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Yasunori Sakurai - One of the best experts on this subject based on the ideXlab platform.
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Salt soluble without jelly-like component from the oviducal gland induces chorionic expansion in the ova of the Japanese common squid Todarodes pacificus
Invertebrate Reproduction & Development, 2016Co-Authors: Kohsuke Adachi, Mao Yabumoto, Hae-kyun Yoo, Katsuji Morioka, Yuzuru Ikeda, Yukio Ueta, Yasunori SakuraiAbstract:AbstractIn vitro fertilization of squid requires the jelly substance found in the female oviducal gland; yet, the active component of this substance that facilitates fertilization remains unknown. Here, we used biochemical methods to separate the jelly substance of Todarodes pacificus (Oegopsida) and Sepioteuthis lessoniana (Myopsida family) into four fractions; specifically, two water soluble fractions (Molecular weight > 10,000 and
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salt soluble without jelly like component from the oviducal gland induces chorionic expansion in the ova of the japanese common squid Todarodes pacificus
Invertebrate Reproduction & Development, 2016Co-Authors: Kohsuke Adachi, Mao Yabumoto, Hae-kyun Yoo, Katsuji Morioka, Yuzuru Ikeda, Yukio Ueta, Yasunori SakuraiAbstract:AbstractIn vitro fertilization of squid requires the jelly substance found in the female oviducal gland; yet, the active component of this substance that facilitates fertilization remains unknown. Here, we used biochemical methods to separate the jelly substance of Todarodes pacificus (Oegopsida) and Sepioteuthis lessoniana (Myopsida family) into four fractions; specifically, two water soluble fractions (Molecular weight > 10,000 and < 10,000), one salt soluble fraction, and one insoluble fraction. The salt soluble fraction of T. pacificus induced chorionic expansion (perivitelline space formation), which precedes the normal embryonic development of ova. In contrast, the salt soluble fraction of S. lessoniana elicited insufficient expansion of the ova, only producing embryos with high abnormality rates. These results suggest that the salt soluble component(s) (not the jelly-like substances) in the oviducal gland induce chorionic expansion and hatching in Oegopsida, and that these components may be similar...
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Male copulatory behavior interrupts Japanese flying squid Todarodes pacificus female spawning activity
Marine Ecology Progress Series, 2016Co-Authors: Pandey Puneeta, Jun Yamamoto, Dharmamony Vijai, Yasunori SakuraiAbstract:Batch spawning, intermittent spawning and multiple spawning represent common reproductive strategies among cephalopods. These flexible spawning strategies are also common in fishes, and are thought to be a female trait that is programmed depending on environmental parameters. The ommastrephid squid Todarodes pacificus, being a terminal spawner, is considered to have a single spawning event, extruding one large egg mass and dying soon thereafter. Females that are interrupted by males exhibiting mating behavior, while extruding the egg mass, spawn multiple egg masses over the course of 2-3 d instead of dying soon after spawning the first egg mass. We demonstrate that male mating behavior causes 'forced' intermittent spawning by females (i.e. more than one spawning event). We hypothesize that in T. pacificus, some males use this strategy to mate with females unable to repel advances while spawning, thus providing the male with the opportunity to contribute sperm and enhance gene flow
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Comparison of growth histories of immature Japanese common squid Todarodes pacificus between the autumn and winter spawning cohorts based on statolith and gladius analyses
Fisheries Science, 2012Co-Authors: Hyejin Song, Hideaki Kidokoro, Norio Yamashita, Yasunori SakuraiAbstract:Growth of the autumn and winter spawning cohorts of the Japanese common squid Todarodes pacificus was examined based on daily growth increments in the statolith and gladius. The samples were taken from three groups of young (≤180 days old) squid: the autumn cohort collected in the Tsushima Current and the winter cohort collected in the Pacific near the coast and 1100 km offshore. The growth rate based on statolith analysis was highest in the winter cohort near the coast and similar in the two other groups. The daily growth based on gladius analysis during the month before capture was also highest in the winter cohort near the coast, and fluctuated more in the autumn cohort than in the winter cohort. The results suggest that gladius growth increments will be an important tool in future studies of growth in T. pacificus .
