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51.
52.
Hitomi MATSUNARI Toshihiro KOBAYASHI Masahito WATANABE Kazuhiro UMEYAMA Kazuaki NAKANO Takahiro KANAI Taisuke MATSUDA Masaki NAGAYA Manami HARA Hiromitsu NAKAUCHI Hiroshi NAGASHIMA 《The Journal of reproduction and development》2014,60(3):230-237
The development and regeneration of the pancreas is of considerable interest because of the role of these processes in
pancreatic diseases, such as diabetes. Here, we sought to develop a large animal model in which the pancreatic cell lineage
could be tracked. The pancreatic and duodenal homeobox-1 (Pdx1) gene promoter was conjugated to Venus, a
green fluorescent protein, and introduced into 370 in vitro-matured porcine oocytes by intracytoplasmic
sperm injection-mediated gene transfer. These oocytes were transferred into four recipient gilts, all of which became
pregnant. Three gilts were sacrificed at 47–65 days of gestation, and the fourth was allowed to farrow. Seven of 16 fetuses
obtained were transgenic (Tg) and exhibited pancreas-specific green fluorescence. The fourth recipient gilt produced a litter
of six piglets, two of which were Tg. The founder Tg offspring matured normally and produced healthy first-generation (G1)
progeny. A postweaning autopsy of four 27-day-old G1 Tg piglets confirmed the pancreas-specific Venus expression.
Immunostaining of the pancreatic tissue indicated the transgene was expressed in β-cells. Pancreatic islets from Tg pigs were
transplanted under the renal capsules of NOD/SCID mice and expressed fluorescence up to one month after transplantation. Tg
G1 pigs developed normally and had blood glucose levels within the normal range. Insulin levels before and after sexual
maturity were within normal ranges, as were other blood biochemistry parameters, indicating that pancreatic function was
normal. We conclude that Pdx1-Venus Tg pigs represent a large animal model suitable for research on
pancreatic development/regeneration and diabetes. 相似文献
53.
Effect of Leukemia Inhibitory Factor and Forskolin on Establishment of Rat
Embryonic Stem Cell Lines
Masumi HIRABAYASHI Teppei GOTO Chihiro TAMURA Makoto SANBO Hiromasa HARA Shinichi HOCHI 《The Journal of reproduction and development》2014,60(1):78-82
This study was designed to investigate whether supplementation of 2i medium with
leukemia inhibitory factor (LIF) and/or forskolin would support establishment of
germline-competent rat embryonic stem (ES) cell lines. Due to the higher likelihood of
outgrowth rates, supplementation of forskolin with or without LIF contributed to the
higher establishment efficiency of ES cell lines in the WDB strain. Germline transmission
competency of the chimeric rats was not influenced by the profile of ES cell lines until
their establishment. When the LIF/forskolin-supplemented 2i medium was used, the rat
strain used as the blastocyst donor, such as the WI strain, was a possible factor
negatively influencing the establishment efficiency of ES cell lines. Once ES cell lines
were established, all lines were found to be germline-competent by a progeny test in
chimeric rats. In conclusion, both LIF and forskolin are not essential but can play a
beneficial role in the establishment of “genuine” rat ES cell lines. 相似文献
54.
Ryuta Kawasaki Akinori Azumano Miya Ueda Souhei Tanaka Aya Yokota Kazuo Katoh Akihiko Hagino 《Animal Science Journal》2014,85(10):910-914
We analyzed the urinary excretion of glucose and N‐acetyl‐β‐D‐glucosaminidase (NAG) in six okapis (Okapia johnstoni) in captivity to investigate the cause of their urinary sugar excretion. The urinary glucose‐positive okapi had significantly higher urinary NAG indices than the urinary glucose‐negative okapi. There was also a positive correlation between urinary glucose levels and urinary NAG indices. These results suggest that the proximal tubular function of the glycosuric okapi may have been obstructed, which impaired glucose reabsorption. 相似文献
55.
