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31.
Kaneko H Kikuchi K Nakai M Noguchi J 《The Journal of reproduction and development》2008,54(6):480-485
Clarification of the endocrine status of host mice provides us with basic knowledge with which we can manipulate the growth and function of xenografted testicular tissues. We investigated the hormonal profiles of castrated mice grafted with porcine immature testicular tissues from 30 to 210 or more days after grafting (day 0=castration and grafting). The serum follicle stimulating hormone (FSH) concentrations of the host mice declined (P<0.05) from day 60 compared with those of the castrated, ungrafted mice. The serum inhibin and testosterone levels were higher (P<0.05) than those in the castrated, ungrafted mice from days 30 and 90 days, respectively. The inhibin levels further increased (P<0.05) from day 90, during which time the levels were higher (P<0.05) than those in the intact male mice. In the grafts, formation of lumens occurred in the seminiferous cords on day 90 and spermatozoa appeared in the lumens from day 120. However, spermatogenesis in the grafts did not reach the qualitatively normal levels observed in adult boars. The intensity of the immune reaction to inhibin alpha subunits in the Sertoli cells of the grafts decreased with differentiation of the seminiferous tubules. The present findings indicate that a feedback loop was established between the mouse hypothalamo-pituitary axis and the grafted porcine tissues from 60 days post-grafting. The results also indicate that the serum inhibin levels in the host mice remained high even after the appearance of lumens in the seminiferous tubules of the grafted tissues; this is strikingly different to the situation in normal male animals, in which the serum inhibin levels decline at around the time of tubular differentiation. The lack of efferent ducts in the tubules of the grafted tissues probably caused the accumulation of inhibin to be released into the lumens, resulting in high concentrations of circulating inhibin. These high levels of inhibin may directly affect spermatogenic activity and suppress FSH secretion. 相似文献
32.
K Kikuchi N Kashiwazaki T Nagai M Nakai T Somfai J Noguchi H Kaneko 《Reproduction in domestic animals》2008,43(S2):401-406
In vitro fertilization (IVF) of in vitro matured (IVM) oocytes in pigs has become the most popular method of studying gametogenesis and embryogenesis in this species. Furthermore, because of recent advances in in vitro culture (IVC) of IVM–IVF embryos, in vitro production (IVP) of embryos now enables us to generate viable embryos as successfully as for in vivo -derived embryos and with less cost and in less time. These technologies contribute not only to developments in reproductive physiology and agriculture but also to the conservation of porcine genetic resources and the production of cloned or genetically modified pigs. However, in IVP, there still remains the problem of abnormal ploidy, which is caused by performing procedures under non-physiological conditions. In recent years, unique technologies such as intracytoplasmic sperm injection (ICSI) or xenografting of gonadal tissue into immunodeficient experimental animals have been developed to help conserve gamete resources. These technologies combined with IVP are expected to be useful for the conservation of gametes from important genetic resources. Here, we discuss the developmental ability and normality of porcine IVP embryos and also the utilization of ICSI and xenografting in advancing biotechnology in pigs. 相似文献
33.
Thanh Quang Dang‐Nguyen Hiep Thi Nguyen Tamas Somfai David Wells Nguyen Thi Men Nguyen Viet‐Linh Junko Noguchi Hiroyuki Kaneko Kazuhiro Kikuchi Takashi Nagai 《Animal Science Journal》2018,89(6):880-887
We investigated whether high‐quality in vitro matured (IVM) oocytes can be distinguished from poor ones based on the morphological changes after treatment with hyperosmotic medium containing 0.2 mol/L sucrose in pigs. We hypothesize that IVM oocytes maintaining round shape have higher quality than mis‐shapened oocytes following dehydration. Oocyte quality was verified by determining embryonic developmental competence using in vitro fertilization, nuclear transfer and parthenogenetic activation. In all cases, the round oocytes had greater (p < .05) developmental competence than that of mis‐shapened oocytes in terms of blastocyst rate and total cell number in blastocysts obtained after 6 days of in vitro culture. We also confirm that round aged oocytes are higher in quality than mis‐shapened aged oocytes. In an attempt to find out why high‐quality oocytes maintain a round shape whereas poorer oocytes become mis‐shapened following sucrose treatment, we examined the arrangement of actin microfilaments and microtubules. Abnormal organization of these cytoskeletal components was higher (p < .05) in mis‐shapened oocytes compared to round oocytes after 52 hr of IVM. In conclusion, sucrose treatment helps selection of high‐quality oocytes, including aged oocytes, in pigs. Abnormal cytoskeleton arrangements partly explain for low developmental competence of mis‐shapened oocytes. 相似文献
34.
Pseurotins A1 (1) and A2 (2) were isolated from a culture broth of the fungal strain Aspergillus fumigatus WFZ-25 as stereoisomers of pseurotin A (3) in 2011. We also isolated 1 and 2 together with 3 from A. fumigatus OUPS-T106B-5 separated from the marine fish Mugil cephalus. In this study, we re-examined the stereochemistry of 1 and 2 using chemical transformation and the CD spectra, and found the relationship between the CD Cotton effect and the absolute configurations of 1 and 2, which led us to revise the stereostructure of pseurotin A2. 相似文献
35.
36.
为了从原子尺度弄清楚因辐射损伤而出现的第二相铜沉淀物对位错运动状况的影响,在Osetsky模型和Malerba势能基础上,通过共轭梯度法进行能量最小化,对BCC铁中刃型位错与铜沉淀物的相互作用进行了模拟.再现作用过程的同时,重点探讨了铜沉淀物直径、间距等因素对相互作用的影响,并将模拟结果与连续体理论模型进行了对比分析.结果表明:铜沉淀物直径越大,相互作用越强,位错越难越过沉淀物.而铜沉淀物间距越大,位错越容易越过沉淀物,Malerba势能下的模拟结果相比Ackland势能下的模拟结果与连续体理论模型结果相符得更好. 相似文献
37.
