Growth inhibition activities of Sugi bark components against Heterosigma akashiwo     

Hiromi Saijo  Kazuya Tsuruta  Norihisa Kusumoto  Tatsuya Ashitani  Koetsu Takahashi 《Journal of Wood Science》2013,59(3):238-242

In our ongoing efforts to develop new uses for wood-based waste streams, the growth inhibition activities of extracts obtained from Sugi (Cryptomeria japonica) bark were examined against Heterosigma akashiwo, otherwise known as red tide plankton. The Sugi bark was separated into its outer and inner barks and then extracted sequentially with hexane, ethyl acetate, and methanol. Strong inhibitory activities against H. akashiwo were observed in the tests involving the hexane extract from the inner and outer barks, as well as the ethyl acetate extract from the inner bark. Gas chromatography mass spectroscopy (GC–MS) analysis revealed that cubebol, phyllocladanol, 6,7-dehydroferruginol, ferruginol, and sugiol were the main components in the active extracts. These components themselves were then tested for their growth inhibition activities against H. akashiwo. Cubebol and ferruginol showed potent inhibitory activities, whereas phyllocladanol, 6,7-dehydroferruginol, and sugiol were only weakly active. Taken together, these results suggested that the Sugi bark extracts could be used as inhibition reagents against red tide plankton.  相似文献   

Relationships between body size and secondary sexual characters,and sperm characters in male Dolly Varden char (Salvelinus malma)          下载免费PDF全文

Toshiaki Yamamoto  Noritaka Hirohashi  Eiji Fujiwara  Tatsuya Suzuki  Hatsuna Maruta  Hirotake Omiya  Shigeru Kitanishi 《Ecology of Freshwater Fish》2017,26(3):397-402

In Salmonidae, subordinate males are exposed to higher risks of sperm competition than dominant males and thus are expected to improve the sperm characteristics (sperm concentrations, sperm velocity and sperm longevity). In this study, we investigated the relationships between body size and secondary sexual characters (breeding colour, hump height and snout length), and sperm characteristics of one‐year‐old (newly matured) Dolly Varden char. Small males displayed higher sperm concentrations than large males. Moreover, males with dull breeding colours, but not with lesser snout length and hump height, displayed an increased sperm velocity compared to males with bright colours, suggesting a trade‐off between sperm quantity and the investment in breeding colour. In addition, sperm longevity decreased as sperm swimming velocity increased. These findings indicate that small males with dull breeding colours improve the quantity and quality of their sperm to a great extent to enhance their chances of reproductive success.  相似文献   

Exfoliation rate of mammary epithelial cells in milk on bovine mastitis caused by Staphylococcus aureus is associated with bacterial load          下载免费PDF全文

Yuya Nagasawa  Yoshio Kiku  Kazue Sugawara  Fuyuko Tanabe  Tomohito Hayashi 《Animal Science Journal》2018,89(1):259-266

The exfoliation rate of mammary epithelial cells (MECs) in milk is affected by physiological, breeding and environmental factors. Little is known about the relationship between the MEC exfoliation into milk and mammary‐infected Staphylococcus aureus (S. aureus) load on bovine mastitis caused by S. aureus. The aim of this study was to investigate the relationship between S. aureus load and the proportion of MEC exfoliation in milk using five substantial bovine mastitis models. In 64 randomly extracted milk samples from udders at 3–21 days after S. aureus infusion, there were various samples with different numbers of S. aureus counts and somatic cell counts. No significant correlations were found between the S. aureus counts and somatic cell count (r = 0.338). In contrast, a significant correlation was noted between S. aureus counts and the proportion of cytokeratin‐positive cells in the milk from the infused udders (r = 0.734, P < 0.01). In conclusion, the increasing MEC exfoliation rate in milk from mastitis udders caused by S. aureus may contribute to reduced milk yield.  相似文献   

