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Ryota Takeuchi Mitsuru Jimbo Fumika Tanimoto Chiaki Tanaka Saki Harii Yoshikatsu Nakano Ko Yasumoto Shugo Watabe 《Fisheries Science》2017,83(3):479-487
Corals harbor symbiotic dinoflagellates, Symbiodinium spp., acquired from surrounding environments. Because Symbiodinium are present at low densities in the water column, corals may attract these symbionts using chemotactic compounds. To examine whether corals contain chemotactic compounds, we established an assay to measure the chemotactic activity for Symbiodinium using an extract of the coral Acropora tenuis, a major reef-building coral in Japan. Our assay revealed that Symbiodinium strain NBRC102920 (clade A), which is taken up by juvenile A. tenuis polyps, is attracted to crude A. tenuis extracts. We found that the chemotactic compounds are water-soluble, heat-labile macromolecules and that the chemotactic activity was inhibited by N-acetyl-d-glucosamine (GlcNAc). We separated the GlcNAc-binding fraction (Fr-ActL) and identified it as the most plausible candidate for the chemoattractant, since the chemotactic activity of the crude A. tenuis extract appeared to be mainly attributable to the activity of Fr-ActL and was also inhibited by the addition of GlcNAc. These results indicate that chemoattraction is mediated via the binding of Symbiodinium to Fr-ActL. 相似文献
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Muniyandi Kailasam Gen Kaneko Aung Kyaw Swar Oo Yori Ozaki Arunachalam Rengasamy Thirunavukkarasu Shugo Watabe 《Fisheries Science》2011,77(3):403-409
Calorie restriction (CR) in the rotifer Brachionus plicatilis extends its lifespan, as it enhances the expression of antioxidant enzymes such as manganese superoxide dismutase (Mn SOD)
and catalase. Here we show that CR also increased the mRNA levels of these antioxidant enzymes upon exposure to oxidative
stress. Rotifers cultured under CR showed a higher survival rate than those fed ad libitum (AL) upon exposure to 0.05–0.2 μM
juglone, an oxidative stress inducer. The relative mRNA levels of Mn SOD and catalase before exposure to juglone were slightly
higher in the CR rotifers than in their AL counterparts, although these differences were not statistically significant. AL
rotifers showed no apparent upregulation of the mRNA levels of these antioxidant enzymes upon exposure to 0.025 and 0.05 μM
juglone. In contrast, the CR rotifers increased the mRNA levels of Mn SOD and catalase by up to 5.4-fold and 4.2-fold, respectively,
resulting in significant differences between their levels in AL and CR rotifers under oxidative stress conditions. Furthermore,
the protein level of catalase was clearly higher in CR than in AL rotifers 6 h after exposure to oxidative stress. These results
suggest that the upregulation of Mn SOD and catalase genes is involved in CR-induced resistance to oxidative stress in the
rotifer. 相似文献
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In order to distinguish the two eel species Anguilla japonica and A. anguilla irrespective of unprocessed and processed samples, a quick, convenient method using polymerase chain reaction (PCR) with
a species-specific primer was established. The comparison of partial sequences of the mitochondrial 16S ribosomal RNA gene
between A. japonica and A. anguilla facilitated designing of a primer pair common to both A. japonica and A. anguilla and a primer specific to A. japonica. PCR was carried out with the three primers for total 110 specimens of A. japonica and A. anguilla. PCR products with the species-specific primer showed two bands for A. japonica and one band for A. anguilla in an agarose gel electrophoresis. This analytical procedure required only a short period and is more convenient than PCR-restriction
fragment length polymorphism, one of the standard methods employed for fish species identification. 相似文献
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Aoki H Ahsan MN Matsuo K Hagiwara T Watabe S 《Journal of agricultural and food chemistry》2003,51(3):777-783
Three gelatinolytic proteases (A1, A2, and B) were purified using a synthetic substrate, DNP-Pro-Gln-Gly-Ile-Ala-Gly-Gln-d-Arg, from the hepatopancreas of Northern shrimp (Pandalus eous) by several chromatographic steps involving hydroxyapatite column chromatography, gel filtration on Superdex75, and ion-exchange chromatography on a MonoQ column. Collagenolytic proteases A2 and B, but not protease A1, were demonstrated to digest native porcine type I collagen at 25 degrees C and pH 7.5. Further characterizations of these two collagenolytic proteases showed that the pH optimum of enzyme A2 against DNP-peptide was found to be 11, whereas that of enzyme B was 8.5. The optimum temperature ranged between 40 and 45 degrees C for both enzymes, although enzyme B appeared to be thermally more stable than enzyme A2 at pH 7.5. Both enzymes were strongly inhibited by PMSF and antipain, which suggests that they belong to collagenolytic serine proteases. 相似文献
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Togashi M Kakinuma M Nakaya M Ooi T Watabe S 《Journal of agricultural and food chemistry》2002,50(17):4803-4811
The thermodynamic properties of myosin and its C-terminal fragment, light meromyosin (LMM), from walleye pollack, a typical cold-water fish efficiently utilized on an industrial scale, were analyzed by using differential scanning calorimetry (DSC) and circular dichroism (CD) spectrometry. Recombinant walleye pollack LMM expressed in Escherichia coli was also subjected to DSC and CD measurements for reference. The two proteins prepared from frozen surimi showed three endothermic peaks, the transition temperatures (T(m)) of which were quite similar, although overall DSC patterns differed considerably from one another. Their alpha-helical contents determined by CD were low compared to values reported before for other species. On the other hand, recombinant LMM gave four endothermic peaks at 27.4, 30.8, 36.5, and 43.4 degrees C in DSC and showed an alpha-helical content of approximately 80%. The peak at 27.4 degrees C could not be observed in walleye pollack LMM prepared from frozen surimi and thus was possibly attributed to its C terminus, because this extreme C-terminal region is supposedly truncated during preparation of LMM by tryptic digestion. 相似文献