AfrLEA3m without trehalose conferred 94% protection. Cell proliferation across 7 d showed an 18-fold increase for cells dried with AfrLEA3m and trehalose, compared with 27-fold for nondried controls. LEA proteins dramatically enhance desiccation tolerance in mammalian cells and offer the opportunity for engineering biostability in the dried state.

  13. The role of amphiphiles.

    Science.gov (United States)

    Hoekstra, Folkert A; Golovina, Elena A

    2002-03-01

    This paper reviews our work on the partitioning of amphiphilic compounds from the cytoplasm into membranes during drying of plant systems, and discusses how relevant this phenomenon might be for anhydrobiosis. Amphiphilic guest molecules do partition into membranes and oil bodies, as demonstrated by the results of in vivo electron paramagnetic resonance spectroscopy on incorporated spin probes. Arguments for the likelihood of endogenous cytoplasmic amphiphiles behaving similarly during dehydration and rehydration of plant systems are presented. Negative and positive aspects of the partitioning are summarized. Positive aspects are the automatic insertion of amphiphilic antioxidants into membranes of the dehydrating organism, and the control of membrane fluidity and the phase transition temperature. A negative aspect is the perturbation of membrane structure, leading to increased permeability and loss of function. The finding that after an initial fluidization during dehydration, the membrane surface becomes immobilized in desiccation-tolerant systems and not in desiccation-sensitive systems, is discussed in the light of a strict control of the effect of partitioning. The adaptive significance of amphiphile partitioning into the membranes of anhydrobiotes is discussed.

  14. Stress tolerance during diapause and quiescence of the brine shrimp, Artemia.

    Science.gov (United States)

    MacRae, Thomas H

    2016-01-01

    Oviparously developing embryos of the brine shrimp, Artemia, arrest at gastrulation and are released from females as cysts before entering diapause, a state of dormancy and stress tolerance. Diapause is terminated by an external signal, and growth resumes if conditions are permissible. However, if circumstances are unfavorable, cysts enter quiescence, a dormant stage that continues as long as adverse conditions persist. Artemia embryos in diapause and quiescence are remarkably resistant to environmental and physiological stressors, withstanding desiccation, cold, heat, oxidation, ultraviolet radiation, and years of anoxia at ambient temperature when fully hydrated. Cysts have adapted to stress in several ways; they are surrounded by a rigid cell wall impermeable to most chemical compounds and which functions as a shield against ultraviolet radiation. Artemia cysts contain large amounts of trehalose, a non-reducing sugar thought to preserve membranes and proteins during desiccation by replacing water molecules and/or contributing to vitrification. Late embryogenesis abundant proteins similar to those in seeds and other anhydrobiotic organisms are found in cysts, and they safeguard cell organelles and proteins during desiccation. Artemia cysts contain abundant amounts of p26, a small heat shock protein, and artemin, a ferritin homologue, both ATP-independent molecular chaperones important in stress tolerance. The evidence provided in this review supports the conclusion that it is the interplay of these protective elements that make Artemia one of the most stress tolerant of all metazoan organisms.

  15. Enhanced drought tolerance of a soil-dwelling springtail by pre-acclimation to a mild drought stress.

    Science.gov (United States)

    Sjursen, H; Bayley, M; Holmstrup, M

    2001-09-01

    The springtail Folsomia candida has a highly permeable cuticle, but is able to survive several weeks at 98.2%RH. This corresponds to a water potential deficit of about 17bars between the environment and the normal osmotic pressure of the body fluids of this animal. Recent studies have shown a water vapour absorption mechanism by accumulation of sugars and polyols (SP) in F. candida, which explains how this species can survive dehydrating conditions. In the present study, adult F. candida were pre-acclimated at 98.2%RH to induce the accumulation of SP, and were subsequently exposed for additional desiccating conditions from 98 to 94%RH. Activity level, water content, osmotic pressure of body fluids and SP composition were investigated. After the desiccation period, the animals were rehydrated at 100%RH and survival was assessed. The results showed that F. candida survived a more severe drought stress when it had been pre-acclimated to 98.2%RH before exposure to lower humidity. This species was able to maintain hyperosmosity to the surroundings at 95.5%RH, suggesting that it can absorb water vapour down to this limit. Below this limit, trehalose levels increased while myo-inositol levels decreased. We propose that this is a change of survival strategy where F. candida at mild desiccation levels seek to retain water by colligative means (remain hyperosmotic), but at severe desiccation levels switches to an anhydrobiotic strategy.

  16. Identification of anhydrobiosis-related genes from an expressed sequence tag database in the cryptobiotic midge Polypedilum vanderplanki (Diptera; Chironomidae).

    Science.gov (United States)

    Cornette, Richard; Kanamori, Yasushi; Watanabe, Masahiko; Nakahara, Yuichi; Gusev, Oleg; Mitsumasu, Kanako; Kadono-Okuda, Keiko; Shimomura, Michihiko; Mita, Kazuei; Kikawada, Takahiro; Okuda, Takashi

    2010-11-12

    Some organisms are able to survive the loss of almost all their body water content, entering a latent state known as anhydrobiosis. The sleeping chironomid (Polypedilum vanderplanki) lives in the semi-arid regions of Africa, and its larvae can survive desiccation in an anhydrobiotic form during the dry season. To unveil the molecular mechanisms of this resistance to desiccation, an anhydrobiosis-related Expressed Sequence Tag (EST) database was obtained from the sequences of three cDNA libraries constructed from P. vanderplanki larvae after 0, 12, and 36 h of desiccation. The database contained 15,056 ESTs distributed into 4,807 UniGene clusters. ESTs were classified according to gene ontology categories, and putative expression patterns were deduced for all clusters on the basis of the number of clones in each library; expression patterns were confirmed by real-time PCR for selected genes. Among up-regulated genes, antioxidants, late embryogenesis abundant (LEA) proteins, and heat shock proteins (Hsps) were identified as important groups for anhydrobiosis. Genes related to trehalose metabolism and various transporters were also strongly induced by desiccation. Those results suggest that the oxidative stress response plays a central role in successful anhydrobiosis. Similarly, protein denaturation and aggregation may be prevented by marked up-regulation of Hsps and the anhydrobiosis-specific LEA proteins. A third major feature is the predicted increase in trehalose synthesis and in the expression of various transporter proteins allowing the distribution of trehalose and other solutes to all tissues.

  17. Distribution and evolution of the serine/aspartate racemase family in invertebrates.

    Science.gov (United States)

    Uda, Kouji; Abe, Keita; Dehara, Yoko; Mizobata, Kiriko; Sogawa, Natsumi; Akagi, Yuki; Saigan, Mai; Radkov, Atanas D; Moe, Luke A

    2016-02-01

    Free D-amino acids have been found in various invertebrate phyla, while amino acid racemase genes have been identified in few species. The purpose of this study is to elucidate the distribution, function, and evolution of amino acid racemases in invertebrate animals. We searched the GenBank databases, and found 11 homologous serine racemase genes from eight species in eight different invertebrate phyla. The cloned genes were identified based on their maximum activity as Acropora millepora (Cnidaria) serine racemase (SerR) and aspartate racemase (AspR), Caenorhabditis elegans (Nematoda) SerR, Capitella teleta (Annelida) SerR, Crassostrea gigas (Mollusca) SerR and AspR, Dugesia japonica (Platyhelminthes) SerR, Milnesium tardigradum (Tardigrada) SerR, Penaeus monodon (Arthropoda) SerR and AspR and Strongylocentrotus purpuratus (Echinodermata) AspR. We found that Acropora, Aplysia, Capitella, Crassostrea and Penaeus had two amino acid racemase paralogous genes and these paralogous genes have evolved independently by gene duplication at their recent ancestral species. The transcriptome analyses using available SRA data and enzyme kinetic data suggested that these paralogous genes are expressed in different tissues and have different functions in vivo. Phylogenetic analyses clearly indicated that animal SerR and AspR are not separated by their particular racemase functions and form a serine/aspartate racemase family cluster. Our results revealed that SerR and AspR are more widely distributed among invertebrates than previously known. Moreover, we propose that the triple serine loop motif at amino acid positions 150-152 may be responsible for the large aspartate racemase activity and the AspR evolution from SerR.

  18. After-ripening induced transcriptional changes of hormonal genes in wheat seeds: the cases of brassinosteroids, ethylene, cytokinin and salicylic acid.

    Directory of Open Access Journals (Sweden)

    Vijaya R Chitnis

    Full Text Available Maintenance and release of seed dormancy is regulated by plant hormones; their levels and seed sensitivity being the critical factors. This study reports transcriptional regulation of brassinosteroids (BR, ethylene (ET, cytokinin (CK and salicylic acid (SA related wheat genes by after-ripening, a period of dry storage that decays dormancy. Changes in the expression of hormonal genes due to seed after-ripening did not occur in the anhydrobiotic state but rather in the hydrated state. After-ripening induced dormancy decay appears to be associated with imbibition mediated increase in the synthesis and signalling of BR, via transcriptional activation of de-etiolated2, dwarf4 and brassinosteroid signaling kinase, and repression of brassinosteroid insensitive 2. Our analysis is also suggestive of the significance of increased ET production, as reflected by enhanced transcription of 1-aminocyclopropane-1-carboxylic acid oxidase in after-ripened seeds, and tight regulation of seed response to ET in regulating dormancy decay. Differential transcriptions of lonely guy, zeatin O-glucosyltransferases and cytokinin oxidases, and pseudo-response regulator between dormant and after-ripened seeds implicate CK in the regulation of seed dormancy in wheat. Our analysis also reflects the association of dormancy decay in wheat with seed SA level and NPR independent SA signaling that appear to be regulated transcriptionally by phenylalanine ammonia lyase, and whirly and suppressor of npr1 inducible1 genes, respectively. Co-expression clustering of the hormonal genes implies the significance of synergistic and antagonistic interaction between the different plant hormones in regulating wheat seed dormancy. These results contribute to further our understanding of the molecular features controlling seed dormancy in wheat.

