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KIM, Daekyung,YAMASAKI, Yasuhiro,YAMATOGI, Toshifumi,YAMAGUCHI, Kenichi,MATSUYAMA, Yukihiko,KANG, Yang-Soon,LEE, Yoon,ODA, Tatsuya Japan Society for Bioscience, Biotechnology, and A 2009 Bioscience, Biotechnology, and Biochemistry Vol.73 No.3
<P>To elucidate the ichthyotoxic mechanism of the harmful dinoflagellate <I>Cochlodinium polykrikoides</I>, a bioassay using damselfish was conducted. After exposure to a live-cell suspension of <I>C. polykrikoides</I>, all the fish were died within 90 min. In the presence of catalase and superoxide dismutase (SOD), no significant reduction in the toxicity of <I>C. polykrikoides</I> on the fish was observed. Furthermore, no significant levels of reactive oxygen species (ROS) were detected in five strains of <I>C. polykrikoides</I> isolated in Japan. Our results support the idea that certain toxic substances, rather than ROS, are mainly responsible for the fish-killing activity of <I>C. polykrikoides</I>.</P>
JIANG, Zedong,KIM, Daekyung,YAMASAKI, Yasuhiro,YAMANISHI, Tomohiro,HATAKEYAMA, Tomomitsu,YAMAGUCHI, Kenichi,ODA, Tatsuya Japan Society for Bioscience, Biotechnology, and A 2010 Bioscience, Biotechnology, and Biochemistry Vol.74 No.8
<P>An <I>N</I>-acetylgalactosamine (GalNAc)-specific Ca<SUP>2+</SUP>-dependent lectin (C-type lectin), isolated from the marine invertebrate Holothuroidea (<I>Cucumaria echinata</I>), CEL-I, showed potent mitogenic activity toward normal mouse spleen cells. The mitogenic activity of CEL-I, which reached a maximum at 100 μg/ml, was inhibited by GalNAc in a concentration-dependent manner. The mitogenic effect of CEL-I at 10 μg/ml on T cell- enriched splenocytes was at a similar level due to a well-known T cell mitogen, concanavalin A (Con A), at 10 μg/ml. Furthermore, CEL-I evoked a mitogenic response from nude mouse spleen cells, while no significant effects of Con A on this cell population were observed over a wide range of concentrations. These results suggest that CEL-I is a potent mitogenic lectin with the ability to stimulate both T and B cells.</P>
Wencheng, Li,Cho, Kichul,Yamasaki, Yasuhiro,Takeshita, Satoshi,Hwang, Kiju,Kim, Daekyung,Oda, Tatsuya Elsevier 2018 Aquatic toxicology Vol.201 No.-
<P><B>Abstract</B></P> <P>The dinoflagellate <I>Heterocapsa circularisquama</I> is highly toxic to bivalves. However, significant toxicity to finfish species has not been reported. We previously found that <I>H. circularisquama</I> has light-dependent haemolytic agents. Purification and chemical structural analyses revealed that the haemolytic agent H2-a is a porphyrin derivative, which exhibits light-dependent cytotoxicity toward tumour cells. To clarify the biological activity of H2-a further, its antibacterial activities against Gram-positive and Gram-negative bacteria were investigated in this study. A fraction (F5) equivalent to H2-a purified from the methanol extract of <I>H. circularisquama</I> showed potent light-dependent bactericidal activity toward <I>Staphylococcus aureus</I>, and the activity was concentration- and light illumination time-dependent; however, <I>Escherichia coli</I> was highly resistant to F5. Electron microscopic observation suggested that F5 induces morphological changes in <I>S. aureus</I> in a light-dependent manner. Further analysis using other bacterial species showed that the Gram-positive bacterium <I>Bacillus subtilis</I> was more sensitive than the Gram-negative bacteria <I>Pseudomonas aeruginosa</I> and <I>Vibrio alginolyticus</I>. These results indicate that F5 is a photo-induced antibacterial agent with relatively higher specificity to Gram-positive bacteria. Iodometric assay suggested that singlet oxygen was generated from light-illuminated F5. Histidine, a specific singlet oxygen scavenger, markedly inhibited the photosensitising antibacterial activity of F5 against <I>S. aureus</I>, suggesting the involvement of singlet oxygen in antibacterial activity. The antibacterial spectrum of F5 was evidently different from that of 5,10,15,20-tetra (<I>N</I>,<I>N</I>,<I>N</I>-trimethylanilinium) porphyrin tetratosylate, a commercially available porphyrin compound with antibacterial activity. Our results demonstrate that <I>H. circularisquama</I> has a novel antibacterial photosensitiser, a porphyrin derivative, with relatively higher specificity to Gram-positive bacteria. To the best of our knowledge, this is the first study to discover a porphyrin derivative with antibacterial activity in marine microalga.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A porphyrin derivative (F5) with antibacterial activity was isolated from dinoflagellate <I>H. circularisquama</I>. </LI> <LI> F5 shows relatively higher specificity to Gram-positive bacteria such as <I>S. aureus</I>, but <I>E. coli</I> was highly resistant to F5. </LI> <LI> Antibacterial spectrum of F5 was evidently different from that of a commercially available porphyrin derivative. </LI> <LI> Singlet oxygen was detected in light-illuminated F5. </LI> <LI> Histidine, a singlet oxygen scavenger, inhibited the antibacterial activity of F5. </LI> </UL> </P>
