Papers by Takekazu Kunieda
PLOS ONE, Aug 21, 2013
The mushroom bodies (a higher center) of the honeybee (Apis mellifera L) brain were considered to... more The mushroom bodies (a higher center) of the honeybee (Apis mellifera L) brain were considered to comprise three types of intrinsic neurons, including large-and small-type Kenyon cells that have distinct gene expression profiles. Although previous neural activity mapping using the immediate early gene kakusei suggested that small-type Kenyon cells are mainly active in forager brains, the precise Kenyon cell types that are active in the forager brain remain to be elucidated. We searched for novel gene(s) that are expressed in an area-preferential manner in the honeybee brain. By identifying and analyzing expression of a gene that we termed mKast (middle-type Kenyon cell-preferential arrestin-related protein), we discovered novel 'middle-type Kenyon cells' that are sandwiched between large-and small-type Kenyon cells and have a gene expression profile almost complementary to those of large-and small-type Kenyon cells. Expression analysis of kakusei revealed that both small-type Kenyon cells and some middle-type Kenyon cells are active in the forager brains, suggesting their possible involvement in information processing during the foraging flight. mKast expression began after the differentiation of small-and large-type Kenyon cells during metamorphosis, suggesting that middle-type Kenyon cells differentiate by modifying some characteristics of large-and/or small-type Kenyon cells. Interestingly, CaMKII and mKast, marker genes for large-and middle-type Kenyon cells, respectively, were preferentially expressed in a distinct set of optic lobe (a visual center) neurons. Our findings suggested that it is not simply the Kenyon cell-preferential gene expression profiles, rather, a 'clustering' of neurons with similar gene expression profiles as particular Kenyon cell types that characterize the honeybee mushroom body structure.
Figure 1. Graphical experimental scheme of the desiccation assay. In total, 29 or 30 tardigrades ... more Figure 1. Graphical experimental scheme of the desiccation assay. In total, 29 or 30 tardigrades were dropped onto the filter paper and placed in the sealed desiccation chamber. The humidity in the chamber was controlled by the presence of saturated salt solution or water, which had no contact with the animals.
Supplementary Text, Figures, and Tables
Amino acid sequences of <i>Paramacrobiotus</i> sp. TYO trehalase genes.
Table S2. Gene loss in stress-response regulatory pathways in tardigrades (in Hara et al., 2021)
Amino acid sequences of <i>Paramacrobiotus</i> sp. TYO TPS-TPP genes.
Dataset S6. The Bayesian tree of the TPP gene in newick format (in Hara et al., 2021)
A nucleotide sequence of <i>Paramacrobiotus</i> sp. TYO 18S rRNA
Coding nucleotide sequences of the genome-based gene set of a trehalose-producing tardigrade <... more Coding nucleotide sequences of the genome-based gene set of a trehalose-producing tardigrade <i>Paramacrobiotus sp.</i> TYO.
The Molecular Biology Society of Japan, 2019
The Molecular Biology Society of Japan, 2018
Tardigrades are able to tolerate almost complete dehydration by entering a reversible ametabolic ... more Tardigrades are able to tolerate almost complete dehydration by entering a reversible ametabolic state called anhydrobiosis and resume their animation upon rehydration. Dehydrated tardigrades are exceptionally stable and withstand various physical extremes. Although trehalose and late embryogenesis abundant (LEA) proteins have been extensively studied as potent protectants against dehydration in other anhydrobiotic organisms, tardigrades produce high amounts of tardigrade-unique protective proteins. Cytoplasmic-abundant heat-soluble (CAHS) proteins are uniquely invented in the lineage of eutardigrades, a major class of the phylum Tardigrada and are essential for their anhydrobiotic survival. However, the precise mechanisms of their action in this protective role are not fully understood. In the present study, we first postulated the presence of tolerance proteins that form protective condensates via phase separation in a stress-dependent manner and searched for tardigrade proteins t...
Scientific Reports, 2020
An amendment to this paper has been published and can be accessed via a link at the top of the pa... more An amendment to this paper has been published and can be accessed via a link at the top of the paper.
