Nikaido M.,Tokyo Institute of Technology |
Noguchi H.,Tokyo Institute of Technology |
Noguchi H.,National Institute of Genetics |
Nishihara H.,Tokyo Institute of Technology |
And 27 more authors.
Genome Research | Year: 2013
Coelacanths are known as ''living fossils,'' as they show remarkable morphological resemblance to the fossil record and belong to the most primitive lineage of living Sarcopterygii (lobe-finned fishes and tetrapods). Coelacanths may be key to elucidating the tempo and mode of evolution from fish to tetrapods. Here, we report the genome sequences of five coelacanths, including four Latimeria chalumnae individuals (three specimens from Tanzania and one from Comoros) and one L. menadoensis individual from Indonesia. These sequences cover two African breeding populations and two known extant coelacanth species. The genome is ~2.74 Gbp and contains a high proportion (~60%) of repetitive elements. The genetic diversity among the individuals was extremely low, suggesting a small population size and/or a slow rate of evolution. We found a substantial number of genes that encode olfactory and pheromone receptors with features characteristic of tetrapod receptors for the detection of airborne ligands. We also found that limb enhancers of bmp7 and gli3, both of which are essential for limb formation, are conserved between coelacanth and tetrapods, but not ray-finned fishes. We expect that some tetrapod-like genes may have existed early in the evolution of primitive Sarcopterygii and were later co-opted to adapt to terrestrial environments. These coelacanth genomes will provide a cornerstone for studies to elucidate how ancestral aquatic vertebrates evolved into terrestrial animals. © 2013, Published by Cold Spring Harbor Laboratory Press.
Yabumoto Y.,Kitakyushu Museum of Natural History and Human History |
Iwata M.,Aquamarine Fukushima |
Abe Y.,Aquamarine Fukushima |
Uyeno T.,3 11 17 Takaido nishi
Ichthyological Research | Year: 2012
The oral region of a coelacanth, Latimeria chalumnae, from the Comoro Islands, was examined in fresh condition, and the complex folding of the membrane between the lower jaw and the skull, and a strut-like structure in the membrane were found. When the mouth opened, the pseudomaxillary folds covered the lateral walls of the mouth. The movement of the membrane is inferred from the observation of the specimen. Coelacanths developed a way of covering the lateral sides of mouth that is different from that of other fishes; especially the pseudomaxillary fold above the strut is unique to coelacanths, but the pseudomaxillary fold below the strut is similar to the lower lip fold of the lepidosirenoid lungfish. © The Ichthyological Society of Japan 2012.
Nagao S.,Kanazawa University |
Kanamori M.,Kanazawa University |
Ochiai S.,Kanazawa University |
Tomihara S.,Aquamarine Fukushima |
And 2 more authors.
Biogeosciences | Year: 2013
At stations on the Natsui River and the Same River in Fukushima Prefecture, Japan, effects of a heavy rain event on radiocesium export were studied after Typhoon Roke during 21-22 September 2011, six months after the Fukushima Dai-ichi Nuclear Power Plant accident. Radioactivity of 134Cs and 137Cs in river waters was 0.009-0.098 Bq L-1 in normal flow conditions during July-September 2011, but it increased to 0.85 Bq L -1 in high flow conditions because of heavy rains occurring with the typhoon. The particulate fractions of 134Cs and 137Cs were 21-56% of total radiocesium in the normal flow condition, but were close to 100% after the typhoon. These results indicate that the pulse input of radiocesium associated with suspended particles from land to coastal ocean occurred because of the heavy rain event. Export flux of 134Cs and 137Cs attributable to the heavy rain accounts for 30-50% of the annual radiocesium flux from inland to coastal ocean region in 2011. Results show that rain events are one factor contributing to the transport and dispersion of radiocesium in river watersheds and coastal marine environments. © 2013 Author(s).
Abe Y.,Aquamarine Fukushima
Der Zoologische Garten | Year: 2016
The husbandry of jellyfish started in 1965 at the Ueno Zoo's Aquarium in Tokyo just by a lucky chance. In one of the reserve tanks ephyra larvae of the Moon jellyfish (Aurelia aurita) were one day observed, quite unexpectedly. These creatures awoke the interest of the aquarium curator and he succeeded by trial and error to keep and exhibit this jellyfish continuously. It was the first time that an aquarium succeeded in the husbandry of jellyfish and could show the visitors the whole life cycle of jellyfish. Because of this success the Ueno Aquarium became famous worldwide, and aquarium curators from the US and Europe visited the Ueno Aquarium to learn their husbandry and exhibition methods. After these colleagues returned home again, it was Antwerp Zoo in Europe and the Monterey Bay Aquarium in the US, which tried the jellyfish husbandry as the first on their continents.In the meantime Jellyfish exhibitions became very popular, and most aquariums today keep jellyfish successfully, although it is even today difficult to keep jellyfish continuously over several years. But some aquariums have specialized in the exhibition of jellyfish. The Kamo Aquarium is an example for such a new trend. © 2015.