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61.
In vivo and in vitro studies on the appearance of LHRH neurons in the hypothalamus of perinatal rats
Prof. Shigeo Daikoku Hitoshi Kawano Hideo Matsumura Shiro Saito 《Cell and tissue research》1978,194(3):433-445
Summary Ontogenetic development of LHRH-containing neurons was studied by fluorescence and enzyme immunohistochemistry in rats. In in vitro studies, the tissues of the septal-chiasmatic and mediobasal hypothalamic areas of fetal rats on day 16.5 or 18.5 of gestation were trypsinized separately for dissociation of the neural cells, and cultured for several days. Immunopositive reaction against LHRH was first detected in nerve cells derived from both areas of the hypothalamus of the fetuses on days 16.5 and 18.5 of gestation, after 8 and 6 days culture, respectively. The cells were small, and seemed to be bipolar in morphology indicating an axon and arborized dendrites. Immunopositive material occurred in the cell soma as well as in the cellular processes. In in vivo studies, immunopositive material, possibly deposited in nerve fibers, appeared first in OVLT and simultaneously in the external layer of the median eminence of fetuses on day 20.5 of gestation. The immunoreactive fibers increased in number in both parts with development, especially after birth in the median eminence. No immunopositive material was detected within any neural cell bodies nor in the cytoplasm of any ependymal cells.This work was financed by the Ministry of Education, Japan. No. 257008. We would like to thank Dr. Katsuhiko Saito (Department of Surgery, Tokushima University) for his kind advice on the preparation of the antibody used for the immunofluorescence study. 相似文献
62.
Kiba A Sangawa Y Ohnishi K Yao N Park P Nakayashiki H Tosa Y Mayama S Hikichi Y 《Molecular plant-microbe interactions : MPMI》2006,19(2):112-122
Pseudomonas cichorii is the major causal agent of bacterial rot of lettuce. Collapse and browning symptoms were observed in lettuce leaf tissue from 15 to 24 h after inoculation (HAI) with P. cichorii; superoxide anion generation was detected at 1 to 6 HAI; and cell death was induced at 6 HAI, reaching a maximum at approximately 9 and 12 HAI. Heterochromatin condensation and DNA laddering also were observed within 3 HAI. Pharmacological studies showed that induction of cell death and DNA laddering was closely associated with de novo protein synthesis, protein kinase, intracellular reactive oxygen species, DNase, serine protease, and caspase III-like protease. Moreover, chemicals, which inhibited the induction of cell death and DNA laddering, also suppressed the development of disease symptoms. These results suggest that apoptotic cell death might be closely associated with the development of bacterial rot caused by P. cichorii. 相似文献
63.
Hitoshi Naraoka Kyoko Ito Michie Suzuki Kunihiko Naito Hideaki Tojo 《Experimental Animals》2006,55(1):1-9
We investigated gender difference in the effects of chronic exposure to human growth hormone (hGH) on cardiac risk biomarkers using transgenic mice with non-pulsatile circulating hGH. Blood plasma was obtained from transgenic and control mice at 8, 12, and 16 weeks of age, and was used for the measurement of hGH and the following cardiac risk biomarkers: total cholesterol (CHO), triglyceride (TG), HDL cholesterol (HDL), LDL cholesterol (LDL), non esterified free fatty acids (NEFA), and lipid peroxides (LPO). The hearts and the livers of transgenic mice were weighed and histopathologically examined, and the results were compared with those of control mice. Transgenic males exhibited higher levels of LDL at 8 and 12 weeks of age and higher levels of LPO at every week of age examined, as compared to those of the control males, while transgenic females exhibited somewhat lower levels of LDL and LPO from 8 to 16 weeks of age, as compared to the control females. The relative heart weight in males increased with aging and was significantly higher in the 16-week-old transgenic males compared to those of the control mice. The present results demonstrate that transgenic males had cardiac risk potential caused by chronic-exposure to hGH as compared to females. The results also show that the present transgenic mouse line is a useful model for the study of gender difference in cardiac disorders caused by hGH. 相似文献
64.
