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991.
Eisaburo Sueoka Naoko Sueoka-Aragane Akemi Sato Masaru Ide Hideaki Nakamura Yusuke Sotomaru Choji Taya Hiromichi Yonekawa Tomoyuki Kitagawa Yasushi Kubota Shinya Kimura Kei Nakachi Keiji Tanimoto 《PloS one》2013,8(4)
Hypoxia-inducible factor-1alpha (HIF-1 alpha) plays an essential role in the regulation of various genes associated with low oxygen consumption. Elevated expression of HIF-1alpha has been reported to be associated with tumor progression, invasion and metastasis in many cancers. To investigate the role of HIF-1alpha in tumor development and metastasis, we established transgenic mice constitutively expressing HIF1A gene under regulation of the cytomegalovirus gene promoter. Although HIF-1alpha protein levels varied among organs, expression of HIF1A mRNA in most organs gradually increased in an age-dependent manner. The transgenic mice showed no gross morphological abnormality up to 8 weeks after birth, although they subsequently developed tumors in the lymphoid, lung, and breast; the most prominent tumor was lymphoma appearing in the intestinal mucosa and intra-mesenchymal tissues. The prevalence of tumors reached 80% in 13 months after birth. The constitution of lymphocyte populations in the transgenic mice did not differ from that in wild-type mice. However, lymphocytes of the transgenic mice revealed prolonged survival under long-term culture conditions and revealed increased resistance to cytotoxic etoposide. These results suggest that HIF-1alpha itself is not oncogenic but it may play an important role in lymphomagenesis mediated through the prolonged survival of lymphocytes in this transgenic mouse model. 相似文献
992.
Hirofumi Sakamoto Tomomi Kuboi Takahiko Nagakura Sayako Hayashi Fumio Hoshi Kenichiro Mutoh Kiyotaka Watanabe Koichi Orino 《Biometals》2009,22(5):793-802
Ferritin-binding proteins (FBPs) such as anti-ferritin antibody, α-2-macroglobulin, apolipoprotein B are expected to interact
with circulating ferritin to eliminate it from circulation. However, we found that feline serum more strongly inhibits the
detection of canine liver ferritin by immunoassay than its apoferritin; putative FBPs probably conceal ferritin epitopes detected
by anti-ferritin antibodies. After complex formation between affinity-purified FBPs and canine liver ferritin, co-immunoprecipitates
of the complex by anti-bovine spleen ferritin antibody were found to contain autoantibodies (IgG, IgM, and IgA) to ferritin
by immunoblot analysis with antibodies specific for feline IgG, IgM, and IgA. On the other hand, affinity-purified samples
did not show any inhibitory effect in the ferritin immunoassay. This result shows that feline serum has another FBP, which
inhibits ferritin immunoassays, but not anti-ferritin autoantibody. A feline FBP was partially purified from feline serum
by (NH4)2SO4 fractionation (33–50%), gel filtration chromatography, and anion exchange chromatography. After binding of the partially
purified sample with canine liver ferritin coupled-Sepharose gel, the FBP was separated and purified from complexes formed
in a native-PAGE gel. SDS–PAGE analysis showed that the purified FBP is a homomultimer composed of 31 kDa monomeric subunits
connected by intermolecular disulfide bonds. Detection of feline liver ferritin by immunoassay was inhibited by FBP in a dose-dependent
manner. The purified protein molecules appeared to be conglomerate of pentraxin-like molecules by its electron micrographic
appearance. These results demonstrate that feline serum contains a novel FBP as inhibitory factor of ferritin immunoassay
with different molecular properties from those of other mammalian FBPs, in addition to auto-antibodies (IgG, IgM, and IgA)
to ferritin. 相似文献
993.
The 1st step initiation essential for allergen‐specific IgE antibody production upon the 2nd step: Induction of non‐specific IgE+ small B cells containing secondly‐sensitized allergen‐specific ones in mice firstly‐sensitized with an allergen 下载免费PDF全文
Natsuki Hannya Hiromi Ogita‐Nakanishi Ryuji Kato Yoshio Ijiri Tetsuya Hayashi Kazuhiko Tanaka Ryo Kawata Hiroshi Takenaka Takahiro Kubota Ryotaro Yoshida 《Microbiology and immunology》2018,62(2):99-110
994.