Embryonic development and morphology of eggs and newly hatched larvae of Pacific herring <Emphasis Type="Italic">Clupea pallasii</Emphasis>     

Tatsuya Kawakami  Hiroyuki Okouchi  Masato Aritaki  Jun Aoyama  Katsumi Tsukamoto 《Fisheries Science》2011,77(2):183-190

The embryonic development and morphology of eggs and newly hatched larvae of the Pacific herring Clupea pallasii were described using laboratory-reared specimens originating from the Miyako Bay stock. The eggs were almost spherical in shape, 1.33–1.46 mm (mean: 1.38 mm) in diameter, and had a thick adherent chorion. They had a segmented pale yellow yolk, no oil globule, and a relatively wide perivitelline space. A subgerminal cavity was observed during the gastrula period, whereas the blastocoel did not appear. Mass hatching occurred by 271 h 45 min after fertilization, and the newly hatched larvae were 7.1–7.7 mm (mean: 7.5 mm) in total length with 53–56 myomeres at 9.6°C. The embryonic development of Pacific herring was substantially similar to that of zebrafish Danio rerio, American shad Alosa sapidissima, as well as Atlantic herring Clupea harengus, and generally followed the basic developmental pattern of teleosts. However, Pacific herring larvae hatched at a more developed stage than some other clupeoids, such as Japanese sardine Sardinops melanostictus, and the progressed developmental stage at hatching could be interpreted as an advanced adaptation.  相似文献   

Vitamin contents of eggs that produce larvae showing a high survival rate in the Japanese eel Anguilla japonica     

Hirofumi Furuita  Tatsuya Unuma  Kazuharu Nomura  Hideki Tanaka  Tsuyoshi Sugita  & Takeshi Yamamoto 《Aquaculture Research》2009,40(11):1270-1278

This paper describes the relationship between the egg vitamin concentrations and the egg quality in the Japanese eel Anguilla japonica . No notable relation was found between any vitamin and the fertilization rate. Hatching and survival rates of larvae, however, significantly increased with an elevated level of egg vitamin C (VC). In contrast to VC, the relation between vitamins E (VE) and A (VA) concentrations and survival rate showed a clear peak, with a reduced survival rate at both higher and lower vitamin concentrations. The ratio of VE to lipid or highly unsaturated fatty acid (HUFA) in eggs positively correlated with hatching and survival rates of larvae. High-quality (HQ) eggs were determined as eggs that produced larvae having a survival rate higher than 80% at 8 days post hatch, and low-quality (LQ) eggs were determined as eggs that did not hatch. The level of VC of HQ was significantly higher than LQ. The results of this study suggest that HQ eggs, which produce larvae having a high survival rate, must have high levels of VC and VE/HUFA ratio and contain optimum levels of VA and VE in Japanese eel.  相似文献   

Annual monitoring of growth of red sea bream by multi-stereo-image measurement     

Tanaka  Tatsuya  Ikeda  Ryunosuke  Yuta  Yuta  Tsurukawa  Kanji  Nakamura  Satoshi  Yamaguchi  Takeharu  Komeyama  Kazuyoshi 《Fisheries Science》2019,85(6):1037-1043

Fisheries Science - In aquaculture, periodic measurement of fish body size is required to suitably assess growth progress. The aim of this study is to monitor the growth of free-swimming red sea...  相似文献   

Characteristics of a self-assembled fibrillar gel prepared from red stingray collagen     

Inwoo Bae  Kiyoshi Osatomi  Asami Yoshida  Atsuko Yamaguchi  Katsuyasu Tachibana  Tatsuya Oda  Kenji Hara 《Fisheries Science》2009,75(3):765-770