Zou, Yanan,Kim, Daekyung,Yagi, Motoaki,Yamasaki, Yasuhiro,Kurita, Jun,Iida, Takaji,Matsuyama, Yukihiko,Yamaguchi, Kenichi,Oda, Tatsuya Japan Society for Bioscience, Biotechnology, and A 2013 Bioscience, biotechnology, and biochemistry Vol.77 No.2
<P>Lactate dehydrogenase (LDH)-release assay was applied to estimate the toxic potential of harmful algal species at the cellular level. African green monkey kidney (Vero), yellowtail fin epithelia (MJF), and rainbow trout gill (RTgill-W1) cells were used as target cells. A live cell suspension of Karenia mikimotoi (SUO-1) induced the release of LDH from these cell lines, while the activity of another strain, FUK, was much lower. The cell-free culture supernatants and ruptured cell suspensions of both strains of K. mikimotoi were less effective on LDH-release assay. Exposure experiments against abalone and shrimp revealed that SUO-1 showed much stronger lethal effects on these organisms than FUK. Among six phytoplankton species, three species known to be harmful algal species induced the release of LDH to different extents depending on the cell line, whereas the other three species, known to be non-toxic, showed no effects on any cell lines. These results suggest that LDH-release assay is a useful micro-plate assay for estimation of the toxic potential of harmful phytoplankton.</P>
TREATMENT OF SOFT TISSUE INFECTIONS WITH HYPERBARIC OXYGEN(HBO) THERAPY
Kazuhiro Uchida,Mahito Kawashima,Hiroaki Tamura,Yasuhiro Yamasaki,Katsuhiro Takao 고신대학교(의대) 고신대학교 의과대학 학술지 1986 고신대학교 의과대학 학술지 Vol.2 No.1
Brathing oxygen under high pressure increases the concentration of oxygen in the blood and reduces hypoxia. Hyperbaric oxygen(HBO) is useful in treating many diseases. It is used orthopedics, for example, to treat anaerobic gas gangrene. At our hospital good results were obtained using it adjunctively to the surgical and antibiotic treatment of soft tissue infections (including aerobic infections).
TREATMENT OF SOFT TISSUE INFECTIONS WITH HYPERBARIC OXYGEN (HBO) THERAPY
Uchida, Kazuhiro,Kawashima, Mahito,Tamura, Hiroaki,Yamasaki, Yasuhiro,Takao, Katsuhiro 고신대학교 의학부 1986 高神大學校 醫學部 論文集 Vol.2 No.1
Breathing oxygen under high pressure increases the concentration of oxygen in the blood and reduces hypoxia. Hyperbanc oxygen(HBO) is useful in treating many diseases. It is used orthopedics, for example, to treat anaerobic gas gangrene. At our hospital good results were obtained using it adjunctively to the surgical and antibiotic treatment of soft tissue infections (including aerobic infections).
Haemolytic activity and reactive oxygen species production of four harmful algal bloom species
Cho, Kichul,Kasaoka, Takuya,Ueno, Mikinori,Basti, Leila,Yamasaki, Yasuhiro,Kim, Daekyung,Oda, Tatsuya Taylor Francis 2017 European journal of phycology Vol.52 No.3
<P>Based on haemolytic activity and reactive oxygen species (ROS) production of Chattonella marina, Chattonella antiqua, Heterocapsa circularisquama, Alexandrium tamiyavanichii and Karenia mikimotoi, the species were categorized into four types. (1) H. circularisquama: haemolytic activity was detected in both cell suspension and cell-free culture supernatant, but with greater activity in cell suspension than in the supernatant suggesting the presence of both cell surface and secreted haemolytic agents. (2) A. tamiyavanichii: equal haemolytic activities were detected in both the cell suspension and cell-free culture supernatant suggesting the presence of only secreted haemolytic agents. (3) K. mikimotoi: haemolytic activity was detected only in the cell suspension, indicating haemolytic agents occur only on the cell surface. (4) C. marina and C. antiqua: no significant haemolytic activity was detected in either cell suspension or cell-free culture supernatant, but high ROS were detected in the cell suspensions. Heterocapsa circularisquama and K. mikimotoi showed lethal effects on rotifers (Brachionus plicatilis), whereas A. tamiyavanichii, C. marina and C. antiqua had no effect. Our results suggest that H. circularisquama, K. mikimotoi and A. tamiyavanichii produce haemolytic agents with distinct characteristics, whereas C. marina and C. antiqua have an extremely potent ability to produce ROS.</P>
KIM, Daekyung,CHOI, Kwang-Sik,HONG, Hyun-Ki,JIANG, Zedong,ZOU, Yanan,CHOI, Kyu-Sung,YAMASAKI, Yasuhiro,MATSUYAMA, Yukihiko,YAMAGUCHI, Kenichi,ODA, Tatsuya Japan Society for Bioscience, Biotechnology, and A 2011 Bioscience, Biotechnology, and Biochemistry Vol.75 No.10
<P><I>Heterocapsa circularisquama</I> showed much higher toxic effects on short-necked clams than <I>Chattonella marina</I>. Clams exposed to <I>H. circularisquama</I> exhibited morphological changes concomitant with an accumulation of mucus-like substances in the gills, a profound reduction in filtration activity, and lysosomal destabilization in hemocytes. <I>Chattonella marina</I> was less effective than <I>H. circularisquama</I>, and <I>Heterocapsa triquetra</I> was almost harmless in all these criteria. These results suggest that <I>H. circularisquama</I> exerted its lethal effect on short-necked clams through gill tissue damage and subsequent induction of physiological stress.</P>