Daniel S. Moura Francisco J. Zapata-Arias Akihiko Ando Augusto Tulmann Neto 《Euphytica》1997,94(1):01-05
A plant regeneration system from rice protoplasts using calli derived from mature embryos was established for the two Brazilian
modern rice cultivars IAC-201 and IAC-165. After 30 to 40 days of in vitro culture it was possible to obtain on average 6
million protoplasts per gram of callus. Microscopic selection of embryogenic calli was a key step for protoplast isolation.
The production of embryogenic calli increased when L-proline and casein hydrolysate were used in the callus induction medium.
The Oc or IR52 nurse cell lines were essential for protoplast division. Different regeneration media were studied and 139
plants were regenerated which set seed. Some of the regenerated plants showed morphological variation such as the presence
of awns in spite of the short time of the in vitro culture.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
56.
Masaki Nagae Hirotoshi Fuda Kazuhiro Ura Hiroshi Kawamura Shinji Adachi Akihiko Hara Kohei Yamauchi 《Fish physiology and biochemistry》1994,13(1):41-48
Immunoglobulin M (IgM) is known as a main factor in the humoral immune system of teleosts. In the present study, the effect
of cortisol on plasma IgM concentrations was investigated using a specific antibody to IgM in masu salmon (Oncorhynchus masou). Cortisol was orally administered each day for 2 weeks at a dose of 1 mg g−1 in the diet, and for the following week the fish were fed a non-treated diet. Blood plasma samples were collected at 0, 1,
2 and 3 weeks after the initiation of treatment. Oral administration of cortisol elevated plasma cortisol concentrations to
about 40 ng/ml for 2 weeks after administration and slightly reduced plasma IgM concentration; the suppression was statistically
significant one week after the period of hormone administration. However, treatment with cortisol did not affect plasma concentrations
of total protein or α1-protein, one of the major serum proteins, during the experimental period. These results indicate that
cortisol specifically suppresses plasma IgM concentrations. 相似文献
57.
Yunxia Tao Akihiko Hara Ronald G. Hodson L. Curr Woods III Craig V. Sullivan 《Fish physiology and biochemistry》1993,12(1):31-46
The egg yolk precursor, vitellogenin (VTG), was purified from blood plasma of striped bass by chromatography on hydroxylapatite
or DEAE-agarose. The fish were first implanted with estradiol-17β (E2), which induced vitellogenesis. A rabbit antiserum (a-FSPP) raised against plasma from mature female striped bass, and then
adsorbed with mature male plasma, was used to detect female-specific plasma protein (FSPP) in the chromatography fractions.
Striped bass VTG (s-VTG) was collected from the peak fraction that was induced by E2, reacted with a-FSPP, and contained all detectable phosphoprotein. It appeared as a single band (Mr ≂ 170,000) in SDS-PAGE or Western blots using a-FSPP, and as a pair of closely-spaced phospholipoprotein bands in native
gradient-PAGE, suggesting that there is more than one circulating form of s-VTG. The relationship of s-VTG to the yolk proteins
was verified using a-FSPP. The antiserum reacted with the main peak from gel filtration of saline ovary extracts, and it specifically
immunostained the two main bands in Western blots of the extracts and the yolk granules of mature oocytes. The amino acid
composition of s-VTG was similar to that of VTG from other fish and Xenopus. A radial immunodiffusion assay for s-VTG was developed using a-FSPP and purified s-VTG as standard. The s-VTG was not detected
in blood plasma of males, immature females, or regressed adult females, but plasma s-VTG levels were highly correlated with
plasma E2 and testosterone levels, and oocyte growth, in maturing females. The results indicate that the maturational status of female
striped bass can be identified by s-VTG immunoassay. 相似文献
58.
