Time filter

Source Type

Nagano Y.,Japan Agency for Marine - Earth Science and Technology | Nagahama T.,Japan Agency for Marine - Earth Science and Technology | Nagahama T.,Higashi Chikushi Junior College
Review of High Pressure Science and Technology/Koatsuryoku No Kagaku To Gijutsu | Year: 2010

Fungi are one of the most important components in ecosystems and they occupy a wide variety of environments by virtue of their highly versatile physiology function. Recently, the presence of fungi in one of the extreme environments, deep-sea, has started to be recognized. In this article, recent scientific findings through the investigation of fungal diversity in deep-sea sediments collected from several deep-sea environments, including water depths of 10,000 m and methane cold-seep sites were described. PCR-mediated analysis revealed the presence of diverse highly novel fungal phylotypes, including new taxonomic groups placed in deep branches within the phylum of Chytridiomycota with Rozella spp. as the closest related organisms, which may provide key insights into the early evolution of fungi.

Nagahama T.,Higashi Chikushi Junior College | Nagahama T.,Japan Agency for Marine - Earth Science and Technology | Takahashi E.,Japan Agency for Marine - Earth Science and Technology | Nagano Y.,Japan Agency for Marine - Earth Science and Technology | And 3 more authors.
Environmental Microbiology | Year: 2011

The motile cells of chytrids were once believed to be relics from the time before the colonization of land by fungi. However, the majority of chytrids had not been found in marine but freshwater environments. We investigated fungal diversity by a fungal-specific PCR-based analysis of environmental DNA in deep-sea methane cold-seep sediments, identifying a total of 35 phylotypes, 12 of which were early diverging fungi (basal fungi, ex 'lower fungi'). The basal fungi occupied a major portion of fungal clones. These were phylogenetically placed into a deep-branching clade of fungi and the LKM11 clade that was a divergent group comprised of only environmental clones from aquatic environments. As suggested by Lara and colleagues, species of the endoparasitic genus Rozella, being recently considered of the earliest branching taxa of fungi, were nested within the LKM11 clade. In the remaining 23 phylotypes identified as the Dikarya, the majority of which were similar to those which appeared in previously deep-sea studies, but also highly novel lineages associated with Soil Clone Group I (SCGI), Entorrhiza sp. and the agaricomycetous fungi were recorded. The fungi of the Dikarya may play a role in the biodegradation of lignin and lignin-derived materials in deep-sea, because the characterized fungal species related to the frequent phylotypes within the Dikarya have been reported to possess an ability to degrade lignin. © 2011 Society for Applied Microbiology and Blackwell Publishing Ltd.

Konishi M.,Japan Agency for Marine - Earth Science and Technology | Nagahama T.,Japan Agency for Marine - Earth Science and Technology | Nagahama T.,Higashi Chikushi Junior College | Fukuoka T.,Japan Advanced Institute of Science and Technology | And 4 more authors.
Journal of Bioscience and Bioengineering | Year: 2011

We improved the culture conditions for a biosurfactant producing yeast, Pseudozyma hubeiensis SY62. We found that yeast extract greatly stimulates MEL production. Furthermore, we demonstrated a highly efficient production of MELs in the improved medium by fed-batch cultivation. The final concentration of MELs reached 129 ± 8.2 g/l for one week. © 2011 The Society for Biotechnology, Japan.

Mochida K.,Kyoto University | Mochida K.,University of Ryukyus | Kitada M.,Nagasaki University | Ikeda K.,Higashi Chikushi Junior College | And 3 more authors.
Journal of Chemical Ecology | Year: 2013

Most animals advertise their unprofitability to potential predators via conspicuous signals. Whether the strength of this aposematic signal indicates the quality and quantity of chemical defenses in animals is controversial. Here, we investigated the relationship between the conspicuousness of an aposematic signal and toxicity, which likely depends, at least in part, on dietary sources, in the newt Cynops pyrrhogaster. Our results indicate that the magnitude of the aposematic signal was not correlated with the amount of tetrodotoxin (TTX) and 6-epi TTX of wild individuals among populations. Using atoxic newts, reared from eggs, we compared the ability to accumulate TTX from diets between mainland and island populations. Newts of a mainland population that exhibited a less conspicuous signal accumulated more TTX than did equivalent newts of an insular population that displayed a more conspicuous signal; this was unrelated to variation in the toxicity of wild individuals of these two populations. We also found toxicity of wild newts changed over approximately one generation (10 years) in both populations. These results indirectly suggest that environmental variance, such as fluctuations in TTX resources in nature, may obscure differences in the ability of wild newts to accumulate TTX, and that this variation may be responsible for a lack of correlation between the strength of a newt's signal and its toxicity in the wild. These results imply that toxicity of wild individuals likely is a phenotypic trait largely dependent on environmental conditions. © 2013 Springer Science+Business Media New York.

Abdel-Wahab M.A.,Japan Agency for Marine - Earth Science and Technology | Abdel-Wahab M.A.,Sohag University | Nagahama T.,Japan Agency for Marine - Earth Science and Technology | Nagahama T.,Higashi Chikushi Junior College
Nova Hedwigia | Year: 2011

A new genus, Gesasha Abdel-Wahab & Nagahama, and three new species therein are described and illustrated from Gesashi mangroves, Okinawa, Japan. Molecular phylogenetic analyses of the partial SSU and LSU rDNA placed the three new species into a clade distantly related to morphologically similar fungi with a high statistical support in the Halosphaeriales, Sordariomycetidae, Sordariomycetes, Ascomycota. The new genus is characterized by hyaline to light-brown, immersed to erumpent coriaceous ascomata, persistent asci with a thickened apical pore with a cytoplasmic retraction below the ascus apex and uni or bi-celled, globose to widely ellipsoidal ascospores with or without ephemeral, amorphous polar to sub-polar appendages. © 2011 J. Cramer in Gebr.

Discover hidden collaborations