  19. Resurrecting Van Leeuwenhoek's rotifers: a reappraisal of the role of disaccharides in anhydrobiosis.

    Science.gov (United States)

    Tunnacliffe, A; Lapinski, J

    2003-10-29

    In 1702, Van Leeuwenhoek was the first to describe the phenomenon of anhydrobiosis in a species of bdelloid rotifer, Philodina roseola. It is the purpose of this review to examine what has been learned since then about the extreme desiccation tolerance in rotifers and how this compares with our understanding of anhydrobiosis in other organisms. Remarkably, much of what is known today about the requirements for successful anhydrobiosis, and the degree of biostability conferred by the dry state, was already determined in principle by the time of Spallanzani in the late 18th century. Most modern research on anhydrobiosis has emphasized the importance of the non-reducing disaccharides trehalose and sucrose, one or other sugar being present at high concentrations during desiccation of anhydrobiotic nematodes, brine shrimp cysts, bakers' yeast, resurrection plants and plant seeds. These sugars are proposed to act as water replacement molecules, and as thermodynamic and kinetic stabilizers of biomolecules and membranes. In apparent contradiction of the prevailing models, recent experiments from our laboratory show that bdelloid rotifers undergo anhydrobiosis without producing trehalose or any analogous molecule. This has prompted us to critically re-examine the association of disaccharides with anhydrobiosis in the literature. Surprisingly, current hypotheses are based almost entirely on in vitro data: there is very limited information which is more than simply correlative in the literature on living systems. In many species, disaccharide accumulation occurs at approximately the same time as desiccation tolerance is acquired. However, several studies indicate that these sugars are not sufficient for anhydrobiosis; furthermore, there is no conclusive evidence, through mutagenesis or functional knockout experiments, for example, that sugars are necessary for anhydrobiosis. Indeed, some plant seeds and micro-organisms, like the rotifer, exhibit excellent desiccation

  20. The induction of anhydrobiosis in the sleeping chironomid: current status of our knowledge.

    Science.gov (United States)

    Cornette, Richard; Kikawada, Takahiro

    2011-06-01

    An African chironomid, Polypedilum vanderplanki, is the only insect known to be capable of extreme desiccation tolerance, or anhydrobiosis. In the 1950s and 1960s, Hinton strenuously studied anhydrobiosis in this insect from a physiological standpoint; however, nobody has afterward investigated the phenomenon. In 2000, research on mechanisms underlying anhydrobiosis was resumed due to successful establishment of a rearing system for P. vanderplanki. This review is focused on the latest findings on the physiological and molecular mechanisms underlying the induction of anhydrobiosis in P. vanderplanki. Early experiments demonstrated that the induction of anhydrobiosis was possible in isolated tissues and independent from the control of central nervous system. However, to achieve successful anhydrobiosis, larvae need a slow regime of desiccation, allowing them to synthesize molecules, which will protect cells and tissues against the deleterious effects of dehydration. Trehalose, a nonreducing disaccharide, which accumulates in P. vanderplanki larvae up to 20% of the dry body mass, is thought to replace the water in its tissues. Similarly, highly hydrophilic proteins called the late embryogenesis abundant (LEA) proteins are expressed in huge quantities and act as a molecular shield to protect biological molecules against aggregation and denaturation. This function is shared by heat shock proteins, which are also upregulated during the desiccation process. At the same time, desiccating larvae express various antioxidant molecules and enzymes, to cope with the massive oxidative stress, which is responsible for general damage to membranes, proteins, and DNA in dehydrating cells. Finally, specific water channels, called aquaporins, accelerate dehydration, and trehalose together with LEA proteins forms a glassy matrix, which protects the biological molecules and the structural integrity of larvae in the anhydrobiotic state.

  1. The responses of cytochrome redox state and energy metabolism to dehydration support a role for cytoplasmic viscosity in desiccation tolerance

    Science.gov (United States)

    Leprince; Hoekstra

    1998-12-01

    To characterize the depression of metabolism in anhydrobiotes, the redox state of cytochromes and energy metabolism were studied during dehydration of soaked cowpea (Vigna unguiculata) cotyledons and pollens of Typha latifolia and Impatiens glandulifera. Between water contents (WC) of 1.0 and 0.6 g H2O/g dry weight (g/g), viscosity as measured by electron spin resonance spectroscopy increased from 0.15 to 0.27 poise. This initial water loss was accompanied by a 50% decrease in respiration rates, whereas the adenylate energy charge remained constant at 0.8, and cytochrome c oxidase (COX) remained fully oxidized. From WC of 0.6 to 0.2 g/g, viscosity increased exponentially. The adenylate energy charge declined to 0.4 in seeds and 0.2 in pollen, whereas COX became progressively reduced. At WC of less than 0.2 g/g, COX remained fully reduced, whereas respiration ceased. When dried under N2, COX remained 63% reduced in cotyledons until WC was 0.7 g/g and was fully reduced at 0.2 g/g. During drying under pure O2, the pattern of COX reduction was similar to that of air-dried tissues, although the maximum reduction was 70% in dried tissues. Thus, at WC of less than 0.6 g/g, the reduction of COX probably originates from a decreased O2 availability as a result of the increased viscosity and impeded diffusion. We suggest that viscosity is a valuable parameter to characterize the relation between desiccation and decrease in metabolism. The implications for desiccation tolerance are discussed.

  2. Liposomes with diverse compositions are protected during desiccation by LEA proteins from Artemia franciscana and trehalose.

    Science.gov (United States)

    Moore, Daniel S; Hansen, Richard; Hand, Steven C

    2016-01-01

    Intracellular accumulation of Late Embryogenesis Abundant (LEA) proteins and the disaccharide trehalose is associated with cellular desiccation tolerance in a number of animal species. Two LEA proteins from anhydrobiotic embryos of the brine shrimp Artemia franciscana were tested for the ability to protect liposomes of various compositions against desiccation-induced damage in the presence and absence of trehalose. Damage was assessed by carboxyfluorescein leakage after drying and rehydration. Further, using a cytoplasmic-localized (AfrLEA2) and a mitochondrial-targeted (AfrLEA3m) LEA protein allowed us to evaluate whether each may preferentially stabilize membranes of a particular lipid composition based on the protein's subcellular location. Both LEA proteins were able to offset damage during drying of liposomes that mimicked the lipid compositions of the inner mitochondrial membrane (with cardiolipin), outer mitochondrial membrane, and the inner leaflet of the plasma membrane. Thus liposome stabilization by AfrLEA3m or AfrLEA2 was not dependent on lipid composition, provided physiological amounts of bilayer and non-bilayer-forming lipids were present (liposomes with a non-biological composition of 100% phosphatidylcholine were not protected by either protein). Additive protection by LEA proteins plus trehalose was dependent on the lipid composition of the target membrane. Minimal additional damage occurred to liposomes stored at room temperature in the dried state for one week compared to liposomes rehydrated after 24h. Consistent with the ability to stabilize lipid bilayers, molecular modeling of the secondary structures for AfrLEA2 and AfrLEA3m revealed bands of charged amino acids similar to other amphipathic proteins that interact directly with membranes.

  3. A randomized crossover study comparing trehalose/hyaluronate eyedrops and standard treatment: patient satisfaction in the treatment of dry eye syndrome.

    Science.gov (United States)

    Pinto-Bonilla, Juan Carlos; Del Olmo-Jimeno, Alberto; Llovet-Osuna, Fernando; Hernández-Galilea, Emiliano

    2015-01-01

    Dry eye is a common disorder in routine ophthalmological practice, and a better understanding of the complex pathophysiology is leading to improved treatment. Thealoz Duo(®) is a novel artificial tear preparation containing two active ingredients: Trehalose, a naturally occurring disaccharide with anhydrobiotic functions in many organisms, and hyaluronate, a widely distributed anionic glycosaminoglycan polysaccharide with lubricative and water-retaining properties in biological systems. In a randomized, single center, open label, crossover study, 17 adult patients with moderate-to-severe dry eye syndrome were randomized to treatment with Thealoz Duo(®) (combining trehalose and hyaluronic acid) or Systane(®). Patients received 7 days of treatment. The primary efficacy variable was patient satisfaction evaluated by a 0-100 visual analog scale evaluated on days 0 and 7 of treatment. Secondary parameters included ocular surface disease index (OSDI), symptoms of dry eye, ocular staining scores (fluorescein and lissamine green), ocular clinical signs, Schirmer test, tear breakup time, and global efficacy assessed by the patient and the investigator. Seventeen patients were included. Patient satisfaction improved from 44.5±19.0 to 70.2±19.2 mm during Thealoz Duo(®) treatment and from 47.2±23 to 57.1±19.1 mm during Systane(®) treatment (P=0.043, mixed-effects analysis of covariance). Two secondary efficacy parameters (dry eye symptoms and the impact of their symptoms on work) showed statistically significant advantages for Thealoz Duo(®) over Systane(®). There were no statistically significant advantages for Systane(®) over Thealoz Duo(®) for any measured parameter. No adverse events were reported. Thealoz Duo(®) appears to be an effective combination of two active ingredients for the treatment of dry eye and is at least as effective as Systane(®).

  4. Identifying contamination with advanced visualization and analysis practices: metagenomic approaches for eukaryotic genome assemblies

    Science.gov (United States)

    Delmont, Tom O.

    2016-01-01

    High-throughput sequencing provides a fast and cost-effective mean to recover genomes of organisms from all domains of life. However, adequate curation of the assembly results against potential contamination of non-target organisms requires advanced bioinformatics approaches and practices. Here, we re-analyzed the sequencing data generated for the tardigrade Hypsibius dujardini, and created a holistic display of the eukaryotic genome assembly using DNA data originating from two groups and eleven sequencing libraries. By using bacterial single-copy genes, k-mer frequencies, and coverage values of scaffolds we could identify and characterize multiple near-complete bacterial genomes from the raw assembly, and curate a 182 Mbp draft genome for H. dujardini supported by RNA-Seq data. Our results indicate that most contaminant scaffolds were assembled from Moleculo long-read libraries, and most of these contaminants have differed between library preparations. Our re-analysis shows that visualization and curation of eukaryotic genome assemblies can benefit from tools designed to address the needs of today’s microbiologists, who are constantly challenged by the difficulties associated with the identification of distinct microbial genomes in complex environmental metagenomes. PMID:27069789

  5. Unlocking the early fossil record of the arthropod central nervous system

    Science.gov (United States)

    Edgecombe, Gregory D.; Ma, Xiaoya; Strausfeld, Nicholas J.

    2015-01-01

    Extant panarthropods (euarthropods, onychophorans and tardigrades) are hallmarked by stunning morphological and taxonomic diversity, but their central nervous systems (CNS) are relatively conserved. The timing of divergences of the ground pattern CNS organization of the major panarthropod clades has been poorly constrained because of a scarcity of data from their early fossil record. Although the CNS has been documented in three-dimensional detail in insects from Cenozoic ambers, it is widely assumed that these tissues are too prone to decay to withstand other styles of fossilization or geologically older preservation. However, Cambrian Burgess Shale-type compressions have emerged as sources of fossilized brains and nerve cords. CNS in these Cambrian fossils are preserved as carbon films or as iron oxides/hydroxides after pyrite in association with carbon. Experiments with carcasses compacted in fine-grained sediment depict preservation of neural tissue for a more prolonged temporal window than anticipated by decay experiments in other media. CNS and compound eye characters in exceptionally preserved Cambrian fossils predict divergences of the mandibulate and chelicerate ground patterns by Cambrian Stage 3 (ca 518 Ma), a dating that is compatible with molecular estimates for these splits. PMID:26554038

  6. Panspermia Survival Scenarios for Organisms that Survive Typical Hypervelocity Solar System Impact Events.

    Science.gov (United States)

    Pasini, D.