Spatial reorganization of cytoplasm in zygotic cells is critically important for establishing the body plans of many animal species. In ascidian zygotes, maternal determinants (mRNAs) are first transported to the vegetal pole a few minutes after fertilization and then to the future posterior side of the zygotes in a later phase of cytoplasmic reorganization, before the first cell division. Here, by using a novel fluorescence polarization microscope that reports the position and the orientation of fluorescently labeled proteins in living cells, we mapped the local alignments and the time-dependent changes of cortical actin networks in Ciona eggs. The initial cytoplasmic reorganization started with the contraction of vegetal hemisphere approximately 20 s after the fertilization-induced [Ca2+] increase. Timing of the vegetal contraction was consistent with the emergence of highly aligned actin filaments at the cell cortex of the vegetal hemisphere, which ran perpendicular to the animal–vegetal axis. We propose that the cytoplasmic reorganization is initiated by the local contraction of laterally aligned cortical actomyosin in the vegetal hemisphere, which in turn generates the directional movement of cytoplasm within the whole egg. 相似文献
995.
996.
Noriaki Takabatake Sayumi Toriyama Yoshikane Tokairin Tsuneo Konta Shuichi Abe Isao Kubota 《Biochemical and biophysical research communications》2009,381(4):554-559
The effect of smoking cessation on the rate of decline in lung function in patients with advanced stages of chronic obstructive pulmonary disease (COPD) has not been clarified. Saccharomyces cerevisiae cell division cycle 6 homolog (CDC6) protein possesses the pro-apoptotic properties. We tested our hypothesis that the individual susceptibility to rapid decline in lung function despite smoking cessation in patients with advanced stages of COPD is attributed to the genetic variants in the CDC6 gene. We prospectively followed 82 patients (ex-smokers) during 30 months and evaluated the differences among the genotypes in the annual rate of decline in FEV1.0 (%predicted) with ten single nucleotide polymorphisms (SNPs) in and around the CDC6 gene. We found significant differences in SNP5 (National Center for Biotechnology Information SNP reference: rs2077464), SNP6 (rs13706), SNP7 (rs7217852), and SNP8 (rs9904270) with a gene-dosage effect (ANOVA overall-P = 0.029-0.030). The individual allele of SNP5G, SNP6A, SNP7G, and SNP8T were associated with rapid decline in FEV1.0 (%predicted) [odds ratio (95% confidence interval) = 2.35 (1.19-4.65), P = 0.014]. The SNP5G/SNP6A/SNP7G/SNP8T haplotype was associated with an increased risk of deterioration of FEV1.0 (%predicted) (P = 0.017). Importantly, SNP6 caused a change in amino acids in CDC6 protein (Val441Ile), immediately upstream of the caspase-3-dependent cleavage site of CDC6 (Asp442) during apoptosis. These results suggest that CDC6 may be one of the susceptibility genes that contribute to rapid decline in lung function despite smoking cessation in these patients with COPD. 相似文献
997.
Luki Subehi Takehiko Fukushima Yuichi Onda Shigeru Mizugaki Takashi Gomi Tomomi Terajima Ken’ichirou Kosugi Shinya Hiramatsu Hikaru Kitahara Koichiro Kuraji Noriatsu Ozaki 《Limnology》2009,10(1):33-45
In order to gain insight into the effect of watershed conditions on fluctuations in stream water temperature, we statistically
analyzed water temperature data for 1 year, using root mean square (Rms) and harmonic (A Amplitude, φ delay time) methods. The average values of delay time (days) between air and water temperatures (T
a and T
w) of small (< 0.5 ha), medium (0.5–100 ha) and large (> 100 ha) watersheds were 4.53 ± 0.82 days, 11.83 ± 3.88 days and 4.45 ± 1.52 days,
respectively. Fluctuations in stream water temperature expressed by Rms (Rms T
w/Rms T
a) and harmonic methods (A −T
w/A −T
a) in the medium-sized watersheds with moderate slope gradients were 0.37 ± 0.09 and 0.56 ± 0.14, respectively. These values
increased in the larger watersheds with low slope gradients, including five large rivers covered by various landscapes, with
their averages of 0.53 ± 0.09 and 0.78 ± 0.09, respectively, indicating the influences of solar radiation and heat transfer
processes. In the smaller watersheds with high slope gradients, these values were 0.73 ± 0.02 and 0.87 ± 0.03, respectively,
suggesting that shorter passage time affected water temperatures. With respect to forest type, these values at badly managed
hinoki forest watersheds (0.45 ± 0.04 and 0.73 ± 0.07) were larger than those at broadleaf forest (0.34 ± 0.04 and 0.51 ± 0.12)
and well-managed hinoki forest (0.33 ± 0.04 and 0.51 ± 0.07) watersheds, indicating different proportions of flow paths. 相似文献
998.