SUN Jun-ming SUN Bao-li HAN Fen-xia YAN Shu-rong YANG Hua Akio Kikuchi 《中国农业科学(英文版)》2011,10(1):70-77
It is important to determine the isoflavone components by high-performance liquid chromatography(HPLC)for the molecular assistant selection of isoflavone in soybean.Based on the standard samples of 12 isoflavone components,the isoflavone components were analyzed using the determination of absorbance peaks method by HPLC.The results showed that there were different maximum ultraviolet(UV)absorbance for the aglycones of daidzein,glycitein,and genistein,which were at 250,257,and 260 nm,respectively.A linear gradient elution of acetonitrile(13-30%)containing 0.1% acetic acid as a mobile phase was applied on a YMC-C18 column at 35℃.The 12 isoflavone components were determined using the UV detector by HPLC.We concluded that this is a rapid and precise method which adapted to determine the large numbers of samples with microanalysis. 相似文献
38.
Keisuke Kikuchi Rie Yamashita Satoshi Sakuragawa Keigo Hasumi Yasuhiro Mukai Hiroya Kobayakawa Shojiro Wakabayashi Yukie Saito 《Journal of Wood Science》2018,64(5):642-649
Bamboo-derived activated carbon prepared by superheated steam (BAC) exhibited performance for utilization as an electric double layer capacitor (EDLC) electrode. Pore structure and EDLC performances were investigated by comparison with phenol resin-derived activated carbon (MSP-20), which is commercially available and often used for the purpose. The nitrogen adsorption isotherm showed that BAC had a large BET-specific surface area of 1268 g/m2 with a developed pore structure, especially of the mesopore, in comparison with MSP-20. It is considered that inherent ash in bamboo promoted activation, in addition to physical activation by superheated steam. Capacitance per electrode volume (CV) was 52 F/cm3 with BAC. Because the density of BAC is high (0.78 g/cm3) compared with that of MSP-20 (0.58 g/cm3), sufficient CV for usage was obtained, although the capacitance per electrode mass (CM) at 5 mA/cm2 itself of BAC (67 F/g) was lower than that of MSP-20 (126 F/g). With IR drop, the resistance value of BAC (9.7 Ω) was lower than that of MSP-20 (10.5 Ω). Especially, the diffusion resistance of BAC disclosed to be smaller than that of MSP-20. These results indicated that BAC produced by steam activation is a promising material with a pore structure suitable for ion transfer in EDLC. 相似文献
39.
The quality after culture in vitro or in vivo of porcine oocytes matured and fertilized in vitro and their ability to develop to term
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The quality of porcine blastocysts produced in vitro is poor in comparison with those that develop in vivo. We examined the quality of in vitro‐matured and fertilized (IVM/IVF) oocytes, their abilities to develop to blastocysts under in vivo and in vitro conditions, and the potential of the embryos to develop to term after transfer. IVM/IVF oocytes were either transferred and the embryos recovered on Days 5 and 6 (100% and 87.5%, respectively) (‘ET‐vivo’ embryos), or cultured in vitro for 5 or 6 days (‘IVC’ embryos). The proportion of blastocysts differed significantly between the two groups on Day 5 (20.6% and 8.0%, respectively), but not on Day 6 (23.8% and 21.2%, respectively). The mean number of cells in ET‐vivo blastocysts on Days 5 or 6 was significantly higher (72.8 and 78.7, respectively) than that in IVC blastocysts (22.1 and 39.7, respectively). When IVM/IVF oocytes and IVC blastocysts on Day 6 were transferred, all (three and three, respectively) developed to piglets (16 and 16, respectively), without any difference in the rates of development to term (2.1% and 2.6%, respectively). These data suggest that, although blastocyst production differs between the two culture conditions, IVM/IVF oocytes possess the same ability to develop to term. 相似文献
40.
Effects of polyethylene glycol and a synthetic ice blocker during vitrification of immature porcine oocytes on survival and subsequent embryo development
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Elisa Caroline da Silva Santos Tamas Somfai Ruth Appeltant Thanh Quang Dang‐Nguyen Junko Noguchi Hiroyuki Kaneko Kazuhiro Kikuchi 《Animal Science Journal》2017,88(8):1042-1048
We evaluated the effects of polyethylene glycol (PEG) and Supercool X‐1000 (SC) as supplements during the vitrification of immature cumulus‐enclosed porcine oocytes in a solution based on 17.5% ethylene glycol + 17.5% propylene glycol. After warming, the oocytes were subjected to in vitro maturation, fertilization and embryo culture. In Experiment 1, equilibration and vitrification solutions were supplemented with or without 2% (w/v) PEG (PEG+ and PEG‐, respectively). The survival rate, cleavage and blastocyst development were similar between PEG+ and PEG‐ groups; however, all values were lower than those in the non‐vitrified control. In Experiment 2, vitrification solution was supplemented with or without 1% (v/v) SC (SC+ and SC‐, respectively). The percentages of survival and blastocyst development were similar between SC+ and SC‐ groups but lower than those in the non‐vitrified control. The percentage of cleavage in the SC‐ group was significantly lower than the control and the SC+ groups, which were in turn similar to one another. In both experiments, the cell numbers in blastocysts were not significantly different among the non‐vitrified and vitrified groups. In conclusion, PEG did not improve oocyte survival and embryo development, whereas SC improved the ability of surviving oocytes to cleave but not to develop into blastocysts. 相似文献