    2014-04-01

    Previous experimental studies have demonstrated the survivability of living cells during hypervelocity impact events, testing the panspermia and litho-panspermia hypotheses [1]. It has been demonstrated by the authors that Nannochloropsis Oculata Phytoplankton, a eukaryotic photosynthesizing autotroph found in the 'euphotic zone' (sunlit surface layers of oceans [2]), survive impacts up to 6.93 km s-1 (approx. shock pressure 40 GPa) [3, 4]. Also shown to survive impacts up to 5.49 km s-1 is the tardigrade species Hypsibius dujardini (a complex micro-animal consisting of 40,000 cells) [5, 6]. It has also been shown that they can survive sustained pressures up to 600 MPa using a water filled pressure capsule [7]. Additionally bacteria can survive impacts up to 5.4 km s-1 (~30 GPa) - albeit with a low probability of survival [1], and the survivability of yeast spores in impacts up to 7.4 km s-1 (~30 GPa) has also recently been demonstrated [8]. Other groups have also reported that the lichen Xanthoria elegans is able to survive shocks in similar pressure ranges (~40 GPa) [9]. Here we present various simulated impact regimes to show which scenarios are condusive to the panspermia hypothesis of the natural transfer of life (via an icy body) through space to an extraterrestrial environment.

  7. A Carboniferous non-onychophoran lobopodian reveals long-term survival of a Cambrian morphotype.

    Science.gov (United States)

    Haug, Joachim T; Mayer, Georg; Haug, Carolin; Briggs, Derek E G

    2012-09-25

    Lobopodians, a nonmonophyletic assemblage of worm-shaped soft-bodied animals most closely related to arthropods, show two major morphotypes: long-legged and short-legged forms. The morphotype with stubby, conical legs has a long evolutionary history, from the early Cambrian through the Carboniferous, including the living onychophorans and tardigrades. Species with tubular lobopods exceeding the body diameter have been reported exclusively from the Cambrian; the three-dimensionally preserved Orstenotubulus evamuellerae from the uppermost middle Cambrian "Orsten" (Sweden) is the youngest long-legged lobopodian reported thus far. Here we describe a new long-legged lobopodian, Carbotubulus waloszeki gen. et sp. nov., from Mazon Creek, Illinois, USA (∼296 million years ago). This first post-Cambrian long-legged lobopodian extends the range of this morphotype by about 200 million years. The three-dimensionally preserved specimen differs significantly from the associated short-legged form Ilyodes inopinata, of which we also present new head details. The discovery of a Carboniferous long-legged lobopodian provides a more striking example of the long-term survival of Cambrian morphotypes than, for example, the occurrence of a Burgess Shale-type biota in the Ordovician of Morocco and dampens the effect of any major extinction of taxa at the end of the middle Cambrian.

  8. Molecular timetrees reveal a Cambrian colonization of land and a new scenario for ecdysozoan evolution.

    Science.gov (United States)

    Rota-Stabelli, Omar; Daley, Allison C; Pisani, Davide

    2013-03-04

    Ecdysozoans have been key components of ecosystems since the early Cambrian, when trilobites and soft-bodied Burgess Shale-type ecdysozoans dominated marine animal communities. Even today, the most abundant animals on Earth are either nematode worms or plankton-forming crustaceans, whereas the most diverse are the insects. Throughout geological time, several ecdysozoan lineages independently colonized land, shaping both marine and terrestrial ecosystems and providing an adequate environment for successive animal terrestrialization. The timing of these events is largely uncertain and has been investigated only partially using molecular data. Here we present a timescale of ecdysozoan evolution based on multiple molecular data sets, the most complete set of fossil calibrations to date, and a thorough series of validation analyses. Results converge on an Ediacaran origin of all major ecdysozoan lineages (∼587-543 million years ago [mya]), followed by a fast Cambrian radiation of the pancrustaceans (∼539-511 mya), a Cambro-Ordovician colonization of land of different arthropod lineages (∼510-471 mya), and a relatively recent radiation of extant nematodes, onychophorans, and tardigrades (∼442 mya). Arthropods colonized land nearly synchronously with land plants. Further diversification within flying insects, nematodes and onychophorans might be related to the evolution of vascular plants and forests.

  9. Hallucigenia's head and the pharyngeal armature of early ecdysozoans.

    Science.gov (United States)

    Smith, Martin R; Caron, Jean-Bernard

    2015-07-02

    The molecularly defined clade Ecdysozoa comprises the panarthropods (Euarthropoda, Onychophora and Tardigrada) and the cycloneuralian worms (Nematoda, Nematomorpha, Priapulida, Loricifera and Kinorhyncha). These disparate phyla are united by their means of moulting, but otherwise share few morphological characters--none of which has a meaningful fossilization potential. As such, the early evolutionary history of the group as a whole is largely uncharted. Here we redescribe the 508-million-year-old stem-group onychophoran Hallucigenia sparsa from the mid-Cambrian Burgess Shale. We document an elongate head with a pair of simple eyes, a terminal buccal chamber containing a radial array of sclerotized elements, and a differentiated foregut that is lined with acicular teeth. The radial elements and pharyngeal teeth resemble the sclerotized circumoral elements and pharyngeal teeth expressed in tardigrades, stem-group euarthropods and cycloneuralian worms. Phylogenetic results indicate that equivalent structures characterized the ancestral panarthropod and, seemingly, the ancestral ecdysozoan, demonstrating the deep homology of panarthropod and cycloneuralian mouthparts, and providing an anatomical synapomorphy for the ecdysozoan supergroup.

  10. Unlocking the early fossil record of the arthropod central nervous system.

    Science.gov (United States)

    Edgecombe, Gregory D; Ma, Xiaoya; Strausfeld, Nicholas J

    2015-12-19

    Extant panarthropods (euarthropods, onychophorans and tardigrades) are hallmarked by stunning morphological and taxonomic diversity, but their central nervous systems (CNS) are relatively conserved. The timing of divergences of the ground pattern CNS organization of the major panarthropod clades has been poorly constrained because of a scarcity of data from their early fossil record. Although the CNS has been documented in three-dimensional detail in insects from Cenozoic ambers, it is widely assumed that these tissues are too prone to decay to withstand other styles of fossilization or geologically older preservation. However, Cambrian Burgess Shale-type compressions have emerged as sources of fossilized brains and nerve cords. CNS in these Cambrian fossils are preserved as carbon films or as iron oxides/hydroxides after pyrite in association with carbon. Experiments with carcasses compacted in fine-grained sediment depict preservation of neural tissue for a more prolonged temporal window than anticipated by decay experiments in other media. CNS and compound eye characters in exceptionally preserved Cambrian fossils predict divergences of the mandibulate and chelicerate ground patterns by Cambrian Stage 3 (ca 518 Ma), a dating that is compatible with molecular estimates for these splits.

  11. Nasa's International Space Station: A Testbed for Planetary Protection Protocol Development

    Science.gov (United States)

    Bell, M. S.; Rucker, M.; Love, S.; Johnson, J.; Chambliss, J.; Pierson, D.; Ott, M.; Mary, N.; Glass, B.; Lupisella, M.; Scheuger, A.; Race, M.

    2015-01-01

    Wherever humans go, they inevitably carry along the critters that live in and on them. Conventional wisdom has long held that it is unlikely those critters could survive the space environment, but in 2007 some microscopic aquatic animals called Tardigrades survived exposure to space and in 2008 Cyanobacteria lived for 548 days outside the ISS. Unlike the Mars rovers that were cleaned once and sent on their way, crew members will provide a constantly regenerating contaminant source. Are we prepared to certify that we can meet forward contamination protocols as we search for life at new destinations? What about the organisms we might reasonably expect a crewed spacecraft to leak or vent? Do we even know what they are? How long might our tiny hitch-hikers survive in close proximity to a warm spacecraft that periodically leaks/vents water or oxygen and how might they mutate with long-duration exposure? How will these contaminants migrate from their source in conditions encountered in space or on other planetary surfaces? This project aims to answer some of these questions by bringing together key stakeholder communities to develop a human forward contamination test, analysis, and integration plan. A system engineering approach to identify the experiments, analysis, and modeling needed to develop the contamination control protocols required will be used as a roadmap to integrate the many different parts of this problem - from launch to landing, living, and working on another planetary surface.

  12. Direct and indirect effects of metal contamination on soil biota in a Zn-Pb post-mining and smelting area (S Poland)

    Energy Technology Data Exchange (ETDEWEB)

    Kapusta, Pawel, E-mail: p.kapusta@botany.pl [Department of Ecology, W. Szafer Institute of Botany, Polish Academy of Sciences, Lubicz 46, 31-512 Krakow (Poland); Szarek-Lukaszewska, Grazyna; Stefanowicz, Anna M. [Department of Ecology, W. Szafer Institute of Botany, Polish Academy of Sciences, Lubicz 46, 31-512 Krakow (Poland)

    2011-06-15

    Effects of metal contamination on soil biota activity were investigated at 43 sites in 5 different habitats (defined by substratum and vegetation type) in a post-mining area. Sites were characterised in terms of soil pH and texture, nutrient status, total and exchangeable metal concentrations, as well as plant species richness and cover, abundances of enchytraeids, nematodes and tardigrades, and microbial respiration and biomass. The concentrations of total trace metals were highest in soils developed on mining waste (metal-rich dolomite), but these habitats were more attractive than sandy sites for plants and soil biota because of their higher content of organic matter, clay and nutrients. Soil mesofauna and microbes were strongly dependent on natural habitat properties. Pollution (exchangeable Zn and Cd) negatively affected only enchytraeid density; due to a positive relationship between enchytraeids and microbes it indirectly reduced microbial activity. - Highlights: > Bioavailable zinc and cadmium reduce enchytraeid density. > Enchytraeids positively influence microbial respiration and biomass. > Total contents of heavy metals in soil are poor predictors of the distribution of plants and soil biota. - Elevated concentrations of exchangeable Zn and Cd reduce enchytraeid density and indirectly affect microbial activity adversely.

  13. Integrative taxonomy allows the identification of synonymous species and the erection of a new genus of Echiniscidae (Tardigrada, Heterotardigrada).