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Effects of environmental variability on the spawning areas, catch, and recruitment of the Japanese common squid, Todarodes pacificus (Cephalopoda: Ommastrephidae), from the 1970s to the 2000s
ICES Journal of Marine Science, 2011Co-Authors: Ana Luisa Rosa, J. Yamamoto, Yasunori SakuraiAbstract:Rosa, A. L., Yamamoto, J., and Sakurai, Y. 2011. Effects of environmental variability on the spawning areas, catch, and recruitment of the Japanese common squid, Todarodes pacificus (Cephalopoda: Ommastrephidae), from the 1970s to the 2000s. – ICES Journal of Marine Science, 68: 1114–1121.The Japanese common squid, Todarodes pacificus, is one of the most commercially valuable squids in the world. It spawns almost throughout the year, with a seasonal peak in autumn and winter. Long-term changes in sea surface temperature (SST) and its effect on the spawning areas and catch of T. pacificus were analysed for 27 spawning seasons (September–April 1978–2006) in the Sea of Japan and East China Sea. The spawning area was inferred between the limits of 21–41°N and 121°–142°E, 100–500-m depth, the mean Kuroshio axis, and the 19.5–23°C SST range. The results revealed that the area surrounding Kyushu Island is gaining importance as a spawning area. In addition, the discontinuity of the spawning ground in the East China Sea (around 29°N 128°E) during the winter spawning period was demonstrated to be associated with a decrease in the catches by both the Japanese and the Korean fleets. This constriction of the spawning ground would act as an obstacle to either the adult squid, making it difficult for them to reach the most southern grounds, or the paralarvae and juveniles, which, because of adverse environmental conditions, might not be able to survive the early stages of the feeding migration.
Kazufumi Osako - One of the best experts on this subject based on the ideXlab platform.
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Mechanism study of high browning degree of mantle muscle meat from Japanese common squid Todarodes pacificus during air-drying.
Food chemistry, 2014Co-Authors: Jie-ting Geng, Emiko Okazaki, Toshiki Kaido, Masaru Kasukawa, Chan Zhong, Le-chang Sun, Kazufumi OsakoAbstract:Mantle meat from the Japanese common squid (Todarodes pacificus) browns more than other squid meats during air-drying. The factors contributing to the browning of Japanese common squid, long-finned squid (Photololigo edulis) and bigfin reef squid (Sepioteuthis lessoniana) were studied in boiled and raw meat both before and after air-drying. Dried raw meat from the Japanese common squid browned more than dried boiled meat (b(∗) value, from 4.7 to 28.5). The results from SDS-PAGE showed significant degradation of myosin heavy chain (MHC) suggesting that protease activity in raw Japanese common squid meat was higher than in the other two species. The concentration of arginine (1932.0mg/100g) and ribose (28.8μmol/g) in Japanese common squid meat was higher than in the other two species. These results suggest that high protease activity and high concentrations of arginine and ribose increase the browning discoloration of Japanese common squid during air-drying.
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Effects of plasticizer type and concentration on the physicochemical properties of edible film from squid Todarodes pacificus mantle muscle
Fisheries Science, 2011Co-Authors: Akasith Leerahawong, Munehiko Tanaka, Emiko Okazaki, Kazufumi OsakoAbstract:Physical properties of edible film from squid Todarodes pacificus mantle muscle plasticized with different plasticizers (glycerol, sorbitol, glucose, and fructose) at various concentrations (10%, 20%, and 30% w/w of protein) were determined. The results showed that tensile strength (TS) significantly decreased (P < 0.05) while elongation at break significantly increased (P < 0.05) upon plasticizer addition. Water vapor permeability (WVP) significantly increased (P < 0.05) upon addition of glycerol or sorbitol but significantly decreased (P < 0.05) upon addition of glucose or fructose. Among the plasticizers used in this study, glycerol showed the greatest ability to decrease film TS. However, glycerol-plasticized film was less transparent than those with other plasticizers. Addition of glucose or fructose seemed to decrease the WVP of the film via a Maillard reaction. However, change in film color also occurred to a greater degree than for glycerol- or sorbitol-plasticized film.
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Edible film from squid (Todarodes pacificus) mantle muscle
Food Chemistry, 2011Co-Authors: Akasith Leerahawong, Rika Arii, Munehiko Tanaka, Kazufumi OsakoAbstract:Abstract Mantle muscle meat of Japanese common squid ( Todarodes pacificus ) was used to produce edible films in this study. The solubility of squid mantle muscle proteins increased upon addition of NaCl and organic salts (Na-citrate, Na-benzoate, Na-acetate and Na-tartrate). At concentrations below 2%, among organic salts, Na-citrate appeared to have the highest ability to dissolve proteins. Film-forming solutions were prepared by dissolving squid mantle meat in 0.5% or 1% salt solutions at neutral pH. Physical properties and SDS–PAGE of the films were determined. The film-forming solution prepared with 0.5% Na-citrate gave the transparent film with the highest tensile strength and least degradation of myosin heavy chain. Organic salt type at the same concentration had no significant effects ( p ⩾ 0.05) on water vapour permeability (WVP) of the films. The films showed excellent UV barrier properties. In addition, organic salts gave no significant effects ( p ⩾ 0.05) on light barrier properties and transparency of the films except for NaCl and Na-tartrate which were crystallised during the drying process. These results suggested that Na-citrate is the most useful for producing the edible films from squid mantle muscle among the organic salts examined in this study.
