Comparison of the transcriptomes of two tardigrades with different hatching coordination

Yoshida, Yuki; Sugiura, Kenta; Tomita, Masaru; Matsumoto, Midori; Arakawa, Kazuharu

doi:10.1186/s12861-019-0205-9

Cited by 19 publications

(28 citation statements)

References 46 publications

(57 reference statements)

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“…This suggests that differences in the photoecology of juvenile and adult tardigrades have driven this opsin divergence within Tardigrada. Prior research in the Tardigrada has also found differential expression of the cryptobiotic response proteins CAHS and SAHS through ontology ( Yoshida et al 2019 ). These orthologs are instrumental in the maintenance of tardigrade desiccation cryptobiosis at all of its life stages, and it is possible that the differential expression of opsin is also linked to this response, considering the common linkage between light intensity and aridity ( Yoshida et al 2019 ).…”

Section: Resultsmentioning

confidence: 99%

“…Prior research in the Tardigrada has also found differential expression of the cryptobiotic response proteins CAHS and SAHS through ontology ( Yoshida et al 2019 ). These orthologs are instrumental in the maintenance of tardigrade desiccation cryptobiosis at all of its life stages, and it is possible that the differential expression of opsin is also linked to this response, considering the common linkage between light intensity and aridity ( Yoshida et al 2019 ). Notably, Hypsibius c-opsin 3 showed no signs of differential expression across the organism’s ontogeny.…”

Section: Resultsmentioning

confidence: 99%

“…Differential expression analyses ( Anders and Huber 2010 ) use a combination of genomic and transcriptomic data to take “snapshots” of the expression level of a gene at multiple stages of life, or under different life conditions. Previous differential expression analyses in Tardigrada have explored the effect of the tun state on the expression of heat-sensitive proteins ( Yoshida et al 2017 , 2019 ). By comparing the transcriptomic expression of opsins across tardigrade life stages, we can assess whether different light-sensitive proteins are employed to tackle different ecological challenges within the organism’s life cycle ( Cronin and Jinks 2001 ).…”

Section: Introductionmentioning

confidence: 99%

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New Tardigrade Opsins and Differential Expression Analyses Show Ontogenic Variation in Light Perception

Fleming

Pisani

Arakawa

2021

Genome Biology and Evolution

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Opsins are light-sensitive proteins involved in many photoreceptive processes, including, but not limited to, vision and regulation of circadian rhythms. Arthropod (e.g. insects, spiders, centipedes and crabs) opsins have been extensively researched, but the relationships and function of opsins found in lineages that are evolutionarily closely-related to the arthropods remains unclear. Multiple, independent, opsin duplications are known in Tardigrada (the water bears), evidencing that protostome opsin duplications are not limited to the Arthropoda. However, the relationships, function and expression of these new opsins are still unknown. Here, we use two tardigrade transcriptomes with deep coverage to greatly expand our knowledge of the diversity of tardigrade opsins. We reconstruct the phylogenetic relationships of the tardigrade opsins and investigate their ontogenetic expression. We found that while tardigrades have multiple opsins that evolved from lineage-specific duplications of well-understood arthropod opsins, their expression levels change during ontogeny such that most of these opsins are not co-temporally expressed. Co-temporal expression of multiple opsins underpins colour vision in Arthropoda and Vertebrata. Our results clearly show duplications of both rhabdomeric and ciliary opsins within Tardigrada, forming clades specific to both the Heterotardigrada and Eutardigrada in addition to multiple independent duplications within genera. However, lack of co-temporal, ontogenetic, expression suggests that while tardigrades possess multiple opsins, they are unlikely to be able to distinguish colour.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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New Tardigrade Opsins and Differential Expression Analyses Show Ontogenic Variation in Light Perception

Fleming

Pisani

Arakawa

2021

Genome Biology and Evolution

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“…Lab culture methods have been developed for other tardigrade species as well (Suzuki, 2003;Horikawa et al, 2008;Tsujimoto et al, 2015;Altiero et al, 2015). We have continued to focus most of our studies on Hypsibius exemplaris because of several advantages they offer over other tardigrade species for the questions we have addressed, including their clear embryos, consistently successful embryonic development in the lab, and their short and consistent embryonic development period and generation time (Goldstein, 2018;Yoshida et al, 2019). Still, some other tardigrade species offer some attractive features including even more compact genomes, a constitutive production of some protectants that contribute to survival in extremes, and an availability of males that might make classical genetics possible (Ramazzotti and Maucci, 1995;Suzuki, 2008;Bemm et al, 2017;Yoshida et al, 2017).…”