Background
Abundant fossils from the Ediacaran and Cambrian showing cnidarian grade grossly suggest that cnidarian diversification occurred earlier than that of other eumetazoans. However, fossils of possible soft-bodied polyps are scanty and modern corals are dated back only to the Middle Triassic, although molecular phylogenetic results support the idea that anthozoans represent the first major branch of the Cnidaria. Because of difficulties in taxonomic assignments owing to imperfect preservation of fossil cnidarian candidates, little is known about forms ancestral to those of living groups.Methods and Findings
We have analyzed the soft-bodied polypoid microfossils Eolympia pediculata gen. et sp. nov. from the lowest Cambrian Kuanchuanpu Formation in southern China by scanning electron microscopy and computer-aided microtomography after isolating fossils from sedimentary rocks by acetic acid maceration. The fossils, about a half mm in body size, are preserved with 18 mesenteries including directives bilaterally arranged, 18 tentacles and a stalk-like pedicle. The pedicle suggests a sexual life cycle, while asexual reproduction by transverse fission also is inferred by circumferential grooves on the body column.Conclusions
The features found in the present fossils fall within the morphological spectrum of modern Hexacorallia excluding Ceriantharia, and thus Eolympia pediculata could be a stem member for this group. The fossils also demonstrate that basic features characterizing modern hexacorallians such as bilateral symmetry and the reproductive system have deep roots in the Early Cambrian. 相似文献999.
The responses of root aerobic respiration to hypoxia in three common Typha species were examined. Typha latifolia L., T. orientalis Presl, and T. angustifolia L. were hydroponically cultivated under both aerobic and hypoxic growth conditions to measure root oxygen consumption rates.
Hypoxia significantly enhanced the root aerobic respiration capacity of the two deep-water species, T. orientalis and T. angustifolia, while it did not affect that of the shallow-water species, T. latifolia. T. angustifolia increased its root porosity and root mass ratio, while T. latifolia increased its root diameter under the hypoxic growth conditions. The relative growth rates in biomass of T. orientalis and T. angustifolia were 59 and 39% higher, respectively, under the hypoxic growth conditions than under the aerobic growth conditions. In contrast,
that of T. latifolia did not differ between the two conditions. In T. orientalis and T. angustifolia, enhanced root aerobic respiration rates under the hypoxic growth conditions would have increased the nutrient uptake, and
thus higher relative growth rates were obtained. For the deep-water species, T. orientalis and T. angustifolia, the root aerobic respiration capacity was enhanced, probably in order to maintain the generation of respiratory energy under
hypoxia. 相似文献
1000.
Ohmura M Ogawa T Ono M Dezawa M Hosaka M Kubota Y Sawada H 《Biology of reproduction》2003,68(6):2304-2313
Recent studies have demonstrated that GnRH-analogues can stimulate regeneration of spermatogenesis of rats when administered after testicular damages. Although the mechanism of this phenomenon has not been elucidated yet, stem cell factor (SCF) produced by Sertoli cells was proposed to mediate the effects of GnRH-analogues on spermatogonial proliferation and/or survival. In the present study, we quantitatively evaluated the proliferation of spermatogonia and addressed whether SCF mediates the effect of GnRH-analogue on spermatogonial proliferation, using a novel approach combining spermatogonial transplantation and laser confocal microscopic observation. In the first experiment, using wild-type mice as recipients for spermatogonial transplantation, the number of donor spermatogonia per 100 Sertoli cells in each spermatogenic colony was significantly higher in the experimental group of mice treated with leuprorelin, a GnRH-agonist, than that of the control group at 4 and 5 wk after transplantation. In the second experiment, Steel/Steeldickie (Sl/Sld) mutant mice, which lack expression of membrane bound form SCF, were used as recipients. As seen in the first experiment, the number of undifferentiated spermatogonia was significantly higher in leuprorelin-treated than in the control group. Since undifferentiated spermatogonia do not express the receptor of SCF, the present study clearly demonstrates that neither membrane-bound nor secreted forms of SCF are involved in the mechanism of GnRH-analogue's effect on spermatogonial proliferation and/or survival. 相似文献