    Science.gov (United States)

    Vicente, Filipe; Fontoura, Paulo; Cesari, Michele; Rebecchi, Lorena; Guidetti, Roberto; Serrano, Artur; Bertolani, Roberto

    2013-02-14

    The taxonomy of tardigrades is challenging as these animals demonstrate a limited number of useful morphological characters, therefore several species descriptions are supported by only minor differences. For example, Echiniscus oihonnae and Echiniscus multispinosus are separated exclusively by the absence or presence of dorsal spines at position Bd. Doubts were raised on the validity of these two species, which were often sampled together. Using an integrative approach, based on genetic and morphological investigations, we studied two new Portuguese populations, and compared these with archived collections. We have determined that the two species must be considered synonymous with Echiniscus oihonnae the senior synonym. Our study showed generally low genetic distances of cox1 gene (with a maximum of 4.1%), with specimens displaying both morphologies sharing the same haplotype, and revealed character Bd to be variable. Addition-ally, a more detailed morphological and phylogenetic study based on the 18S gene uncovered a new evolutionary line within the Echiniscidae, which justified the erection of Diploechiniscus gen. nov. The new genus is in a sister group relationship with Echiniscus and is, for the moment, composed of a single species.

  14. Sexual dimorphism, population dynamics and some aspects of life history of Echiniscus mauccii (Tardigrada; Heterotardigrada

    Directory of Open Access Journals (Sweden)

    Frank A. ROMANO III

    2007-09-01

    Full Text Available A fifteen month study (December 2002 though February 2004 of a meiofaunal community living in moss and lichen from a Pecan tree on the campus of Jacksonville State University reports 9,791 microinvertebrates. Echiniscus mauccii was the most prevalent tardigrade species (1,329 specimens and was chosen to determine population dynamics and some aspects of their life histories. The average length of all the specimens (adults, juveniles, males, and females for each month was determined. A plot of all E. mauccii specimens was used to determine the following life stages of this species; juvenile, pre-reproductive, and reproductive. The studied population exhibited relatively constant population size and juvenile recruitment occurred year round with no increased reproduction during a season of the year. Thus, E. mauccii is an opportunistic breeder. Males of this species were found for the first time on a Laurasian land mass and females were found to be significantly larger than males. A protected Fisher's LSD test revealed a significant negative relationship between average adult length and the number of adults collected per month, but not between adult and juvenile lengths. As the population became more dense the average adult size decreased suggesting competition between at least the adults. Echiniscus mauccii is a sexually dimorphic animal that is iteroparous, breeds whenever conditions are appropriate, has a relatively constant population size, produces a small number of large eggs, and exhibits competition between adults. Thus, E. mauccii exhibits classic K-selected traits.

  15. First molecular evidence for the existence of a Tardigrada + Arthropoda clade.

    Science.gov (United States)

    Giribet, G; Carranza, S; Baguñà, J; Riutort, M; Ribera, C

    1996-01-01

    The complete 18S rDNA gene sequence of Macrobiotus group hufelandi (Tardigrada) was obtained and aligned with 18S rDNA and rRNA gene sequences of 24 metazoans (mainly protostomes). Discrete character (maximum-parsimony) and distance (neighbor-joining) methods were used to infer their phylogeny. The evolution of bootstrap proportions with sequence length (pattern of resolved nodes, PRN) was studied to test the resolution of the nodes in neighbor-joining trees. The results show that arthropods are monophyletic. Tardigrades represent the sister group of arthropods (in parsimony analyses) or they are related with crustaceans (distance analysis and PRN). Arthropoda are divided into two main evolutionary lines, the Hexapoda + Crustacea line (weakly supported), and the Myriapoda + Chelicerata line. The Hexapoda + Crustacea line includes Pentastomida, but the internal resolution is far from clear. The Insecta (Ectognatha) are monophyletic, but no evidence for the monophyly of Hexapoda is found. The Chelicerata are a monophyletic group and the Myriapoda cluster close to Arachnida. Overall, the results obtained represent the first molecular evidence for a Tardigrada + Arthropoda clade. In addition, the congruence between molecular phylogenies of the Arthropoda from other authors and this obtained here indicates the need to review those obtained solely on morphological characters.

  16. Neural development in Onychophora (velvet worms) suggests a step-wise evolution of segmentation in the nervous system of Panarthropoda.

    Science.gov (United States)

    Mayer, Georg; Whitington, Paul M

    2009-11-01

    A fundamental question in biology is how animal segmentation arose during evolution. One particular challenge is to clarify whether segmental ganglia of the nervous system evolved once, twice, or several times within the Bilateria. As close relatives of arthropods, Onychophora play an important role in this debate since their nervous system displays a mixture of both segmental and non-segmental features. We present evidence that the onychophoran "ventral organs," previously interpreted as segmental anlagen of the nervous system, do not contribute to nerve cord formation and therefore cannot be regarded as vestiges of segmental ganglia. The early axonal pathways in the central nervous system arise by an anterior-to-posterior cascade of axonogenesis from neuronal cell bodies, which are distributed irregularly along each presumptive ventral cord. This pattern contrasts with the strictly segmental neuromeres present in arthropod embryos and makes the assumption of a secondary loss of segmentation in the nervous system during the evolution of the Onychophora less plausible. We discuss the implications of these findings for the evolution of neural segmentation in the Panarthropoda (Arthropoda+Onychophora+Tardigrada). Our data best support the hypothesis that the ancestral panarthropod had only a partially segmented nervous system, which evolved progressively into the segmental chain of ganglia seen in extant tardigrades and arthropods.

  17. Ultrastructural changes of the midgut epithelium in Isohypsibius granulifer granulifer Thulin, 1928 (Tardigrada: Eutardigrada) during oogenesis.

    Science.gov (United States)

    Rost-Roszkowska, Magdalena M; Poprawa, Izabela; Wójtowicz, Maria; Kaczmarek, Lukasz

    2011-04-01

    The midgut epithelium of Isohypsibius granulifer granulifer (Eutardigrada) is composed of columnar digestive cells. At its anterior end, a group of cells with cytoplasm which differs from the cytoplasm of digestive cells is present. Probably, those cells respond to crescent-like cells (midgut regenerative cells) described for some tardigrade species. Their mitotic divisions have not been observed. We analyzed the ultrastructure of midgut digestive cells in relation to five different stages of oogenesis (previtellogenesis, beginning of the vitellogenesis, vitellogenesis--early choriogenesis, vitellogenesis--middle choriogenesis, late choriogenesis). In the midgut epithelium cells, the gradual accumulation of glycogen granules, lipid droplets and structures of varying electron density occurs. During vitellogenesis and choriogenesis, in the cytoplasm of midgut cells we observed the increasing number of organelles which are responsible for the intensive synthesis of lipids, proteins and saccharides such as cisterns of endoplasmic reticulum and Golgi complexes. At the end of oogenesis, autophagy also intensifies in midgut epithelial cells, which is probably caused by the great amount of reserve material. Midgut epithelium of analyzed species takes part in the yolk precursor synthesis.

  18. MicroRNAs and phylogenomics resolve the relationships of Tardigrada and suggest that velvet worms are the sister group of Arthropoda.

    Science.gov (United States)

    Campbell, Lahcen I; Rota-Stabelli, Omar; Edgecombe, Gregory D; Marchioro, Trevor; Longhorn, Stuart J; Telford, Maximilian J; Philippe, Hervé; Rebecchi, Lorena; Peterson, Kevin J; Pisani, Davide

    2011-09-20

    Morphological data traditionally group Tardigrada (water bears), Onychophora (velvet worms), and Arthropoda (e.g., spiders, insects, and their allies) into a monophyletic group of invertebrates with walking appendages known as the Panarthropoda. However, molecular data generally do not support the inclusion of tardigrades within the Panarthropoda, but instead place them closer to Nematoda (roundworms). Here we present results from the analyses of two independent genomic datasets, expressed sequence tags (ESTs) and microRNAs (miRNAs), which congruently resolve the phylogenetic relationships of Tardigrada. Our EST analyses, based on 49,023 amino acid sites from 255 proteins, significantly support a monophyletic Panarthropoda including Tardigrada and suggest a sister group relationship between Arthropoda and Onychophora. Using careful experimental manipulations--comparisons of model fit, signal dissection, and taxonomic pruning--we show that support for a Tardigrada + Nematoda group derives from the phylogenetic artifact of long-branch attraction. Our small RNA libraries fully support our EST results; no miRNAs were found to link Tardigrada and Nematoda, whereas all panarthropods were found to share one unique miRNA (miR-276). In addition, Onychophora and Arthropoda were found to share a second miRNA (miR-305). Our study confirms the monophyly of the legged ecdysozoans, shows that past support for a Tardigrada + Nematoda group was due to long-branch attraction, and suggests that the velvet worms are the sister group to the arthropods.

  19. Identifying contamination with advanced visualization and analysis practices: metagenomic approaches for eukaryotic genome assemblies

    Directory of Open Access Journals (Sweden)

    Tom O. Delmont

    2016-03-01

    Full Text Available High-throughput sequencing provides a fast and cost-effective mean to recover genomes of organisms from all domains of life. However, adequate curation of the assembly results against potential contamination of non-target organisms requires advanced bioinformatics approaches and practices. Here, we re-analyzed the sequencing data generated for the tardigrade Hypsibius dujardini, and created a holistic display of the eukaryotic genome assembly using DNA data originating from two groups and eleven sequencing libraries. By using bacterial single-copy genes, k-mer frequencies, and coverage values of scaffolds we could identify and characterize multiple near-complete bacterial genomes from the raw assembly, and curate a 182 Mbp draft genome for H. dujardini supported by RNA-Seq data. Our results indicate that most contaminant scaffolds were assembled from Moleculo long-read libraries, and most of these contaminants have differed between library preparations. Our re-analysis shows that visualization and curation of eukaryotic genome assemblies can benefit from tools designed to address the needs of today’s microbiologists, who are constantly challenged by the difficulties associated with the identification of distinct microbial genomes in complex environmental metagenomes.

  20. Identifying contamination with advanced visualization and analysis practices: metagenomic approaches for eukaryotic genome assemblies.

    Science.gov (United States)

    Delmont, Tom O; Eren, A Murat

    2016-01-01

    High-throughput sequencing provides a fast and cost-effective mean to recover genomes of organisms from all domains of life. However, adequate curation of the assembly results against potential contamination of non-target organisms requires advanced bioinformatics approaches and practices. Here, we re-analyzed the sequencing data generated for the tardigrade Hypsibius dujardini, and created a holistic display of the eukaryotic genome assembly using DNA data originating from two groups and eleven sequencing libraries. By using bacterial single-copy genes, k-mer frequencies, and coverage values of scaffolds we could identify and characterize multiple near-complete bacterial genomes from the raw assembly, and curate a 182 Mbp draft genome for H. dujardini supported by RNA-Seq data. Our results indicate that most contaminant scaffolds were assembled from Moleculo long-read libraries, and most of these contaminants have differed between library preparations. Our re-analysis shows that visualization and curation of eukaryotic genome assemblies can benefit from tools designed to address the needs of today's microbiologists, who are constantly challenged by the difficulties associated with the identification of distinct microbial genomes in complex environmental metagenomes.