A translucent collagen gel was formed from a transparent acidic solution of red stingray collagen by adjusting to physiological ionic strength and pH in phosphate buffer and then incubating at 25–37°C. During fibril formation from red stingray collagen, the turbidity increased when the NaCl concentration was increased at constant pH and the rate of fibril formation was accelerated by higher pH or lower NaCl concentration. The T _m of red stingray collagen fibrillar gel was estimated as 44.3 ± 3.5°C, which was higher than that of the collagen solution, 33.2°C. In addition, red stingray collagen gel maintained its shape without melting and was suitable for culture of mouse stromal cells at 37°C.  相似文献   

Low-fidelity homing behaviour of Biwa salmon <Emphasis Type="Italic">Oncorhynchus</Emphasis> sp. landlocked in Lake Biwa as inferred from otolith elemental and Sr isotopic compositions     

Yosuke Amano  Masayuki Kuwahara  Toshiro Takahashi  Kotaro Shirai  Kodai Yamane  Tatsuya Kawakami  Kazuki Yokouchi  Hiroshi Amakawa  Tsuguo Otake 《Fisheries Science》2018,84(5):799-813

Biwa salmon Oncorhynchus sp. is endemic to Lake Biwa, Japan, where it is an important commercial and recreational fisheries species. However, no information is currently available on its population structure and migration ecology. Therefore, here we evaluated whether otolith Sr/Ca, Ba/Ca and ⁸⁷Sr/⁸⁶Sr ratios can be used as natural signatures in Biwa salmon and then used these to determine the natal origins of lake-migration-phase individuals and spawning adults, and the homing ability of spawning adults in the Lake Biwa water system. Quadratic discriminant function analysis demonstrated that the lake-migration school comprised individuals with multiple origins, including rivers to the east, west and north of Lake Biwa, and that the homing rate of spawning adults was low (18 out of 80 individuals), with ca. 78% of fish straying into non-natal rivers. However, this straying behaviour was not spatially random, with fish tending to migrate upstream in rivers neighbouring their natal rivers. The high rate of straying in spawning adults is considered important for establishing and maintaining this species, which is highly adapted to life in the Lake Biwa water system where environmental disturbances often occur.  相似文献   

Two β-amylase genes,OsBAM2 and OsBAM3, are involved in starch remobilization in rice leaf sheaths     

Tatsuya Hirano  Takayuki Higuchi  Minako Hirano  Yu Sugimura  Hiroyasu Michiyama 《Plant Production Science》2016,19(2):291-299

To identify mechanisms of starch degradation in rice leaf sheaths at the post-heading stage, we investigated the function of OsBAM2 and OsBAM3, which encode plastid-targeted active β-amylase isoforms, in starch remobilization in leaf sheaths. The starch content in the second leaf sheaths below the flag leaf (the third leaf sheaths) peaked at the flag leaf emergence stage and gradually decreased until 15 days after heading. The mRNA levels of OsBAM2 and OsBAM3 in the third leaf sheaths increased from the flag leaf emergence stage to the heading stage when the starch content began to decrease. However, these mRNA levels did not always remain high during post-heading. Overexpression of OsBAM2 or OsBAM3 markedly repressed starch accumulation in the third leaf sheaths, showing that OsBAM2 and OsBAM3 function in starch degradation in rice leaf sheaths. In contrast, no significant differences in starch content in the third leaf sheaths were detected between knockdown plants of OsBAM2 or OsBAM3 and non-transgenic wild-type plants. Our results suggest that reduced expression of the individual genes, OsBAM2 or OsBAM3, does not result in excess accumulation of starch in the leaf sheaths, probably because of the complementary function of another gene or the action of other genes encoding starch-degrading .  相似文献   

Similarity and differences in the physicochemical properties of lactate dehydrogenase isozymes from different tissues of Japanese sandfish <Emphasis Type="Italic">Arctoscopus japonicus</Emphasis>     

Kotomi Sugawara  Mizuki Nakagawa  Mika Yonezawa  Shigeyoshi Nakamura  Shun-ichi Kidokoro  Hideki Wakui  Wataru Nunomura 《Fisheries Science》2016,82(3):519-527

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