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Satoshi TSUKAMOTO Taichi HARA Atsushi YAMAMOTO Yuki OHTA Ayako WADA Yuka ISHIDA Seiji KITO Tetsu NISHIKAWA Naojiro MINAMI Ken SATO Toshiaki KOKUBO 《The Journal of reproduction and development》2013,59(1):33-39
Lysosomes are acidic and highly dynamic organelles that are essential for macromolecule
degradation and many other cellular functions. However, little is known about lysosomal
function during early embryogenesis. Here, we found that the number of lysosomes increased
after fertilization. Lysosomes were abundant during mouse preimplantation development
until the morula stage, but their numbers decreased slightly in blastocysts. Consistently,
the protein expression level of mature cathepsins B and D was high from the one-cell to
morula stages but low in the blastocyst stage. One-cell embryos injected with siRNAs
targeted to both lysosome-associated membrane protein 1 and 2 (LAMP1 and LAMP2) were
developmentally arrested at the two-cell stage. Pharmacological inhibition of lysosomes
also caused developmental retardation, resulting in accumulation of lipofuscin. Our
findings highlight the functional changes in lysosomes in mouse preimplantation
embryos. 相似文献
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KENSUKE NAKAMURA SATOSHI TAKAGI NOBORU SASAKI WICKRAMASEKARA RAJAPAKSHAGE BANDULA KUMARA MASAHIRO MURAKAMI HIROSHI OHTA MASAHIRO YAMASAKI MITSUYOSHI TAKIGUCHI 《Veterinary radiology & ultrasound》2010,51(1):79-85
In six normal beagles and 27 dogs with spontaneous focal or multifocal liver lesions, contrast-enhanced ultrasonography using Sonazoid® was performed. Sonazoid® is a newly developed second-generation contrast agent with the ability to be used for real-time contrast imaging along with parenchymal imaging. An appropriate protocol for the evaluation of all three phases (arterial, portal, and parenchymal) was established based on the results for normal beagles. By evaluation of the echogenicity of hepatic nodules during the arterial and parenchymal phases it was possible to differentiate malignant tumors from benign nodules with very high accuracy. In 15 of 16 dogs diagnosed as malignant tumors, nodules were clearly hypoechoic to the surrounding normal liver during the parenchymal phase. Additionally, malignant tumors had different echogenicity compared with the surrounding normal liver during the arterial phase in 14 of 15 dogs. In the portal phase, there were no characteristic findings. Contrast-enhanced ultrasonography with Sonazoid® appears to improve the characterization of canine focal and multifocal hepatic lesions. 相似文献
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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
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HIROHIKO KAGAWA HIDEKI TANAKA TATSUYA UNUMA HIROMI OHTA KOICHIRO GEN KOICHI OKUZAWA 《Fisheries Science》2003,69(2):234-241
ABSTRACT: The in vitro effects of 17,20β-dihydroxy-4-pregnen-3-one(DHP) and prostaglandins (PGE1 , PGE2 , PGF1α ,PGF2α ) on ovulation in the Japanese eel Anguillajaponica were examined. Oocytes with follicle layers at themigratory nucleus stage (approximately 850–900 µmdiameter) were removed using a polyethylene cannula from artificiallymatured fish. At concentrations of 10 and 100 ng/mL,DHP was found to induce both germinal vesicle breakdown and ovulation.The prostaglandins, except for PGE1 , effectively inducedovulation of previously matured oocytes by DHP treatment in vitro .Prostaglandin F2α was the most effective. Asignificant increase in ovulation rate was observed even at a concentrationof 0.01 µg/mL PGF2α .Indomethacin blocked the in vitro ovulation induced by DHPand addition of PGF2α reversed indomethacin-blockedovulation. Actinomycin D and cycloheximide blocked DHP-induced ovulationand PGF2α reversed the effects of both inhibitors. Theseresults indicate that DHP induces ovulation through endogenous prostaglandinsynthesis in the follicle layers of the Japanese eel. 相似文献
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Characterization of ammonia-assimilating bacteria in a lagoon for wastewater from a paddock of dairy cattle 总被引:2,自引:0,他引:2
Hiraku SASAKI Gen MARUYAMA Hanatsu SUZUKI Jun NONAKA Masaaki SATO Takako SASAKI Minoru OHTA Yutaka NAKAI 《Animal Science Journal》2002,73(1):73-76