  1. A preliminary study of freshwater meiofaunal communities at Greenwich Island, South Shetland Islands, Antarctica

    Institute of Scientific and Technical Information of China (English)

    Soraya J. Silva; Minerva Cordovés; Nory González; Leinny González

    2015-01-01

    Meiofaunal communities of three small, shallow freshwater habitats sampled during the austral summer of 2013 in Greenwich Island, South Shetland Islands, Antarctica, are reported. Communities are dominated by tardigrades (85%), nematodes (11%), and rotifers (3%). Collembola, Oligochaeta, crustacean larvae (nauplii) and unidentified organisms account for 0.3%. Total meiofaunal densities reach 11 770 ind∙cm-2, with mean densities (ind∙cm−2) of 1 365.83 ± 2 716.65 (Zone A), 523.67 ± 1 166.48 (Zone B) and 72.17 ± 110.78 (Zone C). Given the age of freshwater habitats, and the general lack of higher-trophic level predatory taxa, those species we report are likely early stage colonizers, and these communities are at an early stage of ecological succession. Non-parametrical analysis revealed the main variables influencing meiofaunal density and distribution are related to granulometric characteristics of sediments and microphytobenthic biomass. There were close relationships between meiofaunal abundance and microphytobenthic biomass, which indicates that benthic microalgae significantly influence meiofaunal distribution. A strong correlation between nematode abundance and the percentage of silt, clay and carbon in the sediment was also shown by canonical correspondence analysis and Spearman rank correlation.

  2. A randomized crossover study comparing trehalose/hyaluronate eyedrops and standard treatment: patient satisfaction in the treatment of dry eye syndrome

    Directory of Open Access Journals (Sweden)

    Pinto-Bonilla JC

    2015-04-01

    Full Text Available Juan Carlos Pinto-Bonilla,1 Alberto del Olmo-Jimeno,2 Fernando Llovet-Osuna,3 Emiliano Hernández-Galilea4 1Department of Corneal, Refractive, and Cataract Surgery, European Ophthalmological Institute, Clínica Baviera, Pamplona, Navarra, Spain; 2Optometry Department, European Ophthalmological Institute, Clínica Baviera, Pamplona, Navarra, Spain; 3Department of Refractive and Cataract Surgery, European Ophthalmological Institute, Clínica Baviera, Madrid, Madrid, Spain; 4Ophthalmology Department, Hospital Clínico Universitario de Salamanca, Universidad de Salamanca, Salamanca, Salamanca, Spain Abstract: Dry eye is a common disorder in routine ophthalmological practice, and a better understanding of the complex pathophysiology is leading to improved treatment. Thealoz Duo® is a novel artificial tear preparation containing two active ingredients: Trehalose, a naturally occurring disaccharide with anhydrobiotic functions in many organisms, and hyaluronate, a widely distributed anionic glycosaminoglycan polysaccharide with lubricative and water-retaining properties in biological systems. In a randomized, single center, open label, crossover study, 17 adult patients with moderate-to-severe dry eye syndrome were randomized to treatment with Thealoz Duo® (combining trehalose and hyaluronic acid or Systane®. Patients received 7 days of treatment. The primary efficacy variable was patient satisfaction evaluated by a 0–100 visual analog scale evaluated on days 0 and 7 of treatment. Secondary parameters included ocular surface disease index (OSDI, symptoms of dry eye, ocular staining scores (fluorescein and lissamine green, ocular clinical signs, Schirmer test, tear breakup time, and global efficacy assessed by the patient and the investigator. Seventeen patients were included. Patient satisfaction improved from 44.5±19.0 to 70.2±19.2 mm during Thealoz Duo® treatment and from 47.2±23 to 57.1±19.1 mm during Systane® treatment (P=0.043, mixed

  3. Characterize Human Forward Contamination Project

    Science.gov (United States)

    Rucker, Michelle

    2015-01-01

    Let's face it: wherever we go, we will inevitably carry along the little critters that live in and on us. Conventional wisdom has long held that it's unlikely those critters could survive the space environment, but in 2007 microscopic animals called Tardigrades survived exposure to space and in 2008 Cyanobacteria lived for 548 days outside the International Space Station (ISS). But what about the organisms we might reasonably expect a crewed spacecraft to leak or vent? Do we even know what they are? How long might our tiny hitch-hikers survive in close proximity to a warm spacecraft that periodically leaks/vents water or oxygen-and how might they mutate with long-duration exposure? Unlike the Mars rovers that we cleaned once and sent on their way, crew members will provide a constantly regenerating contaminant source. Are we prepared to certify that we can meet forward contamination protocols as we search for life at new destinations? This project has four technical objectives: 1. TEST: Develop a test plan to leverage existing equipment (i.e. ISS) to characterize the kinds of organisms we can reasonably expect pressurized, crewed volumes to vent or leak overboard; as part of testing, we'll need to develop an Extravehicular Activity (EVA)-compatible tool that can withstand the pressure and temperature extremes of space, as well as collect, separate, and store multiple samples; 2. ANALYSIS: Develop an analysis plan to study those organisms in relevant destination environments, including spacecraft-induced conditions; 3. MODEL: Develop a modeling plan to model organism transport mechanisms in relevant destination environments; 4. SHARE: Develop a plan to disseminate findings and integrate recommendations into exploration requirements & ops. In short, we propose a system engineering approach to roadmap the necessary experiments, analysis, and modeling up front--rather than try to knit together disparate chunks of data into a sensible conclusion after the fact.

  4. Environmental Sequencing of Biotic Components of Dust in the Chihuahuan Desert

    Science.gov (United States)

    Walsh, E.; Gill, T. E.; Rivas, J. A., Jr.; Leung, M. Y.; Mohl, J.

    2015-12-01

    A growing number of studies mark the role of wind in dispersing biota. Most of these approaches have used traditional methods to assess taxonomic diversity. Here we used next generation sequencing to characterize microbiota in dust collected from the Chihuahuan Desert. Atmospheric dust was collected during events during 2011-2014 using dry deposition collectors placed at two sites in El Paso Co., TX. In parallel experiments, we rehydrated subsamples of dust and conducted PCR amplifications using conserved primers for 16S and 18S ribosomal genes. Sequenced reads were de-multiplexed, quality filtered, and processed using QIIME. Taxonomy was assigned based on pairwise identity using BLAST for microbial eukaryotes. All samples were rarefied to a set number of sequences per sample prior to downstream analyses. Bioinformatic analysis of four of the dust samples yielded a diversity of biota, including zooplankton, bacteria, fungi, algae, and protists, but fungi predominate (>90% of both 10K and 3K reads). In our rehydrations of dust samples from the U.S. southwest nematodes, gastrotrichs, tardigrades, monogonont and bdelloid rotifers, branchiopods and numerous ciliates have been recovered. Variability in genetic diversity among samples is based, in part, on the source and extent of the particular dust event. We anticipate the same patterns will be seen in the complete data set. These preliminary results indicate that wind is a major transporter of not only fungi, bacteria and other unicellular organisms but may also be important in shaping the distribution patterns of multi-cellular organisms such as those that inhabit aquatic environments in the arid southwestern US.

  5. Cyclomorphosis in Tardigrada: adaptation to environmental constraints.

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    Halberg, Kenneth Agerlin; Persson, Dennis; Ramløv, Hans; Westh, Peter; Kristensen, Reinhardt Møbjerg; Møbjerg, Nadja

    2009-09-01

    Tardigrades exhibit a remarkable resilience against environmental extremes. In the present study, we investigate mechanisms of survival and physiological adaptations associated with sub-zero temperatures and severe osmotic stress in two commonly found cyclomorphic stages of the marine eutardigrade Halobiotus crispae. Our results show that only animals in the so-called pseudosimplex 1 stage are freeze tolerant. In pseudosimplex 1, as well as active-stage animals kept at a salinity of 20 ppt, ice formation proceeds rapidly at a crystallization temperature of around -20 degrees C, revealing extensive supercooling in both stages, while excluding the presence of physiologically relevant ice-nucleating agents. Experiments on osmotic stress tolerance show that the active stage tolerates the largest range of salinities. Changes in body volume and hemolymph osmolality of active-stage specimens (350-500 microm) were measured following salinity transfers from 20 ppt. Hemolymph osmolality at 20 ppt was approximately 950 mOsm kg(-1). Exposure to hypo-osmotic stress in 2 and 10 ppt caused (1) rapid swelling followed by a regulatory volume decrease, with body volume reaching control levels after 48 h and (2) decrease in hemolymph osmolality followed by a stabilization at significantly lower osmolalities. Exposure to hyperosmotic stress in 40 ppt caused (1) rapid volume reduction, followed by a regulatory increase, but with a new steady-state after 24 h below control values and (2) significant increase in hemolymph osmolality. At any investigated external salinity, active-stage H. crispae hyper-regulate, indicating a high water turnover and excretion of dilute urine. This is likely a general feature of eutardigrades.

  6. Ultrastructural changes and programmed cell death of trophocytes in the gonad of Isohypsibius granulifer granulifer Thulin, 1928 (Tardigrada, Eutardigrada, Isohypsibiidae).

    Science.gov (United States)

    Poprawa, Izabela; Hyra, Marta; Kszuk-Jendrysik, Michalina; Rost-Roszkowska, Magdalena Maria

    2015-03-01

    The studies on the fates of the trophocytes, the apoptosis and autophagy in the gonad of Isohypsibius granulifer granulifer have been described using transmission electron microscope, light and fluorescent microscopes. The results presented here are the first that are connected with the cell death of nurse cells in the gonad of tardigrades. However, here we complete the results presented by Węglarska (1987). The reproductive system of I. g. granulifer contains a single sack-like hermaphroditic gonad and a single gonoduct. The gonad is composed of three parts: a germarium filled with proliferating germ cells (oogonia); a vitellarium that has clusters of female germ cells (the region of oocytes development); and a male part filled with male germ cells in which the sperm cells develop. The trophocytes (nurse cells) show distinct alterations during all of the stages of oogenesis: previtello-, vitello- and choriogenesis. During previtellogenesis the female germ cells situated in the vitellarium are connected by cytoplasmic bridges, and form clusters of cells. No ultrastructural differences appear among the germ cells in a cluster during this stage of oogenesis. In early vitellogenesis, the cells in each cluster start to grow and numerous organelles gradually accumulate in their cytoplasm. However, at the beginning of the middle of vitellogenesis, one cell in each cluster starts to grow in order to differentiate into oocyte, while the remaining cells are trophocytes. Eventually, the cytoplasmic bridges between the oocyte and trophocytes disappear. Autophagosomes also appear in the cytoplasm of nurse cells together with many degenerating organelles. The cytoplasm starts to shrink, which causes the degeneration of the cytoplasmic bridges between trophocytes. Apoptosis begins when the cytoplasm of these cells is full of autophagosomes/autolysosomes and causes their death.