Male mice lacking ADAM2 (fertilin beta) or ADAM3 (cyritestin) are infertile; cauda epididymal sperm (mature sperm) from these mutant mice cannot bind to the egg zona pellucida. ADAM3 is barely present in Adam2-null sperm, despite normal levels of this protein in Adam2-null testicular germ cells (TGCs; sperm precursor cells). Here, we have explored the molecular basis for the loss of ADAM3 in Adam2-null TGCs to clarify the biosynthetic and functional linkage of ADAM2 and ADAM3. A small portion of total ADAM3 was found present on the surface of wild-type and Adam2(-/-) TGCs at similar levels. In the Adam2-null TGCs, however, surface-localized ADAM3 exhibited an increased amount of an endoglycosidase H-resistant form that may be related to instability of ADAM3. Moreover, we found a complex between ADAM2 and ADAM3 on the surface of TGCs and sperm. The intracellular chaperone calnexin was a component of the testicular ADAM2-ADAM3 complex. Our findings suggest that the association with ADAM2 is a key element for stability of ADAM3 in epididymal sperm. The presence of the ADAM2-ADAM3 complex in sperm also suggests a potential role of ADAM2 with ADAM3 in sperm binding to the egg zona pellucida. 相似文献
65.
Yoko Nakagawa Naofumi Nakayama Hitoshi Goto Ikuhide Fujisawa Soda Chanthamath Kazutaka Shibatomi Seiji Iwasa 《Chirality》2019,31(1):52-61
Computational chemical analysis of Ru(II)‐Pheox–catalyzed highly enantioselective intramolecular cyclopropanation reactions was performed using density functional theory (DFT). In this study, cyclopropane ring–fused γ‐lactones, which are 5.8 kcal/mol more stable than the corresponding minor enantiomer, are obtained as the major product. The results of the calculations suggest that the enantioselectivity of the Ru(II)‐Pheox–catalyzed intramolecular cyclopropanation reaction is affected by the energy differences between the starting structures 5l and 5i . The reaction pathway was found to be a stepwise mechanism that proceeds through the formation of a metallacyclobutane intermediate. This is the first example of a computational chemical analysis of enantioselective control in an intramolecular carbene‐transfer reaction using C1‐symmetric catalysts. 相似文献
66.
Chk2 is a tumor suppressor that regulates apoptosis in both an ataxia telangiectasia mutated (ATM)-dependent and an ATM-independent manner 总被引:11,自引:0,他引:11 下载免费PDF全文
Hirao A Cheung A Duncan G Girard PM Elia AJ Wakeham A Okada H Sarkissian T Wong JA Sakai T De Stanchina E Bristow RG Suda T Lowe SW Jeggo PA Elledge SJ Mak TW 《Molecular and cellular biology》2002,22(18):6521-6532
In response to ionizing radiation (IR), the tumor suppressor p53 is stabilized and promotes either cell cycle arrest or apoptosis. Chk2 activated by IR contributes to this stabilization, possibly by direct phosphorylation. Like p53, Chk2 is mutated in patients with Li-Fraumeni syndrome. Since the ataxia telangiectasia mutated (ATM) gene is required for IR-induced activation of Chk2, it has been assumed that ATM and Chk2 act in a linear pathway leading to p53 activation. To clarify the role of Chk2 in tumorigenesis, we generated gene-targeted Chk2-deficient mice. Unlike ATM(-/-) and p53(-/-) mice, Chk2(-/-) mice do not spontaneously develop tumors, although Chk2 does suppress 7,12-dimethylbenzanthracene-induced skin tumors. Tissues from Chk2(-/-) mice, including those from the thymus, central nervous system, fibroblasts, epidermis, and hair follicles, show significant defects in IR-induced apoptosis or impaired G(1)/S arrest. Quantitative comparison of the G(1)/S checkpoint, apoptosis, and expression of p53 proteins in Chk2(-/-) versus ATM(-/-) thymocytes suggested that Chk2 can regulate p53-dependent apoptosis in an ATM-independent manner. IR-induced apoptosis was restored in Chk2(-/-) thymocytes by reintroduction of the wild-type Chk2 gene but not by a Chk2 gene in which the sites phosphorylated by ATM and ataxia telangiectasia and rad3(+) related (ATR) were mutated to alanine. ATR may thus selectively contribute to p53-mediated apoptosis. These data indicate that distinct pathways regulate the activation of p53 leading to cell cycle arrest or apoptosis. 相似文献
67.
