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Weiping HUANG Masashi NAGANO Sung-Sik KANG Yojiro YANAGAWA Yoshiyuki TAKAHASHI 《The Journal of reproduction and development》2014,60(1):9-13
The objective of this study was to clarify the effects of prematurational culture
(pre-IVM) supplemented with 3-isobutyl-1-methylxanthine (IBMX) on nuclear and cytoplasmic
maturation of in vitro-grown bovine oocytes. In experiment 1, oocytes (95
μm in diameter) derived from early antral follicles (0.5–1 mm in diameter) were cultured
for 12 days for in vitro growth (IVG). IVG oocytes with a normal
appearance were subjected to examinations of diameter and chromatin structure in the
germinal vesicle (GV) before IVM. In addition, percentages of metaphase II (M II) were
examined after IVM. Regardless of pre-IVM, the mean diameters of IVG oocytes were about
115 μm. The proportions of GV3 (50.0%) and M II stages (80.1%) of IVG oocytes with pre-IVM
were higher than those without pre-IVM (28.0 and 49.4%, respectively). In experiment 2,
the fertilizability and developmental competence of IVG oocytes were examined. Regardless
of pre-IVM, the normal fertilization rates of IVG oocytes were similar (around 70%) but
were lower than that of in vivo-grown oocytes (88.0%). Cleavage and
blastocyst rates of IVG oocytes with pre-IVM (63.0 and 26.1%, respectively) were higher
than those without pre-IVM (45.8 and 12.7%, respectively). The blastocyst rate based on
cleaved IVG oocytes with pre-IVM (41.7%) was similar to that of in
vivo-grown oocytes (48.7%), although the cleavage rate of IVG oocytes with
pre-IVM was lower than that of in vivo-grown oocytes. In conclusion,
pre-IVM with IBMX improved the maturational and developmental competences of IVG oocytes,
probably due to promotion of their chromatin transition and synchronization of meiotic
progression. 相似文献
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We used GIS on a regional scale to estimate and compare supply potentials and costs of small-scale logging systems, a mini-forwarder and a 4-ton truck operated by private logging contractors, and manual logging and a light truck operated by individual forest own- ers, with the mechanized operational system of the Forest Owners' Asso- ciation. Total potential yields of timber and logging residues were esti- mated as 418,895 m3 and 254,962 m3, respectively. The economic bal- ances were estimated and available amounts were projected as supply potentials from profitable sub-compartments. As a result, available amounts of timber and logging residues were estimated at 375,466 m3 (89.9%) and 203,850 m3 (80.0%), respectively. Because their transport expenses were lower than for other systems the most profitable sub-compartments were operated by private logging contractors who sold logging residues at a plant. The profitable sub-compartments operated by individual forest owners were few because the extracting distances were usually greater than 20 m. Raising logging residue prices from 3,000 yen·m-3 to 4,080 yen·m-3 or 6,800 yen·m-3, and establishing forest roads, which reduced some extracting distances to less than 20 m, increased the number and area of profitable sub*compartments, and increased available amounts of logging residues. 相似文献
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Chikara Nakahata Kazuhiro Aruga Ryo Uemura Masashi Saito Kanae Kanetsuki 《Small-Scale Forestry》2014,13(2):251-266
This study examines the optimal method to extract logging residues from small, fragmented and scattered forests separately from the mechanized operational systems used on aggregated forestry operation sites. First, small-scale logging systems operated by a private logging contractor and an individual forest owner were investigated. Regression equations for estimating felling and processing cycle times were established as a function of stem and log volumes, respectively. Equations to estimate the forwarding and transporting cycle times were established as a function of the forwarding and transporting distances using the forwarding and transporting velocities, respectively. Then, equations to estimate productivities and costs were established with the cycle times, volumes and hourly operational expenses consisting of labour and machinery expenses. Finally, costs of the small-scale systems—mini-forwarder and 4 t truck