  7. Energy allocation in two species of Eutardigrada

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    Lorena REBECCHI

    2007-09-01

    Full Text Available To improve our knowledge on life histories in tardigrades and the energy allocated for their reproduction and growth, we have studied two species (Macrobiotus richtersi and Hypsibius convergens differing in evolutionary histories, diet and ways of oviposition. For both species we considered a bisexual population dwelling in the same substrate. In both species we investigated energy allocations in males with a testis rich in spermatozoa and females, each with an ovary containing oocytes in advanced vitellogenesis. The age of the specimens was estimated on the basis of buccal tube length and body size. Body and gonad areas were calculated using an image analysis program. In both species females reach a larger size than males. Macrobiotus richtersi has both a significantly longer buccal tube and wider body area than H. convergens. Statistical analyses show that the buccal tube has a positive correlation with body area and gonad area. For an estimate of the relative energy allocated for reproduction in one reproductive event (relative reproductive effort = RRE, we have used the ratio between gonad area and body area. In males of both species, the absolute amount of energy and the RRE is statistically lower than that of females. Males and females of H. convergens have a RRE higher than those of M. richtersi. In M. richtersi, the gonad increases proportionally more when animals are large (old, whereas in H. convergens this direct relationship is not detectable. In M. richtersi the energy allocated for a reproductive event increases during the life of the females. In males, the increase of the gonad size is progressive during the animal life. In each reproductive event, females of H. convergens allocate a lower amount of energy in absolute value when compared to M. richtersi. Nevertheless, when considering the RRE, their investment is higher than that of M. richtersi.

  8. Environmental DNA sequencing primers for eutardigrades and bdelloid rotifers

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    Martin Andrew P

    2009-12-01

    Full Text Available Abstract Background The time it takes to isolate individuals from environmental samples and then extract DNA from each individual is one of the problems with generating molecular data from meiofauna such as eutardigrades and bdelloid rotifers. The lack of consistent morphological information and the extreme abundance of these classes makes morphological identification of rare, or even common cryptic taxa a large and unwieldy task. This limits the ability to perform large-scale surveys of the diversity of these organisms. Here we demonstrate a culture-independent molecular survey approach that enables the generation of large amounts of eutardigrade and bdelloid rotifer sequence data directly from soil. Our PCR primers, specific to the 18s small-subunit rRNA gene, were developed for both eutardigrades and bdelloid rotifers. Results The developed primers successfully amplified DNA of their target organism from various soil DNA extracts. This was confirmed by both the BLAST similarity searches and phylogenetic analyses. Tardigrades showed much better phylogenetic resolution than bdelloids. Both groups of organisms exhibited varying levels of endemism. Conclusion The development of clade-specific primers for characterizing eutardigrades and bdelloid rotifers from environmental samples should greatly increase our ability to characterize the composition of these taxa in environmental samples. Environmental sequencing as shown here differs from other molecular survey methods in that there is no need to pre-isolate the organisms of interest from soil in order to amplify their DNA. The DNA sequences obtained from methods that do not require culturing can be identified post-hoc and placed phylogenetically as additional closely related sequences are obtained from morphologically identified conspecifics. Our non-cultured environmental sequence based approach will be able to provide a rapid and large-scale screening of the presence, absence and diversity of

  9. Evolution of the AKH/corazonin/ACP/GnRH receptor superfamily and their ligands in the Protostomia.

    Science.gov (United States)

    Hauser, Frank; Grimmelikhuijzen, Cornelis J P

    2014-12-01

    In this review we trace the evolutionary connections between GnRH receptors from vertebrates and the receptors for adipokinetic hormone (AKH), AKH/corazonin-related peptide (ACP), and corazonin from arthropods. We conclude that these G protein-coupled receptors (GPCRs) are closely related and have a common evolutionary origin, which dates back to the split of Proto- and Deuterostomia, about 700 million years ago. We propose that in the protostomian lineage, the ancestral GnRH-like receptor gene duplicated as did its GnRH-like ligand gene, followed by diversification, leading to (i) a corazonin receptor gene and a corazonin-like ligand gene, and (ii) an AKH receptor gene and an AKH-like ligand gene in the Mollusca and Annelida. Subsequently, the AKH receptor and ligand genes duplicated once more, yielding the situation that we know from arthropods today, where three independent hormonal systems exist, signalling with AKH, ACP, and corazonin. Our model for the evolution of GnRH signaling in the Protostomia is a striking example of receptor-ligand co-evolution. This model has been developed using several bioinformatics tools (TBLASTN searches, phylogenetic tree analyses), which also helped us to annotate six novel AKH preprohormones and their corresponding AKH sequences from the following molluscs: the sea hare Aplysia californica (AKH sequence: pQIHFSPDWGTamide), the sea slug Tritonia diomedea (pQIHFSPGWEPamide), the fresh water snail Bithynia siamensis goniomphalos (pQIHFTPGWGSamide), the owl limpet Lottia gigantea (pQIHFSPTWGSamide), the oyster Crassostrea gigas (pQVSFSTNWGSamide), and the freshwater pearl mussel Hyriopsis cumingii (pQISFSTNWGSamide). We also found AKHs in the tardigrade Hysibius dujardini (pQLSFTGWGHamide), the rotifer Brachionus calycifloros (pQLTFSSDWSGamide), and the penis worm Priapulus caudatus (pQIFFSKGWRGamide). This is the first report, showing that AKH signaling is widespread in molluscs.

  10. Controls on microalgal community structures in cryoconite holes upon high-Arctic glaciers, Svalbard

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    Vonnahme, T. R.; Devetter, M.; Žárský, J. D.; Šabacká, M.; Elster, J.

    2016-02-01

    Glaciers are known to harbor surprisingly complex ecosystems. On their surface, distinct cylindrical holes filled with meltwater and sediments are considered hot spots for microbial life. The present paper addresses possible biological interactions within the community of prokaryotic cyanobacteria and eukaryotic microalgae (microalgae) and relations to their potential grazers, such as tardigrades and rotifers, additional to their environmental controls. Svalbard glaciers with substantial allochthonous input of material from local sources reveal high microalgal densities. Small valley glaciers with high sediment coverages and high impact of birds show high biomasses and support a high biological diversity. Invertebrate grazer densities do not show any significant negative correlation with microalgal abundances but rather a positive correlation with eukaryotic microalgae. Shared environmental preferences and a positive effect of grazing are the proposed mechanisms to explain these correlations. Most microalgae found in this study form colonies (cells, or > 25 µm), which may protect them against invertebrate grazing. This finding rather indicates grazing as a positive control on eukaryotic microalgae by nutrient recycling. Density differences between the eukaryotic microalgae and prokaryotic cyanobacteria and their high distinction in redundancy (RDA) and principal component (PCA) analyses indicate that these two groups are in strong contrast. Eukaryotic microalgae occurred mainly in unstable cryoconite holes with high sediment loads, high N : P ratios, and a high impact of nutrient input by bird guano, as a proxy for nutrients. In these environments autochthonous nitrogen fixation appears to be negligible. Selective wind transport of Oscillatoriales via soil and dust particles is proposed to explain their dominance in cryoconites further away from the glacier margins. We propose that, for the studied glaciers, nutrient levels related to recycling of limiting

  11. Trehalose and Trehalose-based Polymers for Environmentally Benign, Biocompatible and Bioactive Materials

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    Mitsuhiro Shibata

    2008-08-01

    Full Text Available Abstract: Trehalose is a non-reducing disaccharide that is found in many organisms but not in mammals. This sugar plays important roles in cryptobiosis of selaginella mosses, tardigrades (water bears, and other animals which revive with water from a state of suspended animation induced by desiccation. The interesting properties of trehalose are due to its unique symmetrical low-energy structure, wherein two glucose units are bonded face-to-face by 1→1-glucoside links. The Hayashibara Co. Ltd., is credited for developing an inexpensive, environmentally benign and industrial-scale process for the enzymatic conversion of α-1,4-linked polyhexoses to α,α-D-trehalose, which made it easy to explore novel food, industrial, and medicinal uses for trehalose and its derivatives. Trehalosechemistry is a relatively new and emerging field, and polymers of trehalose derivatives appear environmentally benign, biocompatible, and biodegradable. The discriminating properties of trehalose are attributed to its structure, symmetry, solubility, kinetic and thermodynamic stability and versatility. While syntheses of trehalose-based polymer networks can be straightforward, syntheses and characterization of well defined linear polymers with tailored properties using trehalose-based monomers is challenging, and typically involves protection and deprotection of hydroxyl groups to attain desired structural, morphological, biological, and physical and chemical properties in the resulting products. In this review, we will overview known literature on trehalose’s fascinating involvement in cryptobiology; highlight its applications in many fields; and then discuss methods we used to prepare new trehalose-based monomers and polymers and explain their properties.

  12. Distribution and diversity of soil microfauna from East Antarctica: assessing the link between biotic and abiotic factors.

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    Alejandro Velasco-Castrillón

    Full Text Available Terrestrial life in Antarctica has been described as some of the simplest on the planet, and mainly confined to soil microfaunal communities. Studies have suggested that the lack of diversity is due to extreme environmental conditions and thought to be driven by abiotic factors. In this study we investigated soil microfauna composition, abundance, and distribution in East Antarctica, and assessed correlations with soil geochemistry and environmental variables. We examined 109 soil samples from a wide range of ice-free habitats, spanning 2000 km from Framnes Mountains to Bailey Peninsula. Microfauna across all samples were patchily distributed, from complete absence of invertebrates to over 1600 specimens/gram of dry weight of soil (gdw, with highest microfauna abundance observed in samples with visible vegetation. Bdelloid rotifers were on average the most widespread found in 87% of sampled sites and the most abundant (44 specimens/gdw. Tardigrades occurred in 57% of the sampled sites with an abundance of 12 specimens/gdw. Nematodes occurred in 71% of samples with a total abundance of 3 specimens/gdw. Ciliates and mites were rarely found in soil samples, with an average abundance of 1.3 and 0.04 specimens/gdw, respectively. We found that microfaunal composition and abundance were mostly correlated with the soil geochemical parameters; phosphorus, NO3 (- and salinity, and likely to be the result of soil properties and historic landscape formation and alteration, rather than the geographic region they were sampled from. Studies focusing on Antarctic biodiversity must take into account soil geochemical and environmental factors that influence population and species heterogeneity.