Section: Raising Hypsibius Exemplaris Cultures In a Labmentioning

confidence: 99%

Tardigrades and Their Emergence as Model Organisms

Goldstein¹

2022

Preprint

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Experimentally tractable organisms like C. elegans, Drosophila, zebrafish, and mouse are popular models for addressing diverse questions in biology. In 1997, two of the most valuable invertebrate model organisms to date – C. elegans and Drosophila – were found to be much more closely related to each other than expected. C. elegans and Drosophila belong to the nematodes and arthropods respectively, and these two phyla and six other phyla make up a clade of molting animals referred to as the Ecdysozoa. The other ecdysozoan phyla could be valuable models for comparative biology, taking advantage of the rich and continual sources of research findings as well as tools from both C. elegans and Drosophila. But when the Ecdysozoa was first recognized, few tools were available for laboratory studies in any of these six other ecdysozoan phyla. In 1999 I began an effort to develop tools for studying one such phylum, the tardigrades. Here, I describe how the tardigrade species Hypsibius exemplaris and tardigrades more generally have emerged over the past two decades as valuable new models for answering diverse questions. To date, these questions have included how animal body plans evolve and how biological materials can survive some remarkably extreme conditions.

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“…For culturing Ramazzottius varieornatus, 2% Bacto agar (Difco) gel, Volvic mineral water, and C. vulgaris algae were used. Animals were transferred to new petri dishes every week, and eggs and juveniles were examined to study life-history traits (27). Tumanov cultured Hypsibius pallidoides for a redescription study.…”

Section: Introductionmentioning

confidence: 99%

How To Culture Limnoterrestrial Heterotardigrades: A Case Study In The Echiniscus, Pseudechiniscus And Viridiscus Genera

Momeni

Fuentes-González

Pienaar³

2021

Preprint

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Background: Tardigradologists have long tried to culture limnoterrestrial heterotardigrades without success. This is likely because they depend on specific conditions in their microhabitats. Most limnoterrestrial heterotardigrades are found associated with bryophytes and lichens (collectively cryptogams). In contrast to eutardigrades, many of which are easily cultured, heterotardigrades are found in cryptogams that prefer drier and sunnier habitats and that tend to grow on the vertical surfaces of boulders, cliffs, or tree trunks. By carefully observing heterotardigrades in the Echniscus and Viridiscus genera over many months, we determined that these organisms feed on chloroplasts and cytoplasm of both moss cells (typically moss protonema) and single-celled green algae associated with the moss (typically Chlorella vulgaris). We also determined that the cryptogams they associate with, and hence the heterotardigrades themselves, spend more time in a dried state than most eutardigrade species. Taking these observations into account we varied food, water, and desiccation cycle conditions with the aim of developing a culturing protocol for heterotardigrades. Results: We have maintained laboratory cultures of several generations and counting of Echiniscus, Pseudechniscus and Viridiscus genera tardigrades using the following experimentally derived protocol: Both moss and algae from their natural habitats are required as food sources and a small layer of rain or spring water is added every morning and allowed to evaporate some overnight. Furthermore, the organisms are more likely to lay eggs on a dense mat of moss protonema, grown by inserting tips of moss branches into a solidified KCM / agar medium. The medium also provides a walking substrate for the tardigrades, and possibly a source of cations. Crucially, the cultures must be allowed to dry out completely every ten days for a period of at least three days. Moss in the culture dish significantly improves the chances of the tardigrades coming out of their desiccation-resistant states successfully. Conclusions: We conclude that periodic drying out, moss and algae are all required to successfully culture heterotardigrades. Furthermore, drying must occur slowly, and the moss protonema enables this by retaining moisture thereby slowing evaporation. We suspect our protocol will work for most limnoterrestrial heterotardigrades with minor tweaking of culturing conditions.

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Comparison of the transcriptomes of two tardigrades with different hatching coordination

Cited by 19 publications

References 46 publications

New Tardigrade Opsins and Differential Expression Analyses Show Ontogenic Variation in Light Perception

New Tardigrade Opsins and Differential Expression Analyses Show Ontogenic Variation in Light Perception

Tardigrades and Their Emergence as Model Organisms

How To Culture Limnoterrestrial Heterotardigrades: A Case Study In The Echiniscus, Pseudechiniscus And Viridiscus Genera

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