operated by a private logging contractor, and manual logging and light truck operated by an individual forest owner—were estimated and compared with the mechanized operation system operated by the Forest Owners’ Association. The mechanized operation system was found to have the highest cost and could not compete for small forestry operational sites and small stem volumes. The small-scale systems could be effective for harvesting small areas. This was especially true when conducting extracting operations without machines, as done by the individual forest owner, and transporting operations by a private logging contractor, in which the hourly income of the individual forest owner was higher than the hourly labour expenses. 相似文献
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Possible degradation of type I collagen in relation to yellowtail muscle softening during chilled storage 总被引:1,自引:0,他引:1
ABSTRACT: In this paper, the detection of type I collagen degradation during the softening phenomenon of yellowtail muscle, was examined. Acid soluble collagen was isolated from dorsal ordinary muscle at death and after 24-h chilled storage. In the abundant ratio of subunit components, an increase in β12 chain (5.4 points) and a decrease in components with molecular weights larger than γ chain (7.0 points) after 24-h chilled storage, was found. Type I collagen was detected in the alkali-soluble fraction by SDS-PAGE. Its amount calculated from hydroxyproline contents in alkali-soluble fraction was increased from 0.097 mg/g muscle to 0.155 mg/g muscle during 24-h storage. The increased alkali-soluble collagen (0.058 mg/g muscle) was about 1.4% of whole collagen. These results suggest that a slight decomposition of type I collagen of yellowtail muscle may occur and subsequently becomes alkali-soluble corresponding to postmortem softening. 相似文献
39.
Masashi Ando Shintaro Mizuochi Yasuyuki Tsukamasa Ken -Ichi Kawasaki 《Fisheries Science》2007,73(3):705-712
ABSTRACT: Changes in meat firmness and structure of cultured yellowtail at several storage temperatures, from −1.5°C to 10°C, were compared. Firmness decreased less at −1.5°C and 10°C than at the other temperatures. During storage at temperatures from −0.5 to 4.0°C, expansion of intercellular space, which indicates weakening of the connecting force between muscle cells, began to increase after 8 h storage, and the ratio of space to the whole area increased by 3.4–4.9 times after 24 h of storage. However, at −1.5°C and 10°C, the increase of intercellular space was suppressed, and the ratio was 2.4–2.6 times, even after 24 h storage. Collagen fibrils connecting muscle cells disintegrated after 24 h storage at all storage temperatures. Conversely, in 10°C storage, the fine structure of muscle, except for collagen fibrils, was maintained better than at other storage temperatures. These findings indicate that −1.5 and 10°C storage could maintain fish-meat quality for longer periods than storage at −0.5, 1.0, or 4.0°C, the normal refrigeration temperature. 相似文献
40.
Wataru Doi Than Than Lwin Masashi Yokota Carlos Augusto Strüssmann Seiichi Watanabe 《Fisheries Science》2007,73(2):331-340
ABSTRACT: Sexual maturity, morphological sexual dimorphism, and reproduction of the goneplacid crab Carcinoplax vestita were investigated in Tokyo Bay, Japan, from November 2002 to October 2003. The puberty molt in males was evidenced by changes in the relative size of the chelipeds and merus of the walking legs, and was estimated to occur at a size range of 13.20–18.85 mm carapace length. Post-pubertal females were identified by the relative size of the abdomen and puberty was estimated to occur at a size range of 12.81–15.46 mm carapace length. Sexual dimorphism in C. vestita was observed in all features that showed secondary sexual characteristics. Monthly changes of gonad index in males, and of seminal receptacle index and occurrence of sperm plugs in females were synchronized, and indicated that mating was intense in spring. Ovaries began developing in March. Ovigerous females were found in all months except December, but were clearly more abundant between August and October. Fecundity ranged from 7800 to 57 000 mature oocytes per female per batch and was highly correlated with body size. The results suggest that some females may spawn more than one batch per year. 相似文献