  13. Survival of plant seeds, their UV screens, and nptII DNA for 18 months outside the International Space Station.

    Science.gov (United States)

    Tepfer, David; Zalar, Andreja; Leach, Sydney

    2012-05-01

    The plausibility that life was imported to Earth from elsewhere can be tested by subjecting life-forms to space travel. Ultraviolet light is the major liability in short-term exposures (Horneck et al., 2001 ), and plant seeds, tardigrades, and lichens-but not microorganisms and their spores-are candidates for long-term survival (Anikeeva et al., 1990 ; Sancho et al., 2007 ; Jönsson et al., 2008 ; de la Torre et al., 2010 ). In the present study, plant seeds germinated after 1.5 years of exposure to solar UV, solar and galactic cosmic radiation, temperature fluctuations, and space vacuum outside the International Space Station. Of the 2100 exposed wild-type Arabidopsis thaliana and Nicotiana tabacum (tobacco) seeds, 23% produced viable plants after return to Earth. Survival was lower in the Arabidopsis Wassilewskija ecotype and in mutants (tt4-8 and fah1-2) lacking UV screens. The highest survival occurred in tobacco (44%). Germination was delayed in seeds shielded from solar light, yet full survival was attained, which indicates that longer space travel would be possible for seeds embedded in an opaque matrix. We conclude that a naked, seed-like entity could have survived exposure to solar UV radiation during a hypothetical transfer from Mars to Earth. Chemical samples of seed flavonoid UV screens were degraded by UV, but their overall capacity to absorb UV was retained. Naked DNA encoding the nptII gene (kanamycin resistance) was also degraded by UV. A fragment, however, was detected by the polymerase chain reaction, and the gene survived in space when protected from UV. Even if seeds do not survive, components (e.g., their DNA) might survive transfer over cosmic distances.

  14. Utilizing ARC EMCS Seedling Cassettes as Highly Versatile Miniature Growth Chambers for Model Organism Experiments

    Science.gov (United States)

    Freeman, John L.; Steele, Marianne K.; Sun, Gwo-Shing; Heathcote, David; Reinsch, S.; DeSimone, Julia C.; Myers, Zachary A.

    2014-01-01

    The aim of our ground testing was to demonstrate the capability of safely putting specific model organisms into dehydrated stasis, and to later rehydrate and successfully grow them inside flight proven ARC EMCS seedling cassettes. The ARC EMCS seedling cassettes were originally developed to support seedling growth during space flight. The seeds are attached to a solid substrate, launched dry, and then rehydrated in a small volume of media on orbit to initiate the experiment. We hypothesized that the same seedling cassettes should be capable of acting as culture chambers for a wide range of organisms with minimal or no modification. The ability to safely preserve live organisms in a dehydrated state allows for on orbit experiments to be conducted at the best time for crew operations and more importantly provides a tightly controlled physiologically relevant growth experiment with specific environmental parameters. Thus, we performed a series of ground tests that involved growing the organisms, preparing them for dehydration on gridded Polyether Sulfone (PES) membranes, dry storage at ambient temperatures for varying periods of time, followed by rehydration. Inside the culture cassettes, the PES membranes were mounted above blotters containing dehydrated growth media. These were mounted on stainless steel bases and sealed with plastic covers that have permeable membrane covered ports for gas exchange. The results showed we were able to demonstrate acceptable normal growth of C.elegans (nematodes), E.coli (bacteria), S.cerevisiae (yeast), Polytrichum (moss) spores and protonemata, C.thalictroides (fern), D.discoideum (amoeba), and H.dujardini (tardigrades). All organisms showed acceptable growth and rehydration in both petri dishes and culture cassettes initially, and after various time lengths of dehydration. At the end of on orbit ISS European Modular Cultivation System experiments the cassettes could be frozen at ultra-low temperatures, refrigerated, or chemically

  15. Assessing effects of the pharmaceutical ivermectin on meiobenthic communities using freshwater microcosms.

    Science.gov (United States)

    Brinke, Marvin; Höss, Sebastian; Fink, Guido; Ternes, Thomas A; Heininger, Peter; Traunspurger, Walter

    2010-08-15

    Ivermectin is a widely applied veterinary pharmaceutical that is highly toxic to several non-target organisms. So far, little is known about its impact on benthic freshwater species, although its rapid sorption to sediment particles and high persistence in aquatic sediments have raised concerns about the risk for benthic organisms. In the present study, indoor microcosms were used to assess the impact of ivermectin on freshwater meiobenthic communities over a period of 224 days. Microcosm sediments were directly spiked with ivermectin to achieve nominal concentrations of 0.9, 9, and 45 microg kg(-1) dw. Initially measured ivermectin concentrations (day 0) were 0.6, 6.2, and 31 microg kg(-1) dw. In addition to abundance of major meiobenthic organism groups, the nematode community was assessed on the species level, assuming a high risk for free-living nematodes due to their close phylogenetic relationship to the main target organisms of ivermectin, parasitic nematodes. Benthic microcrustaceans (cladocerans, ostracods) and nematodes showed the most sensitive response to ivermectin, while tardigrades profited from the presence of the pharmaceutical. The most pronounced effects on the meiofauna community composition occurred at the highest treatment level (31 microg kg(-1) dw), leading to a no observed effect concentration (NOEC(Community)) of 6.2 microg kg(-1) dw. However, the nematode community was already seriously affected at a concentration of 6.2 microg kg(-1) dw with two bacterivorous genera, Monhystera and Eumonhystera, being the most sensitive, whereas species of omnivorous genera (Tripyla, Tobrilus) increased in abundance after the application of ivermectin. Thus, a NOEC(Community) of 0.6 microg kg(-1) dw was derived for nematodes. Direct and indirect effects of ivermectin on meiobenthic communities could be demonstrated. The pharmaceutical is likely to pose a high risk, because its NOECs are close to predicted environmental concentrations (PECs) in sediments

  16. Effects of wood ash on the biologic diversity of the soil fauna. Final report; Effekter av vedaska paa biologisk maangfald hos markfaunan. Slutrapport

    Energy Technology Data Exchange (ETDEWEB)

    Persson, Tryggve; Ahlstroem, Kerstin; Lindberg, Niklas [Swedish Univ. of Agricultural Sciences, Vindeln (Sweden). Dept. of Ecology and Environmental Research

    2005-06-01

    The aim was to assess long-term effects of wood-ash and lime application on the soil fauna diversity. The study was made at three sites, Oeringe and Torup in the county of Halland and Asa in the county of Smaaland, 20, 14 and 10 years after treatment, respectively. The soil fauna groups reported here are Enchytraeidae, Tardigrada and Oribatida. Different kinds of wood ash results in very different effects on soil pH despite similar dose. Non-hardened fresh ash increased pH as indicated by the liming potential (ca. 2 tonnes of CaCO{sub 3} correspond to 2,4 tonnes of loose ash). Hardened wood ash (at Asa) had a smaller effect on pH than corresponding amount of lime, and ca. 6 tonnes of ash/ha were needed to obtain the same effects as 3 tonnes of lime. Granulated wood ash (at Torup) had an even smaller effect on pH than the hardened ash at Asa. A preliminary estimate is that 6 tonnes/ha granulated ash correspond to 3 tonnes/ha of hardened ash, 1.5 tonnes/ha of non-hardened loose ash and 1 tonne/ha of CaCO{sub 3}. The results with regard to soil fauna show that individual numbers, species numbers and single species of Enchytraeidae and Oribatid mites are strongly dependent on the ash/lime effect on pH in the topsoil layer. Lime and ash appear to have similar effect on these animal groups provided that the pH effect is similar. Therefore, it is possible to extrapolate conclusions from liming trials to ash trials, provided that the pH effect is known. The Tardigrades did not seem to react on the treatments. We conclude that the effect of wood ash on the diversity of soil fauna investigated depends on the solubility of the wood ash and its effect on soil pH. Depending on the effect on pH, ash application results in (a) decreasing densities but increasing species numbers of enchytraeids, (b) decreasing densities but no change in species numbers of oribatid mites and (c) a strong change in the community structure of both enchytraeids and oribatid mites.

  17. Evolution of embryonic development in nematodes

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    Schulze Jens

    2011-09-01

    Full Text Available Abstract Background Nematodes can be subdivided into basal Enoplea (clades 1 and 2 and more derived Chromadorea (clades 3 to 12. Embryogenesis of Caenorhabditis elegans (clade 9 has been analyzed in most detail. Their establishment of polarity and asymmetric cleavage requires the differential localization of PAR proteins. Earlier studies on selected other nematodes revealed that embryonic development of nematodes is more diverse than the essentially invariant development of C. elegans and the classic study object Ascaris had suggested. To obtain a more detailed picture of variations and evolutionary trends we compared embryonic cell lineages and pattern formation in embryos of all 12 nematode clades. Methods The study was conducted using 4-D microscopy and 3-D modeling of developing embryos. Results We found dramatic differences compared to C. elegans in Enoplea but also considerable variations among Chromadorea. We discovered 'Polarity Organizing Centers' (POCs that orient cleavage spindles along the anterior-posterior axis in distinct cells over consecutive cell generations. The resulting lineally arranged blastomeres represent a starting point for the establishment of bilateral symmetry within individual lineages. We can discern six different early cleavage types and suggest that these variations are due to modifications in the activity of the POCs in conjunction with changes in the distribution of PAR proteins. In addition, our studies indicate that lineage complexity advanced considerably during evolution, that is we observe trends towards an increase of somatic founder cells, from monoclonal to polyclonal lineages and from a variable (position-dependent to an invariable (lineage-dependent way of cell fate specification. In contrast to the early phase of embryogenesis, the second half ('morphogenesis' appears similar in all studied nematodes. Comparison of early cleavage between the basal nematode Tobrilus stefanskii and the tardigrade

