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Your search keyword '"TAKERU SAKAGUCHI"' showing total 3 results
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3 results on '"TAKERU SAKAGUCHI"'

1. Molecular evidence of cryptic species diversity in the Perinereis nuntia species group (Annelida: Nereididae) with first records of P. nuntia and P. shikueii in southern Japan

Author

Masanori Sato, Hiroaki Tosuji, Hwey-Lian Hsieh, Takeru Sakaguchi, Kiho Nishinosono, and Christopher J. Glasby

Subjects
Perinereis nuntia, Species complex, Ecology, biology, Species group, Zoology, Molecular evidence, Taxonomy (biology), Aquatic Science, Nereididae, Oceanography, biology.organism_classification, Ecology, Evolution, Behavior and Systematics
Published
2019

2. Rapid method for monitoring N-nitrosodimethylamine in drinking water at the ng/L level without pre-concentration using high-performance liquid chromatography-chemiluminescence detection

Author

Keiitsu Saito, Shinya Itoh, Makoto Saga, Takashi Tomiyasu, Yoshimi Iwaya, Hitomi Yamasaki, Takeru Sakaguchi, Ryo Kanzaki, and Hitoshi Kodamatani

Subjects
Ascorbic Acid, 010501 environmental sciences, 01 natural sciences, Biochemistry, Analytical Chemistry, law.invention, Luminol, Dimethylnitrosamine, chemistry.chemical_compound, Tap water, Chlorides, N-Nitrosodimethylamine, law, Limit of Detection, Solid phase extraction, Chromatography, High Pressure Liquid, 0105 earth and related environmental sciences, Chemiluminescence, Detection limit, Chromatography, Drinking Water, 010401 analytical chemistry, Organic Chemistry, Solid Phase Extraction, General Medicine, Ascorbic acid, 0104 chemical sciences, chemistry, Environmental chemistry, Luminescent Measurements, Water quality, Seasons, Water Pollutants, Chemical, Environmental Monitoring
Abstract

As a contaminant in drinking water, N-nitrosodimethylamine (NDMA) is of great concern because of its carcinogenicity; it has been limited to levels of ng/L by regulatory bodies worldwide. Consequently, a rapid and sensitive method for monitoring NDMA in drinking water is urgently required. In this study, we report an improvement of our previously proposed HPLC-based system for NDMA determination. The approach consists of the HPLC separation of NDMA, followed by NDMA photolysis to form peroxynitrite and detection with a luminol chemiluminescence reaction. The detection limit for the improved HPLC method was 0.2ng/L, which is 10 times more sensitive than our previously reported system. For tap water measurements, only the addition of an ascorbic acid solution to eliminate residual chlorine and passage through an Oasis MAX solid-phase extraction cartridge are needed. The proposed NDMA determination method requires a sample volume of less than 2mL and a complete analysis time of less than 15min per sample. The method was utilized for the long-term monitoring of NDMA in tap water. The NDMA level measured in the municipal water survey was 4.9ng/L, and a seasonal change of the NDMA concentration in tap water was confirmed. The proposed method should constitute a useful NDMA monitoring method for protecting drinking water quality.

Published
2016

3. Molecular evidence of cryptic species diversity in the Perinereis nuntia species group (Annelida: Nereididae) with first records of P. nuntia and P. shikueii in southern Japan.

Author

HIROAKI TOSUJI, KIHO NISHINOSONO, HWEY-LIAN HSIEH, GLASBY, CHRISTOPHER J., TAKERU SAKAGUCHI, and MASANORI SATO

Subjects
POLYCHAETA, SPECIES diversity, ANNELIDA, SPECIES, INTERTIDAL ecology, BENTHIC ecology, RECOMBINANT DNA, GENETIC speciation
Abstract

Taxonomic reexamination of Japanese populations of the Perinereis nuntia species group, which constitutes a major polychaete component in intertidal benthic communities, was carried out by analyzing the mitochondrial 16S rDNA and the nuclear ribosomal ITS sequences of 80 specimens, newly collected from 27 sites in Japan, together with 18 museum-preserved specimens collected from southern neighboring countries outside Japan. The Japanese populations of the Perinereis nuntia species group could be divided into four genetically different groups, which corresponded morphologically to four nominal species (P. mictodonta, P. wilsoni, P. shikueii, and P. nuntia), with some exceptions. Perinereis nuntia and P. shikueii were recorded as new to the Japanese fauna, with their distributions restricted to southern Japan. The clade containing P. shikueii was subdivided into two sister clades (forms A and B), indicating that cryptic speciation has occurred within this clade. Our results revealed a remarkable variability in the number of bars in area VI of the proboscis in form B of P. shikueii, which appeared to be caused by breakage of the long bar into short bars during growth from a juvenile to an adult. [ABSTRACT FROM AUTHOR]

Published
2019
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