Jun Yamamoto - One of the best experts on this subject based on the ideXlab platform.
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Male copulatory behavior interrupts Japanese flying squid Todarodes pacificus female spawning activity
Marine Ecology Progress Series, 2016Co-Authors: Pandey Puneeta, Jun Yamamoto, Dharmamony Vijai, Yasunori SakuraiAbstract:Batch spawning, intermittent spawning and multiple spawning represent common reproductive strategies among cephalopods. These flexible spawning strategies are also common in fishes, and are thought to be a female trait that is programmed depending on environmental parameters. The ommastrephid squid Todarodes pacificus, being a terminal spawner, is considered to have a single spawning event, extruding one large egg mass and dying soon thereafter. Females that are interrupted by males exhibiting mating behavior, while extruding the egg mass, spawn multiple egg masses over the course of 2-3 d instead of dying soon after spawning the first egg mass. We demonstrate that male mating behavior causes 'forced' intermittent spawning by females (i.e. more than one spawning event). We hypothesize that in T. pacificus, some males use this strategy to mate with females unable to repel advances while spawning, thus providing the male with the opportunity to contribute sperm and enhance gene flow
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Vertical distribution of Todarodes pacificus (Cephalopoda: Ommastrephidae) paralarvae near the Oki Islands, southwestern Sea of Japan
Marine Biology, 2007Co-Authors: Jun Yamamoto, Tsuyoshi Shimura, Ryosuke Uji, Shinya Masuda, Shuyo Watanabe, Yasunori SakuraiAbstract:The diel vertical distribution patterns of Japanese common squid, Todarodes pacificus , paralarvae were examined using a Multiple Opening Closing Net and Environmental Sensing System (MOCNESS) in the southwest Sea of Japan near the Oki Islands (Japan) during five late-autumn surveys in 1998–2002. A total of 1,511 paralarvae ranging in mantle length (ML) from 0.7 to 7.3 mm were collected at 63 of the 68 stations surveyed. Most (84%) were collected above 75 m depth and in the mixed layer. The vertical distribution patterns varied little between day and night. Hatchling-sized (
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vertical distribution of Todarodes pacificus cephalopoda ommastrephidae paralarvae near the oki islands southwestern sea of japan
Marine Biology, 2007Co-Authors: Jun Yamamoto, Tsuyoshi Shimura, Ryosuke Uji, Shinya Masuda, Shuyo Watanabe, Yasunori SakuraiAbstract:The diel vertical distribution patterns of Japanese common squid, Todarodes pacificus, paralarvae were examined using a Multiple Opening Closing Net and Environmental Sensing System (MOCNESS) in the southwest Sea of Japan near the Oki Islands (Japan) during five late-autumn surveys in 1998–2002. A total of 1,511 paralarvae ranging in mantle length (ML) from 0.7 to 7.3 mm were collected at 63 of the 68 stations surveyed. Most (84%) were collected above 75 m depth and in the mixed layer. The vertical distribution patterns varied little between day and night. Hatchling-sized (<1.0 mm ML) paralarvae were abundant at 0–25 m depth, and paralarval ML increased with increasing sampling depth. Our results suggest that T. pacificus paralarvae do not exhibit large diel vertical migration patterns, but as they increase in size, paralarvae gradually descend in the water column and the variability in depth increases with ontogeny.
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investigation on the early stages of the ommastrephid squid Todarodes pacificus near the oki islands sea of japan
Bulletin of Marine Science, 2002Co-Authors: Jun Yamamoto, Ryosuke Uji, Shinya Masuda, Kazushi Miyashita, Yasunori SakuraiAbstract:The MOCNESS (Multiple Opening Closing Net and Environmental Sampling System) was used to investigate the distribution of the early life stages of the Japanese common squid Todarodes pacificus in the southwest Sea of Japan near the Oki Islands, a suspected spawning ground of this species. The largest catches of hatchling-sized paralarvae occurred at the surface layer (0-25 m), and paralarval mantle lengths increased with increasing sampling depth, suggesting that T pacificus paralarvae gradually descend in the water column life cycle as they grow. There was no clear difference in the horizontal distribution among the different size groups.
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Transport of the ommastrephid squid Todarodes pacificus under cold-water anesthesia
Aquaculture, 1999Co-Authors: John R. Bower, Yasunori Sakurai, Jun Yamamoto, Hiroshi IshiiAbstract:Abstract We describe a method for transporting live squid, Todarodes pacificus (Cephalopoda: Ommastrephidae), using cold-water anesthesia. Squid were placed individually in 30-l plastic bags with 5 l of 0–1°C seawater and 10–15 l of oxygen gas. Thirteen of 14 anesthetized squid survived 6.5 h transport by car and airplane with no signs of distress or shock. The longest survival under anesthesia was 10 h.