Temporal and spatial changes in gene expression,metabolite accumulation and phytohormone content in rice seedlings grown under drought stress conditions 下载免费PDF全文
Daisuke Todaka Yu Zhao Takuya Yoshida Madoka Kudo Satoshi Kidokoro Junya Mizoi Ken‐Suke Kodaira Yumiko Takebayashi Mikiko Kojima Hitoshi Sakakibara Kiminori Toyooka Mayuko Sato Alisdair R. Fernie Kazuo Shinozaki Kazuko Yamaguchi‐Shinozaki 《The Plant journal : for cell and molecular biology》2017,90(1):61-78
68.
Shiro Ohki Yoshimasa Nishigaki Katsuhiro Imaki Masayasu Kurono Fumio Hirata Toshio Hanyu Nobuhiko Nakazawa 《Prostaglandins & other lipid mediators》1976,12(2):181-186
Radioimmunoassay technique for measuring 5α,7α-dihydroxy-11-keto-tetranorprosta-1,16-dioic acid, the main urinary metabolite of PGF1α and PGF2α (PGF2α-MUM), was further improved.It was postulated based on some experimental data that the PGF2α-MUM exists in the urine mostly as dioic acid form, not as δ-lactone formThe daily excretion of PGF2α-MUM in men ranged from 14.43 μg to 36.14 μg and in women from 5.21 μg to 14.25 μg. 相似文献
69.
Hitoshi Suzuki Kimiyuki Tsuchiya Mitsuru Sakaizumi Shigeharu Wakana Susumu Sakurai 《Journal of molecular evolution》1994,38(2):107-112
An analysis by restriction endonuclease digestion of ribosomal DNA (rDNA) was carried out in natural populations of Apodemus speciosus, a field mouse that is endemic to Japan. Two restriction sites, the EcoRI (E3) and DraI (D4) sites, in the nontranscribed spacer region downstream from the gene for 28S RNA showed polymorphism within and between individuals in the populations from the Japanese main islands. By contrast, populations from the small adjoining islands which are thought to have separated from the main islands 1–2 × 104 years ago showed relatively low levels of polymorphism within and between individuals, i.e., one of the polymorphic bands in the case of each enzyme was predominant in these populations, irrespective of the variants. These results indicate that the rate of fixation of site variations depends on population size and that the direction of fixation is random. Furthermore, each polymorphic restriction site seems to be fixed independently.Correspondence to: H. Suzuki 相似文献
70.
Masamitsu Konno Tatsuo S. Hamazaki Satsuki Fukuda Hideho Uchiyama Hitoshi Okochi Makoto Asashima 《Biochemical and biophysical research communications》2010,400(4):461-465
Adipose tissue-derived mesenchymal stem cells (ASCs) have been reported to be multipotent and to differentiate into various cell types, including osteocytes, adipocytes, chondrocytes, and neural cells. Recently, many authors have reported that ASCs are also able to differentiate into vascular endothelial cells (VECs) in vitro. However, these reports included the use of medium containing fetal bovine serum for endothelial differentiation. In the present study, we have developed a novel method for differentiating mouse ASCs into VECs under serum-free conditions. After the differentiation culture, over 80% of the cells expressed vascular endothelial-specific marker proteins and could take up low-density lipoprotein in vitro. This protocol should be helpful in clarifying the mechanisms of ASC differentiation into the VSC lineage. 相似文献