We investigated microorganisms that assimilated ammonia in lagoon treatment processes. Ammonia‐assimilating microorganisms were detected by nitrogen‐limited medium that contained ammonia as the sole nitrogen source. Numbers of ammonia‐assimilating aerobes (log CFU/g) were 3.4, 4.8, 5.0, 4.8 and 5.0 (log CFU/mL) on the culture plate incubated at 4°C, 10°C, 15°C, 20°C and 25°C, respectively. Many isolates used ammonia in high rates when they were purely cultivated in nitrogen‐limited medium added to sterilized lagoon extract. Many of them used ammonia even when they were cultivated in media containing viable microbial flora of the lagoon. Among them, enterobacteriaceae and Pseudomonas sp. were identified by analysis of 16S ribosomal DNA. 相似文献
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Hiroshi OHTA Noriyuki NAGATA Nozomu YOKOYAMA Tatsuyuki OSUGA Noboru SASAKI Keitaro MORISHITA Mitsuyoshi TAKIGUCHI 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2021,83(3):378
To date, little is known about the prognostic significance of ultrasonographic findings in dogs with protein-losing enteropathy (PLE). The aim of this retrospective study was to examine the prognostic value of ultrasonographic findings in dogs with PLE. A total of 26 dogs with PLE were included: 20 dogs with chronic enteropathy and 6 dogs with gastrointestinal lymphoma. The presence of small intestinal dilatation was associated with shorter survival time in dogs with PLE (P=0.003). The presence of hyperechoic intestinal mucosal striations was associated with longer survival time in dogs with PLE (P=0.0085). The results of the current study indicate that the presence of small intestinal dilatation might be associated with poor prognosis in dogs with PLE. 相似文献
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KENSUKE NAKAMURA NOBORU SASAKI MUNEYOSHI YOSHIKAWA HIROSHI OHTA SHIANG-JYI HWANG TAKAHIRO MIMURA MASAHIRO YAMASAKI MITSUYOSHI TAKIGUCHI 《Veterinary radiology & ultrasound》2009,50(1):104-108
Contrast-enhanced ultrasonography has an important role in the detection of tumors in humans. The second-generation contrast agent Sonazoid has the ability of real-time contrast imaging along with parenchymal imaging. The purposes of this study were to determine the effect and duration of Sonazoid on the changes in gray-scale enhancement of canine spleen and to establish an appropriate protocol for contrast-enhanced ultrasonography of canine spleen. Six healthy beagles were injected with an intravenous bolus of Sonazoid. In the spleen parenchyma, the enhancement was maintained up to 30 min after injection. Moreover, for 5–22 s after injection, gray-scale enhancement of splenic arteries afforded arterial imaging. Perfusion of the kidney may be investigated from 3.6 s to 3.5 min after injection of Sonazoid. These results suggest that Sonazoid is applicable to canine spleen parenchymal imaging and that the optimal time for the parenchymal imaging is 7–30 min after injection. The findings of this quantitative study should prove useful in the evaluation of diffuse or focal splenic and renal diseases in dogs. 相似文献
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Tomokazu OHTA Katsuo KOSHI Koichi USHIZAWA Misa HOSOE Toru TAKAHASHI Takahiro YAMAGUCHI Keiichiro KIZAKI Kazuyoshi HASHIZUME 《The Journal of reproduction and development》2013,59(6):507-511
T cells are the dominant lymphocytes in the endometrium and are considered to play a
crucial role in implantation and in the maintenance of gestation through cytokine
production and immune regulation. The mechanisms underlying immunoregulation at the
feto-maternal interface are still obscure for this complex system. Understanding the
role of T cells is a key factor in understanding the endometrial immune system. In
this study, the distribution of endometrial CD3+ T cells in bovines was
examined by immunohistochemical analysis. The estrous cycle and gestation was divided
into 4 stages, and the number of CD3+-positive T cells was counted in each
stage. CD3+ cells were found in the endometrium in significant numbers
throughout the estrous cycle and were mostly located in the subepithelial area. The
number of CD3+ cells significantly increased in the early and mid-luteal
phases but decreased after implantation with the progression of gestation. No T cells
were found in the placentome or specifically in the tissues near the fetus, including
the trophoblastic area. In addition, very few T cells were found in stromal regions
close to the myometrium of the endometrium. These findings suggest that
downregulation of bovine endometrial CD3+ T-cell functions is closely
related to the successful maintenance of gestation in a spatiotemporal manner. 相似文献