Y. Sakurai - One of the best experts on this subject based on the ideXlab platform.
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PERMANENT GENETIC RESOURCES: Development of microsatellite markers in the Japanese common squid Todarodes pacificus (Ommastrephidae)
Molecular ecology resources, 2008Co-Authors: Yoko Iwata, C. L. Lian, Y. SakuraiAbstract:Todarodes pacificus is an important species for commercial fisheries, but its reproductive biology has been little understood. We isolated 11 polymorphic microsatellite loci from this species. These loci provided highly polymorphic microsatellite markers with four to 26 alleles per locus. The observed and expected heterozygosities ranged from 0.150 to 1.000, and from 0.660 to 0.974, respectively. These markers will be useful for research about the mating systems and genetic diversity of T. pacificus.
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Changes in inferred spawning areas of Todarodes pacificus (Cephalopoda: Ommastrephidae) due to changing environmental conditions
ICES Journal of Marine Science, 2000Co-Authors: Y. Sakurai, H. Kiyofuji, S. Saitoh, T. Goto, Y. HiyamaAbstract:Annual catches of Todarodes pacificus in Japan have gradually increased since the late 1980s. Paralarval abundances have also been higher since the late 1980s compared to the late 1970s and mid-1980s. Here is proposed a possible scenario for the recent stock increase based on changing environmental conditions. Based on trends in annual variations in stock and in larval abundances, catches are reviewed and potential spawning areas inferred, assuming that egg masses and hatchlings occur over the continental shelf at temperatures between 15 and 23°C. Changes are then inferred in the spawning areas during 1984-1995, based on GIS data. Since the late 1980s, the autumn and winter spawning areas in the Tsushima Strait and near the Goto Islands appear to have overlapped, and winter spawning sites seem to have expanded over the continental shelf and slope in the East China Sea.
Akasith Leerahawong - One of the best experts on this subject based on the ideXlab platform.
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Effects of plasticizer type and concentration on the physicochemical properties of edible film from squid Todarodes pacificus mantle muscle
Fisheries Science, 2011Co-Authors: Akasith Leerahawong, Munehiko Tanaka, Emiko Okazaki, Kazufumi OsakoAbstract:Physical properties of edible film from squid Todarodes pacificus mantle muscle plasticized with different plasticizers (glycerol, sorbitol, glucose, and fructose) at various concentrations (10%, 20%, and 30% w/w of protein) were determined. The results showed that tensile strength (TS) significantly decreased (P < 0.05) while elongation at break significantly increased (P < 0.05) upon plasticizer addition. Water vapor permeability (WVP) significantly increased (P < 0.05) upon addition of glycerol or sorbitol but significantly decreased (P < 0.05) upon addition of glucose or fructose. Among the plasticizers used in this study, glycerol showed the greatest ability to decrease film TS. However, glycerol-plasticized film was less transparent than those with other plasticizers. Addition of glucose or fructose seemed to decrease the WVP of the film via a Maillard reaction. However, change in film color also occurred to a greater degree than for glycerol- or sorbitol-plasticized film.
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Edible film from squid (Todarodes pacificus) mantle muscle
Food Chemistry, 2011Co-Authors: Akasith Leerahawong, Rika Arii, Munehiko Tanaka, Kazufumi OsakoAbstract:Abstract Mantle muscle meat of Japanese common squid ( Todarodes pacificus ) was used to produce edible films in this study. The solubility of squid mantle muscle proteins increased upon addition of NaCl and organic salts (Na-citrate, Na-benzoate, Na-acetate and Na-tartrate). At concentrations below 2%, among organic salts, Na-citrate appeared to have the highest ability to dissolve proteins. Film-forming solutions were prepared by dissolving squid mantle meat in 0.5% or 1% salt solutions at neutral pH. Physical properties and SDS–PAGE of the films were determined. The film-forming solution prepared with 0.5% Na-citrate gave the transparent film with the highest tensile strength and least degradation of myosin heavy chain. Organic salt type at the same concentration had no significant effects ( p ⩾ 0.05) on water vapour permeability (WVP) of the films. The films showed excellent UV barrier properties. In addition, organic salts gave no significant effects ( p ⩾ 0.05) on light barrier properties and transparency of the films except for NaCl and Na-tartrate which were crystallised during the drying process. These results suggested that Na-citrate is the most useful for producing the edible films from squid mantle muscle among the organic salts examined in this study.