  18. Tree species traits influence soil physical, chemical, and biological properties in high elevation forests.

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    Edward Ayres

    Full Text Available BACKGROUND: Previous studies have shown that plants often have species-specific effects on soil properties. In high elevation forests in the Southern Rocky Mountains, North America, areas that are dominated by a single tree species are often adjacent to areas dominated by another tree species. Here, we assessed soil properties beneath adjacent stands of trembling aspen, lodgepole pine, and Engelmann spruce, which are dominant tree species in this region and are distributed widely in North America. We hypothesized that soil properties would differ among stands dominated by different tree species and expected that aspen stands would have higher soil temperatures due to their open structure, which, combined with higher quality litter, would result in increased soil respiration rates, nitrogen availability, and microbial biomass, and differences in soil faunal community composition. METHODOLOGY/PRINCIPAL FINDINGS: We assessed soil physical, chemical, and biological properties at four sites where stands of aspen, pine, and spruce occurred in close proximity to one-another in the San Juan Mountains, Colorado. Leaf litter quality differed among the tree species, with the highest nitrogen (N concentration and lowest lignin:N in aspen litter. Nitrogen concentration was similar in pine and spruce litter, but lignin:N was highest in pine litter. Soil temperature and moisture were highest in aspen stands, which, in combination with higher litter quality, probably contributed to faster soil respiration rates from stands of aspen. Soil carbon and N content, ammonium concentration, and microbial biomass did not differ among tree species, but nitrate concentration was highest in aspen soil and lowest in spruce soil. In addition, soil fungal, bacterial, and nematode community composition and rotifer, collembolan, and mesostigmatid mite abundance differed among the tree species, while the total abundance of nematodes, tardigrades, oribatid mites, and prostigmatid

  19. Cell-in-Shell Hybrids: Chemical Nanoencapsulation of Individual Cells.

    Science.gov (United States)

    Park, Ji Hun; Hong, Daewha; Lee, Juno; Choi, Insung S

    2016-05-17

    Nature has developed a fascinating strategy of cryptobiosis ("secret life") for counteracting the stressful, and often lethal, environmental conditions that fluctuate sporadically over time. For example, certain bacteria sporulate to transform from a metabolically active, vegetative state to an ametabolic endospore state. The bacterial endospores, encased within tough biomolecular shells, withstand the extremes of harmful stressors, such as radiation, desiccation, and malnutrition, for extended periods of time and return to a vegetative state by breaking their protective shells apart when their environment becomes hospitable for living. Certain ciliates and even higher organisms, for example, tardigrades, and others are also found to adopt a cryptobiotic strategy for survival. A common feature of cryptobiosis is the structural presence of tough sheaths on cellular structures. However, most cells and cellular assemblies are not "spore-forming" and are vulnerable to the outside threats. In particular, mammalian cells, enclosed with labile lipid bilayers, are highly susceptible to in vitro conditions in the laboratory and daily life settings, making manipulation and preservation difficult outside of specialized conditions. The instability of living cells has been a main bottleneck to the advanced development of cell-based applications, such as cell therapy and cell-based sensors. A judicious question arises: can cellular tolerance against harmful stresses be enhanced by simply forming cell-in-shell hybrid structures? Experimental results suggest that the answer is yes. A micrometer-sized "Iron Man" can be generated by chemically forming an ultrathin (cell. Since the report on silica nanoencapsulation of yeast cells, in which cytoprotective yeast-in-silica hybrids were formed, several synthetic strategies have been developed to encapsulate individual cells in a cytocompatible fashion, mimicking the cryptobiotic cell-in-shell structures found in nature, for example

  20. Effects of temperature and thermal acclimation on locomotor performance of Macrobiotus hufelandi Schultze (Tardigrada: Macrobiotidae)%温度和热驯化对胡氏大生熊虫运动行为的影响

    Institute of Scientific and Technical Information of China (English)

    李晓晨; 王立志

    2005-01-01

    The beneficial acclimation hypothesis (BAH) predicts that animals acclimated to a particular temperature have enhanced performance or fitness at that temperature in comparison with animals acclimated to other temperatures. The BAH has been tested by a variety of empirical examinations, and was rejected by some of them. In order to provide new evidences for the BAH, the effects of acute and acclimation temperature (AT) on locomotor performance of Macrobiotus hufelandi (Tardigrada: Macrobiotidae) were investigated. The tardigrades were collected from Nanwutai, Qinling Mountains which traverse from west to east in central China. The subjects were acclimated to either 2℃ or 22℃ for 2 weeks. The animal was transferred onto a frosted slide and allowed to walk freely at the performance temperature (PT) 2℃ or 22℃. Only one individual was tested per test bout, which lasted from three to five minutes. To avoid occurrence of thermal acclimation effect, the standard adaptation time was limited to 1.5 min. Each subject was tested for once at the same PT, and was tested only at one PT. A total of 25 individuals were tested and measured at the same PT. The locomotor performance of the animals was recorded with a digital video camera mounted on a microscope at 4×10 amplification and replayed on a PC. Every subject was identified. Walking speed (WS) and percentage of time moving (PTM) at both PTs (2℃ or 22℃) were selected as the rate parameters of locomotor performance. The two-way repeated measures ANOVA with a significance level of α= 0.05 and Duncan multiple range test were used to analyze the data. WS of the animals acclimated to and tested at the same temperatures was significantly faster than that for animals acclimated to and tested at the different temperatures, similarly, PTM of the animals acclimated to 22℃ and tested at 22℃ was significantly greater than PTM of animals acclimated to 22℃ and tested at 2℃, which indicated that the animals acclimated

  1. Spatial and temporal changes in interstitial meiofauna on a sandy ocean beach of South America

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    Elaine F. Albuquerque

    2007-06-01

    Full Text Available Spatial and temporal patterns of meiofauna community from a Brazilian sandy beach were investigated. The objective of this work was to analyze the meiofauna distribution using a statistical model that considers the biological data as variables, and granulometric characteristics, organic matter, and temperature as covariables.Four zones were sampled throughout one year in a Brazilian sandy beach and three sediment cores were taken monthly from each zone. The meiofauna was composed by 12 taxa, with tardigrades and nematodes comprising 92% of the total fauna. The meiofauna mean density varied from 1556.25 to 13125.25 ind.10 cm-2, with the highest densities in December. The results of multiple regression showed that the mean effects of zones, vertical layers, and months on the organisms were significantly correlated with the principal taxa of meiofauna. The retention zone and the 0-10 cm layer presented the highest densities. The temporal distribution showed different patterns and some taxa were more abundant in the dry season, and others in the rainy season. Sedimentological variables had strong and significant effects on the meiofauna taxa. According to the results, physical variables at the retention zone create optimal living conditions for the meiobentos, making this zone an area that favors the basic and applied ecological studies.Os padrões de distribuição espacial e temporal da meiofauna em uma praia arenosa do Brasil foram analisados usando um modelo estatístico que considerou os dados biológicos como variáveis e as características granulométricas, % de matéria orgânica, temperatura como covariáveis. Quatro zonas litorais foram amostradas durante o período de um ano e três cores de sedimento foram coletados em cada zona. A meiofauna foi composta de 12 taxa principais e os Tardigrada e Nematoda representaram 92% da fauna total. A densidade média da meiofauna variou de 1.556,25 a 13.125,25 ind.10cm-2, com as mais altas

  2. Resolving arthropod phylogeny: exploring phylogenetic signal within 41 kb of protein-coding nuclear gene sequence.

    Science.gov (United States)

    Regier, Jerome C; Shultz, Jeffrey W; Ganley, Austen R D; Hussey, April; Shi, Diane; Ball, Bernard; Zwick, Andreas; Stajich, Jason E; Cummings, Michael P; Martin, Joel W; Cunningham, Clifford W

    2008-12-01

    This study attempts to resolve relationships among and within the four basal arthropod lineages (Pancrustacea, Myriapoda, Euchelicerata, Pycnogonida) and to assess the widespread expectation that remaining phylogenetic problems will yield to increasing amounts of sequence data. Sixty-eight regions of 62 protein-coding nuclear genes (approximately 41 kilobases (kb)/taxon) were sequenced for 12 taxonomically diverse arthropod taxa and a tardigrade outgroup. Parsimony, likelihood, and Bayesian analyses of total nucleotide data generally strongly supported the monophyly of each of the basal lineages represented by more than one species. Other relationships within the Arthropoda were also supported, with support levels depending on method of analysis and inclusion/exclusion of synonymous changes. Removing third codon positions, where the assumption of base compositional homogeneity was rejected, altered the results. Removing the final class of synonymous mutations--first codon positions encoding leucine and arginine, which were also compositionally heterogeneous--yielded a data set that was consistent with a hypothesis of base compositional homogeneity. Furthermore, under such a data-exclusion regime, all 68 gene regions individually were consistent with base compositional homogeneity. Restricting likelihood analyses to nonsynonymous change recovered trees with strong support for the basal lineages but not for other groups that were variably supported with more inclusive data sets. In a further effort to increase phylogenetic signal, three types of data exploration were undertaken. (1) Individual genes were ranked by their average rate of nonsynonymous change, and three rate categories were assigned--fast, intermediate, and slow. Then, bootstrap analysis of each gene was performed separately to see which taxonomic groups received strong support. Five taxonomic groups were strongly supported independently by two or more genes, and these genes mostly belonged to the slow

  3. Study on Principle and Influencing Factors of Cable Tension Sensor Based on Villari-effect%基于逆磁致伸缩的索力传感器原理与影响因素研究

    Institute of Scientific and Technical Information of China (English)

    姜建山; 陈伟民; 黄尚廉; 廖昌荣; 章鹏

    2009-01-01

    Based on Villari-effect, the theoretic mdel d the cable tension sensor is presented. The relationship between mechanical parameters such as stress, strain and electromagnetic parameters like magnetic field and magnetic induction field are discussed. One loop-shaped stinulative structure of cable tension sensor based on Villari--effect is proposed and cable tension sensor principle is deeply analysed. By measuring inductive voltage in inductive loops, cable tension stress may be measured. Sensor output may be determined by air clearance, magnetic permeability, magnetic field, stress and inductive loops denseness. The sensor output effects resulting from magnetic field and stress ate analysed respectively. When stress changes tardigradely, the cable tension stress may be measured by measuring inductive integral voltage. When stress changes expeditiously, the cable tension stress may be measured by measuring inductive voltage. Sensor sensibility may be determined by stress frequency, inductive loops denseness, magnetic field and nagnetic permeability. In addition, the sensor output effects from magnetic changing and stress changing have been analysed with emulational methods. The results indicate that sensor theory model is feasible.%基于逆磁致伸缩效应,建立钢缆索索力传感器理论模型,分析了施加在缆索材料上的力信号(外力和应变)与磁信号(磁感应强度、磁场强度)之间的耦合关系.针对一种环式结构的索力传感器,对索力测量原理做了详细推导,可通过检测感应线圈的感应电压反映材料所受外力.传感器输出感应电压与空气间隙尺寸、外部激励磁场下的材料磁导率、激励磁场变化、加载外力变化等因素有关,重点分析了激励磁场变化和外力变化对传感器输出的影响.当外力是缓变力,可通过检测感应积分电压求得外力;当外力是交变力,直接通过感应电压求得外力;最后通过对磁场变化