基于表观热惯量的土壤水分监测 总被引:4,自引:0,他引:4
土壤水分含量是监测农业干旱的重要指标, 遥感法是大面积监测土壤水分时空特征的主要方法, 热惯量法是遥感方法监测土壤水分的主要研究手段之一。本文提出了一个改进的表观热惯量模型计算表观热惯量, 并通过地面验证试验对该模型的适用性进行了分析。在中国科学院栾城农业生态系统试验站, 通过严格的控制试验, 设计了10 个不同植被覆盖、不同土壤水分含量的试验小区, 针对表观热惯量的适用条件, 利用实测的地表温度、植被指数、反照率、太阳辐射等参数计算了不同植被覆盖不同土壤水分含量下的表观热惯量,并与土壤体积含水量进行了相关和回归分析。结果表明: 在植被覆盖度较低情况下[归一化植被指数(normalized difference vegetation index, NDVI)<0.35], 表观热惯量法具有较好的效果, 表观热惯量与土壤体积含水量之间的相关系数大于0.7, 通过了95%的显著性检验, 两者具有很高的相关性, 可以用热惯量法监测土壤水分状况; 在较高植被覆盖情况下(NDVI>0.35), 表观热惯量与土壤体积含水量之间没有相关性, 热惯量法监测土壤水分失效; NDVI 为0.35 可以作为热惯量法监测土壤水分状况是否可行的判断条件。 相似文献
59.
The effects of medetomidine and xylazine on gastrointestinal motility and gastrin release in the dog
K. NAKAMURA S. HARA & N. TOMIZAWA 《Journal of veterinary pharmacology and therapeutics》1997,20(4):290-295
The effect of medetomidine, a potent and highly selective α2 -adrenoceptor agonist, on the motility of the gastric antrum, duodenum, mid-jejunum and ileum was investigated in ten dogs. Its effect on the release of gastrin was also determined. Administration of medetomidine intramuscularly (i.m.) at a dose of 40 μg/kg inhibited the motility of the gastric antrum, duodenum, mid-jejunum and ileum significantly, in comparison to administration of xylazine intramuscularly at a dose of 2.0 mg/kg. The release of gastrin was also significantly decreased in dogs receiving medetomidine. It was found to inhibit the motility in the gastric antrum and duodenum longer than in the mid-jejunum and ileum, presumably by acting specifically on α2 -adrenoceptors, likely at the peripheral level. Medetomidine also inhibited the gastric contraction associated with gastrin secretion. 相似文献
60.
Kohei OHTA Sonoko YAMAGUCHI Akihiko YAMAGUCHI Koichi OKUZAWA Koichiro GEN Hirohiko KAGAWA Michiya MATSUYAMA 《Fisheries Science》2002,68(3):680-687
ABSTRACT: The red seabream Pagrus major is a useful experimental fish for studying the endocrine control of oogenesis in teleosts. This study investigated the steroidogenic pathway for estradiol-17β (E2) biosynthesis in the ovarian follicles of red seabream. Intact follicles were isolated during vitellogenesis and incubated in vitro with different radiolabeled steroid precursors. When 17-hydroxyprogesterone (17-P), dehydroepiandrosterone (DHEA), or androstenedione (AD) were used as precursors, both testosterone (T) and estrone (E1) were synthesized by follicles, leading to estradiol-17β (E2) production. Serum steroid levels measured by enzyme-linked immunosorbent assay showed that T, E1, and E2 were present in the circulation at levels ranging from 1 ng/mL to 2 ng/mL throughout the day during the spawning season. In vitro conversion of E1 into E2, however, was 15.8-fold greater than T conversion into E2, suggesting that E2 is synthesized mainly via E1 rather than T. The results showed that E2 was synthesized from pregnenolone via 17-hydroxypregnenolone, DHEA, AD, and E1. Thus, the study demonstrated the complete steroidogenic E2 synthesis pathway in the ovarian follicles of red seabream, and revealed that E1 is the major precursor of E2. 相似文献