BioMed Research International, 2020
Space travel has advanced significantly over the last six decades with astronauts spending up to ... more Space travel has advanced significantly over the last six decades with astronauts spending up to 6 months at the International Space Station. Nonetheless, the living environment while in outer space is extremely challenging to astronauts. In particular, exposure to space radiation represents a serious potential long-term threat to the health of astronauts because the amount of radiation exposure accumulates during their time in space. Therefore, health risks associated with exposure to space radiation are an important topic in space travel, and characterizing space radiation in detail is essential for improving the safety of space missions. In the first part of this review, we provide an overview of the space radiation environment and briefly present current and future endeavors that monitor different space radiation environments. We then present research evaluating adverse biological effects caused by exposure to various space radiation environments and how these can be reduced. We...
Zoological Science, 2019
Reproductive strategy is an important aspect of biological diversity. In tardigrades, several rep... more Reproductive strategy is an important aspect of biological diversity. In tardigrades, several reproductive modes, including sexual reproduction, are known. However, tardigrade mating behavior has been observed only rarely in most species, and in some cases, especially in the freely ovipositing eutardigrades, remains entirely unknown. In the present study, we cultured two sexually reproducing tardigrade species that lay eggs freely, Paramacrobiotus sp. TYO strain and Macrobiotus shonaicus, to investigate and compare their courtship, mating, and chromosome morphology. Mating behavior was observed and recorded in both species. The entire mating sequence, including courtship, was categorized into five discrete steps common to two species, as follows: [1] Tracking: the male tracks and orientates toward the female; [2] Touching: the male makes contact with the cloaca of the female; [3] Standstill: the female ceases movement until male ejaculation is complete; [4] Ejaculation: the male curls its caudal end and ejaculates into the cloaca from close range; [5] Contraction: the female contracts its ventral side after ejaculation to capture spermatozoa deposited in the external environment in close proximity to the cloaca. Some notable differences between the two species were observed in the steps 3–4. First, oviposition was observed at 40 min in Paramacrobiotus sp. TYO strain, and a few days after mating in M. shonaicus, respectively. Comparisons of chromosome morphology before and after mating indicated that oocytes are arrested at metaphase I in both species. Spermatozoa attach to the interior of the chorion of laid eggs.
Nature Communications, 2017
Unlike mammals,Xenopus laevistadpoles possess high ability to regenerate their lost organs. In am... more Unlike mammals,Xenopus laevistadpoles possess high ability to regenerate their lost organs. In amphibians, the main source of regenerated tissues is lineage-restricted tissue stem cells, but the mechanisms underlying induction, maintenance and differentiation of these stem/progenitor cells in the regenerating organs are poorly understood. We previously reported thatinterleukin-11(il-11) is highly expressed in the proliferating cells of regeneratingXenopustadpole tails. Here, we show thatil-11knockdown (KD) shortens the regenerated tail length, and the phenotype is rescued by forced-il-11-expression in the KD tadpoles. Moreover, marker genes for undifferentiated notochord, muscle, and sensory neurons are downregulated in the KD tadpoles, and the forced-il-11-expression in intact tadpole tails induces expression of these marker genes. Our findings demonstrate thatil-11is necessary for organ regeneration, and suggest that IL-11 plays a key role in the induction and maintenance of undif...
PloS one, 2017
In insect brains, the mushroom bodies (MBs, a higher center) comprise intrinsic neurons, termed K... more In insect brains, the mushroom bodies (MBs, a higher center) comprise intrinsic neurons, termed Kenyon cells (KCs). We previously showed that the honeybee (Apis mellifera L.) MBs comprise four types of KCs, in addition to the previously known three types of KCs: class I large-type KCs (lKCs), class I small-type KCs (sKCs) and class II KCs, novel class I 'middle-type' KCs (mKCs), which are characterized by the preferential expression of a gene, termed mKast. Although mKast was originally discovered during the search for genes whose expression is enriched in the optic lobes (OLs) in the worker brain, subsequent analysis revealed that the gene is expressed in an mKC-preferential manner in the MBs. To gain more insights into the function of mKast in the honeybee brain, we here performed expression analysis of mKast and immunohistochemistry of the mKast protein. Prominent mKast expression was first detected in the brain after the P7 pupal stage. In addition, mKast was expressed a...
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Papers by Takekazu Kunieda